[PATCH v8 00/22] Introduce the Counter character device interface

[PATCH v8 00/22] Introduce the Counter character device interface

[William Breathitt Gray]

Changes in v8:
 - Consolidated Counter sysfs ABI documentation to single file
 - Added events_queue_size sysfs attribute to allow users to dynamically
   resize the events queue
 - Fixed markup syntax and typos in generic-counter.rst
 - Improved documentation in include/uapi/linux/counter.h and friends
 - Renamed COUNTER_LOAD_WATCHES_IOCTL to COUNTER_ENABLE_EVENTS_IOCTL;
   Renamed COUNTER_CLEAR_WATCHES_IOCTL to COUNTER_DISABLE_EVENTS_IOCTL
 - Renamed the struct counter_event "errno" member to "status"
 - Dropped the "irq_trigger" 104-QUAD-8 sysfs attribute; this
   functionality now occurs implicitly via the Counter chrdev interface
 - Return -ERANGE where appropriate instead of -EINVAL
 - Simplified switch exit paths; return early when possible
 - Call devm_request_irq() before devm_counter_register() for 104-quad-8
 - Renamed devm_counter_unregister() to more apt devm_counter_release()
 - Use enum counter_scope for scope values in counter-sysfs.c
 - Use sysfs_emit() instead of sprintf() where appropriate
 - Renamed find_in_string_array() to more apt counter_find_enum()
 - Renamed *_action_get() and *_action_write() to *_action_read() and
   *_action_write() to match new naming convention of Counter callbacks
 - Use "Counter function" naming convention instead of "Counter count
   function" to avoid confusion about scope

I pulled out a lot of bits and pieces to their own patches; hopefully
that makes reviewing this patchset much simpler than before. This
patchset is also available on my personal public git repo for anyone who
wants a quick way to clone:
https://gitlab.com/vilhelmgray/iio/-/tree/counter_chrdev_v8

The patches preceding "counter: Internalize sysfs interface code" are
primarily cleanup and fixes that can be picked up and applied now to the
IIO tree if so desired. The "counter: Internalize sysfs interface code"
patch as well may be considered for pickup because it is relatively safe
and makes no changes to the userspace interface.

To summarize the main points of this patchset: there are no changes to
the existing Counter sysfs userspace interface; a Counter character
device interface is introduced that allows Counter events and associated
data to be read() by userspace; the events_configure() and
watch_validate() driver callbacks are introduced to support Counter
events; and IRQ support is added to the 104-QUAD-8 driver, serving as an
example of how to support the new Counter events functionality.

Something that should still be discussed: should the struct
counter_event "status" member be 8 bits or 32 bits wide? This member
will provide the return status (system error number) of an event
operation.

William Breathitt Gray (22):
  docs: counter: Consolidate Counter sysfs attributes documentation
  docs: counter: Fix spelling
  counter: 104-quad-8: Return error when invalid mode during
    ceiling_write
  counter: 104-quad-8: Annotate hardware config module parameter
  counter: 104-quad-8: Add const qualifiers for
    quad8_preset_register_set
  counter: 104-quad-8: Add const qualifier for functions_list array
  counter: 104-quad-8: Add const qualifier for actions_list array
  counter: ftm-quaddec: Add const qualifier for actions_list array
  counter: Return error code on invalid modes
  counter: Standardize to ERANGE for limit exceeded errors
  counter: Rename counter_signal_value to counter_signal_level
  counter: Rename counter_count_function to counter_function
  counter: Internalize sysfs interface code
  counter: Update counter.h comments to reflect sysfs internalization
  docs: counter: Update to reflect sysfs internalization
  counter: Move counter enums to uapi header
  counter: Add character device interface
  docs: counter: Document character device interface
  counter: Implement extension*_name sysfs attributes
  counter: Implement events_queue_size sysfs attribute
  counter: 104-quad-8: Replace mutex with spinlock
  counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8

 Documentation/ABI/testing/sysfs-bus-counter   |  100 +-
 .../ABI/testing/sysfs-bus-counter-104-quad-8  |   61 -
 .../ABI/testing/sysfs-bus-counter-ftm-quaddec |   16 -
 Documentation/driver-api/generic-counter.rst  |  426 ++++-
 .../userspace-api/ioctl/ioctl-number.rst      |    1 +
 MAINTAINERS                                   |    6 +-
 drivers/counter/104-quad-8.c                  |  751 +++++----
 drivers/counter/Kconfig                       |    6 +-
 drivers/counter/Makefile                      |    1 +
 drivers/counter/counter-chrdev.c              |  519 ++++++
 drivers/counter/counter-chrdev.h              |   18 +
 drivers/counter/counter-core.c                |  185 ++
 drivers/counter/counter-sysfs.c               |  889 ++++++++++
 drivers/counter/counter-sysfs.h               |   13 +
 drivers/counter/counter.c                     | 1496 -----------------
 drivers/counter/ftm-quaddec.c                 |   69 +-
 drivers/counter/microchip-tcb-capture.c       |  105 +-
 drivers/counter/stm32-lptimer-cnt.c           |  186 +-
 drivers/counter/stm32-timer-cnt.c             |  187 +--
 drivers/counter/ti-eqep.c                     |  226 ++-
 include/linux/counter.h                       |  716 ++++----
 include/linux/counter_enum.h                  |   45 -
 include/uapi/linux/counter.h                  |  126 ++
 23 files changed, 3363 insertions(+), 2785 deletions(-)
 delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
 delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
 create mode 100644 drivers/counter/counter-chrdev.c
 create mode 100644 drivers/counter/counter-chrdev.h
 create mode 100644 drivers/counter/counter-core.c
 create mode 100644 drivers/counter/counter-sysfs.c
 create mode 100644 drivers/counter/counter-sysfs.h
 delete mode 100644 drivers/counter/counter.c
 delete mode 100644 include/linux/counter_enum.h
 create mode 100644 include/uapi/linux/counter.h


base-commit: b72d4f6a5122a78941ce5a3147685d6a44939a75
-- 
2.30.0

[PATCH v8 01/22] docs: counter: Consolidate Counter sysfs attributes documentation

[William Breathitt Gray]

Duplicate ABIs are not valid, so let's consolidate these sysfs
attributes into the main sysfs-bus-counter documentation file.

Cc: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-counter   | 76 ++++++++++++++++++-
 .../ABI/testing/sysfs-bus-counter-104-quad-8  | 61 ---------------
 .../ABI/testing/sysfs-bus-counter-ftm-quaddec | 16 ----
 MAINTAINERS                                   |  4 +-
 4 files changed, 75 insertions(+), 82 deletions(-)
 delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
 delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 566bd99fe0a5..29f54484183f 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -57,6 +57,7 @@ Description:
 What:		/sys/bus/counter/devices/counterX/countY/count_mode_available
 What:		/sys/bus/counter/devices/counterX/countY/error_noise_available
 What:		/sys/bus/counter/devices/counterX/countY/function_available
+What:		/sys/bus/counter/devices/counterX/countY/prescaler_available
 What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_available
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
@@ -154,6 +155,15 @@ Description:
 		Count Y. If possible, this should match the name of the
 		respective channel as it appears in the device datasheet.
 
+What:		/sys/bus/counter/devices/counterX/countY/prescaler
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Configure the prescaler value associated with Count Y.
+		On the FlexTimer, the counter clock source passes through a
+		prescaler (i.e. a counter). This acts like a clock
+		divider.
+
 What:		/sys/bus/counter/devices/counterX/countY/preset
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
@@ -215,11 +225,45 @@ Description:
 		Read-only attribute that indicates the total number of Signals
 		belonging to the Counter.
 
-What:		/sys/bus/counter/devices/counterX/signalY/signal
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault
+KernelVersion:	5.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Read-only attribute that indicates whether a differential
+		encoder cable fault (not connected or loose wires) is detected
+		for the respective channel of Signal Y. Valid attribute values
+		are boolean. Detection must first be enabled via the
+		corresponding cable_fault_enable attribute.
+
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable
+KernelVersion:	5.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Whether detection of differential encoder cable faults for the
+		respective channel of Signal Y is enabled. Valid attribute
+		values are boolean.
+
+What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
+KernelVersion:	5.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Filter clock factor for input Signal Y. This prescaler value
+		affects the inputs of both quadrature pair signals.
+
+What:		/sys/bus/counter/devices/counterX/signalY/index_polarity
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
 Description:
-		Signal data of Signal Y represented as a string.
+		Active level of index input Signal Y; irrelevant in
+		non-synchronous load mode.
+
+What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_available
+What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_available
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Discrete set of available values for the respective Signal Y
+		configuration are listed in this file.
 
 What:		/sys/bus/counter/devices/counterX/signalY/name
 KernelVersion:	5.2
@@ -228,3 +272,31 @@ Description:
 		Read-only attribute that indicates the device-specific name of
 		Signal Y. If possible, this should match the name of the
 		respective signal as it appears in the device datasheet.
+
+What:		/sys/bus/counter/devices/counterX/signalY/signal
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Signal data of Signal Y represented as a string.
+
+What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Configure the counter associated with Signal Y for
+		non-synchronous or synchronous load mode. Synchronous load mode
+		cannot be selected in non-quadrature (Pulse-Direction) clock
+		mode.
+
+		non-synchronous:
+			A logic low level is the active level at this index
+			input. The index function (as enabled via preset_enable)
+			is performed directly on the active level of the index
+			input.
+
+		synchronous:
+			Intended for interfacing with encoder Index output in
+			quadrature clock mode. The active level is configured
+			via index_polarity. The index function (as enabled via
+			preset_enable) is performed synchronously with the
+			quadrature clock on the active level of the index input.
diff --git a/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8 b/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
deleted file mode 100644
index eac32180c40d..000000000000
--- a/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
+++ /dev/null
@@ -1,61 +0,0 @@
-What:		/sys/bus/counter/devices/counterX/signalY/cable_fault
-KernelVersion:	5.7
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Read-only attribute that indicates whether a differential
-		encoder cable fault (not connected or loose wires) is detected
-		for the respective channel of Signal Y. Valid attribute values
-		are boolean. Detection must first be enabled via the
-		corresponding cable_fault_enable attribute.
-
-What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable
-KernelVersion:	5.7
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Whether detection of differential encoder cable faults for the
-		respective channel of Signal Y is enabled. Valid attribute
-		values are boolean.
-
-What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
-KernelVersion:	5.7
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Filter clock factor for input Signal Y. This prescaler value
-		affects the inputs of both quadrature pair signals.
-
-What:		/sys/bus/counter/devices/counterX/signalY/index_polarity
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Active level of index input Signal Y; irrelevant in
-		non-synchronous load mode.
-
-What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_available
-What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_available
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Discrete set of available values for the respective Signal Y
-		configuration are listed in this file.
-
-What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Configure the counter associated with Signal Y for
-		non-synchronous or synchronous load mode. Synchronous load mode
-		cannot be selected in non-quadrature (Pulse-Direction) clock
-		mode.
-
-		non-synchronous:
-			A logic low level is the active level at this index
-			input. The index function (as enabled via preset_enable)
-			is performed directly on the active level of the index
-			input.
-
-		synchronous:
-			Intended for interfacing with encoder Index output in
-			quadrature clock mode. The active level is configured
-			via index_polarity. The index function (as enabled via
-			preset_enable) is performed synchronously with the
-			quadrature clock on the active level of the index input.
diff --git a/Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec b/Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
deleted file mode 100644
index 7d2e7b363467..000000000000
--- a/Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
+++ /dev/null
@@ -1,16 +0,0 @@
-What:		/sys/bus/counter/devices/counterX/countY/prescaler_available
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Discrete set of available values for the respective Count Y
-		configuration are listed in this file. Values are delimited by
-		newline characters.
-
-What:		/sys/bus/counter/devices/counterX/countY/prescaler
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Configure the prescaler value associated with Count Y.
-		On the FlexTimer, the counter clock source passes through a
-		prescaler (i.e. a counter). This acts like a clock
-		divider.
diff --git a/MAINTAINERS b/MAINTAINERS
index e697044d34d6..d858582c917b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -297,7 +297,6 @@ M:	William Breathitt Gray <vilhelm.gray@gmail.com>
 M:	Syed Nayyar Waris <syednwaris@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
 F:	drivers/counter/104-quad-8.c
 
 ACCES PCI-IDIO-16 GPIO DRIVER
@@ -4540,7 +4539,7 @@ COUNTER SUBSYSTEM
 M:	William Breathitt Gray <vilhelm.gray@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter*
+F:	Documentation/ABI/testing/sysfs-bus-counter
 F:	Documentation/driver-api/generic-counter.rst
 F:	drivers/counter/
 F:	include/linux/counter.h
@@ -6925,7 +6924,6 @@ FLEXTIMER FTM-QUADDEC DRIVER
 M:	Patrick Havelange <patrick.havelange@essensium.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
 F:	Documentation/devicetree/bindings/counter/ftm-quaddec.txt
 F:	drivers/counter/ftm-quaddec.c
 
-- 
2.30.0

Re: [PATCH v8 01/22] docs: counter: Consolidate Counter sysfs attributes documentation

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:25 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> Duplicate ABIs are not valid, so let's consolidate these sysfs
> attributes into the main sysfs-bus-counter documentation file.

This is sensible to do, but is there any duplicate ABI?  I went
looking for any resulting build problems and couldn't see what was
actually duplicated.

Jonathan
> 
> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-counter   | 76 ++++++++++++++++++-
>  .../ABI/testing/sysfs-bus-counter-104-quad-8  | 61 ---------------
>  .../ABI/testing/sysfs-bus-counter-ftm-quaddec | 16 ----
>  MAINTAINERS                                   |  4 +-
>  4 files changed, 75 insertions(+), 82 deletions(-)
>  delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
>  delete mode 100644 Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> index 566bd99fe0a5..29f54484183f 100644
> --- a/Documentation/ABI/testing/sysfs-bus-counter
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -57,6 +57,7 @@ Description:
>  What:		/sys/bus/counter/devices/counterX/countY/count_mode_available
>  What:		/sys/bus/counter/devices/counterX/countY/error_noise_available
>  What:		/sys/bus/counter/devices/counterX/countY/function_available
> +What:		/sys/bus/counter/devices/counterX/countY/prescaler_available
>  What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_available
>  KernelVersion:	5.2
>  Contact:	linux-iio@vger.kernel.org
> @@ -154,6 +155,15 @@ Description:
>  		Count Y. If possible, this should match the name of the
>  		respective channel as it appears in the device datasheet.
>  
> +What:		/sys/bus/counter/devices/counterX/countY/prescaler
> +KernelVersion:	5.2
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Configure the prescaler value associated with Count Y.
> +		On the FlexTimer, the counter clock source passes through a
> +		prescaler (i.e. a counter). This acts like a clock
> +		divider.
> +
>  What:		/sys/bus/counter/devices/counterX/countY/preset
>  KernelVersion:	5.2
>  Contact:	linux-iio@vger.kernel.org
> @@ -215,11 +225,45 @@ Description:
>  		Read-only attribute that indicates the total number of Signals
>  		belonging to the Counter.
>  
> -What:		/sys/bus/counter/devices/counterX/signalY/signal
> +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault
> +KernelVersion:	5.7
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Read-only attribute that indicates whether a differential
> +		encoder cable fault (not connected or loose wires) is detected
> +		for the respective channel of Signal Y. Valid attribute values
> +		are boolean. Detection must first be enabled via the
> +		corresponding cable_fault_enable attribute.
> +
> +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable
> +KernelVersion:	5.7
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Whether detection of differential encoder cable faults for the
> +		respective channel of Signal Y is enabled. Valid attribute
> +		values are boolean.
> +
> +What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
> +KernelVersion:	5.7
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Filter clock factor for input Signal Y. This prescaler value
> +		affects the inputs of both quadrature pair signals.
> +
> +What:		/sys/bus/counter/devices/counterX/signalY/index_polarity
>  KernelVersion:	5.2
>  Contact:	linux-iio@vger.kernel.org
>  Description:
> -		Signal data of Signal Y represented as a string.
> +		Active level of index input Signal Y; irrelevant in
> +		non-synchronous load mode.
> +
> +What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_available
> +What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_available
> +KernelVersion:	5.2
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Discrete set of available values for the respective Signal Y
> +		configuration are listed in this file.
>  
>  What:		/sys/bus/counter/devices/counterX/signalY/name
>  KernelVersion:	5.2
> @@ -228,3 +272,31 @@ Description:
>  		Read-only attribute that indicates the device-specific name of
>  		Signal Y. If possible, this should match the name of the
>  		respective signal as it appears in the device datasheet.
> +
> +What:		/sys/bus/counter/devices/counterX/signalY/signal
> +KernelVersion:	5.2
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Signal data of Signal Y represented as a string.
> +
> +What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
> +KernelVersion:	5.2
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Configure the counter associated with Signal Y for
> +		non-synchronous or synchronous load mode. Synchronous load mode
> +		cannot be selected in non-quadrature (Pulse-Direction) clock
> +		mode.
> +
> +		non-synchronous:
> +			A logic low level is the active level at this index
> +			input. The index function (as enabled via preset_enable)
> +			is performed directly on the active level of the index
> +			input.
> +
> +		synchronous:
> +			Intended for interfacing with encoder Index output in
> +			quadrature clock mode. The active level is configured
> +			via index_polarity. The index function (as enabled via
> +			preset_enable) is performed synchronously with the
> +			quadrature clock on the active level of the index input.
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8 b/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
> deleted file mode 100644
> index eac32180c40d..000000000000
> --- a/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
> +++ /dev/null
> @@ -1,61 +0,0 @@
> -What:		/sys/bus/counter/devices/counterX/signalY/cable_fault
> -KernelVersion:	5.7
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Read-only attribute that indicates whether a differential
> -		encoder cable fault (not connected or loose wires) is detected
> -		for the respective channel of Signal Y. Valid attribute values
> -		are boolean. Detection must first be enabled via the
> -		corresponding cable_fault_enable attribute.
> -
> -What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable
> -KernelVersion:	5.7
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Whether detection of differential encoder cable faults for the
> -		respective channel of Signal Y is enabled. Valid attribute
> -		values are boolean.
> -
> -What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
> -KernelVersion:	5.7
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Filter clock factor for input Signal Y. This prescaler value
> -		affects the inputs of both quadrature pair signals.
> -
> -What:		/sys/bus/counter/devices/counterX/signalY/index_polarity
> -KernelVersion:	5.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Active level of index input Signal Y; irrelevant in
> -		non-synchronous load mode.
> -
> -What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_available
> -What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_available
> -KernelVersion:	5.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Discrete set of available values for the respective Signal Y
> -		configuration are listed in this file.
> -
> -What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
> -KernelVersion:	5.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Configure the counter associated with Signal Y for
> -		non-synchronous or synchronous load mode. Synchronous load mode
> -		cannot be selected in non-quadrature (Pulse-Direction) clock
> -		mode.
> -
> -		non-synchronous:
> -			A logic low level is the active level at this index
> -			input. The index function (as enabled via preset_enable)
> -			is performed directly on the active level of the index
> -			input.
> -
> -		synchronous:
> -			Intended for interfacing with encoder Index output in
> -			quadrature clock mode. The active level is configured
> -			via index_polarity. The index function (as enabled via
> -			preset_enable) is performed synchronously with the
> -			quadrature clock on the active level of the index input.
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec b/Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
> deleted file mode 100644
> index 7d2e7b363467..000000000000
> --- a/Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
> +++ /dev/null
> @@ -1,16 +0,0 @@
> -What:		/sys/bus/counter/devices/counterX/countY/prescaler_available
> -KernelVersion:	5.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Discrete set of available values for the respective Count Y
> -		configuration are listed in this file. Values are delimited by
> -		newline characters.
> -
> -What:		/sys/bus/counter/devices/counterX/countY/prescaler
> -KernelVersion:	5.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Configure the prescaler value associated with Count Y.
> -		On the FlexTimer, the counter clock source passes through a
> -		prescaler (i.e. a counter). This acts like a clock
> -		divider.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e697044d34d6..d858582c917b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -297,7 +297,6 @@ M:	William Breathitt Gray <vilhelm.gray@gmail.com>
>  M:	Syed Nayyar Waris <syednwaris@gmail.com>
>  L:	linux-iio@vger.kernel.org
>  S:	Maintained
> -F:	Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
>  F:	drivers/counter/104-quad-8.c
>  
>  ACCES PCI-IDIO-16 GPIO DRIVER
> @@ -4540,7 +4539,7 @@ COUNTER SUBSYSTEM
>  M:	William Breathitt Gray <vilhelm.gray@gmail.com>
>  L:	linux-iio@vger.kernel.org
>  S:	Maintained
> -F:	Documentation/ABI/testing/sysfs-bus-counter*
> +F:	Documentation/ABI/testing/sysfs-bus-counter
>  F:	Documentation/driver-api/generic-counter.rst
>  F:	drivers/counter/
>  F:	include/linux/counter.h
> @@ -6925,7 +6924,6 @@ FLEXTIMER FTM-QUADDEC DRIVER
>  M:	Patrick Havelange <patrick.havelange@essensium.com>
>  L:	linux-iio@vger.kernel.org
>  S:	Maintained
> -F:	Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
>  F:	Documentation/devicetree/bindings/counter/ftm-quaddec.txt
>  F:	drivers/counter/ftm-quaddec.c
>  

Re: [PATCH v8 01/22] docs: counter: Consolidate Counter sysfs attributes documentation

[William Breathitt Gray]

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On Sun, Feb 14, 2021 at 04:57:52PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:25 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > Duplicate ABIs are not valid, so let's consolidate these sysfs
> > attributes into the main sysfs-bus-counter documentation file.
> 
> This is sensible to do, but is there any duplicate ABI?  I went
> looking for any resulting build problems and couldn't see what was
> actually duplicated.
> 
> Jonathan

There's no duplication currently, so this is just a preventative
measure. These files were started for the purpose of permitting future
duplication; now that duplication is explicitly disallowed, we're better
off consolidating these now in order to prevent fragmentation of the
documentation.

William Breathitt Gray

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Re: [PATCH v8 01/22] docs: counter: Consolidate Counter sysfs attributes documentation

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> Duplicate ABIs are not valid, so let's consolidate these sysfs
> attributes into the main sysfs-bus-counter documentation file.
> 
> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

Reviewed-by: David Lechner <david@lechnology.com>

[PATCH v8 02/22] docs: counter: Fix spelling

[William Breathitt Gray]

"Miscellaneous" is the correct spelling.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 Documentation/driver-api/generic-counter.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index b02c52cd69d6..64fe7db080e5 100644
--- a/Documentation/driver-api/generic-counter.rst
+++ b/Documentation/driver-api/generic-counter.rst
@@ -307,7 +307,7 @@ Determining the type of extension to create is a matter of scope.
 
 * Device extensions are attributes that expose information/control
   non-specific to a particular Count or Signal. This is where you would
-  put your global features or other miscellanous functionality.
+  put your global features or other miscellaneous functionality.
 
   For example, if your device has an overtemp sensor, you can report the
   chip overheated via a device extension called "error_overtemp":
-- 
2.30.0

Re: [PATCH v8 02/22] docs: counter: Fix spelling

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> "Miscellaneous" is the correct spelling.
> 
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

Reviewed-by: David Lechner <david@lechnology.com>

[PATCH v8 03/22] counter: 104-quad-8: Return error when invalid mode during ceiling_write

[William Breathitt Gray]

The 104-QUAD-8 only has two count modes where a ceiling value makes
sense: Range Limit and Modulo-N. Outside of these two modes, setting a
ceiling value is an invalid operation -- so let's report it as such by
returning -EINVAL.

Fixes: fc069262261c ("counter: 104-quad-8: Add lock guards - generic interface")
Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 9691f8612be8..f0608b21196a 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -714,13 +714,14 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
 	switch (priv->count_mode[count->id]) {
 	case 1:
 	case 3:
+		mutex_unlock(&priv->lock);
 		quad8_preset_register_set(priv, count->id, ceiling);
-		break;
+		return len;
 	}
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return -EINVAL;
 }
 
 static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
-- 
2.30.0

Re: [PATCH v8 03/22] counter: 104-quad-8: Return error when invalid mode during ceiling_write

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> The 104-QUAD-8 only has two count modes where a ceiling value makes
> sense: Range Limit and Modulo-N. Outside of these two modes, setting a
> ceiling value is an invalid operation -- so let's report it as such by
> returning -EINVAL.
> 
> Fixes: fc069262261c ("counter: 104-quad-8: Add lock guards - generic interface")
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>   drivers/counter/104-quad-8.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 9691f8612be8..f0608b21196a 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -714,13 +714,14 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
>   	switch (priv->count_mode[count->id]) {
>   	case 1:
>   	case 3:
> +		mutex_unlock(&priv->lock);
>   		quad8_preset_register_set(priv, count->id, ceiling);
> -		break;
> +		return len;
>   	}
>   
>   	mutex_unlock(&priv->lock);
>   
> -	return len;
> +	return -EINVAL;
>   }
>   
>   static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
> 

What happens if the register is written to when in the wrong mode?

If it doesn't hurt anything, I would suggest always writing the register
instead so that users don't have to know worry about the fact that the mode
has to be set first.

Re: [PATCH v8 03/22] counter: 104-quad-8: Return error when invalid mode during ceiling_write

[William Breathitt Gray]

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On Sat, Feb 20, 2021 at 10:30:03AM -0600, David Lechner wrote:
> On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> > The 104-QUAD-8 only has two count modes where a ceiling value makes
> > sense: Range Limit and Modulo-N. Outside of these two modes, setting a
> > ceiling value is an invalid operation -- so let's report it as such by
> > returning -EINVAL.
> > 
> > Fixes: fc069262261c ("counter: 104-quad-8: Add lock guards - generic interface")
> > Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> >   drivers/counter/104-quad-8.c | 5 +++--
> >   1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> > index 9691f8612be8..f0608b21196a 100644
> > --- a/drivers/counter/104-quad-8.c
> > +++ b/drivers/counter/104-quad-8.c
> > @@ -714,13 +714,14 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
> >   	switch (priv->count_mode[count->id]) {
> >   	case 1:
> >   	case 3:
> > +		mutex_unlock(&priv->lock);
> >   		quad8_preset_register_set(priv, count->id, ceiling);
> > -		break;
> > +		return len;
> >   	}
> >   
> >   	mutex_unlock(&priv->lock);
> >   
> > -	return len;
> > +	return -EINVAL;
> >   }
> >   
> >   static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
> > 
> 
> What happens if the register is written to when in the wrong mode?
> 
> If it doesn't hurt anything, I would suggest always writing the register
> instead so that users don't have to know worry about the fact that the mode
> has to be set first.

Unfortunately this register is used for two different functions: as a
ceiling limit and as a preset value. When we're in the preset mode, the
value of this register will be used to set the counter value when an
interrupt occurs; whereas in ceiling mode, this value is used as the
upper counting limit for the counter. We should only set this value when
in the correct mode, lest we end clobbering the value for the other mode
(e.g. user sets ceiling value, but driver unexpectantly changes the
preset value).

William Breathitt Gray

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[PATCH v8 04/22] counter: 104-quad-8: Annotate hardware config module parameter

[William Breathitt Gray]

When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image.  Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify.  The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates the 104-QUAD-8 driver.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index f0608b21196a..37551d3016de 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -21,7 +21,7 @@
 
 static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
 static unsigned int num_quad8;
-module_param_array(base, uint, &num_quad8, 0);
+module_param_hw_array(base, uint, ioport, &num_quad8, 0);
 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
 
 #define QUAD8_NUM_COUNTERS 8
-- 
2.30.0

[PATCH v8 05/22] counter: 104-quad-8: Add const qualifiers for quad8_preset_register_set

[William Breathitt Gray]

Add some safety by qualifying the quad8_preset_register_set() function
parameters as const.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 37551d3016de..70383b792ec6 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -632,8 +632,8 @@ static ssize_t quad8_count_preset_read(struct counter_device *counter,
 	return sprintf(buf, "%u\n", priv->preset[count->id]);
 }
 
-static void quad8_preset_register_set(struct quad8 *priv, int id,
-				      unsigned int preset)
+static void quad8_preset_register_set(struct quad8 *const priv, const int id,
+				      const unsigned int preset)
 {
 	const unsigned int base_offset = priv->base + 2 * id;
 	int i;
-- 
2.30.0

[PATCH v8 06/22] counter: 104-quad-8: Add const qualifier for functions_list array

[William Breathitt Gray]

The struct counter_count functions_list member expects a const enum
counter_count_function array. This patch adds the const qualifier to the
quad8_functions_list to match functions_list.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 70383b792ec6..af4e0503b074 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -193,7 +193,7 @@ enum quad8_count_function {
 	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
 };
 
-static enum counter_count_function quad8_count_functions_list[] = {
+static const enum counter_count_function quad8_functions_list[] = {
 	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-- 
2.30.0

[PATCH v8 07/22] counter: 104-quad-8: Add const qualifier for actions_list array

[William Breathitt Gray]

The struct counter_synapse actions_list member expects a const enum
counter_synapse_action array. This patch adds the const qualifier to the
quad8_index_actions_list and quad8_synapse_actions_list to match
actions_list.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index af4e0503b074..9a96296b0625 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -305,12 +305,12 @@ enum quad8_synapse_action {
 	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
 };
 
-static enum counter_synapse_action quad8_index_actions_list[] = {
+static const enum counter_synapse_action quad8_index_actions_list[] = {
 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
 };
 
-static enum counter_synapse_action quad8_synapse_actions_list[] = {
+static const enum counter_synapse_action quad8_synapse_actions_list[] = {
 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
-- 
2.30.0

[PATCH v8 08/22] counter: ftm-quaddec: Add const qualifier for actions_list array

[William Breathitt Gray]

The struct counter_synapse actions_list member expects a const enum
counter_synapse_action array. This patch adds the const qualifier to the
ftm_quaddec_synapse_actions to match actions_list.

Cc: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/ftm-quaddec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c
index c2b3fdfd8b77..9371532406ca 100644
--- a/drivers/counter/ftm-quaddec.c
+++ b/drivers/counter/ftm-quaddec.c
@@ -162,7 +162,7 @@ enum ftm_quaddec_synapse_action {
 	FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
 };
 
-static enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
+static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
 	[FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };
-- 
2.30.0

[PATCH v8 09/22] counter: Return error code on invalid modes

[William Breathitt Gray]

Only a select set of modes (function, action, etc.) are valid for a
given device configuration. This patch ensures that invalid modes result
in a return -EINVAL. Such a situation should never occur in reality, but
it's good to define a default switch cases for the sake of making the
intent of the code clear.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c            | 10 ++++++++++
 drivers/counter/microchip-tcb-capture.c |  6 ++++++
 drivers/counter/stm32-lptimer-cnt.c     | 10 ++++++----
 drivers/counter/stm32-timer-cnt.c       |  3 +++
 drivers/counter/ti-eqep.c               |  3 +++
 5 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 9a96296b0625..674263b4d2c4 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -273,6 +273,10 @@ static int quad8_function_set(struct counter_device *counter,
 			*scale = 2;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
 			break;
+		default:
+			/* should never reach this path */
+			mutex_unlock(&priv->lock);
+			return -EINVAL;
 		}
 	}
 
@@ -367,6 +371,9 @@ static int quad8_action_get(struct counter_device *counter,
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
 		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	return 0;
@@ -529,6 +536,9 @@ static int quad8_count_mode_set(struct counter_device *counter,
 	case COUNTER_COUNT_MODE_MODULO_N:
 		cnt_mode = 3;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	mutex_lock(&priv->lock);
diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 710acc0a3704..ee979b011012 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -133,6 +133,9 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
 		bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
 		cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
@@ -226,6 +229,9 @@ static int mchp_tc_count_action_set(struct counter_device *counter,
 	case MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE:
 		edge = ATMEL_TC_ETRGEDG_BOTH;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	return regmap_write_bits(priv->regmap,
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 937439635d53..daf988e7b208 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -206,9 +206,10 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
 		priv->quadrature_mode = 1;
 		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
 		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return -EINVAL;
 }
 
 static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
@@ -326,9 +327,10 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
 	case STM32_LPTIM_ENCODER_BOTH_EDGE:
 		*action = priv->polarity;
 		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return -EINVAL;
 }
 
 static int stm32_lptim_cnt_action_set(struct counter_device *counter,
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index ef2a974a2f10..431a3d08ed6c 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -296,6 +296,9 @@ static int stm32_action_get(struct counter_device *counter,
 		/* counts up/down on both TI1FP1 and TI2FP2 edges */
 		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	return 0;
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
index a60aee1a1a29..7844fdf78a97 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -192,6 +192,9 @@ static int ti_eqep_action_get(struct counter_device *counter,
 			break;
 		}
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	return 0;
-- 
2.30.0

Re: [PATCH v8 09/22] counter: Return error code on invalid modes

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:33 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> Only a select set of modes (function, action, etc.) are valid for a
> given device configuration. This patch ensures that invalid modes result
> in a return -EINVAL. Such a situation should never occur in reality, but
> it's good to define a default switch cases for the sake of making the
> intent of the code clear.

In many of these cases it may make sense to also return early
in the good paths rather than share a return 0 at the
end of the function?


> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>  drivers/counter/104-quad-8.c            | 10 ++++++++++
>  drivers/counter/microchip-tcb-capture.c |  6 ++++++
>  drivers/counter/stm32-lptimer-cnt.c     | 10 ++++++----
>  drivers/counter/stm32-timer-cnt.c       |  3 +++
>  drivers/counter/ti-eqep.c               |  3 +++
>  5 files changed, 28 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 9a96296b0625..674263b4d2c4 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -273,6 +273,10 @@ static int quad8_function_set(struct counter_device *counter,
>  			*scale = 2;
>  			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
>  			break;
> +		default:
> +			/* should never reach this path */
> +			mutex_unlock(&priv->lock);
> +			return -EINVAL;
>  		}
>  	}
>  
> @@ -367,6 +371,9 @@ static int quad8_action_get(struct counter_device *counter,
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
>  		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
>  
>  	return 0;
> @@ -529,6 +536,9 @@ static int quad8_count_mode_set(struct counter_device *counter,
>  	case COUNTER_COUNT_MODE_MODULO_N:
>  		cnt_mode = 3;
>  		break;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
>  
>  	mutex_lock(&priv->lock);
> diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
> index 710acc0a3704..ee979b011012 100644
> --- a/drivers/counter/microchip-tcb-capture.c
> +++ b/drivers/counter/microchip-tcb-capture.c
> @@ -133,6 +133,9 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
>  		bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
>  		cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
>  		break;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
>  
>  	regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
> @@ -226,6 +229,9 @@ static int mchp_tc_count_action_set(struct counter_device *counter,
>  	case MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE:
>  		edge = ATMEL_TC_ETRGEDG_BOTH;
>  		break;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
>  
>  	return regmap_write_bits(priv->regmap,
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index 937439635d53..daf988e7b208 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -206,9 +206,10 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
>  		priv->quadrature_mode = 1;
>  		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
>  		return 0;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
> -
> -	return -EINVAL;
>  }
>  
>  static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
> @@ -326,9 +327,10 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
>  	case STM32_LPTIM_ENCODER_BOTH_EDGE:
>  		*action = priv->polarity;
>  		return 0;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
> -
> -	return -EINVAL;
>  }
>  
>  static int stm32_lptim_cnt_action_set(struct counter_device *counter,
> diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> index ef2a974a2f10..431a3d08ed6c 100644
> --- a/drivers/counter/stm32-timer-cnt.c
> +++ b/drivers/counter/stm32-timer-cnt.c
> @@ -296,6 +296,9 @@ static int stm32_action_get(struct counter_device *counter,
>  		/* counts up/down on both TI1FP1 and TI2FP2 edges */
>  		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
>  
>  	return 0;
> diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
> index a60aee1a1a29..7844fdf78a97 100644
> --- a/drivers/counter/ti-eqep.c
> +++ b/drivers/counter/ti-eqep.c
> @@ -192,6 +192,9 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  			break;
>  		}
>  		break;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
>  
>  	return 0;

Re: [PATCH v8 09/22] counter: Return error code on invalid modes

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> Only a select set of modes (function, action, etc.) are valid for a
> given device configuration. This patch ensures that invalid modes result
> in a return -EINVAL. Such a situation should never occur in reality, but
> it's good to define a default switch cases for the sake of making the
> intent of the code clear.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

Reviewed-by: David Lechner <david@lechnology.com>

(In response to Jonathan's comment, I think this is fine rather than
adding more churn to change all of the breaks to returns - but will
keep that in mind for future changes.)

Re: [PATCH v8 09/22] counter: Return error code on invalid modes

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 1440 bytes --]

On Sat, Feb 20, 2021 at 10:43:06AM -0600, David Lechner wrote:
> On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> > Only a select set of modes (function, action, etc.) are valid for a
> > given device configuration. This patch ensures that invalid modes result
> > in a return -EINVAL. Such a situation should never occur in reality, but
> > it's good to define a default switch cases for the sake of making the
> > intent of the code clear.
> > 
> > Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> > Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> > Cc: Alexandre Torgue <alexandre.torgue@st.com>
> > Cc: David Lechner <david@lechnology.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> 
> Reviewed-by: David Lechner <david@lechnology.com>
> 
> (In response to Jonathan's comment, I think this is fine rather than
> adding more churn to change all of the breaks to returns - but will
> keep that in mind for future changes.)

Due to some other updates I'm making to this patchset, I went ahead
already and updated the breaks to returns in the few places where
applicable. The changes to this patch are minor, but being pedantic I'll
hold off on adding your Reviewed-by line until the next revision so you
have the opportunity to formally approve it.

William Breathitt Gray

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[PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors

[William Breathitt Gray]

ERANGE is a semantically better error code to return when an argument
value falls outside the supported limit range of a device.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c        | 6 +++---
 drivers/counter/stm32-lptimer-cnt.c | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 674263b4d2c4..a2cabb028db0 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -154,7 +154,7 @@ static int quad8_count_write(struct counter_device *counter,
 
 	/* Only 24-bit values are supported */
 	if (val > 0xFFFFFF)
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&priv->lock);
 
@@ -671,7 +671,7 @@ static ssize_t quad8_count_preset_write(struct counter_device *counter,
 
 	/* Only 24-bit values are supported */
 	if (preset > 0xFFFFFF)
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&priv->lock);
 
@@ -716,7 +716,7 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
 
 	/* Only 24-bit values are supported */
 	if (ceiling > 0xFFFFFF)
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&priv->lock);
 
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index daf988e7b208..d5f9d580d06d 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -283,7 +283,7 @@ static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
 		return ret;
 
 	if (ceiling > STM32_LPTIM_MAX_ARR)
-		return -EINVAL;
+		return -ERANGE;
 
 	priv->ceiling = ceiling;
 
-- 
2.30.0

Re: [PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:34 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> ERANGE is a semantically better error code to return when an argument
> value falls outside the supported limit range of a device.

#define	ERANGE		34	/* Math result not representable */

Not generally applicable to a parameter being out of range
despite the name.
#define	EINVAL		22	/* Invalid argument */
Is probably closer to what we want to describe here.

Jonathan


> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>  drivers/counter/104-quad-8.c        | 6 +++---
>  drivers/counter/stm32-lptimer-cnt.c | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 674263b4d2c4..a2cabb028db0 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -154,7 +154,7 @@ static int quad8_count_write(struct counter_device *counter,
>  
>  	/* Only 24-bit values are supported */
>  	if (val > 0xFFFFFF)
> -		return -EINVAL;
> +		return -ERANGE;
>  
>  	mutex_lock(&priv->lock);
>  
> @@ -671,7 +671,7 @@ static ssize_t quad8_count_preset_write(struct counter_device *counter,
>  
>  	/* Only 24-bit values are supported */
>  	if (preset > 0xFFFFFF)
> -		return -EINVAL;
> +		return -ERANGE;
>  
>  	mutex_lock(&priv->lock);
>  
> @@ -716,7 +716,7 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
>  
>  	/* Only 24-bit values are supported */
>  	if (ceiling > 0xFFFFFF)
> -		return -EINVAL;
> +		return -ERANGE;
>  
>  	mutex_lock(&priv->lock);
>  
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index daf988e7b208..d5f9d580d06d 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -283,7 +283,7 @@ static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
>  		return ret;
>  
>  	if (ceiling > STM32_LPTIM_MAX_ARR)
> -		return -EINVAL;
> +		return -ERANGE;
>  
>  	priv->ceiling = ceiling;
>  

Re: [PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 1495 bytes --]

On Sun, Feb 14, 2021 at 05:10:21PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:34 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > ERANGE is a semantically better error code to return when an argument
> > value falls outside the supported limit range of a device.
> 
> #define	ERANGE		34	/* Math result not representable */
> 
> Not generally applicable to a parameter being out of range
> despite the name.
> #define	EINVAL		22	/* Invalid argument */
> Is probably closer to what we want to describe here.
> 
> Jonathan

The comment for ERANGE in error-base.h may be terse to a fault. I
believe there's a connotation here provided by ERANGE that is absent
from EINVAL: primarily that the device buffer is incapable of supporting
the desired value (i.e. there is a hardware limitation).

This is why strtoul() returns ERANGE if the correct value is outside the
range of representable values: the result of the operation is valid in
theory (it would be an unsigned integer), but it cannot be returned to
the user due to a limitation of the hardware to support that value (e.g.
32-bit registers) [1].

The changes in this patch follow the same logic: these are arguments
that are valid in theory (e.g. they are unsigned integers), but the
underlying devices are incapable of processing such a value (e.g. the
104-QUAD-8 can only handle 24-bit values).

[1] https://stackoverflow.com/a/34981398/1806289

William Breathitt Gray

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Re: [PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors

[Jonathan Cameron]

On Tue, 16 Feb 2021 10:26:52 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> On Sun, Feb 14, 2021 at 05:10:21PM +0000, Jonathan Cameron wrote:
> > On Fri, 12 Feb 2021 21:13:34 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >   
> > > ERANGE is a semantically better error code to return when an argument
> > > value falls outside the supported limit range of a device.  
> > 
> > #define	ERANGE		34	/* Math result not representable */
> > 
> > Not generally applicable to a parameter being out of range
> > despite the name.
> > #define	EINVAL		22	/* Invalid argument */
> > Is probably closer to what we want to describe here.
> > 
> > Jonathan  
> 
> The comment for ERANGE in error-base.h may be terse to a fault. I
> believe there's a connotation here provided by ERANGE that is absent
> from EINVAL: primarily that the device buffer is incapable of supporting
> the desired value (i.e. there is a hardware limitation).
> 
> This is why strtoul() returns ERANGE if the correct value is outside the
> range of representable values: the result of the operation is valid in
> theory (it would be an unsigned integer), but it cannot be returned to
> the user due to a limitation of the hardware to support that value (e.g.
> 32-bit registers) [1].
> 
> The changes in this patch follow the same logic: these are arguments
> that are valid in theory (e.g. they are unsigned integers), but the
> underlying devices are incapable of processing such a value (e.g. the
> 104-QUAD-8 can only handle 24-bit values).
> 
> [1] https://stackoverflow.com/a/34981398/1806289

Its a bit of a stretch, but I can't claim to feel that strongly about
this.

Jonathan

> 
> William Breathitt Gray

Re: [PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> ERANGE is a semantically better error code to return when an argument
> value falls outside the supported limit range of a device.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

Reviewed-by: David Lechner <david@lechnology.com>

(I agree with William's assessment that this use of ERANGE
is consistent with other uses in the kernel.)

[PATCH v8 11/22] counter: Rename counter_signal_value to counter_signal_level

[William Breathitt Gray]

Signal values will always be levels so let's be explicit it about it to
make the intent of the code clear.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c            |  5 +++--
 drivers/counter/counter.c               | 12 ++++++------
 drivers/counter/microchip-tcb-capture.c |  4 ++--
 include/linux/counter.h                 | 12 ++++++------
 4 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index a2cabb028db0..ead0eeb6c846 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -97,7 +97,8 @@ struct quad8 {
 #define QUAD8_CMR_QUADRATURE_X4 0x18
 
 static int quad8_signal_read(struct counter_device *counter,
-	struct counter_signal *signal, enum counter_signal_value *val)
+			     struct counter_signal *signal,
+			     enum counter_signal_level *level)
 {
 	const struct quad8 *const priv = counter->priv;
 	unsigned int state;
@@ -109,7 +110,7 @@ static int quad8_signal_read(struct counter_device *counter,
 	state = inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
 		& BIT(signal->id - 16);
 
-	*val = (state) ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+	*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 
 	return 0;
 }
diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
index 6a683d086008..cb92673552b5 100644
--- a/drivers/counter/counter.c
+++ b/drivers/counter/counter.c
@@ -289,9 +289,9 @@ struct counter_signal_unit {
 	struct counter_signal *signal;
 };
 
-static const char *const counter_signal_value_str[] = {
-	[COUNTER_SIGNAL_LOW] = "low",
-	[COUNTER_SIGNAL_HIGH] = "high"
+static const char *const counter_signal_level_str[] = {
+	[COUNTER_SIGNAL_LEVEL_LOW] = "low",
+	[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
 };
 
 static ssize_t counter_signal_show(struct device *dev,
@@ -302,13 +302,13 @@ static ssize_t counter_signal_show(struct device *dev,
 	const struct counter_signal_unit *const component = devattr->component;
 	struct counter_signal *const signal = component->signal;
 	int err;
-	enum counter_signal_value val;
+	enum counter_signal_level level;
 
-	err = counter->ops->signal_read(counter, signal, &val);
+	err = counter->ops->signal_read(counter, signal, &level);
 	if (err)
 		return err;
 
-	return sprintf(buf, "%s\n", counter_signal_value_str[val]);
+	return sprintf(buf, "%s\n", counter_signal_level_str[level]);
 }
 
 struct counter_name_unit {
diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index ee979b011012..f56c4e328018 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -158,7 +158,7 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
 
 static int mchp_tc_count_signal_read(struct counter_device *counter,
 				     struct counter_signal *signal,
-				     enum counter_signal_value *val)
+				     enum counter_signal_level *lvl)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	bool sigstatus;
@@ -171,7 +171,7 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
 	else
 		sigstatus = (sr & ATMEL_TC_MTIOA);
 
-	*val = sigstatus ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+	*lvl = sigstatus ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 
 	return 0;
 }
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 9dbd5df4cd34..79f5dcaf6ba0 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -290,16 +290,16 @@ struct counter_device_state {
 	const struct attribute_group **groups;
 };
 
-enum counter_signal_value {
-	COUNTER_SIGNAL_LOW = 0,
-	COUNTER_SIGNAL_HIGH
+enum counter_signal_level {
+	COUNTER_SIGNAL_LEVEL_LOW,
+	COUNTER_SIGNAL_LEVEL_HIGH,
 };
 
 /**
  * struct counter_ops - Callbacks from driver
  * @signal_read:	optional read callback for Signal attribute. The read
- *			value of the respective Signal should be passed back via
- *			the val parameter.
+ *			level of the respective Signal should be passed back via
+ *			the level parameter.
  * @count_read:		optional read callback for Count attribute. The read
  *			value of the respective Count should be passed back via
  *			the val parameter.
@@ -324,7 +324,7 @@ enum counter_signal_value {
 struct counter_ops {
 	int (*signal_read)(struct counter_device *counter,
 			   struct counter_signal *signal,
-			   enum counter_signal_value *val);
+			   enum counter_signal_level *level);
 	int (*count_read)(struct counter_device *counter,
 			  struct counter_count *count, unsigned long *val);
 	int (*count_write)(struct counter_device *counter,
-- 
2.30.0

Re: [PATCH v8 11/22] counter: Rename counter_signal_value to counter_signal_level

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> Signal values will always be levels so let's be explicit it about it to
> make the intent of the code clear.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

Reviewed-by: David Lechner <david@lechnology.com>

[PATCH v8 12/22] counter: Rename counter_count_function to counter_function

[William Breathitt Gray]

The phrase "Counter Count function" is verbose and unintentionally
implies that function is a Count extension. This patch adjusts the
Counter subsystem code to use the more direct "Counter function" phrase
to make the intent of this code clearer. The phrase "Count action" is
adjusted herein as well for the same reason.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c            | 62 +++++++++++-----------
 drivers/counter/counter.c               | 38 +++++++-------
 drivers/counter/ftm-quaddec.c           | 23 ++++-----
 drivers/counter/microchip-tcb-capture.c | 44 ++++++++--------
 drivers/counter/stm32-lptimer-cnt.c     | 56 ++++++++++----------
 drivers/counter/stm32-timer-cnt.c       | 68 ++++++++++++-------------
 drivers/counter/ti-eqep.c               | 28 +++++-----
 include/linux/counter.h                 | 20 ++++----
 8 files changed, 166 insertions(+), 173 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index ead0eeb6c846..eca3f6482719 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -187,18 +187,18 @@ static int quad8_count_write(struct counter_device *counter,
 	return 0;
 }
 
-enum quad8_count_function {
-	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = 0,
-	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
-	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
-	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
+enum quad8_function {
+	QUAD8_FUNCTION_PULSE_DIRECTION = 0,
+	QUAD8_FUNCTION_QUADRATURE_X1,
+	QUAD8_FUNCTION_QUADRATURE_X2,
+	QUAD8_FUNCTION_QUADRATURE_X4
 };
 
-static const enum counter_count_function quad8_functions_list[] = {
-	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
-	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
-	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+static const enum counter_function quad8_functions_list[] = {
+	[QUAD8_FUNCTION_PULSE_DIRECTION] = COUNTER_FUNCTION_PULSE_DIRECTION,
+	[QUAD8_FUNCTION_QUADRATURE_X1] = COUNTER_FUNCTION_QUADRATURE_X1_A,
+	[QUAD8_FUNCTION_QUADRATURE_X2] = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	[QUAD8_FUNCTION_QUADRATURE_X4] = COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 static int quad8_function_get(struct counter_device *counter,
@@ -212,17 +212,17 @@ static int quad8_function_get(struct counter_device *counter,
 	if (priv->quadrature_mode[id])
 		switch (priv->quadrature_scale[id]) {
 		case 0:
-			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X1;
+			*function = QUAD8_FUNCTION_QUADRATURE_X1;
 			break;
 		case 1:
-			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X2;
+			*function = QUAD8_FUNCTION_QUADRATURE_X2;
 			break;
 		case 2:
-			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X4;
+			*function = QUAD8_FUNCTION_QUADRATURE_X4;
 			break;
 		}
 	else
-		*function = QUAD8_COUNT_FUNCTION_PULSE_DIRECTION;
+		*function = QUAD8_FUNCTION_PULSE_DIRECTION;
 
 	mutex_unlock(&priv->lock);
 
@@ -246,7 +246,7 @@ static int quad8_function_set(struct counter_device *counter,
 	mode_cfg = priv->count_mode[id] << 1;
 	idr_cfg = priv->index_polarity[id] << 1;
 
-	if (function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
+	if (function == QUAD8_FUNCTION_PULSE_DIRECTION) {
 		*quadrature_mode = 0;
 
 		/* Quadrature scaling only available in quadrature mode */
@@ -262,15 +262,15 @@ static int quad8_function_set(struct counter_device *counter,
 		*quadrature_mode = 1;
 
 		switch (function) {
-		case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
+		case QUAD8_FUNCTION_QUADRATURE_X1:
 			*scale = 0;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
 			break;
-		case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
+		case QUAD8_FUNCTION_QUADRATURE_X2:
 			*scale = 1;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
 			break;
-		case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
+		case QUAD8_FUNCTION_QUADRATURE_X4:
 			*scale = 2;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
 			break;
@@ -351,11 +351,11 @@ static int quad8_action_get(struct counter_device *counter,
 
 	/* Determine action mode based on current count function mode */
 	switch (function) {
-	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
+	case QUAD8_FUNCTION_PULSE_DIRECTION:
 		if (synapse->signal->id == signal_a_id)
 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
 		break;
-	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
+	case QUAD8_FUNCTION_QUADRATURE_X1:
 		if (synapse->signal->id == signal_a_id) {
 			quad8_direction_get(counter, count, &direction);
 
@@ -365,11 +365,11 @@ static int quad8_action_get(struct counter_device *counter,
 				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
 		}
 		break;
-	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
+	case QUAD8_FUNCTION_QUADRATURE_X2:
 		if (synapse->signal->id == signal_a_id)
 			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
-	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
+	case QUAD8_FUNCTION_QUADRATURE_X4:
 		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	default:
@@ -1010,15 +1010,15 @@ static const struct counter_count_ext quad8_count_ext[] = {
 	}
 };
 
-#define QUAD8_COUNT(_id, _cntname) {					\
-	.id = (_id),							\
-	.name = (_cntname),						\
-	.functions_list = quad8_count_functions_list,			\
-	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
-	.synapses = quad8_count_synapses[(_id)],			\
-	.num_synapses =	2,						\
-	.ext = quad8_count_ext,						\
-	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
+#define QUAD8_COUNT(_id, _cntname) {				\
+	.id = (_id),						\
+	.name = (_cntname),					\
+	.functions_list = quad8_functions_list,			\
+	.num_functions = ARRAY_SIZE(quad8_functions_list),	\
+	.synapses = quad8_count_synapses[(_id)],		\
+	.num_synapses =	2,					\
+	.ext = quad8_count_ext,					\
+	.num_ext = ARRAY_SIZE(quad8_count_ext)			\
 }
 
 static struct counter_count quad8_counts[] = {
diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
index cb92673552b5..de921e8a3f72 100644
--- a/drivers/counter/counter.c
+++ b/drivers/counter/counter.c
@@ -744,15 +744,15 @@ static ssize_t counter_count_store(struct device *dev,
 	return len;
 }
 
-static const char *const counter_count_function_str[] = {
-	[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
-	[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
-	[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
+static const char *const counter_function_str[] = {
+	[COUNTER_FUNCTION_INCREASE] = "increase",
+	[COUNTER_FUNCTION_DECREASE] = "decrease",
+	[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
+	[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
+	[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
+	[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
+	[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
+	[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
 };
 
 static ssize_t counter_function_show(struct device *dev,
@@ -764,7 +764,7 @@ static ssize_t counter_function_show(struct device *dev,
 	const struct counter_count_unit *const component = devattr->component;
 	struct counter_count *const count = component->count;
 	size_t func_index;
-	enum counter_count_function function;
+	enum counter_function function;
 
 	err = counter->ops->function_get(counter, count, &func_index);
 	if (err)
@@ -773,7 +773,7 @@ static ssize_t counter_function_show(struct device *dev,
 	count->function = func_index;
 
 	function = count->functions_list[func_index];
-	return sprintf(buf, "%s\n", counter_count_function_str[function]);
+	return sprintf(buf, "%s\n", counter_function_str[function]);
 }
 
 static ssize_t counter_function_store(struct device *dev,
@@ -785,14 +785,14 @@ static ssize_t counter_function_store(struct device *dev,
 	struct counter_count *const count = component->count;
 	const size_t num_functions = count->num_functions;
 	size_t func_index;
-	enum counter_count_function function;
+	enum counter_function function;
 	int err;
 	struct counter_device *const counter = dev_get_drvdata(dev);
 
 	/* Find requested Count function mode */
 	for (func_index = 0; func_index < num_functions; func_index++) {
 		function = count->functions_list[func_index];
-		if (sysfs_streq(buf, counter_count_function_str[function]))
+		if (sysfs_streq(buf, counter_function_str[function]))
 			break;
 	}
 	/* Return error if requested Count function mode not found */
@@ -880,25 +880,25 @@ static int counter_count_ext_register(
 }
 
 struct counter_func_avail_unit {
-	const enum counter_count_function *functions_list;
+	const enum counter_function *functions_list;
 	size_t num_functions;
 };
 
-static ssize_t counter_count_function_available_show(struct device *dev,
+static ssize_t counter_function_available_show(struct device *dev,
 	struct device_attribute *attr, char *buf)
 {
 	const struct counter_device_attr *const devattr = to_counter_attr(attr);
 	const struct counter_func_avail_unit *const component = devattr->component;
-	const enum counter_count_function *const func_list = component->functions_list;
+	const enum counter_function *const func_list = component->functions_list;
 	const size_t num_functions = component->num_functions;
 	size_t i;
-	enum counter_count_function function;
+	enum counter_function function;
 	ssize_t len = 0;
 
 	for (i = 0; i < num_functions; i++) {
 		function = func_list[i];
 		len += sprintf(buf + len, "%s\n",
-			       counter_count_function_str[function]);
+			       counter_function_str[function]);
 	}
 
 	return len;
@@ -968,7 +968,7 @@ static int counter_count_attributes_create(
 	parm.group = group;
 	parm.prefix = "";
 	parm.name = "function_available";
-	parm.show = counter_count_function_available_show;
+	parm.show = counter_function_available_show;
 	parm.store = NULL;
 	parm.component = avail_comp;
 	err = counter_attribute_create(&parm);
diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c
index 9371532406ca..97599061ca31 100644
--- a/drivers/counter/ftm-quaddec.c
+++ b/drivers/counter/ftm-quaddec.c
@@ -167,13 +167,12 @@ static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };
 
-enum ftm_quaddec_count_function {
-	FTM_QUADDEC_COUNT_ENCODER_MODE_1,
+enum ftm_quaddec_function {
+	FTM_QUADDEC_ENCODER_MODE_1,
 };
 
-static const enum counter_count_function ftm_quaddec_count_functions[] = {
-	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] =
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+static const enum counter_function ftm_quaddec_functions[] = {
+	[FTM_QUADDEC_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 static int ftm_quaddec_count_read(struct counter_device *counter,
@@ -206,11 +205,11 @@ static int ftm_quaddec_count_write(struct counter_device *counter,
 	return 0;
 }
 
-static int ftm_quaddec_count_function_get(struct counter_device *counter,
-					  struct counter_count *count,
-					  size_t *function)
+static int ftm_quaddec_function_get(struct counter_device *counter,
+				    struct counter_count *count,
+				    size_t *function)
 {
-	*function = FTM_QUADDEC_COUNT_ENCODER_MODE_1;
+	*function = FTM_QUADDEC_ENCODER_MODE_1;
 
 	return 0;
 }
@@ -228,7 +227,7 @@ static int ftm_quaddec_action_get(struct counter_device *counter,
 static const struct counter_ops ftm_quaddec_cnt_ops = {
 	.count_read = ftm_quaddec_count_read,
 	.count_write = ftm_quaddec_count_write,
-	.function_get = ftm_quaddec_count_function_get,
+	.function_get = ftm_quaddec_function_get,
 	.action_get = ftm_quaddec_action_get,
 };
 
@@ -264,8 +263,8 @@ static const struct counter_count_ext ftm_quaddec_count_ext[] = {
 static struct counter_count ftm_quaddec_counts = {
 	.id = 0,
 	.name = "Channel 1 Count",
-	.functions_list = ftm_quaddec_count_functions,
-	.num_functions = ARRAY_SIZE(ftm_quaddec_count_functions),
+	.functions_list = ftm_quaddec_functions,
+	.num_functions = ARRAY_SIZE(ftm_quaddec_functions),
 	.synapses = ftm_quaddec_count_synapses,
 	.num_synapses = ARRAY_SIZE(ftm_quaddec_count_synapses),
 	.ext = ftm_quaddec_count_ext,
diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index f56c4e328018..d4cfaffe9499 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -32,14 +32,14 @@ struct mchp_tc_data {
 	bool trig_inverted;
 };
 
-enum mchp_tc_count_function {
+enum mchp_tc_function {
 	MCHP_TC_FUNCTION_INCREASE,
 	MCHP_TC_FUNCTION_QUADRATURE,
 };
 
-static enum counter_count_function mchp_tc_count_functions[] = {
-	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
-	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+static enum counter_function mchp_tc_functions[] = {
+	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_FUNCTION_INCREASE,
+	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 enum mchp_tc_synapse_action {
@@ -80,9 +80,8 @@ static struct counter_synapse mchp_tc_count_synapses[] = {
 	}
 };
 
-static int mchp_tc_count_function_get(struct counter_device *counter,
-				      struct counter_count *count,
-				      size_t *function)
+static int mchp_tc_function_get(struct counter_device *counter,
+				struct counter_count *count, size_t *function)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 
@@ -94,9 +93,8 @@ static int mchp_tc_count_function_get(struct counter_device *counter,
 	return 0;
 }
 
-static int mchp_tc_count_function_set(struct counter_device *counter,
-				      struct counter_count *count,
-				      size_t function)
+static int mchp_tc_function_set(struct counter_device *counter,
+				struct counter_count *count, size_t function)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 bmr, cmr;
@@ -176,10 +174,9 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
 	return 0;
 }
 
-static int mchp_tc_count_action_get(struct counter_device *counter,
-				    struct counter_count *count,
-				    struct counter_synapse *synapse,
-				    size_t *action)
+static int mchp_tc_action_get(struct counter_device *counter,
+			      struct counter_count *count,
+			      struct counter_synapse *synapse, size_t *action)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 cmr;
@@ -204,10 +201,9 @@ static int mchp_tc_count_action_get(struct counter_device *counter,
 	return 0;
 }
 
-static int mchp_tc_count_action_set(struct counter_device *counter,
-				    struct counter_count *count,
-				    struct counter_synapse *synapse,
-				    size_t action)
+static int mchp_tc_action_set(struct counter_device *counter,
+			      struct counter_count *count,
+			      struct counter_synapse *synapse, size_t action)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 edge = ATMEL_TC_ETRGEDG_NONE;
@@ -256,8 +252,8 @@ static struct counter_count mchp_tc_counts[] = {
 	{
 		.id = 0,
 		.name = "Timer Counter",
-		.functions_list = mchp_tc_count_functions,
-		.num_functions = ARRAY_SIZE(mchp_tc_count_functions),
+		.functions_list = mchp_tc_functions,
+		.num_functions = ARRAY_SIZE(mchp_tc_functions),
 		.synapses = mchp_tc_count_synapses,
 		.num_synapses = ARRAY_SIZE(mchp_tc_count_synapses),
 	},
@@ -266,10 +262,10 @@ static struct counter_count mchp_tc_counts[] = {
 static const struct counter_ops mchp_tc_ops = {
 	.signal_read  = mchp_tc_count_signal_read,
 	.count_read   = mchp_tc_count_read,
-	.function_get = mchp_tc_count_function_get,
-	.function_set = mchp_tc_count_function_set,
-	.action_get   = mchp_tc_count_action_get,
-	.action_set   = mchp_tc_count_action_set
+	.function_get = mchp_tc_function_get,
+	.function_set = mchp_tc_function_set,
+	.action_get   = mchp_tc_action_get,
+	.action_set   = mchp_tc_action_set
 };
 
 static const struct atmel_tcb_config tcb_rm9200_config = {
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index d5f9d580d06d..31477c6a0611 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -108,7 +108,7 @@ static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable)
 }
 
 /**
- * enum stm32_lptim_cnt_function - enumerates LPTimer counter & encoder modes
+ * enum stm32_lptim_function - enumerates LPTimer counter & encoder modes
  * @STM32_LPTIM_COUNTER_INCREASE: up count on IN1 rising, falling or both edges
  * @STM32_LPTIM_ENCODER_BOTH_EDGE: count on both edges (IN1 & IN2 quadrature)
  *
@@ -129,14 +129,14 @@ static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable)
  * | edges   | Low  ->  |   Up     |   Down  |   Down   |   Up    |
  * +---------+----------+----------+---------+----------+---------+
  */
-enum stm32_lptim_cnt_function {
+enum stm32_lptim_function {
 	STM32_LPTIM_COUNTER_INCREASE,
 	STM32_LPTIM_ENCODER_BOTH_EDGE,
 };
 
-static enum counter_count_function stm32_lptim_cnt_functions[] = {
-	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
-	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+static enum counter_function stm32_lptim_functions[] = {
+	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_FUNCTION_INCREASE,
+	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 enum stm32_lptim_synapse_action {
@@ -170,9 +170,9 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
 	return 0;
 }
 
-static int stm32_lptim_cnt_function_get(struct counter_device *counter,
-					struct counter_count *count,
-					size_t *function)
+static int stm32_lptim_function_get(struct counter_device *counter,
+				    struct counter_count *count,
+				    size_t *function)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 
@@ -189,9 +189,9 @@ static int stm32_lptim_cnt_function_get(struct counter_device *counter,
 	return -EINVAL;
 }
 
-static int stm32_lptim_cnt_function_set(struct counter_device *counter,
-					struct counter_count *count,
-					size_t function)
+static int stm32_lptim_function_set(struct counter_device *counter,
+				    struct counter_count *count,
+				    size_t function)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 
@@ -303,16 +303,16 @@ static const struct counter_count_ext stm32_lptim_cnt_ext[] = {
 	},
 };
 
-static int stm32_lptim_cnt_action_get(struct counter_device *counter,
-				      struct counter_count *count,
-				      struct counter_synapse *synapse,
-				      size_t *action)
+static int stm32_lptim_action_get(struct counter_device *counter,
+				  struct counter_count *count,
+				  struct counter_synapse *synapse,
+				  size_t *action)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 	size_t function;
 	int err;
 
-	err = stm32_lptim_cnt_function_get(counter, count, &function);
+	err = stm32_lptim_function_get(counter, count, &function);
 	if (err)
 		return err;
 
@@ -333,10 +333,10 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
 	}
 }
 
-static int stm32_lptim_cnt_action_set(struct counter_device *counter,
-				      struct counter_count *count,
-				      struct counter_synapse *synapse,
-				      size_t action)
+static int stm32_lptim_action_set(struct counter_device *counter,
+				  struct counter_count *count,
+				  struct counter_synapse *synapse,
+				  size_t action)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 	size_t function;
@@ -345,7 +345,7 @@ static int stm32_lptim_cnt_action_set(struct counter_device *counter,
 	if (stm32_lptim_is_enabled(priv))
 		return -EBUSY;
 
-	err = stm32_lptim_cnt_function_get(counter, count, &function);
+	err = stm32_lptim_function_get(counter, count, &function);
 	if (err)
 		return err;
 
@@ -366,10 +366,10 @@ static int stm32_lptim_cnt_action_set(struct counter_device *counter,
 
 static const struct counter_ops stm32_lptim_cnt_ops = {
 	.count_read = stm32_lptim_cnt_read,
-	.function_get = stm32_lptim_cnt_function_get,
-	.function_set = stm32_lptim_cnt_function_set,
-	.action_get = stm32_lptim_cnt_action_get,
-	.action_set = stm32_lptim_cnt_action_set,
+	.function_get = stm32_lptim_function_get,
+	.function_set = stm32_lptim_function_set,
+	.action_get = stm32_lptim_action_get,
+	.action_set = stm32_lptim_action_set,
 };
 
 static struct counter_signal stm32_lptim_cnt_signals[] = {
@@ -400,8 +400,8 @@ static struct counter_synapse stm32_lptim_cnt_synapses[] = {
 static struct counter_count stm32_lptim_enc_counts = {
 	.id = 0,
 	.name = "LPTimer Count",
-	.functions_list = stm32_lptim_cnt_functions,
-	.num_functions = ARRAY_SIZE(stm32_lptim_cnt_functions),
+	.functions_list = stm32_lptim_functions,
+	.num_functions = ARRAY_SIZE(stm32_lptim_functions),
 	.synapses = stm32_lptim_cnt_synapses,
 	.num_synapses = ARRAY_SIZE(stm32_lptim_cnt_synapses),
 	.ext = stm32_lptim_cnt_ext,
@@ -412,7 +412,7 @@ static struct counter_count stm32_lptim_enc_counts = {
 static struct counter_count stm32_lptim_in1_counts = {
 	.id = 0,
 	.name = "LPTimer Count",
-	.functions_list = stm32_lptim_cnt_functions,
+	.functions_list = stm32_lptim_functions,
 	.num_functions = 1,
 	.synapses = stm32_lptim_cnt_synapses,
 	.num_synapses = 1,
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 431a3d08ed6c..02a7c8bd77df 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -37,23 +37,23 @@ struct stm32_timer_cnt {
 };
 
 /**
- * enum stm32_count_function - enumerates stm32 timer counter encoder modes
- * @STM32_COUNT_SLAVE_MODE_DISABLED: counts on internal clock when CEN=1
- * @STM32_COUNT_ENCODER_MODE_1: counts TI1FP1 edges, depending on TI2FP2 level
- * @STM32_COUNT_ENCODER_MODE_2: counts TI2FP2 edges, depending on TI1FP1 level
- * @STM32_COUNT_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
+ * enum stm32_function - enumerates stm32 timer counter encoder modes
+ * @STM32_SLAVE_MODE_DISABLED: counts on internal clock when CEN=1
+ * @STM32_ENCODER_MODE_1: counts TI1FP1 edges, depending on TI2FP2 level
+ * @STM32_ENCODER_MODE_2: counts TI2FP2 edges, depending on TI1FP1 level
+ * @STM32_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
  */
-enum stm32_count_function {
-	STM32_COUNT_SLAVE_MODE_DISABLED = -1,
-	STM32_COUNT_ENCODER_MODE_1,
-	STM32_COUNT_ENCODER_MODE_2,
-	STM32_COUNT_ENCODER_MODE_3,
+enum stm32_function {
+	STM32_SLAVE_MODE_DISABLED = -1,
+	STM32_ENCODER_MODE_1,
+	STM32_ENCODER_MODE_2,
+	STM32_ENCODER_MODE_3,
 };
 
-static enum counter_count_function stm32_count_functions[] = {
-	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
-	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+static enum counter_function stm32_functions[] = {
+	[STM32_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	[STM32_ENCODER_MODE_2] = COUNTER_FUNCTION_QUADRATURE_X2_B,
+	[STM32_ENCODER_MODE_3] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 static int stm32_count_read(struct counter_device *counter,
@@ -80,9 +80,8 @@ static int stm32_count_write(struct counter_device *counter,
 	return regmap_write(priv->regmap, TIM_CNT, val);
 }
 
-static int stm32_count_function_get(struct counter_device *counter,
-				    struct counter_count *count,
-				    size_t *function)
+static int stm32_function_get(struct counter_device *counter,
+			      struct counter_count *count, size_t *function)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 smcr;
@@ -91,34 +90,33 @@ static int stm32_count_function_get(struct counter_device *counter,
 
 	switch (smcr & TIM_SMCR_SMS) {
 	case 1:
-		*function = STM32_COUNT_ENCODER_MODE_1;
+		*function = STM32_ENCODER_MODE_1;
 		return 0;
 	case 2:
-		*function = STM32_COUNT_ENCODER_MODE_2;
+		*function = STM32_ENCODER_MODE_2;
 		return 0;
 	case 3:
-		*function = STM32_COUNT_ENCODER_MODE_3;
+		*function = STM32_ENCODER_MODE_3;
 		return 0;
 	}
 
 	return -EINVAL;
 }
 
-static int stm32_count_function_set(struct counter_device *counter,
-				    struct counter_count *count,
-				    size_t function)
+static int stm32_function_set(struct counter_device *counter,
+			      struct counter_count *count, size_t function)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 cr1, sms;
 
 	switch (function) {
-	case STM32_COUNT_ENCODER_MODE_1:
+	case STM32_ENCODER_MODE_1:
 		sms = 1;
 		break;
-	case STM32_COUNT_ENCODER_MODE_2:
+	case STM32_ENCODER_MODE_2:
 		sms = 2;
 		break;
-	case STM32_COUNT_ENCODER_MODE_3:
+	case STM32_ENCODER_MODE_3:
 		sms = 3;
 		break;
 	default:
@@ -274,25 +272,25 @@ static int stm32_action_get(struct counter_device *counter,
 	size_t function;
 	int err;
 
-	/* Default action mode (e.g. STM32_COUNT_SLAVE_MODE_DISABLED) */
+	/* Default action mode (e.g. STM32_SLAVE_MODE_DISABLED) */
 	*action = STM32_SYNAPSE_ACTION_NONE;
 
-	err = stm32_count_function_get(counter, count, &function);
+	err = stm32_function_get(counter, count, &function);
 	if (err)
 		return 0;
 
 	switch (function) {
-	case STM32_COUNT_ENCODER_MODE_1:
+	case STM32_ENCODER_MODE_1:
 		/* counts up/down on TI1FP1 edge depending on TI2FP2 level */
 		if (synapse->signal->id == count->synapses[0].signal->id)
 			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
-	case STM32_COUNT_ENCODER_MODE_2:
+	case STM32_ENCODER_MODE_2:
 		/* counts up/down on TI2FP2 edge depending on TI1FP1 level */
 		if (synapse->signal->id == count->synapses[1].signal->id)
 			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
-	case STM32_COUNT_ENCODER_MODE_3:
+	case STM32_ENCODER_MODE_3:
 		/* counts up/down on both TI1FP1 and TI2FP2 edges */
 		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
@@ -307,8 +305,8 @@ static int stm32_action_get(struct counter_device *counter,
 static const struct counter_ops stm32_timer_cnt_ops = {
 	.count_read = stm32_count_read,
 	.count_write = stm32_count_write,
-	.function_get = stm32_count_function_get,
-	.function_set = stm32_count_function_set,
+	.function_get = stm32_function_get,
+	.function_set = stm32_function_set,
 	.action_get = stm32_action_get,
 };
 
@@ -339,8 +337,8 @@ static struct counter_synapse stm32_count_synapses[] = {
 static struct counter_count stm32_counts = {
 	.id = 0,
 	.name = "Channel 1 Count",
-	.functions_list = stm32_count_functions,
-	.num_functions = ARRAY_SIZE(stm32_count_functions),
+	.functions_list = stm32_functions,
+	.num_functions = ARRAY_SIZE(stm32_functions),
 	.synapses = stm32_count_synapses,
 	.num_synapses = ARRAY_SIZE(stm32_count_synapses),
 	.ext = stm32_count_ext,
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
index 7844fdf78a97..8d45b0443610 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -73,11 +73,11 @@ enum {
 };
 
 /* Position Counter Input Modes */
-enum {
-	TI_EQEP_COUNT_FUNC_QUAD_COUNT,
-	TI_EQEP_COUNT_FUNC_DIR_COUNT,
-	TI_EQEP_COUNT_FUNC_UP_COUNT,
-	TI_EQEP_COUNT_FUNC_DOWN_COUNT,
+enum ti_eqep_function {
+	TI_EQEP_FUNCTION_QUAD_COUNT,
+	TI_EQEP_FUNCTION_DIR_COUNT,
+	TI_EQEP_FUNCTION_UP_COUNT,
+	TI_EQEP_FUNCTION_DOWN_COUNT,
 };
 
 enum {
@@ -152,13 +152,13 @@ static int ti_eqep_action_get(struct counter_device *counter,
 		return err;
 
 	switch (function) {
-	case TI_EQEP_COUNT_FUNC_QUAD_COUNT:
+	case TI_EQEP_FUNCTION_QUAD_COUNT:
 		/* In quadrature mode, the rising and falling edge of both
 		 * QEPA and QEPB trigger QCLK.
 		 */
 		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
-	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
+	case TI_EQEP_FUNCTION_DIR_COUNT:
 		/* In direction-count mode only rising edge of QEPA is counted
 		 * and QEPB gives direction.
 		 */
@@ -171,8 +171,8 @@ static int ti_eqep_action_get(struct counter_device *counter,
 			break;
 		}
 		break;
-	case TI_EQEP_COUNT_FUNC_UP_COUNT:
-	case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
+	case TI_EQEP_FUNCTION_UP_COUNT:
+	case TI_EQEP_FUNCTION_DOWN_COUNT:
 		/* In up/down-count modes only QEPA is counted and QEPB is not
 		 * used.
 		 */
@@ -327,11 +327,11 @@ static struct counter_signal ti_eqep_signals[] = {
 	},
 };
 
-static const enum counter_count_function ti_eqep_position_functions[] = {
-	[TI_EQEP_COUNT_FUNC_QUAD_COUNT]	= COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
-	[TI_EQEP_COUNT_FUNC_DIR_COUNT]	= COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
-	[TI_EQEP_COUNT_FUNC_UP_COUNT]	= COUNTER_COUNT_FUNCTION_INCREASE,
-	[TI_EQEP_COUNT_FUNC_DOWN_COUNT]	= COUNTER_COUNT_FUNCTION_DECREASE,
+static const enum counter_function ti_eqep_position_functions[] = {
+	[TI_EQEP_FUNCTION_QUAD_COUNT]	= COUNTER_FUNCTION_QUADRATURE_X4,
+	[TI_EQEP_FUNCTION_DIR_COUNT]	= COUNTER_FUNCTION_PULSE_DIRECTION,
+	[TI_EQEP_FUNCTION_UP_COUNT]	= COUNTER_FUNCTION_INCREASE,
+	[TI_EQEP_FUNCTION_DOWN_COUNT]	= COUNTER_FUNCTION_DECREASE,
 };
 
 static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 79f5dcaf6ba0..d16ce2819b48 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -162,15 +162,15 @@ struct counter_count_ext {
 	void *priv;
 };
 
-enum counter_count_function {
-	COUNTER_COUNT_FUNCTION_INCREASE = 0,
-	COUNTER_COUNT_FUNCTION_DECREASE,
-	COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+enum counter_function {
+	COUNTER_FUNCTION_INCREASE = 0,
+	COUNTER_FUNCTION_DECREASE,
+	COUNTER_FUNCTION_PULSE_DIRECTION,
+	COUNTER_FUNCTION_QUADRATURE_X1_A,
+	COUNTER_FUNCTION_QUADRATURE_X1_B,
+	COUNTER_FUNCTION_QUADRATURE_X2_A,
+	COUNTER_FUNCTION_QUADRATURE_X2_B,
+	COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 /**
@@ -192,7 +192,7 @@ struct counter_count {
 	const char *name;
 
 	size_t function;
-	const enum counter_count_function *functions_list;
+	const enum counter_function *functions_list;
 	size_t num_functions;
 
 	struct counter_synapse *synapses;
-- 
2.30.0

Re: [PATCH v8 12/22] counter: Rename counter_count_function to counter_function

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:36 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The phrase "Counter Count function" is verbose and unintentionally
> implies that function is a Count extension. This patch adjusts the
> Counter subsystem code to use the more direct "Counter function" phrase
> to make the intent of this code clearer. The phrase "Count action" is
> adjusted herein as well for the same reason.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

I agree this makes sense in the counter core code, but in the drivers
it may not be quite so obvious we are talking about a counter function
given some of the bits of hardware do a number of other things.

I guess up to the various driver maintainers on whether they
think the new meaning is clear enough!

Jonathan

> ---
>  drivers/counter/104-quad-8.c            | 62 +++++++++++-----------
>  drivers/counter/counter.c               | 38 +++++++-------
>  drivers/counter/ftm-quaddec.c           | 23 ++++-----
>  drivers/counter/microchip-tcb-capture.c | 44 ++++++++--------
>  drivers/counter/stm32-lptimer-cnt.c     | 56 ++++++++++----------
>  drivers/counter/stm32-timer-cnt.c       | 68 ++++++++++++-------------
>  drivers/counter/ti-eqep.c               | 28 +++++-----
>  include/linux/counter.h                 | 20 ++++----
>  8 files changed, 166 insertions(+), 173 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index ead0eeb6c846..eca3f6482719 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -187,18 +187,18 @@ static int quad8_count_write(struct counter_device *counter,
>  	return 0;
>  }
>  
> -enum quad8_count_function {
> -	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = 0,
> -	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
> -	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
> -	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
> +enum quad8_function {
> +	QUAD8_FUNCTION_PULSE_DIRECTION = 0,
> +	QUAD8_FUNCTION_QUADRATURE_X1,
> +	QUAD8_FUNCTION_QUADRATURE_X2,
> +	QUAD8_FUNCTION_QUADRATURE_X4
>  };
>  
> -static const enum counter_count_function quad8_functions_list[] = {
> -	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> -	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
> -	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> -	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +static const enum counter_function quad8_functions_list[] = {
> +	[QUAD8_FUNCTION_PULSE_DIRECTION] = COUNTER_FUNCTION_PULSE_DIRECTION,
> +	[QUAD8_FUNCTION_QUADRATURE_X1] = COUNTER_FUNCTION_QUADRATURE_X1_A,
> +	[QUAD8_FUNCTION_QUADRATURE_X2] = COUNTER_FUNCTION_QUADRATURE_X2_A,
> +	[QUAD8_FUNCTION_QUADRATURE_X4] = COUNTER_FUNCTION_QUADRATURE_X4
>  };
>  
>  static int quad8_function_get(struct counter_device *counter,
> @@ -212,17 +212,17 @@ static int quad8_function_get(struct counter_device *counter,
>  	if (priv->quadrature_mode[id])
>  		switch (priv->quadrature_scale[id]) {
>  		case 0:
> -			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X1;
> +			*function = QUAD8_FUNCTION_QUADRATURE_X1;
>  			break;
>  		case 1:
> -			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X2;
> +			*function = QUAD8_FUNCTION_QUADRATURE_X2;
>  			break;
>  		case 2:
> -			*function = QUAD8_COUNT_FUNCTION_QUADRATURE_X4;
> +			*function = QUAD8_FUNCTION_QUADRATURE_X4;
>  			break;
>  		}
>  	else
> -		*function = QUAD8_COUNT_FUNCTION_PULSE_DIRECTION;
> +		*function = QUAD8_FUNCTION_PULSE_DIRECTION;
>  
>  	mutex_unlock(&priv->lock);
>  
> @@ -246,7 +246,7 @@ static int quad8_function_set(struct counter_device *counter,
>  	mode_cfg = priv->count_mode[id] << 1;
>  	idr_cfg = priv->index_polarity[id] << 1;
>  
> -	if (function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
> +	if (function == QUAD8_FUNCTION_PULSE_DIRECTION) {
>  		*quadrature_mode = 0;
>  
>  		/* Quadrature scaling only available in quadrature mode */
> @@ -262,15 +262,15 @@ static int quad8_function_set(struct counter_device *counter,
>  		*quadrature_mode = 1;
>  
>  		switch (function) {
> -		case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
> +		case QUAD8_FUNCTION_QUADRATURE_X1:
>  			*scale = 0;
>  			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
>  			break;
> -		case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
> +		case QUAD8_FUNCTION_QUADRATURE_X2:
>  			*scale = 1;
>  			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
>  			break;
> -		case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
> +		case QUAD8_FUNCTION_QUADRATURE_X4:
>  			*scale = 2;
>  			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
>  			break;
> @@ -351,11 +351,11 @@ static int quad8_action_get(struct counter_device *counter,
>  
>  	/* Determine action mode based on current count function mode */
>  	switch (function) {
> -	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
> +	case QUAD8_FUNCTION_PULSE_DIRECTION:
>  		if (synapse->signal->id == signal_a_id)
>  			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
>  		break;
> -	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
> +	case QUAD8_FUNCTION_QUADRATURE_X1:
>  		if (synapse->signal->id == signal_a_id) {
>  			quad8_direction_get(counter, count, &direction);
>  
> @@ -365,11 +365,11 @@ static int quad8_action_get(struct counter_device *counter,
>  				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
>  		}
>  		break;
> -	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
> +	case QUAD8_FUNCTION_QUADRATURE_X2:
>  		if (synapse->signal->id == signal_a_id)
>  			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> -	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
> +	case QUAD8_FUNCTION_QUADRATURE_X4:
>  		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
>  	default:
> @@ -1010,15 +1010,15 @@ static const struct counter_count_ext quad8_count_ext[] = {
>  	}
>  };
>  
> -#define QUAD8_COUNT(_id, _cntname) {					\
> -	.id = (_id),							\
> -	.name = (_cntname),						\
> -	.functions_list = quad8_count_functions_list,			\
> -	.num_functions = ARRAY_SIZE(quad8_count_functions_list),	\
> -	.synapses = quad8_count_synapses[(_id)],			\
> -	.num_synapses =	2,						\
> -	.ext = quad8_count_ext,						\
> -	.num_ext = ARRAY_SIZE(quad8_count_ext)				\
> +#define QUAD8_COUNT(_id, _cntname) {				\
> +	.id = (_id),						\
> +	.name = (_cntname),					\
> +	.functions_list = quad8_functions_list,			\
> +	.num_functions = ARRAY_SIZE(quad8_functions_list),	\
> +	.synapses = quad8_count_synapses[(_id)],		\
> +	.num_synapses =	2,					\
> +	.ext = quad8_count_ext,					\
> +	.num_ext = ARRAY_SIZE(quad8_count_ext)			\
>  }
>  
>  static struct counter_count quad8_counts[] = {
> diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
> index cb92673552b5..de921e8a3f72 100644
> --- a/drivers/counter/counter.c
> +++ b/drivers/counter/counter.c
> @@ -744,15 +744,15 @@ static ssize_t counter_count_store(struct device *dev,
>  	return len;
>  }
>  
> -static const char *const counter_count_function_str[] = {
> -	[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
> -	[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
> -	[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
> +static const char *const counter_function_str[] = {
> +	[COUNTER_FUNCTION_INCREASE] = "increase",
> +	[COUNTER_FUNCTION_DECREASE] = "decrease",
> +	[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
> +	[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
> +	[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
> +	[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
> +	[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
> +	[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
>  };
>  
>  static ssize_t counter_function_show(struct device *dev,
> @@ -764,7 +764,7 @@ static ssize_t counter_function_show(struct device *dev,
>  	const struct counter_count_unit *const component = devattr->component;
>  	struct counter_count *const count = component->count;
>  	size_t func_index;
> -	enum counter_count_function function;
> +	enum counter_function function;
>  
>  	err = counter->ops->function_get(counter, count, &func_index);
>  	if (err)
> @@ -773,7 +773,7 @@ static ssize_t counter_function_show(struct device *dev,
>  	count->function = func_index;
>  
>  	function = count->functions_list[func_index];
> -	return sprintf(buf, "%s\n", counter_count_function_str[function]);
> +	return sprintf(buf, "%s\n", counter_function_str[function]);
>  }
>  
>  static ssize_t counter_function_store(struct device *dev,
> @@ -785,14 +785,14 @@ static ssize_t counter_function_store(struct device *dev,
>  	struct counter_count *const count = component->count;
>  	const size_t num_functions = count->num_functions;
>  	size_t func_index;
> -	enum counter_count_function function;
> +	enum counter_function function;
>  	int err;
>  	struct counter_device *const counter = dev_get_drvdata(dev);
>  
>  	/* Find requested Count function mode */
>  	for (func_index = 0; func_index < num_functions; func_index++) {
>  		function = count->functions_list[func_index];
> -		if (sysfs_streq(buf, counter_count_function_str[function]))
> +		if (sysfs_streq(buf, counter_function_str[function]))
>  			break;
>  	}
>  	/* Return error if requested Count function mode not found */
> @@ -880,25 +880,25 @@ static int counter_count_ext_register(
>  }
>  
>  struct counter_func_avail_unit {
> -	const enum counter_count_function *functions_list;
> +	const enum counter_function *functions_list;
>  	size_t num_functions;
>  };
>  
> -static ssize_t counter_count_function_available_show(struct device *dev,
> +static ssize_t counter_function_available_show(struct device *dev,
>  	struct device_attribute *attr, char *buf)
>  {
>  	const struct counter_device_attr *const devattr = to_counter_attr(attr);
>  	const struct counter_func_avail_unit *const component = devattr->component;
> -	const enum counter_count_function *const func_list = component->functions_list;
> +	const enum counter_function *const func_list = component->functions_list;
>  	const size_t num_functions = component->num_functions;
>  	size_t i;
> -	enum counter_count_function function;
> +	enum counter_function function;
>  	ssize_t len = 0;
>  
>  	for (i = 0; i < num_functions; i++) {
>  		function = func_list[i];
>  		len += sprintf(buf + len, "%s\n",
> -			       counter_count_function_str[function]);
> +			       counter_function_str[function]);
>  	}
>  
>  	return len;
> @@ -968,7 +968,7 @@ static int counter_count_attributes_create(
>  	parm.group = group;
>  	parm.prefix = "";
>  	parm.name = "function_available";
> -	parm.show = counter_count_function_available_show;
> +	parm.show = counter_function_available_show;
>  	parm.store = NULL;
>  	parm.component = avail_comp;
>  	err = counter_attribute_create(&parm);
> diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c
> index 9371532406ca..97599061ca31 100644
> --- a/drivers/counter/ftm-quaddec.c
> +++ b/drivers/counter/ftm-quaddec.c
> @@ -167,13 +167,12 @@ static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
>  	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
>  };
>  
> -enum ftm_quaddec_count_function {
> -	FTM_QUADDEC_COUNT_ENCODER_MODE_1,
> +enum ftm_quaddec_function {
> +	FTM_QUADDEC_ENCODER_MODE_1,
>  };
>  
> -static const enum counter_count_function ftm_quaddec_count_functions[] = {
> -	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] =
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +static const enum counter_function ftm_quaddec_functions[] = {
> +	[FTM_QUADDEC_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X4
>  };
>  
>  static int ftm_quaddec_count_read(struct counter_device *counter,
> @@ -206,11 +205,11 @@ static int ftm_quaddec_count_write(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int ftm_quaddec_count_function_get(struct counter_device *counter,
> -					  struct counter_count *count,
> -					  size_t *function)
> +static int ftm_quaddec_function_get(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    size_t *function)
>  {
> -	*function = FTM_QUADDEC_COUNT_ENCODER_MODE_1;
> +	*function = FTM_QUADDEC_ENCODER_MODE_1;
>  
>  	return 0;
>  }
> @@ -228,7 +227,7 @@ static int ftm_quaddec_action_get(struct counter_device *counter,
>  static const struct counter_ops ftm_quaddec_cnt_ops = {
>  	.count_read = ftm_quaddec_count_read,
>  	.count_write = ftm_quaddec_count_write,
> -	.function_get = ftm_quaddec_count_function_get,
> +	.function_get = ftm_quaddec_function_get,
>  	.action_get = ftm_quaddec_action_get,
>  };
>  
> @@ -264,8 +263,8 @@ static const struct counter_count_ext ftm_quaddec_count_ext[] = {
>  static struct counter_count ftm_quaddec_counts = {
>  	.id = 0,
>  	.name = "Channel 1 Count",
> -	.functions_list = ftm_quaddec_count_functions,
> -	.num_functions = ARRAY_SIZE(ftm_quaddec_count_functions),
> +	.functions_list = ftm_quaddec_functions,
> +	.num_functions = ARRAY_SIZE(ftm_quaddec_functions),
>  	.synapses = ftm_quaddec_count_synapses,
>  	.num_synapses = ARRAY_SIZE(ftm_quaddec_count_synapses),
>  	.ext = ftm_quaddec_count_ext,
> diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
> index f56c4e328018..d4cfaffe9499 100644
> --- a/drivers/counter/microchip-tcb-capture.c
> +++ b/drivers/counter/microchip-tcb-capture.c
> @@ -32,14 +32,14 @@ struct mchp_tc_data {
>  	bool trig_inverted;
>  };
>  
> -enum mchp_tc_count_function {
> +enum mchp_tc_function {
>  	MCHP_TC_FUNCTION_INCREASE,
>  	MCHP_TC_FUNCTION_QUADRATURE,
>  };
>  
> -static enum counter_count_function mchp_tc_count_functions[] = {
> -	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
> -	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +static enum counter_function mchp_tc_functions[] = {
> +	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_FUNCTION_INCREASE,
> +	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_FUNCTION_QUADRATURE_X4,
>  };
>  
>  enum mchp_tc_synapse_action {
> @@ -80,9 +80,8 @@ static struct counter_synapse mchp_tc_count_synapses[] = {
>  	}
>  };
>  
> -static int mchp_tc_count_function_get(struct counter_device *counter,
> -				      struct counter_count *count,
> -				      size_t *function)
> +static int mchp_tc_function_get(struct counter_device *counter,
> +				struct counter_count *count, size_t *function)
>  {
>  	struct mchp_tc_data *const priv = counter->priv;
>  
> @@ -94,9 +93,8 @@ static int mchp_tc_count_function_get(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int mchp_tc_count_function_set(struct counter_device *counter,
> -				      struct counter_count *count,
> -				      size_t function)
> +static int mchp_tc_function_set(struct counter_device *counter,
> +				struct counter_count *count, size_t function)
>  {
>  	struct mchp_tc_data *const priv = counter->priv;
>  	u32 bmr, cmr;
> @@ -176,10 +174,9 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int mchp_tc_count_action_get(struct counter_device *counter,
> -				    struct counter_count *count,
> -				    struct counter_synapse *synapse,
> -				    size_t *action)
> +static int mchp_tc_action_get(struct counter_device *counter,
> +			      struct counter_count *count,
> +			      struct counter_synapse *synapse, size_t *action)
>  {
>  	struct mchp_tc_data *const priv = counter->priv;
>  	u32 cmr;
> @@ -204,10 +201,9 @@ static int mchp_tc_count_action_get(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int mchp_tc_count_action_set(struct counter_device *counter,
> -				    struct counter_count *count,
> -				    struct counter_synapse *synapse,
> -				    size_t action)
> +static int mchp_tc_action_set(struct counter_device *counter,
> +			      struct counter_count *count,
> +			      struct counter_synapse *synapse, size_t action)
>  {
>  	struct mchp_tc_data *const priv = counter->priv;
>  	u32 edge = ATMEL_TC_ETRGEDG_NONE;
> @@ -256,8 +252,8 @@ static struct counter_count mchp_tc_counts[] = {
>  	{
>  		.id = 0,
>  		.name = "Timer Counter",
> -		.functions_list = mchp_tc_count_functions,
> -		.num_functions = ARRAY_SIZE(mchp_tc_count_functions),
> +		.functions_list = mchp_tc_functions,
> +		.num_functions = ARRAY_SIZE(mchp_tc_functions),
>  		.synapses = mchp_tc_count_synapses,
>  		.num_synapses = ARRAY_SIZE(mchp_tc_count_synapses),
>  	},
> @@ -266,10 +262,10 @@ static struct counter_count mchp_tc_counts[] = {
>  static const struct counter_ops mchp_tc_ops = {
>  	.signal_read  = mchp_tc_count_signal_read,
>  	.count_read   = mchp_tc_count_read,
> -	.function_get = mchp_tc_count_function_get,
> -	.function_set = mchp_tc_count_function_set,
> -	.action_get   = mchp_tc_count_action_get,
> -	.action_set   = mchp_tc_count_action_set
> +	.function_get = mchp_tc_function_get,
> +	.function_set = mchp_tc_function_set,
> +	.action_get   = mchp_tc_action_get,
> +	.action_set   = mchp_tc_action_set
>  };
>  
>  static const struct atmel_tcb_config tcb_rm9200_config = {
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index d5f9d580d06d..31477c6a0611 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -108,7 +108,7 @@ static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable)
>  }
>  
>  /**
> - * enum stm32_lptim_cnt_function - enumerates LPTimer counter & encoder modes
> + * enum stm32_lptim_function - enumerates LPTimer counter & encoder modes
>   * @STM32_LPTIM_COUNTER_INCREASE: up count on IN1 rising, falling or both edges
>   * @STM32_LPTIM_ENCODER_BOTH_EDGE: count on both edges (IN1 & IN2 quadrature)
>   *
> @@ -129,14 +129,14 @@ static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable)
>   * | edges   | Low  ->  |   Up     |   Down  |   Down   |   Up    |
>   * +---------+----------+----------+---------+----------+---------+
>   */
> -enum stm32_lptim_cnt_function {
> +enum stm32_lptim_function {
>  	STM32_LPTIM_COUNTER_INCREASE,
>  	STM32_LPTIM_ENCODER_BOTH_EDGE,
>  };
>  
> -static enum counter_count_function stm32_lptim_cnt_functions[] = {
> -	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
> -	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +static enum counter_function stm32_lptim_functions[] = {
> +	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_FUNCTION_INCREASE,
> +	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_FUNCTION_QUADRATURE_X4,
>  };
>  
>  enum stm32_lptim_synapse_action {
> @@ -170,9 +170,9 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int stm32_lptim_cnt_function_get(struct counter_device *counter,
> -					struct counter_count *count,
> -					size_t *function)
> +static int stm32_lptim_function_get(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    size_t *function)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  
> @@ -189,9 +189,9 @@ static int stm32_lptim_cnt_function_get(struct counter_device *counter,
>  	return -EINVAL;
>  }
>  
> -static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> -					struct counter_count *count,
> -					size_t function)
> +static int stm32_lptim_function_set(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    size_t function)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  
> @@ -303,16 +303,16 @@ static const struct counter_count_ext stm32_lptim_cnt_ext[] = {
>  	},
>  };
>  
> -static int stm32_lptim_cnt_action_get(struct counter_device *counter,
> -				      struct counter_count *count,
> -				      struct counter_synapse *synapse,
> -				      size_t *action)
> +static int stm32_lptim_action_get(struct counter_device *counter,
> +				  struct counter_count *count,
> +				  struct counter_synapse *synapse,
> +				  size_t *action)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  	size_t function;
>  	int err;
>  
> -	err = stm32_lptim_cnt_function_get(counter, count, &function);
> +	err = stm32_lptim_function_get(counter, count, &function);
>  	if (err)
>  		return err;
>  
> @@ -333,10 +333,10 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
>  	}
>  }
>  
> -static int stm32_lptim_cnt_action_set(struct counter_device *counter,
> -				      struct counter_count *count,
> -				      struct counter_synapse *synapse,
> -				      size_t action)
> +static int stm32_lptim_action_set(struct counter_device *counter,
> +				  struct counter_count *count,
> +				  struct counter_synapse *synapse,
> +				  size_t action)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  	size_t function;
> @@ -345,7 +345,7 @@ static int stm32_lptim_cnt_action_set(struct counter_device *counter,
>  	if (stm32_lptim_is_enabled(priv))
>  		return -EBUSY;
>  
> -	err = stm32_lptim_cnt_function_get(counter, count, &function);
> +	err = stm32_lptim_function_get(counter, count, &function);
>  	if (err)
>  		return err;
>  
> @@ -366,10 +366,10 @@ static int stm32_lptim_cnt_action_set(struct counter_device *counter,
>  
>  static const struct counter_ops stm32_lptim_cnt_ops = {
>  	.count_read = stm32_lptim_cnt_read,
> -	.function_get = stm32_lptim_cnt_function_get,
> -	.function_set = stm32_lptim_cnt_function_set,
> -	.action_get = stm32_lptim_cnt_action_get,
> -	.action_set = stm32_lptim_cnt_action_set,
> +	.function_get = stm32_lptim_function_get,
> +	.function_set = stm32_lptim_function_set,
> +	.action_get = stm32_lptim_action_get,
> +	.action_set = stm32_lptim_action_set,
>  };
>  
>  static struct counter_signal stm32_lptim_cnt_signals[] = {
> @@ -400,8 +400,8 @@ static struct counter_synapse stm32_lptim_cnt_synapses[] = {
>  static struct counter_count stm32_lptim_enc_counts = {
>  	.id = 0,
>  	.name = "LPTimer Count",
> -	.functions_list = stm32_lptim_cnt_functions,
> -	.num_functions = ARRAY_SIZE(stm32_lptim_cnt_functions),
> +	.functions_list = stm32_lptim_functions,
> +	.num_functions = ARRAY_SIZE(stm32_lptim_functions),
>  	.synapses = stm32_lptim_cnt_synapses,
>  	.num_synapses = ARRAY_SIZE(stm32_lptim_cnt_synapses),
>  	.ext = stm32_lptim_cnt_ext,
> @@ -412,7 +412,7 @@ static struct counter_count stm32_lptim_enc_counts = {
>  static struct counter_count stm32_lptim_in1_counts = {
>  	.id = 0,
>  	.name = "LPTimer Count",
> -	.functions_list = stm32_lptim_cnt_functions,
> +	.functions_list = stm32_lptim_functions,
>  	.num_functions = 1,
>  	.synapses = stm32_lptim_cnt_synapses,
>  	.num_synapses = 1,
> diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> index 431a3d08ed6c..02a7c8bd77df 100644
> --- a/drivers/counter/stm32-timer-cnt.c
> +++ b/drivers/counter/stm32-timer-cnt.c
> @@ -37,23 +37,23 @@ struct stm32_timer_cnt {
>  };
>  
>  /**
> - * enum stm32_count_function - enumerates stm32 timer counter encoder modes
> - * @STM32_COUNT_SLAVE_MODE_DISABLED: counts on internal clock when CEN=1
> - * @STM32_COUNT_ENCODER_MODE_1: counts TI1FP1 edges, depending on TI2FP2 level
> - * @STM32_COUNT_ENCODER_MODE_2: counts TI2FP2 edges, depending on TI1FP1 level
> - * @STM32_COUNT_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
> + * enum stm32_function - enumerates stm32 timer counter encoder modes
> + * @STM32_SLAVE_MODE_DISABLED: counts on internal clock when CEN=1
> + * @STM32_ENCODER_MODE_1: counts TI1FP1 edges, depending on TI2FP2 level
> + * @STM32_ENCODER_MODE_2: counts TI2FP2 edges, depending on TI1FP1 level
> + * @STM32_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
>   */
> -enum stm32_count_function {
> -	STM32_COUNT_SLAVE_MODE_DISABLED = -1,
> -	STM32_COUNT_ENCODER_MODE_1,
> -	STM32_COUNT_ENCODER_MODE_2,
> -	STM32_COUNT_ENCODER_MODE_3,
> +enum stm32_function {
> +	STM32_SLAVE_MODE_DISABLED = -1,
> +	STM32_ENCODER_MODE_1,
> +	STM32_ENCODER_MODE_2,
> +	STM32_ENCODER_MODE_3,
>  };
>  
> -static enum counter_count_function stm32_count_functions[] = {
> -	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> -	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> -	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +static enum counter_function stm32_functions[] = {
> +	[STM32_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X2_A,
> +	[STM32_ENCODER_MODE_2] = COUNTER_FUNCTION_QUADRATURE_X2_B,
> +	[STM32_ENCODER_MODE_3] = COUNTER_FUNCTION_QUADRATURE_X4,
>  };
>  
>  static int stm32_count_read(struct counter_device *counter,
> @@ -80,9 +80,8 @@ static int stm32_count_write(struct counter_device *counter,
>  	return regmap_write(priv->regmap, TIM_CNT, val);
>  }
>  
> -static int stm32_count_function_get(struct counter_device *counter,
> -				    struct counter_count *count,
> -				    size_t *function)
> +static int stm32_function_get(struct counter_device *counter,
> +			      struct counter_count *count, size_t *function)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
>  	u32 smcr;
> @@ -91,34 +90,33 @@ static int stm32_count_function_get(struct counter_device *counter,
>  
>  	switch (smcr & TIM_SMCR_SMS) {
>  	case 1:
> -		*function = STM32_COUNT_ENCODER_MODE_1;
> +		*function = STM32_ENCODER_MODE_1;
>  		return 0;
>  	case 2:
> -		*function = STM32_COUNT_ENCODER_MODE_2;
> +		*function = STM32_ENCODER_MODE_2;
>  		return 0;
>  	case 3:
> -		*function = STM32_COUNT_ENCODER_MODE_3;
> +		*function = STM32_ENCODER_MODE_3;
>  		return 0;
>  	}
>  
>  	return -EINVAL;
>  }
>  
> -static int stm32_count_function_set(struct counter_device *counter,
> -				    struct counter_count *count,
> -				    size_t function)
> +static int stm32_function_set(struct counter_device *counter,
> +			      struct counter_count *count, size_t function)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
>  	u32 cr1, sms;
>  
>  	switch (function) {
> -	case STM32_COUNT_ENCODER_MODE_1:
> +	case STM32_ENCODER_MODE_1:
>  		sms = 1;
>  		break;
> -	case STM32_COUNT_ENCODER_MODE_2:
> +	case STM32_ENCODER_MODE_2:
>  		sms = 2;
>  		break;
> -	case STM32_COUNT_ENCODER_MODE_3:
> +	case STM32_ENCODER_MODE_3:
>  		sms = 3;
>  		break;
>  	default:
> @@ -274,25 +272,25 @@ static int stm32_action_get(struct counter_device *counter,
>  	size_t function;
>  	int err;
>  
> -	/* Default action mode (e.g. STM32_COUNT_SLAVE_MODE_DISABLED) */
> +	/* Default action mode (e.g. STM32_SLAVE_MODE_DISABLED) */
>  	*action = STM32_SYNAPSE_ACTION_NONE;
>  
> -	err = stm32_count_function_get(counter, count, &function);
> +	err = stm32_function_get(counter, count, &function);
>  	if (err)
>  		return 0;
>  
>  	switch (function) {
> -	case STM32_COUNT_ENCODER_MODE_1:
> +	case STM32_ENCODER_MODE_1:
>  		/* counts up/down on TI1FP1 edge depending on TI2FP2 level */
>  		if (synapse->signal->id == count->synapses[0].signal->id)
>  			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> -	case STM32_COUNT_ENCODER_MODE_2:
> +	case STM32_ENCODER_MODE_2:
>  		/* counts up/down on TI2FP2 edge depending on TI1FP1 level */
>  		if (synapse->signal->id == count->synapses[1].signal->id)
>  			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> -	case STM32_COUNT_ENCODER_MODE_3:
> +	case STM32_ENCODER_MODE_3:
>  		/* counts up/down on both TI1FP1 and TI2FP2 edges */
>  		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> @@ -307,8 +305,8 @@ static int stm32_action_get(struct counter_device *counter,
>  static const struct counter_ops stm32_timer_cnt_ops = {
>  	.count_read = stm32_count_read,
>  	.count_write = stm32_count_write,
> -	.function_get = stm32_count_function_get,
> -	.function_set = stm32_count_function_set,
> +	.function_get = stm32_function_get,
> +	.function_set = stm32_function_set,
>  	.action_get = stm32_action_get,
>  };
>  
> @@ -339,8 +337,8 @@ static struct counter_synapse stm32_count_synapses[] = {
>  static struct counter_count stm32_counts = {
>  	.id = 0,
>  	.name = "Channel 1 Count",
> -	.functions_list = stm32_count_functions,
> -	.num_functions = ARRAY_SIZE(stm32_count_functions),
> +	.functions_list = stm32_functions,
> +	.num_functions = ARRAY_SIZE(stm32_functions),
>  	.synapses = stm32_count_synapses,
>  	.num_synapses = ARRAY_SIZE(stm32_count_synapses),
>  	.ext = stm32_count_ext,
> diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
> index 7844fdf78a97..8d45b0443610 100644
> --- a/drivers/counter/ti-eqep.c
> +++ b/drivers/counter/ti-eqep.c
> @@ -73,11 +73,11 @@ enum {
>  };
>  
>  /* Position Counter Input Modes */
> -enum {
> -	TI_EQEP_COUNT_FUNC_QUAD_COUNT,
> -	TI_EQEP_COUNT_FUNC_DIR_COUNT,
> -	TI_EQEP_COUNT_FUNC_UP_COUNT,
> -	TI_EQEP_COUNT_FUNC_DOWN_COUNT,
> +enum ti_eqep_function {
> +	TI_EQEP_FUNCTION_QUAD_COUNT,
> +	TI_EQEP_FUNCTION_DIR_COUNT,
> +	TI_EQEP_FUNCTION_UP_COUNT,
> +	TI_EQEP_FUNCTION_DOWN_COUNT,
>  };
>  
>  enum {
> @@ -152,13 +152,13 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  		return err;
>  
>  	switch (function) {
> -	case TI_EQEP_COUNT_FUNC_QUAD_COUNT:
> +	case TI_EQEP_FUNCTION_QUAD_COUNT:
>  		/* In quadrature mode, the rising and falling edge of both
>  		 * QEPA and QEPB trigger QCLK.
>  		 */
>  		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> -	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
> +	case TI_EQEP_FUNCTION_DIR_COUNT:
>  		/* In direction-count mode only rising edge of QEPA is counted
>  		 * and QEPB gives direction.
>  		 */
> @@ -171,8 +171,8 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  			break;
>  		}
>  		break;
> -	case TI_EQEP_COUNT_FUNC_UP_COUNT:
> -	case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
> +	case TI_EQEP_FUNCTION_UP_COUNT:
> +	case TI_EQEP_FUNCTION_DOWN_COUNT:
>  		/* In up/down-count modes only QEPA is counted and QEPB is not
>  		 * used.
>  		 */
> @@ -327,11 +327,11 @@ static struct counter_signal ti_eqep_signals[] = {
>  	},
>  };
>  
> -static const enum counter_count_function ti_eqep_position_functions[] = {
> -	[TI_EQEP_COUNT_FUNC_QUAD_COUNT]	= COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> -	[TI_EQEP_COUNT_FUNC_DIR_COUNT]	= COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> -	[TI_EQEP_COUNT_FUNC_UP_COUNT]	= COUNTER_COUNT_FUNCTION_INCREASE,
> -	[TI_EQEP_COUNT_FUNC_DOWN_COUNT]	= COUNTER_COUNT_FUNCTION_DECREASE,
> +static const enum counter_function ti_eqep_position_functions[] = {
> +	[TI_EQEP_FUNCTION_QUAD_COUNT]	= COUNTER_FUNCTION_QUADRATURE_X4,
> +	[TI_EQEP_FUNCTION_DIR_COUNT]	= COUNTER_FUNCTION_PULSE_DIRECTION,
> +	[TI_EQEP_FUNCTION_UP_COUNT]	= COUNTER_FUNCTION_INCREASE,
> +	[TI_EQEP_FUNCTION_DOWN_COUNT]	= COUNTER_FUNCTION_DECREASE,
>  };
>  
>  static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
> diff --git a/include/linux/counter.h b/include/linux/counter.h
> index 79f5dcaf6ba0..d16ce2819b48 100644
> --- a/include/linux/counter.h
> +++ b/include/linux/counter.h
> @@ -162,15 +162,15 @@ struct counter_count_ext {
>  	void *priv;
>  };
>  
> -enum counter_count_function {
> -	COUNTER_COUNT_FUNCTION_INCREASE = 0,
> -	COUNTER_COUNT_FUNCTION_DECREASE,
> -	COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +enum counter_function {
> +	COUNTER_FUNCTION_INCREASE = 0,
> +	COUNTER_FUNCTION_DECREASE,
> +	COUNTER_FUNCTION_PULSE_DIRECTION,
> +	COUNTER_FUNCTION_QUADRATURE_X1_A,
> +	COUNTER_FUNCTION_QUADRATURE_X1_B,
> +	COUNTER_FUNCTION_QUADRATURE_X2_A,
> +	COUNTER_FUNCTION_QUADRATURE_X2_B,
> +	COUNTER_FUNCTION_QUADRATURE_X4
>  };
>  
>  /**
> @@ -192,7 +192,7 @@ struct counter_count {
>  	const char *name;
>  
>  	size_t function;
> -	const enum counter_count_function *functions_list;
> +	const enum counter_function *functions_list;
>  	size_t num_functions;
>  
>  	struct counter_synapse *synapses;

Re: [PATCH v8 12/22] counter: Rename counter_count_function to counter_function

[David Lechner]

On 2/14/21 11:13 AM, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:36 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
>> The phrase "Counter Count function" is verbose and unintentionally
>> implies that function is a Count extension. This patch adjusts the
>> Counter subsystem code to use the more direct "Counter function" phrase
>> to make the intent of this code clearer. The phrase "Count action" is
>> adjusted herein as well for the same reason.
>>
>> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
>> Cc: Patrick Havelange <patrick.havelange@essensium.com>
>> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
>> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
>> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
>> Cc: Alexandre Torgue <alexandre.torgue@st.com>
>> Cc: David Lechner <david@lechnology.com>
>> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> 
> I agree this makes sense in the counter core code, but in the drivers
> it may not be quite so obvious we are talking about a counter function
> given some of the bits of hardware do a number of other things.
> 
> I guess up to the various driver maintainers on whether they
> think the new meaning is clear enough!
> 
> Jonathan
> 

TBH, I think "counter count function" makes more sense to me.

Re: [PATCH v8 12/22] counter: Rename counter_count_function to counter_function

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 1685 bytes --]

On Sat, Feb 20, 2021 at 10:56:13AM -0600, David Lechner wrote:
> On 2/14/21 11:13 AM, Jonathan Cameron wrote:
> > On Fri, 12 Feb 2021 21:13:36 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > 
> >> The phrase "Counter Count function" is verbose and unintentionally
> >> implies that function is a Count extension. This patch adjusts the
> >> Counter subsystem code to use the more direct "Counter function" phrase
> >> to make the intent of this code clearer. The phrase "Count action" is
> >> adjusted herein as well for the same reason.
> >>
> >> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> >> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> >> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> >> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> >> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> >> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> >> Cc: David Lechner <david@lechnology.com>
> >> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > 
> > I agree this makes sense in the counter core code, but in the drivers
> > it may not be quite so obvious we are talking about a counter function
> > given some of the bits of hardware do a number of other things.
> > 
> > I guess up to the various driver maintainers on whether they
> > think the new meaning is clear enough!
> > 
> > Jonathan
> > 
> 
> TBH, I think "counter count function" makes more sense to me.

That's a fair point. I'll revert this for the individual drivers and
leave it up to the maintainers if they want to adjust their namings.
Instead, I'll limit the name changes to the counter core code.

William Breathitt Gray


[-- Attachment #2: signature.asc --]
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[PATCH v8 13/22] counter: Internalize sysfs interface code

[William Breathitt Gray]

This is a reimplementation of the Generic Counter driver interface.
There are no modifications to the Counter subsystem userspace interface,
so existing userspace applications should continue to run seamlessly.

The purpose of this patch is to internalize the sysfs interface code
among the various counter drivers into a shared module. Counter drivers
pass and take data natively (i.e. u8, u64, etc.) and the shared counter
module handles the translation between the sysfs interface and the
device drivers. This guarantees a standard userspace interface for all
counter drivers, and helps generalize the Generic Counter driver ABI in
order to support the Generic Counter chrdev interface (introduced in a
subsequent patch) without significant changes to the existing counter
drivers.

Note, Counter device registration is the same as before: drivers
populate a struct counter_device with components and callbacks, then
pass the structure to the devm_counter_register function. However,
what's different now is how the Counter subsystem code handles this
registration internally.

Whereas before callbacks would interact directly with sysfs data, this
interaction is now abstracted and instead callbacks interact with native
C data types. The counter_comp structure forms the basis for Counter
extensions.

The counter-sysfs.c file contains the code to parse through the
counter_device structure and register the requested components and
extensions. Attributes are created and populated based on type, with
respective translation functions to handle the mapping between sysfs and
the counter driver callbacks.

The translation performed for each attribute is straightforward: the
attribute type and data is parsed from the counter_attribute structure,
the respective counter driver read/write callback is called, and sysfs
I/O is handled before or after the driver read/write function is called.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: David Lechner <david@lechnology.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 MAINTAINERS                             |    1 -
 drivers/counter/104-quad-8.c            |  449 +++----
 drivers/counter/Makefile                |    1 +
 drivers/counter/counter-core.c          |  153 +++
 drivers/counter/counter-sysfs.c         |  833 +++++++++++++
 drivers/counter/counter-sysfs.h         |   13 +
 drivers/counter/counter.c               | 1496 -----------------------
 drivers/counter/ftm-quaddec.c           |   56 +-
 drivers/counter/microchip-tcb-capture.c |   87 +-
 drivers/counter/stm32-lptimer-cnt.c     |  164 ++-
 drivers/counter/stm32-timer-cnt.c       |  142 +--
 drivers/counter/ti-eqep.c               |  211 ++--
 include/linux/counter.h                 |  631 +++++-----
 include/linux/counter_enum.h            |   45 -
 14 files changed, 1816 insertions(+), 2466 deletions(-)
 create mode 100644 drivers/counter/counter-core.c
 create mode 100644 drivers/counter/counter-sysfs.c
 create mode 100644 drivers/counter/counter-sysfs.h
 delete mode 100644 drivers/counter/counter.c
 delete mode 100644 include/linux/counter_enum.h

diff --git a/MAINTAINERS b/MAINTAINERS
index d858582c917b..94a19606d947 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4543,7 +4543,6 @@ F:	Documentation/ABI/testing/sysfs-bus-counter
 F:	Documentation/driver-api/generic-counter.rst
 F:	drivers/counter/
 F:	include/linux/counter.h
-F:	include/linux/counter_enum.h
 
 CPMAC ETHERNET DRIVER
 M:	Florian Fainelli <f.fainelli@gmail.com>
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index eca3f6482719..41fdbd228be3 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -116,7 +116,7 @@ static int quad8_signal_read(struct counter_device *counter,
 }
 
 static int quad8_count_read(struct counter_device *counter,
-	struct counter_count *count, unsigned long *val)
+			    struct counter_count *count, u64 *val)
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id;
@@ -147,7 +147,7 @@ static int quad8_count_read(struct counter_device *counter,
 }
 
 static int quad8_count_write(struct counter_device *counter,
-	struct counter_count *count, unsigned long val)
+			     struct counter_count *count, u64 val)
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id;
@@ -187,22 +187,16 @@ static int quad8_count_write(struct counter_device *counter,
 	return 0;
 }
 
-enum quad8_function {
-	QUAD8_FUNCTION_PULSE_DIRECTION = 0,
-	QUAD8_FUNCTION_QUADRATURE_X1,
-	QUAD8_FUNCTION_QUADRATURE_X2,
-	QUAD8_FUNCTION_QUADRATURE_X4
-};
-
 static const enum counter_function quad8_functions_list[] = {
-	[QUAD8_FUNCTION_PULSE_DIRECTION] = COUNTER_FUNCTION_PULSE_DIRECTION,
-	[QUAD8_FUNCTION_QUADRATURE_X1] = COUNTER_FUNCTION_QUADRATURE_X1_A,
-	[QUAD8_FUNCTION_QUADRATURE_X2] = COUNTER_FUNCTION_QUADRATURE_X2_A,
-	[QUAD8_FUNCTION_QUADRATURE_X4] = COUNTER_FUNCTION_QUADRATURE_X4
+	COUNTER_FUNCTION_PULSE_DIRECTION,
+	COUNTER_FUNCTION_QUADRATURE_X1_A,
+	COUNTER_FUNCTION_QUADRATURE_X2_A,
+	COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
-static int quad8_function_get(struct counter_device *counter,
-	struct counter_count *count, size_t *function)
+static int quad8_function_read(struct counter_device *counter,
+			       struct counter_count *count,
+			       enum counter_function *function)
 {
 	struct quad8 *const priv = counter->priv;
 	const int id = count->id;
@@ -212,25 +206,26 @@ static int quad8_function_get(struct counter_device *counter,
 	if (priv->quadrature_mode[id])
 		switch (priv->quadrature_scale[id]) {
 		case 0:
-			*function = QUAD8_FUNCTION_QUADRATURE_X1;
+			*function = COUNTER_FUNCTION_QUADRATURE_X1_A;
 			break;
 		case 1:
-			*function = QUAD8_FUNCTION_QUADRATURE_X2;
+			*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
 			break;
 		case 2:
-			*function = QUAD8_FUNCTION_QUADRATURE_X4;
+			*function = COUNTER_FUNCTION_QUADRATURE_X4;
 			break;
 		}
 	else
-		*function = QUAD8_FUNCTION_PULSE_DIRECTION;
+		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
 
 	mutex_unlock(&priv->lock);
 
 	return 0;
 }
 
-static int quad8_function_set(struct counter_device *counter,
-	struct counter_count *count, size_t function)
+static int quad8_function_write(struct counter_device *counter,
+				struct counter_count *count,
+				enum counter_function function)
 {
 	struct quad8 *const priv = counter->priv;
 	const int id = count->id;
@@ -246,7 +241,7 @@ static int quad8_function_set(struct counter_device *counter,
 	mode_cfg = priv->count_mode[id] << 1;
 	idr_cfg = priv->index_polarity[id] << 1;
 
-	if (function == QUAD8_FUNCTION_PULSE_DIRECTION) {
+	if (function == COUNTER_FUNCTION_PULSE_DIRECTION) {
 		*quadrature_mode = 0;
 
 		/* Quadrature scaling only available in quadrature mode */
@@ -262,15 +257,15 @@ static int quad8_function_set(struct counter_device *counter,
 		*quadrature_mode = 1;
 
 		switch (function) {
-		case QUAD8_FUNCTION_QUADRATURE_X1:
+		case COUNTER_FUNCTION_QUADRATURE_X1_A:
 			*scale = 0;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
 			break;
-		case QUAD8_FUNCTION_QUADRATURE_X2:
+		case COUNTER_FUNCTION_QUADRATURE_X2_A:
 			*scale = 1;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X2;
 			break;
-		case QUAD8_FUNCTION_QUADRATURE_X4:
+		case COUNTER_FUNCTION_QUADRATURE_X4:
 			*scale = 2;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
 			break;
@@ -289,8 +284,9 @@ static int quad8_function_set(struct counter_device *counter,
 	return 0;
 }
 
-static void quad8_direction_get(struct counter_device *counter,
-	struct counter_count *count, enum counter_count_direction *direction)
+static int quad8_direction_read(struct counter_device *counter,
+				struct counter_count *count,
+				enum counter_count_direction *direction)
 {
 	const struct quad8 *const priv = counter->priv;
 	unsigned int ud_flag;
@@ -301,76 +297,74 @@ static void quad8_direction_get(struct counter_device *counter,
 
 	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
 		COUNTER_COUNT_DIRECTION_BACKWARD;
-}
 
-enum quad8_synapse_action {
-	QUAD8_SYNAPSE_ACTION_NONE = 0,
-	QUAD8_SYNAPSE_ACTION_RISING_EDGE,
-	QUAD8_SYNAPSE_ACTION_FALLING_EDGE,
-	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
-};
+	return 0;
+}
 
 static const enum counter_synapse_action quad8_index_actions_list[] = {
-	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
-	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 };
 
 static const enum counter_synapse_action quad8_synapse_actions_list[] = {
-	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
-	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
-	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
-	[QUAD8_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
 };
 
-static int quad8_action_get(struct counter_device *counter,
-	struct counter_count *count, struct counter_synapse *synapse,
-	size_t *action)
+static int quad8_action_read(struct counter_device *counter,
+			     struct counter_count *count,
+			     struct counter_synapse *synapse,
+			     enum counter_synapse_action *action)
 {
 	struct quad8 *const priv = counter->priv;
 	int err;
-	size_t function = 0;
+	enum counter_function function;
 	const size_t signal_a_id = count->synapses[0].signal->id;
 	enum counter_count_direction direction;
 
 	/* Handle Index signals */
 	if (synapse->signal->id >= 16) {
 		if (priv->preset_enable[count->id])
-			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
+			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 		else
-			*action = QUAD8_SYNAPSE_ACTION_NONE;
+			*action = COUNTER_SYNAPSE_ACTION_NONE;
 
 		return 0;
 	}
 
-	err = quad8_function_get(counter, count, &function);
+	err = quad8_function_read(counter, count, &function);
 	if (err)
 		return err;
 
 	/* Default action mode */
-	*action = QUAD8_SYNAPSE_ACTION_NONE;
+	*action = COUNTER_SYNAPSE_ACTION_NONE;
 
 	/* Determine action mode based on current count function mode */
 	switch (function) {
-	case QUAD8_FUNCTION_PULSE_DIRECTION:
+	case COUNTER_FUNCTION_PULSE_DIRECTION:
 		if (synapse->signal->id == signal_a_id)
-			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
+			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 		break;
-	case QUAD8_FUNCTION_QUADRATURE_X1:
+	case COUNTER_FUNCTION_QUADRATURE_X1_A:
 		if (synapse->signal->id == signal_a_id) {
-			quad8_direction_get(counter, count, &direction);
+			err = quad8_direction_read(counter, count, &direction);
+			if (err)
+				return err;
 
 			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
-				*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
+				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 			else
-				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
+				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
 		}
 		break;
-	case QUAD8_FUNCTION_QUADRATURE_X2:
+	case COUNTER_FUNCTION_QUADRATURE_X2_A:
 		if (synapse->signal->id == signal_a_id)
-			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
+			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
-	case QUAD8_FUNCTION_QUADRATURE_X4:
-		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
+	case COUNTER_FUNCTION_QUADRATURE_X4:
+		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	default:
 		/* should never reach this path */
@@ -384,9 +378,9 @@ static const struct counter_ops quad8_ops = {
 	.signal_read = quad8_signal_read,
 	.count_read = quad8_count_read,
 	.count_write = quad8_count_write,
-	.function_get = quad8_function_get,
-	.function_set = quad8_function_set,
-	.action_get = quad8_action_get
+	.function_read = quad8_function_read,
+	.function_write = quad8_function_write,
+	.action_read = quad8_action_read
 };
 
 static const char *const quad8_index_polarity_modes[] = {
@@ -395,7 +389,8 @@ static const char *const quad8_index_polarity_modes[] = {
 };
 
 static int quad8_index_polarity_get(struct counter_device *counter,
-	struct counter_signal *signal, size_t *index_polarity)
+				    struct counter_signal *signal,
+				    u32 *index_polarity)
 {
 	const struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id - 16;
@@ -406,7 +401,8 @@ static int quad8_index_polarity_get(struct counter_device *counter,
 }
 
 static int quad8_index_polarity_set(struct counter_device *counter,
-	struct counter_signal *signal, size_t index_polarity)
+				    struct counter_signal *signal,
+				    u32 index_polarity)
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id - 16;
@@ -427,20 +423,14 @@ static int quad8_index_polarity_set(struct counter_device *counter,
 	return 0;
 }
 
-static struct counter_signal_enum_ext quad8_index_pol_enum = {
-	.items = quad8_index_polarity_modes,
-	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
-	.get = quad8_index_polarity_get,
-	.set = quad8_index_polarity_set
-};
-
 static const char *const quad8_synchronous_modes[] = {
 	"non-synchronous",
 	"synchronous"
 };
 
 static int quad8_synchronous_mode_get(struct counter_device *counter,
-	struct counter_signal *signal, size_t *synchronous_mode)
+				      struct counter_signal *signal,
+				      u32 *synchronous_mode)
 {
 	const struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id - 16;
@@ -451,7 +441,8 @@ static int quad8_synchronous_mode_get(struct counter_device *counter,
 }
 
 static int quad8_synchronous_mode_set(struct counter_device *counter,
-	struct counter_signal *signal, size_t synchronous_mode)
+				      struct counter_signal *signal,
+				      u32 synchronous_mode)
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id - 16;
@@ -478,22 +469,18 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
 	return 0;
 }
 
-static struct counter_signal_enum_ext quad8_syn_mode_enum = {
-	.items = quad8_synchronous_modes,
-	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
-	.get = quad8_synchronous_mode_get,
-	.set = quad8_synchronous_mode_set
-};
-
-static ssize_t quad8_count_floor_read(struct counter_device *counter,
-	struct counter_count *count, void *private, char *buf)
+static int quad8_count_floor_read(struct counter_device *counter,
+				  struct counter_count *count, u64 *floor)
 {
 	/* Only a floor of 0 is supported */
-	return sprintf(buf, "0\n");
+	*floor = 0;
+
+	return 0;
 }
 
-static int quad8_count_mode_get(struct counter_device *counter,
-	struct counter_count *count, size_t *cnt_mode)
+static int quad8_count_mode_read(struct counter_device *counter,
+				 struct counter_count *count,
+				 enum counter_count_mode *cnt_mode)
 {
 	const struct quad8 *const priv = counter->priv;
 
@@ -516,26 +503,28 @@ static int quad8_count_mode_get(struct counter_device *counter,
 	return 0;
 }
 
-static int quad8_count_mode_set(struct counter_device *counter,
-	struct counter_count *count, size_t cnt_mode)
+static int quad8_count_mode_write(struct counter_device *counter,
+				  struct counter_count *count,
+				  enum counter_count_mode cnt_mode)
 {
 	struct quad8 *const priv = counter->priv;
+	unsigned int count_mode;
 	unsigned int mode_cfg;
 	const int base_offset = priv->base + 2 * count->id + 1;
 
 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
 	switch (cnt_mode) {
 	case COUNTER_COUNT_MODE_NORMAL:
-		cnt_mode = 0;
+		count_mode = 0;
 		break;
 	case COUNTER_COUNT_MODE_RANGE_LIMIT:
-		cnt_mode = 1;
+		count_mode = 1;
 		break;
 	case COUNTER_COUNT_MODE_NON_RECYCLE:
-		cnt_mode = 2;
+		count_mode = 2;
 		break;
 	case COUNTER_COUNT_MODE_MODULO_N:
-		cnt_mode = 3;
+		count_mode = 3;
 		break;
 	default:
 		/* should never reach this path */
@@ -544,10 +533,10 @@ static int quad8_count_mode_set(struct counter_device *counter,
 
 	mutex_lock(&priv->lock);
 
-	priv->count_mode[count->id] = cnt_mode;
+	priv->count_mode[count->id] = count_mode;
 
 	/* Set count mode configuration value */
-	mode_cfg = cnt_mode << 1;
+	mode_cfg = count_mode << 1;
 
 	/* Add quadrature mode configuration */
 	if (priv->quadrature_mode[count->id])
@@ -561,56 +550,35 @@ static int quad8_count_mode_set(struct counter_device *counter,
 	return 0;
 }
 
-static struct counter_count_enum_ext quad8_cnt_mode_enum = {
-	.items = counter_count_mode_str,
-	.num_items = ARRAY_SIZE(counter_count_mode_str),
-	.get = quad8_count_mode_get,
-	.set = quad8_count_mode_set
-};
-
-static ssize_t quad8_count_direction_read(struct counter_device *counter,
-	struct counter_count *count, void *priv, char *buf)
-{
-	enum counter_count_direction dir;
-
-	quad8_direction_get(counter, count, &dir);
-
-	return sprintf(buf, "%s\n", counter_count_direction_str[dir]);
-}
-
-static ssize_t quad8_count_enable_read(struct counter_device *counter,
-	struct counter_count *count, void *private, char *buf)
+static int quad8_count_enable_read(struct counter_device *counter,
+				   struct counter_count *count, u8 *enable)
 {
 	const struct quad8 *const priv = counter->priv;
 
-	return sprintf(buf, "%u\n", priv->ab_enable[count->id]);
+	*enable = priv->ab_enable[count->id];
+
+	return 0;
 }
 
-static ssize_t quad8_count_enable_write(struct counter_device *counter,
-	struct counter_count *count, void *private, const char *buf, size_t len)
+static int quad8_count_enable_write(struct counter_device *counter,
+				    struct counter_count *count, u8 enable)
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id;
-	int err;
-	bool ab_enable;
 	unsigned int ior_cfg;
 
-	err = kstrtobool(buf, &ab_enable);
-	if (err)
-		return err;
-
 	mutex_lock(&priv->lock);
 
-	priv->ab_enable[count->id] = ab_enable;
+	priv->ab_enable[count->id] = enable;
 
-	ior_cfg = ab_enable | priv->preset_enable[count->id] << 1;
+	ior_cfg = enable | priv->preset_enable[count->id] << 1;
 
 	/* Load I/O control configuration */
 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return 0;
 }
 
 static const char *const quad8_noise_error_states[] = {
@@ -619,7 +587,7 @@ static const char *const quad8_noise_error_states[] = {
 };
 
 static int quad8_error_noise_get(struct counter_device *counter,
-	struct counter_count *count, size_t *noise_error)
+				 struct counter_count *count, u32 *noise_error)
 {
 	const struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id + 1;
@@ -629,18 +597,14 @@ static int quad8_error_noise_get(struct counter_device *counter,
 	return 0;
 }
 
-static struct counter_count_enum_ext quad8_error_noise_enum = {
-	.items = quad8_noise_error_states,
-	.num_items = ARRAY_SIZE(quad8_noise_error_states),
-	.get = quad8_error_noise_get
-};
-
-static ssize_t quad8_count_preset_read(struct counter_device *counter,
-	struct counter_count *count, void *private, char *buf)
+static int quad8_count_preset_read(struct counter_device *counter,
+				   struct counter_count *count, u64 *preset)
 {
 	const struct quad8 *const priv = counter->priv;
 
-	return sprintf(buf, "%u\n", priv->preset[count->id]);
+	*preset = priv->preset[count->id];
+
+	return 0;
 }
 
 static void quad8_preset_register_set(struct quad8 *const priv, const int id,
@@ -659,16 +623,10 @@ static void quad8_preset_register_set(struct quad8 *const priv, const int id,
 		outb(preset >> (8 * i), base_offset);
 }
 
-static ssize_t quad8_count_preset_write(struct counter_device *counter,
-	struct counter_count *count, void *private, const char *buf, size_t len)
+static int quad8_count_preset_write(struct counter_device *counter,
+				    struct counter_count *count, u64 preset)
 {
 	struct quad8 *const priv = counter->priv;
-	unsigned int preset;
-	int ret;
-
-	ret = kstrtouint(buf, 0, &preset);
-	if (ret)
-		return ret;
 
 	/* Only 24-bit values are supported */
 	if (preset > 0xFFFFFF)
@@ -680,11 +638,11 @@ static ssize_t quad8_count_preset_write(struct counter_device *counter,
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return 0;
 }
 
-static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
-	struct counter_count *count, void *private, char *buf)
+static int quad8_count_ceiling_read(struct counter_device *counter,
+				    struct counter_count *count, u64 *ceiling)
 {
 	struct quad8 *const priv = counter->priv;
 
@@ -694,26 +652,23 @@ static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
 	switch (priv->count_mode[count->id]) {
 	case 1:
 	case 3:
-		mutex_unlock(&priv->lock);
-		return sprintf(buf, "%u\n", priv->preset[count->id]);
+		*ceiling = priv->preset[count->id];
+		break;
+	default:
+		/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
+		*ceiling = 0x1FFFFFF;
+		break;
 	}
 
 	mutex_unlock(&priv->lock);
 
-	/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
-	return sprintf(buf, "33554431\n");
+	return 0;
 }
 
-static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
-	struct counter_count *count, void *private, const char *buf, size_t len)
+static int quad8_count_ceiling_write(struct counter_device *counter,
+				     struct counter_count *count, u64 ceiling)
 {
 	struct quad8 *const priv = counter->priv;
-	unsigned int ceiling;
-	int ret;
-
-	ret = kstrtouint(buf, 0, &ceiling);
-	if (ret)
-		return ret;
 
 	/* Only 24-bit values are supported */
 	if (ceiling > 0xFFFFFF)
@@ -727,7 +682,7 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
 	case 3:
 		mutex_unlock(&priv->lock);
 		quad8_preset_register_set(priv, count->id, ceiling);
-		return len;
+		return 0;
 	}
 
 	mutex_unlock(&priv->lock);
@@ -735,27 +690,25 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
 	return -EINVAL;
 }
 
-static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
-	struct counter_count *count, void *private, char *buf)
+static int quad8_count_preset_enable_read(struct counter_device *counter,
+					  struct counter_count *count,
+					  u8 *preset_enable)
 {
 	const struct quad8 *const priv = counter->priv;
 
-	return sprintf(buf, "%u\n", !priv->preset_enable[count->id]);
+	*preset_enable = !priv->preset_enable[count->id];
+
+	return 0;
 }
 
-static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
-	struct counter_count *count, void *private, const char *buf, size_t len)
+static int quad8_count_preset_enable_write(struct counter_device *counter,
+					   struct counter_count *count,
+					   u8 preset_enable)
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id + 1;
-	bool preset_enable;
-	int ret;
 	unsigned int ior_cfg;
 
-	ret = kstrtobool(buf, &preset_enable);
-	if (ret)
-		return ret;
-
 	/* Preset enable is active low in Input/Output Control register */
 	preset_enable = !preset_enable;
 
@@ -763,25 +716,24 @@ static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
 
 	priv->preset_enable[count->id] = preset_enable;
 
-	ior_cfg = priv->ab_enable[count->id] | (unsigned int)preset_enable << 1;
+	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1;
 
 	/* Load I/O control configuration to Input / Output Control Register */
 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return 0;
 }
 
-static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
-					     struct counter_signal *signal,
-					     void *private, char *buf)
+static int quad8_signal_cable_fault_read(struct counter_device *counter,
+					 struct counter_signal *signal,
+					 u8 *cable_fault)
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
 	bool disabled;
 	unsigned int status;
-	unsigned int fault;
 
 	mutex_lock(&priv->lock);
 
@@ -798,36 +750,31 @@ static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
 	mutex_unlock(&priv->lock);
 
 	/* Mask respective channel and invert logic */
-	fault = !(status & BIT(channel_id));
+	*cable_fault = !(status & BIT(channel_id));
 
-	return sprintf(buf, "%u\n", fault);
+	return 0;
 }
 
-static ssize_t quad8_signal_cable_fault_enable_read(
-	struct counter_device *counter, struct counter_signal *signal,
-	void *private, char *buf)
+static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
+						struct counter_signal *signal,
+						u8 *enable)
 {
 	const struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
-	const unsigned int enb = !!(priv->cable_fault_enable & BIT(channel_id));
 
-	return sprintf(buf, "%u\n", enb);
+	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
+
+	return 0;
 }
 
-static ssize_t quad8_signal_cable_fault_enable_write(
-	struct counter_device *counter, struct counter_signal *signal,
-	void *private, const char *buf, size_t len)
+static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
+						 struct counter_signal *signal,
+						 u8 enable)
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
-	bool enable;
-	int ret;
 	unsigned int cable_fault_enable;
 
-	ret = kstrtobool(buf, &enable);
-	if (ret)
-		return ret;
-
 	mutex_lock(&priv->lock);
 
 	if (enable)
@@ -842,31 +789,27 @@ static ssize_t quad8_signal_cable_fault_enable_write(
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return 0;
 }
 
-static ssize_t quad8_signal_fck_prescaler_read(struct counter_device *counter,
-	struct counter_signal *signal, void *private, char *buf)
+static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
+					   struct counter_signal *signal,
+					   u8 *prescaler)
 {
 	const struct quad8 *const priv = counter->priv;
-	const size_t channel_id = signal->id / 2;
 
-	return sprintf(buf, "%u\n", priv->fck_prescaler[channel_id]);
+	*prescaler = priv->fck_prescaler[signal->id / 2];
+
+	return 0;
 }
 
-static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
-	struct counter_signal *signal, void *private, const char *buf,
-	size_t len)
+static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
+					    struct counter_signal *signal,
+					    u8 prescaler)
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
 	const int base_offset = priv->base + 2 * channel_id;
-	u8 prescaler;
-	int ret;
-
-	ret = kstrtou8(buf, 0, &prescaler);
-	if (ret)
-		return ret;
 
 	mutex_lock(&priv->lock);
 
@@ -882,31 +825,30 @@ static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return 0;
 }
 
-static const struct counter_signal_ext quad8_signal_ext[] = {
-	{
-		.name = "cable_fault",
-		.read = quad8_signal_cable_fault_read
-	},
-	{
-		.name = "cable_fault_enable",
-		.read = quad8_signal_cable_fault_enable_read,
-		.write = quad8_signal_cable_fault_enable_write
-	},
-	{
-		.name = "filter_clock_prescaler",
-		.read = quad8_signal_fck_prescaler_read,
-		.write = quad8_signal_fck_prescaler_write
-	}
+static struct counter_comp quad8_signal_ext[] = {
+	COUNTER_COMP_SIGNAL_BOOL("cable_fault", quad8_signal_cable_fault_read,
+				 NULL),
+	COUNTER_COMP_SIGNAL_BOOL("cable_fault_enable",
+				 quad8_signal_cable_fault_enable_read,
+				 quad8_signal_cable_fault_enable_write),
+	COUNTER_COMP_SIGNAL_U8("filter_clock_prescaler",
+			       quad8_signal_fck_prescaler_read,
+			       quad8_signal_fck_prescaler_write)
 };
 
-static const struct counter_signal_ext quad8_index_ext[] = {
-	COUNTER_SIGNAL_ENUM("index_polarity", &quad8_index_pol_enum),
-	COUNTER_SIGNAL_ENUM_AVAILABLE("index_polarity",	&quad8_index_pol_enum),
-	COUNTER_SIGNAL_ENUM("synchronous_mode", &quad8_syn_mode_enum),
-	COUNTER_SIGNAL_ENUM_AVAILABLE("synchronous_mode", &quad8_syn_mode_enum)
+static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
+static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
+
+static struct counter_comp quad8_index_ext[] = {
+	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
+				 quad8_index_polarity_set,
+				 quad8_index_pol_enum),
+	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
+				 quad8_synchronous_mode_set,
+				 quad8_synch_mode_enum),
 };
 
 #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
@@ -975,39 +917,30 @@ static struct counter_synapse quad8_count_synapses[][3] = {
 	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
 };
 
-static const struct counter_count_ext quad8_count_ext[] = {
-	{
-		.name = "ceiling",
-		.read = quad8_count_ceiling_read,
-		.write = quad8_count_ceiling_write
-	},
-	{
-		.name = "floor",
-		.read = quad8_count_floor_read
-	},
-	COUNTER_COUNT_ENUM("count_mode", &quad8_cnt_mode_enum),
-	COUNTER_COUNT_ENUM_AVAILABLE("count_mode", &quad8_cnt_mode_enum),
-	{
-		.name = "direction",
-		.read = quad8_count_direction_read
-	},
-	{
-		.name = "enable",
-		.read = quad8_count_enable_read,
-		.write = quad8_count_enable_write
-	},
-	COUNTER_COUNT_ENUM("error_noise", &quad8_error_noise_enum),
-	COUNTER_COUNT_ENUM_AVAILABLE("error_noise", &quad8_error_noise_enum),
-	{
-		.name = "preset",
-		.read = quad8_count_preset_read,
-		.write = quad8_count_preset_write
-	},
-	{
-		.name = "preset_enable",
-		.read = quad8_count_preset_enable_read,
-		.write = quad8_count_preset_enable_write
-	}
+static const enum counter_count_mode quad8_cnt_modes[] = {
+	COUNTER_COUNT_MODE_NORMAL,
+	COUNTER_COUNT_MODE_RANGE_LIMIT,
+	COUNTER_COUNT_MODE_NON_RECYCLE,
+	COUNTER_COUNT_MODE_MODULO_N,
+};
+
+static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
+
+static DEFINE_COUNTER_ENUM(quad8_error_noise_enum, quad8_noise_error_states);
+
+static struct counter_comp quad8_count_ext[] = {
+	COUNTER_COMP_CEILING(quad8_count_ceiling_read,
+			     quad8_count_ceiling_write),
+	COUNTER_COMP_FLOOR(quad8_count_floor_read, NULL),
+	COUNTER_COMP_COUNT_MODE(quad8_count_mode_read, quad8_count_mode_write,
+				quad8_count_mode_available),
+	COUNTER_COMP_DIRECTION(quad8_direction_read),
+	COUNTER_COMP_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
+	COUNTER_COMP_COUNT_ENUM("error_noise", quad8_error_noise_get, NULL,
+				quad8_error_noise_enum),
+	COUNTER_COMP_PRESET(quad8_count_preset_read, quad8_count_preset_write),
+	COUNTER_COMP_PRESET_ENABLE(quad8_count_preset_enable_read,
+				   quad8_count_preset_enable_write),
 };
 
 #define QUAD8_COUNT(_id, _cntname) {				\
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 0a393f71e481..cbe1d06af6a9 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_COUNTER) += counter.o
+counter-y := counter-core.o counter-sysfs.o
 
 obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
 obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
new file mode 100644
index 000000000000..1577a6562cad
--- /dev/null
+++ b/drivers/counter/counter-core.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/gfp.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+#include "counter-sysfs.h"
+
+/* Provides a unique ID for each counter device */
+static DEFINE_IDA(counter_ida);
+
+static void counter_device_release(struct device *dev)
+{
+	struct counter_device *const counter = dev_get_drvdata(dev);
+
+	counter_chrdev_remove(counter);
+	ida_simple_remove(&counter_ida, counter->id);
+}
+
+static struct device_type counter_device_type = {
+	.name = "counter_device",
+	.release = counter_device_release
+};
+
+static struct bus_type counter_bus_type = {
+	.name = "counter"
+};
+
+/**
+ * counter_register - register Counter to the system
+ * @counter:	pointer to Counter to register
+ *
+ * This function registers a Counter to the system. A sysfs "counter" directory
+ * will be created and populated with sysfs attributes correlating with the
+ * Counter Signals, Synapses, and Counts respectively.
+ */
+int counter_register(struct counter_device *const counter)
+{
+	struct device *const dev = &counter->dev;
+	int err;
+
+	/* Acquire unique ID */
+	counter->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
+	if (counter->id < 0)
+		return counter->id;
+
+	/* Configure device structure for Counter */
+	dev->type = &counter_device_type;
+	dev->bus = &counter_bus_type;
+	if (counter->parent) {
+		dev->parent = counter->parent;
+		dev->of_node = counter->parent->of_node;
+	}
+	dev_set_name(dev, "counter%d", counter->id);
+	device_initialize(dev);
+	dev_set_drvdata(dev, counter);
+
+	/* Add Counter sysfs attributes */
+	err = counter_sysfs_add(counter);
+	if (err < 0)
+		goto err_free_id;
+
+	/* Add device to system */
+	err = device_add(dev);
+	if (err < 0)
+		goto err_free_id;
+
+	return 0;
+
+err_free_id:
+	put_device(dev);
+	return err;
+}
+EXPORT_SYMBOL_GPL(counter_register);
+
+/**
+ * counter_unregister - unregister Counter from the system
+ * @counter:	pointer to Counter to unregister
+ *
+ * The Counter is unregistered from the system; all allocated memory is freed.
+ */
+void counter_unregister(struct counter_device *const counter)
+{
+	if (!counter)
+		return;
+
+	device_unregister(&counter->dev);
+}
+EXPORT_SYMBOL_GPL(counter_unregister);
+
+static void devm_counter_release(struct device *dev, void *res)
+{
+	counter_unregister(*(struct counter_device **)res);
+}
+
+/**
+ * devm_counter_register - Resource-managed counter_register
+ * @dev:	device to allocate counter_device for
+ * @counter:	pointer to Counter to register
+ *
+ * Managed counter_register. The Counter registered with this function is
+ * automatically unregistered on driver detach. This function calls
+ * counter_register internally. Refer to that function for more information.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int devm_counter_register(struct device *dev,
+			  struct counter_device *const counter)
+{
+	struct counter_device **ptr;
+	int err;
+
+	ptr = devres_alloc(devm_counter_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	err = counter_register(counter);
+	if (err < 0) {
+		devres_free(ptr);
+		return err;
+	}
+
+	*ptr = counter;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_counter_register);
+
+static int __init counter_init(void)
+{
+	return bus_register(&counter_bus_type);
+}
+
+static void __exit counter_exit(void)
+{
+	bus_unregister(&counter_bus_type);
+}
+
+subsys_initcall(counter_init);
+module_exit(counter_exit);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("Generic Counter interface");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
new file mode 100644
index 000000000000..52513a213cc5
--- /dev/null
+++ b/drivers/counter/counter-sysfs.c
@@ -0,0 +1,833 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter sysfs interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+#include "counter-sysfs.h"
+
+/**
+ * struct counter_attribute - Counter sysfs attribute
+ * @dev_attr:	device attribute for sysfs
+ * @l:		node to add Counter attribute to attribute group list
+ * @comp:	Counter component callbacks and data
+ * @scope:	Counter scope of the attribute
+ * @parent:	pointer to the parent component
+ */
+struct counter_attribute {
+	struct device_attribute dev_attr;
+	struct list_head l;
+
+	struct counter_comp comp;
+	enum counter_scope scope;
+	void *parent;
+};
+
+#define to_counter_attribute(_dev_attr) \
+	container_of(_dev_attr, struct counter_attribute, dev_attr)
+
+/**
+ * struct counter_attribute_group - container for attribute group
+ * @name:	name of the attribute group
+ * @attr_list:	list to keep track of created attributes
+ * @num_attr:	number of attributes
+ */
+struct counter_attribute_group {
+	const char *name;
+	struct list_head attr_list;
+	size_t num_attr;
+};
+
+static const char *const counter_function_str[] = {
+	[COUNTER_FUNCTION_INCREASE] = "increase",
+	[COUNTER_FUNCTION_DECREASE] = "decrease",
+	[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
+	[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
+	[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
+	[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
+	[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
+	[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
+};
+
+static const char *const counter_signal_value_str[] = {
+	[COUNTER_SIGNAL_LEVEL_LOW] = "low",
+	[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
+};
+
+static const char *const counter_synapse_action_str[] = {
+	[COUNTER_SYNAPSE_ACTION_NONE] = "none",
+	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
+	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
+	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
+};
+
+static const char *const counter_count_direction_str[] = {
+	[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
+	[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
+};
+
+static const char *const counter_count_mode_str[] = {
+	[COUNTER_COUNT_MODE_NORMAL] = "normal",
+	[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
+	[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
+	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
+};
+
+static ssize_t counter_comp_u8_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	int err;
+	u8 data = 0;
+
+	switch (a->scope) {
+	case COUNTER_SCOPE_DEVICE:
+		err = a->comp.device_u8_read(counter, &data);
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		err = a->comp.signal_u8_read(counter, a->parent, &data);
+		break;
+	case COUNTER_SCOPE_COUNT:
+		err = a->comp.count_u8_read(counter, a->parent, &data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	if (a->comp.type == COUNTER_COMP_BOOL)
+		data = !!data;
+
+	return sprintf(buf, "%u\n", (unsigned int)data);
+}
+
+static ssize_t counter_comp_u8_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	int err;
+	bool bool_data = 0;
+	u8 data = 0;
+
+	if (a->comp.type == COUNTER_COMP_BOOL) {
+		err = kstrtobool(buf, &bool_data);
+		data = bool_data;
+	} else
+		err = kstrtou8(buf, 0, &data);
+	if (err < 0)
+		return err;
+
+	switch (a->scope) {
+	case COUNTER_SCOPE_DEVICE:
+		err = a->comp.device_u8_write(counter, data);
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		err = a->comp.signal_u8_write(counter, a->parent, data);
+		break;
+	case COUNTER_SCOPE_COUNT:
+		err = a->comp.count_u8_write(counter, a->parent, data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	return len;
+}
+
+static ssize_t counter_comp_u32_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	const struct counter_available *const avail = a->comp.priv;
+	int err;
+	u32 data = 0;
+
+	switch (a->scope) {
+	case COUNTER_SCOPE_DEVICE:
+		err = a->comp.device_u32_read(counter, &data);
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		err = a->comp.signal_u32_read(counter, a->parent, &data);
+		break;
+	case COUNTER_SCOPE_COUNT:
+		if (a->comp.type == COUNTER_COMP_SYNAPSE_ACTION)
+			err = a->comp.action_read(counter, a->parent,
+						  a->comp.priv, &data);
+		else
+			err = a->comp.count_u32_read(counter, a->parent, &data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	switch (a->comp.type) {
+	case COUNTER_COMP_FUNCTION:
+		return sysfs_emit(buf, "%s\n", counter_function_str[data]);
+	case COUNTER_COMP_SIGNAL_LEVEL:
+		return sysfs_emit(buf, "%s\n", counter_signal_value_str[data]);
+	case COUNTER_COMP_SYNAPSE_ACTION:
+		return sysfs_emit(buf, "%s\n", counter_synapse_action_str[data]);
+	case COUNTER_COMP_ENUM:
+		return sysfs_emit(buf, "%s\n", avail->strs[data]);
+	case COUNTER_COMP_COUNT_DIRECTION:
+		return sysfs_emit(buf, "%s\n", counter_count_direction_str[data]);
+	case COUNTER_COMP_COUNT_MODE:
+		return sysfs_emit(buf, "%s\n", counter_count_mode_str[data]);
+	default:
+		return sprintf(buf, "%u\n", (unsigned int)data);
+	}
+}
+
+static int counter_find_enum(u32 *const enum_item, const u32 *const enums,
+			     const size_t num_enums, const char *const buf,
+			     const char *const string_array[])
+{
+	size_t index;
+
+	for (index = 0; index < num_enums; index++) {
+		*enum_item = enums[index];
+		if (sysfs_streq(buf, string_array[*enum_item]))
+			return 0;
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t counter_comp_u32_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t len)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_count *const count = a->parent;
+	struct counter_synapse *const synapse = a->comp.priv;
+	const struct counter_available *const avail = a->comp.priv;
+	int err;
+	u32 data = 0;
+
+	switch (a->comp.type) {
+	case COUNTER_COMP_FUNCTION:
+		err = counter_find_enum(&data, count->functions_list,
+					count->num_functions, buf,
+					counter_function_str);
+		break;
+	case COUNTER_COMP_SYNAPSE_ACTION:
+		err = counter_find_enum(&data, synapse->actions_list,
+					synapse->num_actions, buf,
+					counter_synapse_action_str);
+		break;
+	case COUNTER_COMP_ENUM:
+		err = __sysfs_match_string(avail->strs, avail->num_items, buf);
+		data = err;
+		break;
+	case COUNTER_COMP_COUNT_MODE:
+		err = counter_find_enum(&data, avail->enums, avail->num_items,
+					buf, counter_count_mode_str);
+		break;
+	default:
+		err = kstrtou32(buf, 0, &data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	switch (a->scope) {
+	case COUNTER_SCOPE_DEVICE:
+		err = a->comp.device_u32_write(counter, data);
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		err = a->comp.signal_u32_write(counter, a->parent, data);
+		break;
+	case COUNTER_SCOPE_COUNT:
+		if (a->comp.type == COUNTER_COMP_SYNAPSE_ACTION)
+			err = a->comp.action_write(counter, count, synapse,
+						   data);
+		else
+			err = a->comp.count_u32_write(counter, count, data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	return len;
+}
+
+static ssize_t counter_comp_u64_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	int err;
+	u64 data = 0;
+
+	switch (a->scope) {
+	case COUNTER_SCOPE_DEVICE:
+		err = a->comp.device_u64_read(counter, &data);
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		err = a->comp.signal_u64_read(counter, a->parent, &data);
+		break;
+	case COUNTER_SCOPE_COUNT:
+		err = a->comp.count_u64_read(counter, a->parent, &data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	return sprintf(buf, "%llu\n", (unsigned long long)data);
+}
+
+static ssize_t counter_comp_u64_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t len)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	struct counter_device *const counter = dev_get_drvdata(dev);
+	int err;
+	u64 data = 0;
+
+	err = kstrtou64(buf, 0, &data);
+	if (err < 0)
+		return err;
+
+	switch (a->scope) {
+	case COUNTER_SCOPE_DEVICE:
+		err = a->comp.device_u64_write(counter, data);
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		err = a->comp.signal_u64_write(counter, a->parent, data);
+		break;
+	case COUNTER_SCOPE_COUNT:
+		err = a->comp.count_u64_write(counter, a->parent, data);
+		break;
+	}
+	if (err < 0)
+		return err;
+
+	return len;
+}
+
+static ssize_t enums_available_show(const u32 *const enums,
+				    const size_t num_enums,
+				    const char *const strs[], char *buf)
+{
+	size_t len = 0;
+	size_t index;
+
+	for (index = 0; index < num_enums; index++)
+		len += sysfs_emit(buf + len, "%s\n", strs[enums[index]]);
+
+	return len;
+}
+
+static ssize_t strs_available_show(const struct counter_available *const avail,
+				   char *buf)
+{
+	size_t len = 0;
+	size_t index;
+
+	for (index = 0; index < avail->num_items; index++)
+		len += sysfs_emit(buf + len, "%s\n", avail->strs[index]);
+
+	return len;
+}
+
+static ssize_t counter_comp_available_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	const struct counter_attribute *const a = to_counter_attribute(attr);
+	const struct counter_count *const count = a->parent;
+	const struct counter_synapse *const synapse = a->comp.priv;
+	const struct counter_available *const avail = a->comp.priv;
+
+	switch (a->comp.type) {
+	case COUNTER_COMP_FUNCTION:
+		return enums_available_show(count->functions_list,
+					    count->num_functions,
+					    counter_function_str, buf);
+	case COUNTER_COMP_SYNAPSE_ACTION:
+		return enums_available_show(synapse->actions_list,
+					    synapse->num_actions,
+					    counter_synapse_action_str, buf);
+	case COUNTER_COMP_ENUM:
+		return strs_available_show(avail, buf);
+	case COUNTER_COMP_COUNT_MODE:
+		return enums_available_show(avail->enums, avail->num_items,
+					    counter_count_mode_str, buf);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int counter_avail_attr_create(struct device *const dev,
+	struct counter_attribute_group *const group,
+	const struct counter_comp *const comp, void *const parent)
+{
+	struct counter_attribute *counter_attr;
+	struct device_attribute *dev_attr;
+
+	/* Allocate Counter attribute */
+	counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
+	if (!counter_attr)
+		return -ENOMEM;
+
+	/* Configure Counter attribute */
+	counter_attr->comp.type = comp->type;
+	counter_attr->comp.priv = comp->priv;
+	counter_attr->parent = parent;
+
+	/* Initialize sysfs attribute */
+	dev_attr = &counter_attr->dev_attr;
+	sysfs_attr_init(&dev_attr->attr);
+
+	/* Configure device attribute */
+	dev_attr->attr.name = devm_kasprintf(dev, GFP_KERNEL, "%s_available",
+					     comp->name);
+	if (!dev_attr->attr.name)
+		return -ENOMEM;
+	dev_attr->attr.mode = 0444;
+	dev_attr->show = counter_comp_available_show;
+
+	/* Store list node */
+	list_add(&counter_attr->l, &group->attr_list);
+	group->num_attr++;
+
+	return 0;
+}
+
+static int counter_attr_create(struct device *const dev,
+			       struct counter_attribute_group *const group,
+			       const struct counter_comp *const comp,
+			       const enum counter_scope scope,
+			       void *const parent)
+{
+	struct counter_attribute *counter_attr;
+	struct device_attribute *dev_attr;
+
+	/* Allocate Counter attribute */
+	counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
+	if (!counter_attr)
+		return -ENOMEM;
+
+	/* Configure Counter attribute */
+	counter_attr->comp = *comp;
+	counter_attr->scope = scope;
+	counter_attr->parent = parent;
+
+	/* Configure device attribute */
+	dev_attr = &counter_attr->dev_attr;
+	sysfs_attr_init(&dev_attr->attr);
+	dev_attr->attr.name = comp->name;
+	switch (comp->type) {
+	case COUNTER_COMP_U8:
+	case COUNTER_COMP_BOOL:
+		if (comp->device_u8_read) {
+			dev_attr->attr.mode |= 0444;
+			dev_attr->show = counter_comp_u8_show;
+		}
+		if (comp->device_u8_write) {
+			dev_attr->attr.mode |= 0200;
+			dev_attr->store = counter_comp_u8_store;
+		}
+		break;
+	case COUNTER_COMP_SIGNAL_LEVEL:
+	case COUNTER_COMP_FUNCTION:
+	case COUNTER_COMP_SYNAPSE_ACTION:
+	case COUNTER_COMP_ENUM:
+	case COUNTER_COMP_COUNT_DIRECTION:
+	case COUNTER_COMP_COUNT_MODE:
+		if (comp->device_u32_read) {
+			dev_attr->attr.mode |= 0444;
+			dev_attr->show = counter_comp_u32_show;
+		}
+		if (comp->device_u32_write) {
+			dev_attr->attr.mode |= 0200;
+			dev_attr->store = counter_comp_u32_store;
+		}
+		break;
+	case COUNTER_COMP_U64:
+		if (comp->device_u64_read) {
+			dev_attr->attr.mode |= 0444;
+			dev_attr->show = counter_comp_u64_show;
+		}
+		if (comp->device_u64_write) {
+			dev_attr->attr.mode |= 0200;
+			dev_attr->store = counter_comp_u64_store;
+		}
+		break;
+	}
+
+	/* Store list node */
+	list_add(&counter_attr->l, &group->attr_list);
+	group->num_attr++;
+
+	/* Create "*_available" attribute if needed */
+	switch (comp->type) {
+	case COUNTER_COMP_FUNCTION:
+	case COUNTER_COMP_SYNAPSE_ACTION:
+	case COUNTER_COMP_ENUM:
+	case COUNTER_COMP_COUNT_MODE:
+		return counter_avail_attr_create(dev, group, comp, parent);
+	default:
+		return 0;
+	}
+}
+
+static ssize_t counter_comp_name_show(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", to_counter_attribute(attr)->comp.name);
+}
+
+static int counter_name_attr_create(struct device *const dev,
+				    struct counter_attribute_group *const group,
+				    const char *const name)
+{
+	struct counter_attribute *counter_attr;
+
+	/* Allocate Counter attribute */
+	counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
+	if (!counter_attr)
+		return -ENOMEM;
+
+	/* Configure Counter attribute */
+	counter_attr->comp.name = name;
+
+	/* Configure device attribute */
+	sysfs_attr_init(&counter_attr->dev_attr.attr);
+	counter_attr->dev_attr.attr.name = "name";
+	counter_attr->dev_attr.attr.mode = 0444;
+	counter_attr->dev_attr.show = counter_comp_name_show;
+
+	/* Store list node */
+	list_add(&counter_attr->l, &group->attr_list);
+	group->num_attr++;
+
+	return 0;
+}
+
+
+static struct counter_comp counter_signal_comp = {
+	.type = COUNTER_COMP_SIGNAL_LEVEL,
+	.name = "signal",
+};
+
+static int counter_signal_attrs_create(struct counter_device *const counter,
+	struct counter_attribute_group *const group,
+	struct counter_signal *const signal)
+{
+	const enum counter_scope scope = COUNTER_SCOPE_SIGNAL;
+	struct device *const dev = &counter->dev;
+	int err;
+	struct counter_comp comp;
+	size_t i;
+
+	/* Create main Signal attribute */
+	comp = counter_signal_comp;
+	comp.signal_u32_read = counter->ops->signal_read;
+	err = counter_attr_create(dev, group, &comp, scope, signal);
+	if (err < 0)
+		return err;
+
+	/* Create Signal name attribute */
+	err = counter_name_attr_create(dev, group, signal->name);
+	if (err < 0)
+		return err;
+
+	/* Create an attribute for each extension */
+	for (i = 0; i < signal->num_ext; i++) {
+		err = counter_attr_create(dev, group, signal->ext + i, scope,
+					  signal);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int counter_sysfs_signals_add(struct counter_device *const counter,
+	struct counter_attribute_group *const groups)
+{
+	size_t i;
+	int err;
+
+	/* Add each Signal */
+	for (i = 0; i < counter->num_signals; i++) {
+		/* Generate Signal attribute directory name */
+		groups[i].name = devm_kasprintf(&counter->dev, GFP_KERNEL,
+						"signal%zu", i);
+		if (!groups[i].name)
+			return -ENOMEM;
+
+		/* Create all attributes associated with Signal */
+		err = counter_signal_attrs_create(counter, groups + i,
+						  counter->signals + i);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int counter_sysfs_synapses_add(struct counter_device *const counter,
+	struct counter_attribute_group *const group,
+	struct counter_count *const count)
+{
+	size_t i;
+
+	/* Add each Synapse */
+	for (i = 0; i < count->num_synapses; i++) {
+		struct device *const dev = &counter->dev;
+		struct counter_synapse *synapse;
+		size_t id;
+		struct counter_comp comp;
+		int err;
+
+		synapse = count->synapses + i;
+
+		/* Generate Synapse action name */
+		id = synapse->signal - counter->signals;
+		comp.name = devm_kasprintf(dev, GFP_KERNEL, "signal%zu_action",
+					   id);
+		if (!comp.name)
+			return -ENOMEM;
+
+		/* Create action attribute */
+		comp.type = COUNTER_COMP_SYNAPSE_ACTION;
+		comp.action_read = counter->ops->action_read;
+		comp.action_write = counter->ops->action_write;
+		comp.priv = synapse;
+		err = counter_attr_create(dev, group, &comp,
+					  COUNTER_SCOPE_COUNT, count);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static struct counter_comp counter_count_comp =
+	COUNTER_COMP_COUNT_U64("count", NULL, NULL);
+
+static struct counter_comp counter_function_comp = {
+	.type = COUNTER_COMP_FUNCTION,
+	.name = "function",
+};
+
+static int counter_count_attrs_create(struct counter_device *const counter,
+	struct counter_attribute_group *const group,
+	struct counter_count *const count)
+{
+	const enum counter_scope scope = COUNTER_SCOPE_COUNT;
+	struct device *const dev = &counter->dev;
+	int err;
+	struct counter_comp comp;
+	size_t i;
+
+	/* Create main Count attribute */
+	comp = counter_count_comp;
+	comp.count_u64_read = counter->ops->count_read;
+	comp.count_u64_write = counter->ops->count_write;
+	err = counter_attr_create(dev, group, &comp, scope, count);
+	if (err < 0)
+		return err;
+
+	/* Create Count name attribute */
+	err = counter_name_attr_create(dev, group, count->name);
+	if (err < 0)
+		return err;
+
+	/* Create Count function attribute */
+	comp = counter_function_comp;
+	comp.count_u32_read = counter->ops->function_read;
+	comp.count_u32_write = counter->ops->function_write;
+	err = counter_attr_create(dev, group, &comp, scope, count);
+	if (err < 0)
+		return err;
+
+	/* Create an attribute for each extension */
+	for (i = 0; i < count->num_ext; i++) {
+		err = counter_attr_create(dev, group, count->ext + i, scope,
+					  count);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int counter_sysfs_counts_add(struct counter_device *const counter,
+	struct counter_attribute_group *const groups)
+{
+	size_t i;
+	struct counter_count *count;
+	int err;
+
+	/* Add each Count */
+	for (i = 0; i < counter->num_counts; i++) {
+		count = counter->counts + i;
+
+		/* Generate Count attribute directory name */
+		groups[i].name = devm_kasprintf(&counter->dev, GFP_KERNEL,
+						"count%zu", i);
+		if (!groups[i].name)
+			return -ENOMEM;
+
+		/* Add sysfs attributes of the Synapses */
+		err = counter_sysfs_synapses_add(counter, groups + i, count);
+		if (err < 0)
+			return err;
+
+		/* Create all attributes associated with Count */
+		err = counter_count_attrs_create(counter, groups + i, count);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int counter_num_signals_read(struct counter_device *counter, u8 *val)
+{
+	*val = counter->num_signals;
+	return 0;
+}
+
+static int counter_num_counts_read(struct counter_device *counter, u8 *val)
+{
+	*val = counter->num_counts;
+	return 0;
+}
+
+static struct counter_comp counter_num_signals_comp =
+	COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL);
+
+static struct counter_comp counter_num_counts_comp =
+	COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL);
+
+static int counter_sysfs_attr_add(struct counter_device *const counter,
+				  struct counter_attribute_group *group)
+{
+	const enum counter_scope scope = COUNTER_SCOPE_DEVICE;
+	struct device *const dev = &counter->dev;
+	int err;
+	size_t i;
+
+	/* Add Signals sysfs attributes */
+	err = counter_sysfs_signals_add(counter, group);
+	if (err < 0)
+		return err;
+	group += counter->num_signals;
+
+	/* Add Counts sysfs attributes */
+	err = counter_sysfs_counts_add(counter, group);
+	if (err < 0)
+		return err;
+	group += counter->num_counts;
+
+	/* Create name attribute */
+	err = counter_name_attr_create(dev, group, counter->name);
+	if (err < 0)
+		return err;
+
+	/* Create num_signals attribute */
+	err = counter_attr_create(dev, group, &counter_num_signals_comp, scope,
+				  NULL);
+	if (err < 0)
+		return err;
+
+	/* Create num_counts attribute */
+	err = counter_attr_create(dev, group, &counter_num_counts_comp, scope,
+				  NULL);
+	if (err < 0)
+		return err;
+
+	/* Create an attribute for each extension */
+	for (i = 0; i < counter->num_ext; i++) {
+		err = counter_attr_create(dev, group, counter->ext + i, scope,
+					  NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/**
+ * counter_sysfs_add - Adds Counter sysfs attributes to the device structure
+ * @counter:	Pointer to the Counter device structure
+ *
+ * Counter sysfs attributes are created and added to the respective device
+ * structure for later registration to the system. Resource-managed memory
+ * allocation is performed by this function, and this memory should be freed
+ * when no longer needed (automatically by a device_unregister call, or
+ * manually by a devres_release_all call).
+ */
+int counter_sysfs_add(struct counter_device *const counter)
+{
+	struct device *const dev = &counter->dev;
+	const size_t num_groups = counter->num_signals + counter->num_counts + 1;
+	struct counter_attribute_group *groups;
+	size_t i, j;
+	int err;
+	struct attribute_group *group;
+	struct counter_attribute *p;
+
+	/* Allocate space for attribute groups (signals, counts, and ext) */
+	groups = devm_kcalloc(dev, num_groups, sizeof(*groups), GFP_KERNEL);
+	if (!groups)
+		return -ENOMEM;
+
+	/* Initialize attribute lists */
+	for (i = 0; i < num_groups; i++)
+		INIT_LIST_HEAD(&groups[i].attr_list);
+
+	/* Add Counter device sysfs attributes */
+	err = counter_sysfs_attr_add(counter, groups);
+	if (err < 0)
+		return err;
+
+	/* Allocate attribute groups for association with device */
+	dev->groups = devm_kcalloc(dev, num_groups + 1, sizeof(*dev->groups),
+				   GFP_KERNEL);
+	if (!dev->groups)
+		return -ENOMEM;
+
+	/* Prepare each group of attributes for association */
+	for (i = 0; i < num_groups; i++) {
+		/* Allocate space for attribute group */
+		group = devm_kzalloc(dev, sizeof(*group), GFP_KERNEL);
+		if (!group)
+			return -ENOMEM;
+		group->name = groups[i].name;
+
+		/* Allocate space for attribute pointers */
+		group->attrs = devm_kcalloc(dev, groups[i].num_attr + 1,
+					    sizeof(*group->attrs), GFP_KERNEL);
+		if (!group->attrs)
+			return -ENOMEM;
+
+		/* Add attribute pointers to attribute group */
+		j = 0;
+		list_for_each_entry(p, &groups[i].attr_list, l)
+			group->attrs[j++] = &p->dev_attr.attr;
+
+		/* Associate attribute group */
+		dev->groups[i] = group;
+	}
+
+	return 0;
+}
diff --git a/drivers/counter/counter-sysfs.h b/drivers/counter/counter-sysfs.h
new file mode 100644
index 000000000000..14fe566aca0e
--- /dev/null
+++ b/drivers/counter/counter-sysfs.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter sysfs interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _COUNTER_SYSFS_H_
+#define _COUNTER_SYSFS_H_
+
+#include <linux/counter.h>
+
+int counter_sysfs_add(struct counter_device *const counter);
+
+#endif /* _COUNTER_SYSFS_H_ */
diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
deleted file mode 100644
index de921e8a3f72..000000000000
--- a/drivers/counter/counter.c
+++ /dev/null
@@ -1,1496 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Generic Counter interface
- * Copyright (C) 2018 William Breathitt Gray
- */
-#include <linux/counter.h>
-#include <linux/device.h>
-#include <linux/err.h>
-#include <linux/export.h>
-#include <linux/fs.h>
-#include <linux/gfp.h>
-#include <linux/idr.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/list.h>
-#include <linux/module.h>
-#include <linux/printk.h>
-#include <linux/slab.h>
-#include <linux/string.h>
-#include <linux/sysfs.h>
-#include <linux/types.h>
-
-const char *const counter_count_direction_str[2] = {
-	[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
-	[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
-};
-EXPORT_SYMBOL_GPL(counter_count_direction_str);
-
-const char *const counter_count_mode_str[4] = {
-	[COUNTER_COUNT_MODE_NORMAL] = "normal",
-	[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
-	[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
-	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
-};
-EXPORT_SYMBOL_GPL(counter_count_mode_str);
-
-ssize_t counter_signal_enum_read(struct counter_device *counter,
-				 struct counter_signal *signal, void *priv,
-				 char *buf)
-{
-	const struct counter_signal_enum_ext *const e = priv;
-	int err;
-	size_t index;
-
-	if (!e->get)
-		return -EINVAL;
-
-	err = e->get(counter, signal, &index);
-	if (err)
-		return err;
-
-	if (index >= e->num_items)
-		return -EINVAL;
-
-	return sprintf(buf, "%s\n", e->items[index]);
-}
-EXPORT_SYMBOL_GPL(counter_signal_enum_read);
-
-ssize_t counter_signal_enum_write(struct counter_device *counter,
-				  struct counter_signal *signal, void *priv,
-				  const char *buf, size_t len)
-{
-	const struct counter_signal_enum_ext *const e = priv;
-	ssize_t index;
-	int err;
-
-	if (!e->set)
-		return -EINVAL;
-
-	index = __sysfs_match_string(e->items, e->num_items, buf);
-	if (index < 0)
-		return index;
-
-	err = e->set(counter, signal, index);
-	if (err)
-		return err;
-
-	return len;
-}
-EXPORT_SYMBOL_GPL(counter_signal_enum_write);
-
-ssize_t counter_signal_enum_available_read(struct counter_device *counter,
-					   struct counter_signal *signal,
-					   void *priv, char *buf)
-{
-	const struct counter_signal_enum_ext *const e = priv;
-	size_t i;
-	size_t len = 0;
-
-	if (!e->num_items)
-		return 0;
-
-	for (i = 0; i < e->num_items; i++)
-		len += sprintf(buf + len, "%s\n", e->items[i]);
-
-	return len;
-}
-EXPORT_SYMBOL_GPL(counter_signal_enum_available_read);
-
-ssize_t counter_count_enum_read(struct counter_device *counter,
-				struct counter_count *count, void *priv,
-				char *buf)
-{
-	const struct counter_count_enum_ext *const e = priv;
-	int err;
-	size_t index;
-
-	if (!e->get)
-		return -EINVAL;
-
-	err = e->get(counter, count, &index);
-	if (err)
-		return err;
-
-	if (index >= e->num_items)
-		return -EINVAL;
-
-	return sprintf(buf, "%s\n", e->items[index]);
-}
-EXPORT_SYMBOL_GPL(counter_count_enum_read);
-
-ssize_t counter_count_enum_write(struct counter_device *counter,
-				 struct counter_count *count, void *priv,
-				 const char *buf, size_t len)
-{
-	const struct counter_count_enum_ext *const e = priv;
-	ssize_t index;
-	int err;
-
-	if (!e->set)
-		return -EINVAL;
-
-	index = __sysfs_match_string(e->items, e->num_items, buf);
-	if (index < 0)
-		return index;
-
-	err = e->set(counter, count, index);
-	if (err)
-		return err;
-
-	return len;
-}
-EXPORT_SYMBOL_GPL(counter_count_enum_write);
-
-ssize_t counter_count_enum_available_read(struct counter_device *counter,
-					  struct counter_count *count,
-					  void *priv, char *buf)
-{
-	const struct counter_count_enum_ext *const e = priv;
-	size_t i;
-	size_t len = 0;
-
-	if (!e->num_items)
-		return 0;
-
-	for (i = 0; i < e->num_items; i++)
-		len += sprintf(buf + len, "%s\n", e->items[i]);
-
-	return len;
-}
-EXPORT_SYMBOL_GPL(counter_count_enum_available_read);
-
-ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
-				 char *buf)
-{
-	const struct counter_device_enum_ext *const e = priv;
-	int err;
-	size_t index;
-
-	if (!e->get)
-		return -EINVAL;
-
-	err = e->get(counter, &index);
-	if (err)
-		return err;
-
-	if (index >= e->num_items)
-		return -EINVAL;
-
-	return sprintf(buf, "%s\n", e->items[index]);
-}
-EXPORT_SYMBOL_GPL(counter_device_enum_read);
-
-ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
-				  const char *buf, size_t len)
-{
-	const struct counter_device_enum_ext *const e = priv;
-	ssize_t index;
-	int err;
-
-	if (!e->set)
-		return -EINVAL;
-
-	index = __sysfs_match_string(e->items, e->num_items, buf);
-	if (index < 0)
-		return index;
-
-	err = e->set(counter, index);
-	if (err)
-		return err;
-
-	return len;
-}
-EXPORT_SYMBOL_GPL(counter_device_enum_write);
-
-ssize_t counter_device_enum_available_read(struct counter_device *counter,
-					   void *priv, char *buf)
-{
-	const struct counter_device_enum_ext *const e = priv;
-	size_t i;
-	size_t len = 0;
-
-	if (!e->num_items)
-		return 0;
-
-	for (i = 0; i < e->num_items; i++)
-		len += sprintf(buf + len, "%s\n", e->items[i]);
-
-	return len;
-}
-EXPORT_SYMBOL_GPL(counter_device_enum_available_read);
-
-struct counter_attr_parm {
-	struct counter_device_attr_group *group;
-	const char *prefix;
-	const char *name;
-	ssize_t (*show)(struct device *dev, struct device_attribute *attr,
-			char *buf);
-	ssize_t (*store)(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t len);
-	void *component;
-};
-
-struct counter_device_attr {
-	struct device_attribute dev_attr;
-	struct list_head l;
-	void *component;
-};
-
-static int counter_attribute_create(const struct counter_attr_parm *const parm)
-{
-	struct counter_device_attr *counter_attr;
-	struct device_attribute *dev_attr;
-	int err;
-	struct list_head *const attr_list = &parm->group->attr_list;
-
-	/* Allocate a Counter device attribute */
-	counter_attr = kzalloc(sizeof(*counter_attr), GFP_KERNEL);
-	if (!counter_attr)
-		return -ENOMEM;
-	dev_attr = &counter_attr->dev_attr;
-
-	sysfs_attr_init(&dev_attr->attr);
-
-	/* Configure device attribute */
-	dev_attr->attr.name = kasprintf(GFP_KERNEL, "%s%s", parm->prefix,
-					parm->name);
-	if (!dev_attr->attr.name) {
-		err = -ENOMEM;
-		goto err_free_counter_attr;
-	}
-	if (parm->show) {
-		dev_attr->attr.mode |= 0444;
-		dev_attr->show = parm->show;
-	}
-	if (parm->store) {
-		dev_attr->attr.mode |= 0200;
-		dev_attr->store = parm->store;
-	}
-
-	/* Store associated Counter component with attribute */
-	counter_attr->component = parm->component;
-
-	/* Keep track of the attribute for later cleanup */
-	list_add(&counter_attr->l, attr_list);
-	parm->group->num_attr++;
-
-	return 0;
-
-err_free_counter_attr:
-	kfree(counter_attr);
-	return err;
-}
-
-#define to_counter_attr(_dev_attr) \
-	container_of(_dev_attr, struct counter_device_attr, dev_attr)
-
-struct counter_signal_unit {
-	struct counter_signal *signal;
-};
-
-static const char *const counter_signal_level_str[] = {
-	[COUNTER_SIGNAL_LEVEL_LOW] = "low",
-	[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
-};
-
-static ssize_t counter_signal_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
-{
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_signal_unit *const component = devattr->component;
-	struct counter_signal *const signal = component->signal;
-	int err;
-	enum counter_signal_level level;
-
-	err = counter->ops->signal_read(counter, signal, &level);
-	if (err)
-		return err;
-
-	return sprintf(buf, "%s\n", counter_signal_level_str[level]);
-}
-
-struct counter_name_unit {
-	const char *name;
-};
-
-static ssize_t counter_device_attr_name_show(struct device *dev,
-					     struct device_attribute *attr,
-					     char *buf)
-{
-	const struct counter_name_unit *const comp = to_counter_attr(attr)->component;
-
-	return sprintf(buf, "%s\n", comp->name);
-}
-
-static int counter_name_attribute_create(
-	struct counter_device_attr_group *const group,
-	const char *const name)
-{
-	struct counter_name_unit *name_comp;
-	struct counter_attr_parm parm;
-	int err;
-
-	/* Skip if no name */
-	if (!name)
-		return 0;
-
-	/* Allocate name attribute component */
-	name_comp = kmalloc(sizeof(*name_comp), GFP_KERNEL);
-	if (!name_comp)
-		return -ENOMEM;
-	name_comp->name = name;
-
-	/* Allocate Signal name attribute */
-	parm.group = group;
-	parm.prefix = "";
-	parm.name = "name";
-	parm.show = counter_device_attr_name_show;
-	parm.store = NULL;
-	parm.component = name_comp;
-	err = counter_attribute_create(&parm);
-	if (err)
-		goto err_free_name_comp;
-
-	return 0;
-
-err_free_name_comp:
-	kfree(name_comp);
-	return err;
-}
-
-struct counter_signal_ext_unit {
-	struct counter_signal *signal;
-	const struct counter_signal_ext *ext;
-};
-
-static ssize_t counter_signal_ext_show(struct device *dev,
-				       struct device_attribute *attr, char *buf)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_signal_ext_unit *const comp = devattr->component;
-	const struct counter_signal_ext *const ext = comp->ext;
-
-	return ext->read(dev_get_drvdata(dev), comp->signal, ext->priv, buf);
-}
-
-static ssize_t counter_signal_ext_store(struct device *dev,
-					struct device_attribute *attr,
-					const char *buf, size_t len)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_signal_ext_unit *const comp = devattr->component;
-	const struct counter_signal_ext *const ext = comp->ext;
-
-	return ext->write(dev_get_drvdata(dev), comp->signal, ext->priv, buf,
-		len);
-}
-
-static void counter_device_attr_list_free(struct list_head *attr_list)
-{
-	struct counter_device_attr *p, *n;
-
-	list_for_each_entry_safe(p, n, attr_list, l) {
-		/* free attribute name and associated component memory */
-		kfree(p->dev_attr.attr.name);
-		kfree(p->component);
-		list_del(&p->l);
-		kfree(p);
-	}
-}
-
-static int counter_signal_ext_register(
-	struct counter_device_attr_group *const group,
-	struct counter_signal *const signal)
-{
-	const size_t num_ext = signal->num_ext;
-	size_t i;
-	const struct counter_signal_ext *ext;
-	struct counter_signal_ext_unit *signal_ext_comp;
-	struct counter_attr_parm parm;
-	int err;
-
-	/* Create an attribute for each extension */
-	for (i = 0 ; i < num_ext; i++) {
-		ext = signal->ext + i;
-
-		/* Allocate signal_ext attribute component */
-		signal_ext_comp = kmalloc(sizeof(*signal_ext_comp), GFP_KERNEL);
-		if (!signal_ext_comp) {
-			err = -ENOMEM;
-			goto err_free_attr_list;
-		}
-		signal_ext_comp->signal = signal;
-		signal_ext_comp->ext = ext;
-
-		/* Allocate a Counter device attribute */
-		parm.group = group;
-		parm.prefix = "";
-		parm.name = ext->name;
-		parm.show = (ext->read) ? counter_signal_ext_show : NULL;
-		parm.store = (ext->write) ? counter_signal_ext_store : NULL;
-		parm.component = signal_ext_comp;
-		err = counter_attribute_create(&parm);
-		if (err) {
-			kfree(signal_ext_comp);
-			goto err_free_attr_list;
-		}
-	}
-
-	return 0;
-
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-static int counter_signal_attributes_create(
-	struct counter_device_attr_group *const group,
-	const struct counter_device *const counter,
-	struct counter_signal *const signal)
-{
-	struct counter_signal_unit *signal_comp;
-	struct counter_attr_parm parm;
-	int err;
-
-	/* Allocate Signal attribute component */
-	signal_comp = kmalloc(sizeof(*signal_comp), GFP_KERNEL);
-	if (!signal_comp)
-		return -ENOMEM;
-	signal_comp->signal = signal;
-
-	/* Create main Signal attribute */
-	parm.group = group;
-	parm.prefix = "";
-	parm.name = "signal";
-	parm.show = (counter->ops->signal_read) ? counter_signal_show : NULL;
-	parm.store = NULL;
-	parm.component = signal_comp;
-	err = counter_attribute_create(&parm);
-	if (err) {
-		kfree(signal_comp);
-		return err;
-	}
-
-	/* Create Signal name attribute */
-	err = counter_name_attribute_create(group, signal->name);
-	if (err)
-		goto err_free_attr_list;
-
-	/* Register Signal extension attributes */
-	err = counter_signal_ext_register(group, signal);
-	if (err)
-		goto err_free_attr_list;
-
-	return 0;
-
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-static int counter_signals_register(
-	struct counter_device_attr_group *const groups_list,
-	const struct counter_device *const counter)
-{
-	const size_t num_signals = counter->num_signals;
-	size_t i;
-	struct counter_signal *signal;
-	const char *name;
-	int err;
-
-	/* Register each Signal */
-	for (i = 0; i < num_signals; i++) {
-		signal = counter->signals + i;
-
-		/* Generate Signal attribute directory name */
-		name = kasprintf(GFP_KERNEL, "signal%d", signal->id);
-		if (!name) {
-			err = -ENOMEM;
-			goto err_free_attr_groups;
-		}
-		groups_list[i].attr_group.name = name;
-
-		/* Create all attributes associated with Signal */
-		err = counter_signal_attributes_create(groups_list + i, counter,
-						       signal);
-		if (err)
-			goto err_free_attr_groups;
-	}
-
-	return 0;
-
-err_free_attr_groups:
-	do {
-		kfree(groups_list[i].attr_group.name);
-		counter_device_attr_list_free(&groups_list[i].attr_list);
-	} while (i--);
-	return err;
-}
-
-static const char *const counter_synapse_action_str[] = {
-	[COUNTER_SYNAPSE_ACTION_NONE] = "none",
-	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
-	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
-	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
-};
-
-struct counter_action_unit {
-	struct counter_synapse *synapse;
-	struct counter_count *count;
-};
-
-static ssize_t counter_action_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	int err;
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	const struct counter_action_unit *const component = devattr->component;
-	struct counter_count *const count = component->count;
-	struct counter_synapse *const synapse = component->synapse;
-	size_t action_index;
-	enum counter_synapse_action action;
-
-	err = counter->ops->action_get(counter, count, synapse, &action_index);
-	if (err)
-		return err;
-
-	synapse->action = action_index;
-
-	action = synapse->actions_list[action_index];
-	return sprintf(buf, "%s\n", counter_synapse_action_str[action]);
-}
-
-static ssize_t counter_action_store(struct device *dev,
-				    struct device_attribute *attr,
-				    const char *buf, size_t len)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_action_unit *const component = devattr->component;
-	struct counter_synapse *const synapse = component->synapse;
-	size_t action_index;
-	const size_t num_actions = synapse->num_actions;
-	enum counter_synapse_action action;
-	int err;
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	struct counter_count *const count = component->count;
-
-	/* Find requested action mode */
-	for (action_index = 0; action_index < num_actions; action_index++) {
-		action = synapse->actions_list[action_index];
-		if (sysfs_streq(buf, counter_synapse_action_str[action]))
-			break;
-	}
-	/* If requested action mode not found */
-	if (action_index >= num_actions)
-		return -EINVAL;
-
-	err = counter->ops->action_set(counter, count, synapse, action_index);
-	if (err)
-		return err;
-
-	synapse->action = action_index;
-
-	return len;
-}
-
-struct counter_action_avail_unit {
-	const enum counter_synapse_action *actions_list;
-	size_t num_actions;
-};
-
-static ssize_t counter_synapse_action_available_show(struct device *dev,
-	struct device_attribute *attr, char *buf)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_action_avail_unit *const component = devattr->component;
-	size_t i;
-	enum counter_synapse_action action;
-	ssize_t len = 0;
-
-	for (i = 0; i < component->num_actions; i++) {
-		action = component->actions_list[i];
-		len += sprintf(buf + len, "%s\n",
-			       counter_synapse_action_str[action]);
-	}
-
-	return len;
-}
-
-static int counter_synapses_register(
-	struct counter_device_attr_group *const group,
-	const struct counter_device *const counter,
-	struct counter_count *const count, const char *const count_attr_name)
-{
-	size_t i;
-	struct counter_synapse *synapse;
-	const char *prefix;
-	struct counter_action_unit *action_comp;
-	struct counter_attr_parm parm;
-	int err;
-	struct counter_action_avail_unit *avail_comp;
-
-	/* Register each Synapse */
-	for (i = 0; i < count->num_synapses; i++) {
-		synapse = count->synapses + i;
-
-		/* Generate attribute prefix */
-		prefix = kasprintf(GFP_KERNEL, "signal%d_",
-				   synapse->signal->id);
-		if (!prefix) {
-			err = -ENOMEM;
-			goto err_free_attr_list;
-		}
-
-		/* Allocate action attribute component */
-		action_comp = kmalloc(sizeof(*action_comp), GFP_KERNEL);
-		if (!action_comp) {
-			err = -ENOMEM;
-			goto err_free_prefix;
-		}
-		action_comp->synapse = synapse;
-		action_comp->count = count;
-
-		/* Create action attribute */
-		parm.group = group;
-		parm.prefix = prefix;
-		parm.name = "action";
-		parm.show = (counter->ops->action_get) ? counter_action_show : NULL;
-		parm.store = (counter->ops->action_set) ? counter_action_store : NULL;
-		parm.component = action_comp;
-		err = counter_attribute_create(&parm);
-		if (err) {
-			kfree(action_comp);
-			goto err_free_prefix;
-		}
-
-		/* Allocate action available attribute component */
-		avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
-		if (!avail_comp) {
-			err = -ENOMEM;
-			goto err_free_prefix;
-		}
-		avail_comp->actions_list = synapse->actions_list;
-		avail_comp->num_actions = synapse->num_actions;
-
-		/* Create action_available attribute */
-		parm.group = group;
-		parm.prefix = prefix;
-		parm.name = "action_available";
-		parm.show = counter_synapse_action_available_show;
-		parm.store = NULL;
-		parm.component = avail_comp;
-		err = counter_attribute_create(&parm);
-		if (err) {
-			kfree(avail_comp);
-			goto err_free_prefix;
-		}
-
-		kfree(prefix);
-	}
-
-	return 0;
-
-err_free_prefix:
-	kfree(prefix);
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-struct counter_count_unit {
-	struct counter_count *count;
-};
-
-static ssize_t counter_count_show(struct device *dev,
-				  struct device_attribute *attr,
-				  char *buf)
-{
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_count_unit *const component = devattr->component;
-	struct counter_count *const count = component->count;
-	int err;
-	unsigned long val;
-
-	err = counter->ops->count_read(counter, count, &val);
-	if (err)
-		return err;
-
-	return sprintf(buf, "%lu\n", val);
-}
-
-static ssize_t counter_count_store(struct device *dev,
-				   struct device_attribute *attr,
-				   const char *buf, size_t len)
-{
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_count_unit *const component = devattr->component;
-	struct counter_count *const count = component->count;
-	int err;
-	unsigned long val;
-
-	err = kstrtoul(buf, 0, &val);
-	if (err)
-		return err;
-
-	err = counter->ops->count_write(counter, count, val);
-	if (err)
-		return err;
-
-	return len;
-}
-
-static const char *const counter_function_str[] = {
-	[COUNTER_FUNCTION_INCREASE] = "increase",
-	[COUNTER_FUNCTION_DECREASE] = "decrease",
-	[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
-	[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
-	[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
-	[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
-	[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
-	[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
-};
-
-static ssize_t counter_function_show(struct device *dev,
-				     struct device_attribute *attr, char *buf)
-{
-	int err;
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_count_unit *const component = devattr->component;
-	struct counter_count *const count = component->count;
-	size_t func_index;
-	enum counter_function function;
-
-	err = counter->ops->function_get(counter, count, &func_index);
-	if (err)
-		return err;
-
-	count->function = func_index;
-
-	function = count->functions_list[func_index];
-	return sprintf(buf, "%s\n", counter_function_str[function]);
-}
-
-static ssize_t counter_function_store(struct device *dev,
-				      struct device_attribute *attr,
-				      const char *buf, size_t len)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_count_unit *const component = devattr->component;
-	struct counter_count *const count = component->count;
-	const size_t num_functions = count->num_functions;
-	size_t func_index;
-	enum counter_function function;
-	int err;
-	struct counter_device *const counter = dev_get_drvdata(dev);
-
-	/* Find requested Count function mode */
-	for (func_index = 0; func_index < num_functions; func_index++) {
-		function = count->functions_list[func_index];
-		if (sysfs_streq(buf, counter_function_str[function]))
-			break;
-	}
-	/* Return error if requested Count function mode not found */
-	if (func_index >= num_functions)
-		return -EINVAL;
-
-	err = counter->ops->function_set(counter, count, func_index);
-	if (err)
-		return err;
-
-	count->function = func_index;
-
-	return len;
-}
-
-struct counter_count_ext_unit {
-	struct counter_count *count;
-	const struct counter_count_ext *ext;
-};
-
-static ssize_t counter_count_ext_show(struct device *dev,
-				      struct device_attribute *attr, char *buf)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_count_ext_unit *const comp = devattr->component;
-	const struct counter_count_ext *const ext = comp->ext;
-
-	return ext->read(dev_get_drvdata(dev), comp->count, ext->priv, buf);
-}
-
-static ssize_t counter_count_ext_store(struct device *dev,
-				       struct device_attribute *attr,
-				       const char *buf, size_t len)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_count_ext_unit *const comp = devattr->component;
-	const struct counter_count_ext *const ext = comp->ext;
-
-	return ext->write(dev_get_drvdata(dev), comp->count, ext->priv, buf,
-		len);
-}
-
-static int counter_count_ext_register(
-	struct counter_device_attr_group *const group,
-	struct counter_count *const count)
-{
-	size_t i;
-	const struct counter_count_ext *ext;
-	struct counter_count_ext_unit *count_ext_comp;
-	struct counter_attr_parm parm;
-	int err;
-
-	/* Create an attribute for each extension */
-	for (i = 0 ; i < count->num_ext; i++) {
-		ext = count->ext + i;
-
-		/* Allocate count_ext attribute component */
-		count_ext_comp = kmalloc(sizeof(*count_ext_comp), GFP_KERNEL);
-		if (!count_ext_comp) {
-			err = -ENOMEM;
-			goto err_free_attr_list;
-		}
-		count_ext_comp->count = count;
-		count_ext_comp->ext = ext;
-
-		/* Allocate count_ext attribute */
-		parm.group = group;
-		parm.prefix = "";
-		parm.name = ext->name;
-		parm.show = (ext->read) ? counter_count_ext_show : NULL;
-		parm.store = (ext->write) ? counter_count_ext_store : NULL;
-		parm.component = count_ext_comp;
-		err = counter_attribute_create(&parm);
-		if (err) {
-			kfree(count_ext_comp);
-			goto err_free_attr_list;
-		}
-	}
-
-	return 0;
-
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-struct counter_func_avail_unit {
-	const enum counter_function *functions_list;
-	size_t num_functions;
-};
-
-static ssize_t counter_function_available_show(struct device *dev,
-	struct device_attribute *attr, char *buf)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_func_avail_unit *const component = devattr->component;
-	const enum counter_function *const func_list = component->functions_list;
-	const size_t num_functions = component->num_functions;
-	size_t i;
-	enum counter_function function;
-	ssize_t len = 0;
-
-	for (i = 0; i < num_functions; i++) {
-		function = func_list[i];
-		len += sprintf(buf + len, "%s\n",
-			       counter_function_str[function]);
-	}
-
-	return len;
-}
-
-static int counter_count_attributes_create(
-	struct counter_device_attr_group *const group,
-	const struct counter_device *const counter,
-	struct counter_count *const count)
-{
-	struct counter_count_unit *count_comp;
-	struct counter_attr_parm parm;
-	int err;
-	struct counter_count_unit *func_comp;
-	struct counter_func_avail_unit *avail_comp;
-
-	/* Allocate count attribute component */
-	count_comp = kmalloc(sizeof(*count_comp), GFP_KERNEL);
-	if (!count_comp)
-		return -ENOMEM;
-	count_comp->count = count;
-
-	/* Create main Count attribute */
-	parm.group = group;
-	parm.prefix = "";
-	parm.name = "count";
-	parm.show = (counter->ops->count_read) ? counter_count_show : NULL;
-	parm.store = (counter->ops->count_write) ? counter_count_store : NULL;
-	parm.component = count_comp;
-	err = counter_attribute_create(&parm);
-	if (err) {
-		kfree(count_comp);
-		return err;
-	}
-
-	/* Allocate function attribute component */
-	func_comp = kmalloc(sizeof(*func_comp), GFP_KERNEL);
-	if (!func_comp) {
-		err = -ENOMEM;
-		goto err_free_attr_list;
-	}
-	func_comp->count = count;
-
-	/* Create Count function attribute */
-	parm.group = group;
-	parm.prefix = "";
-	parm.name = "function";
-	parm.show = (counter->ops->function_get) ? counter_function_show : NULL;
-	parm.store = (counter->ops->function_set) ? counter_function_store : NULL;
-	parm.component = func_comp;
-	err = counter_attribute_create(&parm);
-	if (err) {
-		kfree(func_comp);
-		goto err_free_attr_list;
-	}
-
-	/* Allocate function available attribute component */
-	avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
-	if (!avail_comp) {
-		err = -ENOMEM;
-		goto err_free_attr_list;
-	}
-	avail_comp->functions_list = count->functions_list;
-	avail_comp->num_functions = count->num_functions;
-
-	/* Create Count function_available attribute */
-	parm.group = group;
-	parm.prefix = "";
-	parm.name = "function_available";
-	parm.show = counter_function_available_show;
-	parm.store = NULL;
-	parm.component = avail_comp;
-	err = counter_attribute_create(&parm);
-	if (err) {
-		kfree(avail_comp);
-		goto err_free_attr_list;
-	}
-
-	/* Create Count name attribute */
-	err = counter_name_attribute_create(group, count->name);
-	if (err)
-		goto err_free_attr_list;
-
-	/* Register Count extension attributes */
-	err = counter_count_ext_register(group, count);
-	if (err)
-		goto err_free_attr_list;
-
-	return 0;
-
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-static int counter_counts_register(
-	struct counter_device_attr_group *const groups_list,
-	const struct counter_device *const counter)
-{
-	size_t i;
-	struct counter_count *count;
-	const char *name;
-	int err;
-
-	/* Register each Count */
-	for (i = 0; i < counter->num_counts; i++) {
-		count = counter->counts + i;
-
-		/* Generate Count attribute directory name */
-		name = kasprintf(GFP_KERNEL, "count%d", count->id);
-		if (!name) {
-			err = -ENOMEM;
-			goto err_free_attr_groups;
-		}
-		groups_list[i].attr_group.name = name;
-
-		/* Register the Synapses associated with each Count */
-		err = counter_synapses_register(groups_list + i, counter, count,
-						name);
-		if (err)
-			goto err_free_attr_groups;
-
-		/* Create all attributes associated with Count */
-		err = counter_count_attributes_create(groups_list + i, counter,
-						      count);
-		if (err)
-			goto err_free_attr_groups;
-	}
-
-	return 0;
-
-err_free_attr_groups:
-	do {
-		kfree(groups_list[i].attr_group.name);
-		counter_device_attr_list_free(&groups_list[i].attr_list);
-	} while (i--);
-	return err;
-}
-
-struct counter_size_unit {
-	size_t size;
-};
-
-static ssize_t counter_device_attr_size_show(struct device *dev,
-					     struct device_attribute *attr,
-					     char *buf)
-{
-	const struct counter_size_unit *const comp = to_counter_attr(attr)->component;
-
-	return sprintf(buf, "%zu\n", comp->size);
-}
-
-static int counter_size_attribute_create(
-	struct counter_device_attr_group *const group,
-	const size_t size, const char *const name)
-{
-	struct counter_size_unit *size_comp;
-	struct counter_attr_parm parm;
-	int err;
-
-	/* Allocate size attribute component */
-	size_comp = kmalloc(sizeof(*size_comp), GFP_KERNEL);
-	if (!size_comp)
-		return -ENOMEM;
-	size_comp->size = size;
-
-	parm.group = group;
-	parm.prefix = "";
-	parm.name = name;
-	parm.show = counter_device_attr_size_show;
-	parm.store = NULL;
-	parm.component = size_comp;
-	err = counter_attribute_create(&parm);
-	if (err)
-		goto err_free_size_comp;
-
-	return 0;
-
-err_free_size_comp:
-	kfree(size_comp);
-	return err;
-}
-
-struct counter_ext_unit {
-	const struct counter_device_ext *ext;
-};
-
-static ssize_t counter_device_ext_show(struct device *dev,
-				       struct device_attribute *attr, char *buf)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_ext_unit *const component = devattr->component;
-	const struct counter_device_ext *const ext = component->ext;
-
-	return ext->read(dev_get_drvdata(dev), ext->priv, buf);
-}
-
-static ssize_t counter_device_ext_store(struct device *dev,
-					struct device_attribute *attr,
-					const char *buf, size_t len)
-{
-	const struct counter_device_attr *const devattr = to_counter_attr(attr);
-	const struct counter_ext_unit *const component = devattr->component;
-	const struct counter_device_ext *const ext = component->ext;
-
-	return ext->write(dev_get_drvdata(dev), ext->priv, buf, len);
-}
-
-static int counter_device_ext_register(
-	struct counter_device_attr_group *const group,
-	struct counter_device *const counter)
-{
-	size_t i;
-	struct counter_ext_unit *ext_comp;
-	struct counter_attr_parm parm;
-	int err;
-
-	/* Create an attribute for each extension */
-	for (i = 0 ; i < counter->num_ext; i++) {
-		/* Allocate extension attribute component */
-		ext_comp = kmalloc(sizeof(*ext_comp), GFP_KERNEL);
-		if (!ext_comp) {
-			err = -ENOMEM;
-			goto err_free_attr_list;
-		}
-
-		ext_comp->ext = counter->ext + i;
-
-		/* Allocate extension attribute */
-		parm.group = group;
-		parm.prefix = "";
-		parm.name = counter->ext[i].name;
-		parm.show = (counter->ext[i].read) ? counter_device_ext_show : NULL;
-		parm.store = (counter->ext[i].write) ? counter_device_ext_store : NULL;
-		parm.component = ext_comp;
-		err = counter_attribute_create(&parm);
-		if (err) {
-			kfree(ext_comp);
-			goto err_free_attr_list;
-		}
-	}
-
-	return 0;
-
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-static int counter_global_attr_register(
-	struct counter_device_attr_group *const group,
-	struct counter_device *const counter)
-{
-	int err;
-
-	/* Create name attribute */
-	err = counter_name_attribute_create(group, counter->name);
-	if (err)
-		return err;
-
-	/* Create num_counts attribute */
-	err = counter_size_attribute_create(group, counter->num_counts,
-					    "num_counts");
-	if (err)
-		goto err_free_attr_list;
-
-	/* Create num_signals attribute */
-	err = counter_size_attribute_create(group, counter->num_signals,
-					    "num_signals");
-	if (err)
-		goto err_free_attr_list;
-
-	/* Register Counter device extension attributes */
-	err = counter_device_ext_register(group, counter);
-	if (err)
-		goto err_free_attr_list;
-
-	return 0;
-
-err_free_attr_list:
-	counter_device_attr_list_free(&group->attr_list);
-	return err;
-}
-
-static void counter_device_groups_list_free(
-	struct counter_device_attr_group *const groups_list,
-	const size_t num_groups)
-{
-	struct counter_device_attr_group *group;
-	size_t i;
-
-	/* loop through all attribute groups (signals, counts, global, etc.) */
-	for (i = 0; i < num_groups; i++) {
-		group = groups_list + i;
-
-		/* free all attribute group and associated attributes memory */
-		kfree(group->attr_group.name);
-		kfree(group->attr_group.attrs);
-		counter_device_attr_list_free(&group->attr_list);
-	}
-
-	kfree(groups_list);
-}
-
-static int counter_device_groups_list_prepare(
-	struct counter_device *const counter)
-{
-	const size_t total_num_groups =
-		counter->num_signals + counter->num_counts + 1;
-	struct counter_device_attr_group *groups_list;
-	size_t i;
-	int err;
-	size_t num_groups = 0;
-
-	/* Allocate space for attribute groups (signals, counts, and ext) */
-	groups_list = kcalloc(total_num_groups, sizeof(*groups_list),
-			      GFP_KERNEL);
-	if (!groups_list)
-		return -ENOMEM;
-
-	/* Initialize attribute lists */
-	for (i = 0; i < total_num_groups; i++)
-		INIT_LIST_HEAD(&groups_list[i].attr_list);
-
-	/* Register Signals */
-	err = counter_signals_register(groups_list, counter);
-	if (err)
-		goto err_free_groups_list;
-	num_groups += counter->num_signals;
-
-	/* Register Counts and respective Synapses */
-	err = counter_counts_register(groups_list + num_groups, counter);
-	if (err)
-		goto err_free_groups_list;
-	num_groups += counter->num_counts;
-
-	/* Register Counter global attributes */
-	err = counter_global_attr_register(groups_list + num_groups, counter);
-	if (err)
-		goto err_free_groups_list;
-	num_groups++;
-
-	/* Store groups_list in device_state */
-	counter->device_state->groups_list = groups_list;
-	counter->device_state->num_groups = num_groups;
-
-	return 0;
-
-err_free_groups_list:
-	counter_device_groups_list_free(groups_list, num_groups);
-	return err;
-}
-
-static int counter_device_groups_prepare(
-	struct counter_device_state *const device_state)
-{
-	size_t i, j;
-	struct counter_device_attr_group *group;
-	int err;
-	struct counter_device_attr *p;
-
-	/* Allocate attribute groups for association with device */
-	device_state->groups = kcalloc(device_state->num_groups + 1,
-				       sizeof(*device_state->groups),
-				       GFP_KERNEL);
-	if (!device_state->groups)
-		return -ENOMEM;
-
-	/* Prepare each group of attributes for association */
-	for (i = 0; i < device_state->num_groups; i++) {
-		group = device_state->groups_list + i;
-
-		/* Allocate space for attribute pointers in attribute group */
-		group->attr_group.attrs = kcalloc(group->num_attr + 1,
-			sizeof(*group->attr_group.attrs), GFP_KERNEL);
-		if (!group->attr_group.attrs) {
-			err = -ENOMEM;
-			goto err_free_groups;
-		}
-
-		/* Add attribute pointers to attribute group */
-		j = 0;
-		list_for_each_entry(p, &group->attr_list, l)
-			group->attr_group.attrs[j++] = &p->dev_attr.attr;
-
-		/* Group attributes in attribute group */
-		device_state->groups[i] = &group->attr_group;
-	}
-	/* Associate attributes with device */
-	device_state->dev.groups = device_state->groups;
-
-	return 0;
-
-err_free_groups:
-	do {
-		group = device_state->groups_list + i;
-		kfree(group->attr_group.attrs);
-		group->attr_group.attrs = NULL;
-	} while (i--);
-	kfree(device_state->groups);
-	return err;
-}
-
-/* Provides a unique ID for each counter device */
-static DEFINE_IDA(counter_ida);
-
-static void counter_device_release(struct device *dev)
-{
-	struct counter_device *const counter = dev_get_drvdata(dev);
-	struct counter_device_state *const device_state = counter->device_state;
-
-	kfree(device_state->groups);
-	counter_device_groups_list_free(device_state->groups_list,
-					device_state->num_groups);
-	ida_simple_remove(&counter_ida, device_state->id);
-	kfree(device_state);
-}
-
-static struct device_type counter_device_type = {
-	.name = "counter_device",
-	.release = counter_device_release
-};
-
-static struct bus_type counter_bus_type = {
-	.name = "counter"
-};
-
-/**
- * counter_register - register Counter to the system
- * @counter:	pointer to Counter to register
- *
- * This function registers a Counter to the system. A sysfs "counter" directory
- * will be created and populated with sysfs attributes correlating with the
- * Counter Signals, Synapses, and Counts respectively.
- */
-int counter_register(struct counter_device *const counter)
-{
-	struct counter_device_state *device_state;
-	int err;
-
-	/* Allocate internal state container for Counter device */
-	device_state = kzalloc(sizeof(*device_state), GFP_KERNEL);
-	if (!device_state)
-		return -ENOMEM;
-	counter->device_state = device_state;
-
-	/* Acquire unique ID */
-	device_state->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
-	if (device_state->id < 0) {
-		err = device_state->id;
-		goto err_free_device_state;
-	}
-
-	/* Configure device structure for Counter */
-	device_state->dev.type = &counter_device_type;
-	device_state->dev.bus = &counter_bus_type;
-	if (counter->parent) {
-		device_state->dev.parent = counter->parent;
-		device_state->dev.of_node = counter->parent->of_node;
-	}
-	dev_set_name(&device_state->dev, "counter%d", device_state->id);
-	device_initialize(&device_state->dev);
-	dev_set_drvdata(&device_state->dev, counter);
-
-	/* Prepare device attributes */
-	err = counter_device_groups_list_prepare(counter);
-	if (err)
-		goto err_free_id;
-
-	/* Organize device attributes to groups and match to device */
-	err = counter_device_groups_prepare(device_state);
-	if (err)
-		goto err_free_groups_list;
-
-	/* Add device to system */
-	err = device_add(&device_state->dev);
-	if (err)
-		goto err_free_groups;
-
-	return 0;
-
-err_free_groups:
-	kfree(device_state->groups);
-err_free_groups_list:
-	counter_device_groups_list_free(device_state->groups_list,
-					device_state->num_groups);
-err_free_id:
-	ida_simple_remove(&counter_ida, device_state->id);
-err_free_device_state:
-	kfree(device_state);
-	return err;
-}
-EXPORT_SYMBOL_GPL(counter_register);
-
-/**
- * counter_unregister - unregister Counter from the system
- * @counter:	pointer to Counter to unregister
- *
- * The Counter is unregistered from the system; all allocated memory is freed.
- */
-void counter_unregister(struct counter_device *const counter)
-{
-	if (counter)
-		device_del(&counter->device_state->dev);
-}
-EXPORT_SYMBOL_GPL(counter_unregister);
-
-static void devm_counter_unreg(struct device *dev, void *res)
-{
-	counter_unregister(*(struct counter_device **)res);
-}
-
-/**
- * devm_counter_register - Resource-managed counter_register
- * @dev:	device to allocate counter_device for
- * @counter:	pointer to Counter to register
- *
- * Managed counter_register. The Counter registered with this function is
- * automatically unregistered on driver detach. This function calls
- * counter_register internally. Refer to that function for more information.
- *
- * If an Counter registered with this function needs to be unregistered
- * separately, devm_counter_unregister must be used.
- *
- * RETURNS:
- * 0 on success, negative error number on failure.
- */
-int devm_counter_register(struct device *dev,
-			  struct counter_device *const counter)
-{
-	struct counter_device **ptr;
-	int ret;
-
-	ptr = devres_alloc(devm_counter_unreg, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return -ENOMEM;
-
-	ret = counter_register(counter);
-	if (!ret) {
-		*ptr = counter;
-		devres_add(dev, ptr);
-	} else {
-		devres_free(ptr);
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(devm_counter_register);
-
-static int devm_counter_match(struct device *dev, void *res, void *data)
-{
-	struct counter_device **r = res;
-
-	if (!r || !*r) {
-		WARN_ON(!r || !*r);
-		return 0;
-	}
-
-	return *r == data;
-}
-
-/**
- * devm_counter_unregister - Resource-managed counter_unregister
- * @dev:	device this counter_device belongs to
- * @counter:	pointer to Counter associated with the device
- *
- * Unregister Counter registered with devm_counter_register.
- */
-void devm_counter_unregister(struct device *dev,
-			     struct counter_device *const counter)
-{
-	int rc;
-
-	rc = devres_release(dev, devm_counter_unreg, devm_counter_match,
-			    counter);
-	WARN_ON(rc);
-}
-EXPORT_SYMBOL_GPL(devm_counter_unregister);
-
-static int __init counter_init(void)
-{
-	return bus_register(&counter_bus_type);
-}
-
-static void __exit counter_exit(void)
-{
-	bus_unregister(&counter_bus_type);
-}
-
-subsys_initcall(counter_init);
-module_exit(counter_exit);
-
-MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
-MODULE_DESCRIPTION("Generic Counter interface");
-MODULE_LICENSE("GPL v2");
diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c
index 97599061ca31..6e8e7323a303 100644
--- a/drivers/counter/ftm-quaddec.c
+++ b/drivers/counter/ftm-quaddec.c
@@ -14,6 +14,7 @@
 #include <linux/mutex.h>
 #include <linux/counter.h>
 #include <linux/bitfield.h>
+#include <linux/types.h>
 
 #define FTM_FIELD_UPDATE(ftm, offset, mask, val)			\
 	({								\
@@ -115,8 +116,7 @@ static void ftm_quaddec_disable(void *ftm)
 }
 
 static int ftm_quaddec_get_prescaler(struct counter_device *counter,
-				     struct counter_count *count,
-				     size_t *cnt_mode)
+				     struct counter_count *count, u32 *cnt_mode)
 {
 	struct ftm_quaddec *ftm = counter->priv;
 	uint32_t scflags;
@@ -129,8 +129,7 @@ static int ftm_quaddec_get_prescaler(struct counter_device *counter,
 }
 
 static int ftm_quaddec_set_prescaler(struct counter_device *counter,
-				     struct counter_count *count,
-				     size_t cnt_mode)
+				     struct counter_count *count, u32 cnt_mode)
 {
 	struct ftm_quaddec *ftm = counter->priv;
 
@@ -151,33 +150,21 @@ static const char * const ftm_quaddec_prescaler[] = {
 	"1", "2", "4", "8", "16", "32", "64", "128"
 };
 
-static struct counter_count_enum_ext ftm_quaddec_prescaler_enum = {
-	.items = ftm_quaddec_prescaler,
-	.num_items = ARRAY_SIZE(ftm_quaddec_prescaler),
-	.get = ftm_quaddec_get_prescaler,
-	.set = ftm_quaddec_set_prescaler
-};
-
-enum ftm_quaddec_synapse_action {
-	FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
-};
-
 static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
-	[FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };
 
 enum ftm_quaddec_function {
-	FTM_QUADDEC_ENCODER_MODE_1,
+	FTM_QUADDEC_ENCODER_MODE_1 = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 static const enum counter_function ftm_quaddec_functions[] = {
-	[FTM_QUADDEC_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X4
+	FTM_QUADDEC_ENCODER_MODE_1
 };
 
 static int ftm_quaddec_count_read(struct counter_device *counter,
 				  struct counter_count *count,
-				  unsigned long *val)
+				  u64 *val)
 {
 	struct ftm_quaddec *const ftm = counter->priv;
 	uint32_t cntval;
@@ -191,7 +178,7 @@ static int ftm_quaddec_count_read(struct counter_device *counter,
 
 static int ftm_quaddec_count_write(struct counter_device *counter,
 				   struct counter_count *count,
-				   const unsigned long val)
+				   const u64 val)
 {
 	struct ftm_quaddec *const ftm = counter->priv;
 
@@ -205,21 +192,21 @@ static int ftm_quaddec_count_write(struct counter_device *counter,
 	return 0;
 }
 
-static int ftm_quaddec_function_get(struct counter_device *counter,
-				    struct counter_count *count,
-				    size_t *function)
+static int ftm_quaddec_function_read(struct counter_device *counter,
+				     struct counter_count *count,
+				     enum counter_function *function)
 {
 	*function = FTM_QUADDEC_ENCODER_MODE_1;
 
 	return 0;
 }
 
-static int ftm_quaddec_action_get(struct counter_device *counter,
-				  struct counter_count *count,
-				  struct counter_synapse *synapse,
-				  size_t *action)
+static int ftm_quaddec_action_read(struct counter_device *counter,
+				   struct counter_count *count,
+				   struct counter_synapse *synapse,
+				   enum counter_synapse_action *action)
 {
-	*action = FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES;
+	*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 
 	return 0;
 }
@@ -227,8 +214,8 @@ static int ftm_quaddec_action_get(struct counter_device *counter,
 static const struct counter_ops ftm_quaddec_cnt_ops = {
 	.count_read = ftm_quaddec_count_read,
 	.count_write = ftm_quaddec_count_write,
-	.function_get = ftm_quaddec_function_get,
-	.action_get = ftm_quaddec_action_get,
+	.function_read = ftm_quaddec_function_read,
+	.action_read = ftm_quaddec_action_read,
 };
 
 static struct counter_signal ftm_quaddec_signals[] = {
@@ -255,9 +242,12 @@ static struct counter_synapse ftm_quaddec_count_synapses[] = {
 	}
 };
 
-static const struct counter_count_ext ftm_quaddec_count_ext[] = {
-	COUNTER_COUNT_ENUM("prescaler", &ftm_quaddec_prescaler_enum),
-	COUNTER_COUNT_ENUM_AVAILABLE("prescaler", &ftm_quaddec_prescaler_enum),
+static DEFINE_COUNTER_ENUM(ftm_quaddec_prescaler_enum, ftm_quaddec_prescaler);
+
+static struct counter_comp ftm_quaddec_count_ext[] = {
+	COUNTER_COMP_COUNT_ENUM("prescaler", ftm_quaddec_get_prescaler,
+				ftm_quaddec_set_prescaler,
+				ftm_quaddec_prescaler_enum),
 };
 
 static struct counter_count ftm_quaddec_counts = {
diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index d4cfaffe9499..f58f606e918e 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -32,28 +32,16 @@ struct mchp_tc_data {
 	bool trig_inverted;
 };
 
-enum mchp_tc_function {
-	MCHP_TC_FUNCTION_INCREASE,
-	MCHP_TC_FUNCTION_QUADRATURE,
+static const enum counter_function mchp_tc_functions[] = {
+	COUNTER_FUNCTION_INCREASE,
+	COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
-static enum counter_function mchp_tc_functions[] = {
-	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_FUNCTION_INCREASE,
-	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_FUNCTION_QUADRATURE_X4,
-};
-
-enum mchp_tc_synapse_action {
-	MCHP_TC_SYNAPSE_ACTION_NONE = 0,
-	MCHP_TC_SYNAPSE_ACTION_RISING_EDGE,
-	MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE,
-	MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE
-};
-
-static enum counter_synapse_action mchp_tc_synapse_actions[] = {
-	[MCHP_TC_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
-	[MCHP_TC_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
-	[MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
-	[MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+static const enum counter_synapse_action mchp_tc_synapse_actions[] = {
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
 };
 
 static struct counter_signal mchp_tc_count_signals[] = {
@@ -80,21 +68,23 @@ static struct counter_synapse mchp_tc_count_synapses[] = {
 	}
 };
 
-static int mchp_tc_function_get(struct counter_device *counter,
-				struct counter_count *count, size_t *function)
+static int mchp_tc_function_read(struct counter_device *counter,
+				 struct counter_count *count,
+				 enum counter_function *function)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 
 	if (priv->qdec_mode)
-		*function = MCHP_TC_FUNCTION_QUADRATURE;
+		*function = COUNTER_FUNCTION_QUADRATURE_X4;
 	else
-		*function = MCHP_TC_FUNCTION_INCREASE;
+		*function = COUNTER_FUNCTION_INCREASE;
 
 	return 0;
 }
 
-static int mchp_tc_function_set(struct counter_device *counter,
-				struct counter_count *count, size_t function)
+static int mchp_tc_function_write(struct counter_device *counter,
+				  struct counter_count *count,
+				  enum counter_function function)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 bmr, cmr;
@@ -106,7 +96,7 @@ static int mchp_tc_function_set(struct counter_device *counter,
 	cmr &= ~ATMEL_TC_WAVE;
 
 	switch (function) {
-	case MCHP_TC_FUNCTION_INCREASE:
+	case COUNTER_FUNCTION_INCREASE:
 		priv->qdec_mode = 0;
 		/* Set highest rate based on whether soc has gclk or not */
 		bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN);
@@ -118,7 +108,7 @@ static int mchp_tc_function_set(struct counter_device *counter,
 		cmr |=  ATMEL_TC_CMR_MASK;
 		cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0);
 		break;
-	case MCHP_TC_FUNCTION_QUADRATURE:
+	case COUNTER_FUNCTION_QUADRATURE_X4:
 		if (!priv->tc_cfg->has_qdec)
 			return -EINVAL;
 		/* In QDEC mode settings both channels 0 and 1 are required */
@@ -174,9 +164,10 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
 	return 0;
 }
 
-static int mchp_tc_action_get(struct counter_device *counter,
-			      struct counter_count *count,
-			      struct counter_synapse *synapse, size_t *action)
+static int mchp_tc_action_read(struct counter_device *counter,
+			       struct counter_count *count,
+			       struct counter_synapse *synapse,
+			       enum counter_synapse_action *action)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 cmr;
@@ -185,25 +176,26 @@ static int mchp_tc_action_get(struct counter_device *counter,
 
 	switch (cmr & ATMEL_TC_ETRGEDG) {
 	default:
-		*action = MCHP_TC_SYNAPSE_ACTION_NONE;
+		*action = COUNTER_SYNAPSE_ACTION_NONE;
 		break;
 	case ATMEL_TC_ETRGEDG_RISING:
-		*action = MCHP_TC_SYNAPSE_ACTION_RISING_EDGE;
+		*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 		break;
 	case ATMEL_TC_ETRGEDG_FALLING:
-		*action = MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE;
+		*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
 		break;
 	case ATMEL_TC_ETRGEDG_BOTH:
-		*action = MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE;
+		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	}
 
 	return 0;
 }
 
-static int mchp_tc_action_set(struct counter_device *counter,
-			      struct counter_count *count,
-			      struct counter_synapse *synapse, size_t action)
+static int mchp_tc_action_write(struct counter_device *counter,
+				struct counter_count *count,
+				struct counter_synapse *synapse,
+				enum counter_synapse_action action)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 edge = ATMEL_TC_ETRGEDG_NONE;
@@ -213,16 +205,16 @@ static int mchp_tc_action_set(struct counter_device *counter,
 		return -EINVAL;
 
 	switch (action) {
-	case MCHP_TC_SYNAPSE_ACTION_NONE:
+	case COUNTER_SYNAPSE_ACTION_NONE:
 		edge = ATMEL_TC_ETRGEDG_NONE;
 		break;
-	case MCHP_TC_SYNAPSE_ACTION_RISING_EDGE:
+	case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
 		edge = ATMEL_TC_ETRGEDG_RISING;
 		break;
-	case MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE:
+	case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
 		edge = ATMEL_TC_ETRGEDG_FALLING;
 		break;
-	case MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE:
+	case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
 		edge = ATMEL_TC_ETRGEDG_BOTH;
 		break;
 	default:
@@ -236,8 +228,7 @@ static int mchp_tc_action_set(struct counter_device *counter,
 }
 
 static int mchp_tc_count_read(struct counter_device *counter,
-			      struct counter_count *count,
-			      unsigned long *val)
+			      struct counter_count *count, u64 *val)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 cnt;
@@ -262,10 +253,10 @@ static struct counter_count mchp_tc_counts[] = {
 static const struct counter_ops mchp_tc_ops = {
 	.signal_read  = mchp_tc_count_signal_read,
 	.count_read   = mchp_tc_count_read,
-	.function_get = mchp_tc_function_get,
-	.function_set = mchp_tc_function_set,
-	.action_get   = mchp_tc_action_get,
-	.action_set   = mchp_tc_action_set
+	.function_read = mchp_tc_function_read,
+	.function_write = mchp_tc_function_write,
+	.action_read   = mchp_tc_action_read,
+	.action_write   = mchp_tc_action_write
 };
 
 static const struct atmel_tcb_config tcb_rm9200_config = {
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 31477c6a0611..af3cdc448e8b 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
+#include <linux/types.h>
 
 struct stm32_lptim_cnt {
 	struct counter_device counter;
@@ -130,32 +131,46 @@ static int stm32_lptim_setup(struct stm32_lptim_cnt *priv, int enable)
  * +---------+----------+----------+---------+----------+---------+
  */
 enum stm32_lptim_function {
-	STM32_LPTIM_COUNTER_INCREASE,
-	STM32_LPTIM_ENCODER_BOTH_EDGE,
+	STM32_LPTIM_COUNTER_INCREASE = COUNTER_FUNCTION_INCREASE,
+	STM32_LPTIM_ENCODER_BOTH_EDGE = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
-static enum counter_function stm32_lptim_functions[] = {
-	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_FUNCTION_INCREASE,
-	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_FUNCTION_QUADRATURE_X4,
+static const enum counter_function stm32_lptim_functions[] = {
+	STM32_LPTIM_COUNTER_INCREASE,
+	STM32_LPTIM_ENCODER_BOTH_EDGE,
 };
 
 enum stm32_lptim_synapse_action {
+	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
 	STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
 	STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
 	STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
 	STM32_LPTIM_SYNAPSE_ACTION_NONE,
 };
 
-static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
-	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
+static const enum stm32_lptim_synapse_action stm32_lptim_c2l_actions_map[] = {
+	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
+	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
+	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
+	[COUNTER_SYNAPSE_ACTION_NONE] = STM32_LPTIM_SYNAPSE_ACTION_NONE,
+};
+
+static const enum counter_synapse_action stm32_lptim_l2c_actions_map[] = {
 	[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 	[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
 	[STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
 	[STM32_LPTIM_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 };
 
+static const enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+	COUNTER_SYNAPSE_ACTION_NONE,
+};
+
 static int stm32_lptim_cnt_read(struct counter_device *counter,
-				struct counter_count *count, unsigned long *val)
+				struct counter_count *count, u64 *val)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 	u32 cnt;
@@ -170,9 +185,9 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
 	return 0;
 }
 
-static int stm32_lptim_function_get(struct counter_device *counter,
-				    struct counter_count *count,
-				    size_t *function)
+static int stm32_lptim_function_read(struct counter_device *counter,
+				     struct counter_count *count,
+				     enum counter_function *function)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 
@@ -189,9 +204,9 @@ static int stm32_lptim_function_get(struct counter_device *counter,
 	return -EINVAL;
 }
 
-static int stm32_lptim_function_set(struct counter_device *counter,
-				    struct counter_count *count,
-				    size_t function)
+static int stm32_lptim_function_write(struct counter_device *counter,
+				      struct counter_count *count,
+				      enum counter_function function)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 
@@ -212,9 +227,9 @@ static int stm32_lptim_function_set(struct counter_device *counter,
 	}
 }
 
-static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
-					   struct counter_count *count,
-					   void *private, char *buf)
+static int stm32_lptim_cnt_enable_read(struct counter_device *counter,
+				       struct counter_count *count,
+				       u8 *enable)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 	int ret;
@@ -223,22 +238,18 @@ static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
 	if (ret < 0)
 		return ret;
 
-	return scnprintf(buf, PAGE_SIZE, "%u\n", ret);
+	*enable = ret;
+
+	return 0;
 }
 
-static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,
-					    struct counter_count *count,
-					    void *private,
-					    const char *buf, size_t len)
+static int stm32_lptim_cnt_enable_write(struct counter_device *counter,
+					struct counter_count *count,
+					u8 enable)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
-	bool enable;
 	int ret;
 
-	ret = kstrtobool(buf, &enable);
-	if (ret)
-		return ret;
-
 	/* Check nobody uses the timer, or already disabled/enabled */
 	ret = stm32_lptim_is_enabled(priv);
 	if ((ret < 0) || (!ret && !enable))
@@ -254,65 +265,54 @@ static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,
 	if (ret)
 		return ret;
 
-	return len;
+	return 0;
 }
 
-static ssize_t stm32_lptim_cnt_ceiling_read(struct counter_device *counter,
-					    struct counter_count *count,
-					    void *private, char *buf)
+static int stm32_lptim_cnt_ceiling_read(struct counter_device *counter,
+					struct counter_count *count,
+					u64 *ceiling)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", priv->ceiling);
+	*ceiling = priv->ceiling;
+
+	return 0;
 }
 
-static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
-					     struct counter_count *count,
-					     void *private,
-					     const char *buf, size_t len)
+static int stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
+					 struct counter_count *count,
+					 u64 ceiling)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
-	unsigned int ceiling;
-	int ret;
 
 	if (stm32_lptim_is_enabled(priv))
 		return -EBUSY;
 
-	ret = kstrtouint(buf, 0, &ceiling);
-	if (ret)
-		return ret;
-
 	if (ceiling > STM32_LPTIM_MAX_ARR)
 		return -ERANGE;
 
 	priv->ceiling = ceiling;
 
-	return len;
+	return 0;
 }
 
-static const struct counter_count_ext stm32_lptim_cnt_ext[] = {
-	{
-		.name = "enable",
-		.read = stm32_lptim_cnt_enable_read,
-		.write = stm32_lptim_cnt_enable_write
-	},
-	{
-		.name = "ceiling",
-		.read = stm32_lptim_cnt_ceiling_read,
-		.write = stm32_lptim_cnt_ceiling_write
-	},
+static struct counter_comp stm32_lptim_cnt_ext[] = {
+	COUNTER_COMP_ENABLE(stm32_lptim_cnt_enable_read,
+			    stm32_lptim_cnt_enable_write),
+	COUNTER_COMP_CEILING(stm32_lptim_cnt_ceiling_read,
+			     stm32_lptim_cnt_ceiling_write),
 };
 
-static int stm32_lptim_action_get(struct counter_device *counter,
-				  struct counter_count *count,
-				  struct counter_synapse *synapse,
-				  size_t *action)
+static int stm32_lptim_action_read(struct counter_device *counter,
+				   struct counter_count *count,
+				   struct counter_synapse *synapse,
+				   enum counter_synapse_action *action)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
-	size_t function;
+	enum counter_function function;
 	int err;
 
-	err = stm32_lptim_function_get(counter, count, &function);
+	err = stm32_lptim_function_read(counter, count, &function);
 	if (err)
 		return err;
 
@@ -320,12 +320,12 @@ static int stm32_lptim_action_get(struct counter_device *counter,
 	case STM32_LPTIM_COUNTER_INCREASE:
 		/* LP Timer acts as up-counter on input 1 */
 		if (synapse->signal->id == count->synapses[0].signal->id)
-			*action = priv->polarity;
+			*action = stm32_lptim_l2c_actions_map[priv->polarity];
 		else
-			*action = STM32_LPTIM_SYNAPSE_ACTION_NONE;
+			*action = COUNTER_SYNAPSE_ACTION_NONE;
 		return 0;
 	case STM32_LPTIM_ENCODER_BOTH_EDGE:
-		*action = priv->polarity;
+		*action = stm32_lptim_l2c_actions_map[priv->polarity];
 		return 0;
 	default:
 		/* should never reach this path */
@@ -333,43 +333,39 @@ static int stm32_lptim_action_get(struct counter_device *counter,
 	}
 }
 
-static int stm32_lptim_action_set(struct counter_device *counter,
-				  struct counter_count *count,
-				  struct counter_synapse *synapse,
-				  size_t action)
+static int stm32_lptim_action_write(struct counter_device *counter,
+				    struct counter_count *count,
+				    struct counter_synapse *synapse,
+				    enum counter_synapse_action action)
 {
 	struct stm32_lptim_cnt *const priv = counter->priv;
-	size_t function;
+	enum counter_function function;
 	int err;
 
 	if (stm32_lptim_is_enabled(priv))
 		return -EBUSY;
 
-	err = stm32_lptim_function_get(counter, count, &function);
+	err = stm32_lptim_function_read(counter, count, &function);
 	if (err)
 		return err;
 
 	/* only set polarity when in counter mode (on input 1) */
-	if (function == STM32_LPTIM_COUNTER_INCREASE
-	    && synapse->signal->id == count->synapses[0].signal->id) {
-		switch (action) {
-		case STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE:
-		case STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE:
-		case STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES:
-			priv->polarity = action;
-			return 0;
-		}
-	}
+	if ((enum stm32_lptim_function)function != STM32_LPTIM_COUNTER_INCREASE
+	    || synapse->signal->id != count->synapses[0].signal->id
+	    || action == COUNTER_SYNAPSE_ACTION_NONE)
+		return -EINVAL;
 
-	return -EINVAL;
+	priv->polarity = stm32_lptim_c2l_actions_map[action];
+
+	return 0;
 }
 
 static const struct counter_ops stm32_lptim_cnt_ops = {
 	.count_read = stm32_lptim_cnt_read,
-	.function_get = stm32_lptim_function_get,
-	.function_set = stm32_lptim_function_set,
-	.action_get = stm32_lptim_action_get,
-	.action_set = stm32_lptim_action_set,
+	.function_read = stm32_lptim_function_read,
+	.function_write = stm32_lptim_function_write,
+	.action_read = stm32_lptim_action_read,
+	.action_write = stm32_lptim_action_write,
 };
 
 static struct counter_signal stm32_lptim_cnt_signals[] = {
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 02a7c8bd77df..9cc45948c9e1 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
+#include <linux/types.h>
 
 #define TIM_CCMR_CCXS	(BIT(8) | BIT(0))
 #define TIM_CCMR_MASK	(TIM_CCMR_CC1S | TIM_CCMR_CC2S | \
@@ -45,19 +46,19 @@ struct stm32_timer_cnt {
  */
 enum stm32_function {
 	STM32_SLAVE_MODE_DISABLED = -1,
+	STM32_ENCODER_MODE_1 = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	STM32_ENCODER_MODE_2 = COUNTER_FUNCTION_QUADRATURE_X2_B,
+	STM32_ENCODER_MODE_3 = COUNTER_FUNCTION_QUADRATURE_X4,
+};
+
+static const enum counter_function stm32_functions[] = {
 	STM32_ENCODER_MODE_1,
 	STM32_ENCODER_MODE_2,
 	STM32_ENCODER_MODE_3,
 };
 
-static enum counter_function stm32_functions[] = {
-	[STM32_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X2_A,
-	[STM32_ENCODER_MODE_2] = COUNTER_FUNCTION_QUADRATURE_X2_B,
-	[STM32_ENCODER_MODE_3] = COUNTER_FUNCTION_QUADRATURE_X4,
-};
-
 static int stm32_count_read(struct counter_device *counter,
-			    struct counter_count *count, unsigned long *val)
+			    struct counter_count *count, u64 *val)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 cnt;
@@ -69,8 +70,7 @@ static int stm32_count_read(struct counter_device *counter,
 }
 
 static int stm32_count_write(struct counter_device *counter,
-			     struct counter_count *count,
-			     const unsigned long val)
+			     struct counter_count *count, const u64 val)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 
@@ -80,8 +80,9 @@ static int stm32_count_write(struct counter_device *counter,
 	return regmap_write(priv->regmap, TIM_CNT, val);
 }
 
-static int stm32_function_get(struct counter_device *counter,
-			      struct counter_count *count, size_t *function)
+static int stm32_function_read(struct counter_device *counter,
+			       struct counter_count *count,
+			       enum counter_function *function)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 smcr;
@@ -103,8 +104,9 @@ static int stm32_function_get(struct counter_device *counter,
 	return -EINVAL;
 }
 
-static int stm32_function_set(struct counter_device *counter,
-			      struct counter_count *count, size_t function)
+static int stm32_function_write(struct counter_device *counter,
+				struct counter_count *count,
+				enum counter_function function)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 cr1, sms;
@@ -144,78 +146,67 @@ static int stm32_function_set(struct counter_device *counter,
 	return 0;
 }
 
-static ssize_t stm32_count_direction_read(struct counter_device *counter,
+static int stm32_count_direction_read(struct counter_device *counter,
 				      struct counter_count *count,
-				      void *private, char *buf)
+				      enum counter_count_direction *direction)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
-	const char *direction;
 	u32 cr1;
 
 	regmap_read(priv->regmap, TIM_CR1, &cr1);
-	direction = (cr1 & TIM_CR1_DIR) ? "backward" : "forward";
+	*direction = (cr1 & TIM_CR1_DIR) ? COUNTER_COUNT_DIRECTION_BACKWARD :
+		COUNTER_COUNT_DIRECTION_FORWARD;
 
-	return scnprintf(buf, PAGE_SIZE, "%s\n", direction);
+	return 0;
 }
 
-static ssize_t stm32_count_ceiling_read(struct counter_device *counter,
-					struct counter_count *count,
-					void *private, char *buf)
+static int stm32_count_ceiling_read(struct counter_device *counter,
+				    struct counter_count *count, u64 *ceiling)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 arr;
 
 	regmap_read(priv->regmap, TIM_ARR, &arr);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", arr);
+	*ceiling = arr;
+
+	return 0;
 }
 
-static ssize_t stm32_count_ceiling_write(struct counter_device *counter,
-					 struct counter_count *count,
-					 void *private,
-					 const char *buf, size_t len)
+static int stm32_count_ceiling_write(struct counter_device *counter,
+				     struct counter_count *count, u64 ceiling)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
-	unsigned int ceiling;
-	int ret;
 
-	ret = kstrtouint(buf, 0, &ceiling);
-	if (ret)
-		return ret;
+	if (ceiling != (u32)ceiling)
+		return -ERANGE;
 
 	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 	regmap_write(priv->regmap, TIM_ARR, ceiling);
 
 	priv->ceiling = ceiling;
-	return len;
+	return 0;
 }
 
-static ssize_t stm32_count_enable_read(struct counter_device *counter,
-				       struct counter_count *count,
-				       void *private, char *buf)
+static int stm32_count_enable_read(struct counter_device *counter,
+				   struct counter_count *count, u8 *enable)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
 	u32 cr1;
 
 	regmap_read(priv->regmap, TIM_CR1, &cr1);
 
-	return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)(cr1 & TIM_CR1_CEN));
+	*enable = cr1 & TIM_CR1_CEN;
+
+	return 0;
 }
 
-static ssize_t stm32_count_enable_write(struct counter_device *counter,
-					struct counter_count *count,
-					void *private,
-					const char *buf, size_t len)
+static int stm32_count_enable_write(struct counter_device *counter,
+				    struct counter_count *count, u8 enable)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
-	int err;
 	u32 cr1;
-	bool enable;
-
-	err = kstrtobool(buf, &enable);
-	if (err)
-		return err;
 
 	if (enable) {
 		regmap_read(priv->regmap, TIM_CR1, &cr1);
@@ -234,48 +225,33 @@ static ssize_t stm32_count_enable_write(struct counter_device *counter,
 	/* Keep enabled state to properly handle low power states */
 	priv->enabled = enable;
 
-	return len;
+	return 0;
 }
 
-static const struct counter_count_ext stm32_count_ext[] = {
-	{
-		.name = "direction",
-		.read = stm32_count_direction_read,
-	},
-	{
-		.name = "enable",
-		.read = stm32_count_enable_read,
-		.write = stm32_count_enable_write
-	},
-	{
-		.name = "ceiling",
-		.read = stm32_count_ceiling_read,
-		.write = stm32_count_ceiling_write
-	},
+static struct counter_comp stm32_count_ext[] = {
+	COUNTER_COMP_DIRECTION(stm32_count_direction_read),
+	COUNTER_COMP_ENABLE(stm32_count_enable_read, stm32_count_enable_write),
+	COUNTER_COMP_CEILING(stm32_count_ceiling_read,
+			     stm32_count_ceiling_write),
 };
 
-enum stm32_synapse_action {
-	STM32_SYNAPSE_ACTION_NONE,
-	STM32_SYNAPSE_ACTION_BOTH_EDGES
+static const enum counter_synapse_action stm32_synapse_actions[] = {
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };
 
-static enum counter_synapse_action stm32_synapse_actions[] = {
-	[STM32_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
-	[STM32_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
-};
-
-static int stm32_action_get(struct counter_device *counter,
-			    struct counter_count *count,
-			    struct counter_synapse *synapse,
-			    size_t *action)
+static int stm32_action_read(struct counter_device *counter,
+			     struct counter_count *count,
+			     struct counter_synapse *synapse,
+			     enum counter_synapse_action *action)
 {
-	size_t function;
+	enum counter_function function;
 	int err;
 
 	/* Default action mode (e.g. STM32_SLAVE_MODE_DISABLED) */
-	*action = STM32_SYNAPSE_ACTION_NONE;
+	*action = COUNTER_SYNAPSE_ACTION_NONE;
 
-	err = stm32_function_get(counter, count, &function);
+	err = stm32_function_read(counter, count, &function);
 	if (err)
 		return 0;
 
@@ -283,16 +259,16 @@ static int stm32_action_get(struct counter_device *counter,
 	case STM32_ENCODER_MODE_1:
 		/* counts up/down on TI1FP1 edge depending on TI2FP2 level */
 		if (synapse->signal->id == count->synapses[0].signal->id)
-			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
+			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	case STM32_ENCODER_MODE_2:
 		/* counts up/down on TI2FP2 edge depending on TI1FP1 level */
 		if (synapse->signal->id == count->synapses[1].signal->id)
-			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
+			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	case STM32_ENCODER_MODE_3:
 		/* counts up/down on both TI1FP1 and TI2FP2 edges */
-		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
+		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	default:
 		/* should never reach this path */
@@ -305,9 +281,9 @@ static int stm32_action_get(struct counter_device *counter,
 static const struct counter_ops stm32_timer_cnt_ops = {
 	.count_read = stm32_count_read,
 	.count_write = stm32_count_write,
-	.function_get = stm32_function_get,
-	.function_set = stm32_function_set,
-	.action_get = stm32_action_get,
+	.function_read = stm32_function_read,
+	.function_write = stm32_function_write,
+	.action_read = stm32_action_read,
 };
 
 static struct counter_signal stm32_signals[] = {
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
index 8d45b0443610..e1ca2ce5a9d9 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
+#include <linux/types.h>
 
 /* 32-bit registers */
 #define QPOSCNT		0x0
@@ -80,12 +81,6 @@ enum ti_eqep_function {
 	TI_EQEP_FUNCTION_DOWN_COUNT,
 };
 
-enum {
-	TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES,
-	TI_EQEP_SYNAPSE_ACTION_RISING_EDGE,
-	TI_EQEP_SYNAPSE_ACTION_NONE,
-};
-
 struct ti_eqep_cnt {
 	struct counter_device counter;
 	struct regmap *regmap32;
@@ -93,7 +88,7 @@ struct ti_eqep_cnt {
 };
 
 static int ti_eqep_count_read(struct counter_device *counter,
-			      struct counter_count *count, unsigned long *val)
+			      struct counter_count *count, u64 *val)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
 	u32 cnt;
@@ -105,7 +100,7 @@ static int ti_eqep_count_read(struct counter_device *counter,
 }
 
 static int ti_eqep_count_write(struct counter_device *counter,
-			       struct counter_count *count, unsigned long val)
+			       struct counter_count *count, u64 val)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
 	u32 max;
@@ -117,62 +112,98 @@ static int ti_eqep_count_write(struct counter_device *counter,
 	return regmap_write(priv->regmap32, QPOSCNT, val);
 }
 
-static int ti_eqep_function_get(struct counter_device *counter,
-				struct counter_count *count, size_t *function)
+static int ti_eqep_function_read(struct counter_device *counter,
+				 struct counter_count *count,
+				 enum counter_function *function)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
 	u32 qdecctl;
 
 	regmap_read(priv->regmap16, QDECCTL, &qdecctl);
-	*function = (qdecctl & QDECCTL_QSRC) >> QDECCTL_QSRC_SHIFT;
+
+	switch ((qdecctl & QDECCTL_QSRC) >> QDECCTL_QSRC_SHIFT) {
+	case TI_EQEP_FUNCTION_QUAD_COUNT:
+		*function = COUNTER_FUNCTION_QUADRATURE_X4;
+		break;
+	case TI_EQEP_FUNCTION_DIR_COUNT:
+		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
+		break;
+	case TI_EQEP_FUNCTION_UP_COUNT:
+		*function = COUNTER_FUNCTION_INCREASE;
+		break;
+	case TI_EQEP_FUNCTION_DOWN_COUNT:
+		*function = COUNTER_FUNCTION_DECREASE;
+		break;
+	}
 
 	return 0;
 }
 
-static int ti_eqep_function_set(struct counter_device *counter,
-				struct counter_count *count, size_t function)
+static int ti_eqep_function_write(struct counter_device *counter,
+				  struct counter_count *count,
+				  enum counter_function function)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
+	enum ti_eqep_function qsrc;
+
+	switch (function) {
+	case COUNTER_FUNCTION_QUADRATURE_X4:
+		qsrc = TI_EQEP_FUNCTION_QUAD_COUNT;
+		break;
+	case COUNTER_FUNCTION_PULSE_DIRECTION:
+		qsrc = TI_EQEP_FUNCTION_DIR_COUNT;
+		break;
+	case COUNTER_FUNCTION_INCREASE:
+		qsrc = TI_EQEP_FUNCTION_UP_COUNT;
+		break;
+	case COUNTER_FUNCTION_DECREASE:
+		qsrc = TI_EQEP_FUNCTION_DOWN_COUNT;
+		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
+	}
 
 	return regmap_write_bits(priv->regmap16, QDECCTL, QDECCTL_QSRC,
-				 function << QDECCTL_QSRC_SHIFT);
+				 qsrc << QDECCTL_QSRC_SHIFT);
 }
 
-static int ti_eqep_action_get(struct counter_device *counter,
-			      struct counter_count *count,
-			      struct counter_synapse *synapse, size_t *action)
+static int ti_eqep_action_read(struct counter_device *counter,
+			       struct counter_count *count,
+			       struct counter_synapse *synapse,
+			       enum counter_synapse_action *action)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
-	size_t function;
+	enum counter_function function;
 	u32 qdecctl;
 	int err;
 
-	err = ti_eqep_function_get(counter, count, &function);
+	err = ti_eqep_function_read(counter, count, &function);
 	if (err)
 		return err;
 
 	switch (function) {
-	case TI_EQEP_FUNCTION_QUAD_COUNT:
+	case COUNTER_FUNCTION_QUADRATURE_X4:
 		/* In quadrature mode, the rising and falling edge of both
 		 * QEPA and QEPB trigger QCLK.
 		 */
-		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
+		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
-	case TI_EQEP_FUNCTION_DIR_COUNT:
+	case COUNTER_FUNCTION_PULSE_DIRECTION:
 		/* In direction-count mode only rising edge of QEPA is counted
 		 * and QEPB gives direction.
 		 */
 		switch (synapse->signal->id) {
 		case TI_EQEP_SIGNAL_QEPA:
-			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 			break;
 		default:
-			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
+			*action = COUNTER_SYNAPSE_ACTION_NONE;
 			break;
 		}
 		break;
-	case TI_EQEP_FUNCTION_UP_COUNT:
-	case TI_EQEP_FUNCTION_DOWN_COUNT:
+	case COUNTER_FUNCTION_INCREASE:
+	case COUNTER_FUNCTION_DECREASE:
 		/* In up/down-count modes only QEPA is counted and QEPB is not
 		 * used.
 		 */
@@ -183,12 +214,12 @@ static int ti_eqep_action_get(struct counter_device *counter,
 				return err;
 
 			if (qdecctl & QDECCTL_XCR)
-				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
+				*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 			else
-				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 			break;
 		default:
-			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
+			*action = COUNTER_SYNAPSE_ACTION_NONE;
 			break;
 		}
 		break;
@@ -203,117 +234,67 @@ static int ti_eqep_action_get(struct counter_device *counter,
 static const struct counter_ops ti_eqep_counter_ops = {
 	.count_read	= ti_eqep_count_read,
 	.count_write	= ti_eqep_count_write,
-	.function_get	= ti_eqep_function_get,
-	.function_set	= ti_eqep_function_set,
-	.action_get	= ti_eqep_action_get,
+	.function_read	= ti_eqep_function_read,
+	.function_write	= ti_eqep_function_write,
+	.action_read	= ti_eqep_action_read,
 };
 
-static ssize_t ti_eqep_position_ceiling_read(struct counter_device *counter,
-					     struct counter_count *count,
-					     void *ext_priv, char *buf)
+static int ti_eqep_position_ceiling_read(struct counter_device *counter,
+					 struct counter_count *count,
+					 u64 *ceiling)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
 	u32 qposmax;
 
 	regmap_read(priv->regmap32, QPOSMAX, &qposmax);
 
-	return sprintf(buf, "%u\n", qposmax);
-}
+	*ceiling = qposmax;
 
-static ssize_t ti_eqep_position_ceiling_write(struct counter_device *counter,
-					      struct counter_count *count,
-					      void *ext_priv, const char *buf,
-					      size_t len)
-{
-	struct ti_eqep_cnt *priv = counter->priv;
-	int err;
-	u32 res;
-
-	err = kstrtouint(buf, 0, &res);
-	if (err < 0)
-		return err;
-
-	regmap_write(priv->regmap32, QPOSMAX, res);
-
-	return len;
-}
-
-static ssize_t ti_eqep_position_floor_read(struct counter_device *counter,
-					   struct counter_count *count,
-					   void *ext_priv, char *buf)
-{
-	struct ti_eqep_cnt *priv = counter->priv;
-	u32 qposinit;
-
-	regmap_read(priv->regmap32, QPOSINIT, &qposinit);
-
-	return sprintf(buf, "%u\n", qposinit);
+	return 0;
 }
 
-static ssize_t ti_eqep_position_floor_write(struct counter_device *counter,
-					    struct counter_count *count,
-					    void *ext_priv, const char *buf,
-					    size_t len)
+static int ti_eqep_position_ceiling_write(struct counter_device *counter,
+					  struct counter_count *count,
+					  u64 ceiling)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
-	int err;
-	u32 res;
 
-	err = kstrtouint(buf, 0, &res);
-	if (err < 0)
-		return err;
+	if (ceiling != (u32)ceiling)
+		return -ERANGE;
 
-	regmap_write(priv->regmap32, QPOSINIT, res);
+	regmap_write(priv->regmap32, QPOSMAX, ceiling);
 
-	return len;
+	return 0;
 }
 
-static ssize_t ti_eqep_position_enable_read(struct counter_device *counter,
-					    struct counter_count *count,
-					    void *ext_priv, char *buf)
+static int ti_eqep_position_enable_read(struct counter_device *counter,
+					struct counter_count *count, u8 *enable)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
 	u32 qepctl;
 
 	regmap_read(priv->regmap16, QEPCTL, &qepctl);
 
-	return sprintf(buf, "%u\n", !!(qepctl & QEPCTL_PHEN));
+	*enable = !!(qepctl & QEPCTL_PHEN);
+
+	return 0;
 }
 
-static ssize_t ti_eqep_position_enable_write(struct counter_device *counter,
-					     struct counter_count *count,
-					     void *ext_priv, const char *buf,
-					     size_t len)
+static int ti_eqep_position_enable_write(struct counter_device *counter,
+					 struct counter_count *count, u8 enable)
 {
 	struct ti_eqep_cnt *priv = counter->priv;
-	int err;
-	bool res;
-
-	err = kstrtobool(buf, &res);
-	if (err < 0)
-		return err;
 
-	regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, res ? -1 : 0);
+	regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, enable ? -1 : 0);
 
-	return len;
+	return 0;
 }
 
-static struct counter_count_ext ti_eqep_position_ext[] = {
-	{
-		.name	= "ceiling",
-		.read	= ti_eqep_position_ceiling_read,
-		.write	= ti_eqep_position_ceiling_write,
-	},
-	{
-		.name	= "floor",
-		.read	= ti_eqep_position_floor_read,
-		.write	= ti_eqep_position_floor_write,
-	},
-	{
-		.name	= "enable",
-		.read	= ti_eqep_position_enable_read,
-		.write	= ti_eqep_position_enable_write,
-	},
+static struct counter_comp ti_eqep_position_ext[] = {
+	COUNTER_COMP_CEILING(ti_eqep_position_ceiling_read,
+			     ti_eqep_position_ceiling_write),
+	COUNTER_COMP_ENABLE(ti_eqep_position_enable_read,
+			    ti_eqep_position_enable_write),
 };
 
 static struct counter_signal ti_eqep_signals[] = {
@@ -328,16 +309,16 @@ static struct counter_signal ti_eqep_signals[] = {
 };
 
 static const enum counter_function ti_eqep_position_functions[] = {
-	[TI_EQEP_FUNCTION_QUAD_COUNT]	= COUNTER_FUNCTION_QUADRATURE_X4,
-	[TI_EQEP_FUNCTION_DIR_COUNT]	= COUNTER_FUNCTION_PULSE_DIRECTION,
-	[TI_EQEP_FUNCTION_UP_COUNT]	= COUNTER_FUNCTION_INCREASE,
-	[TI_EQEP_FUNCTION_DOWN_COUNT]	= COUNTER_FUNCTION_DECREASE,
+	COUNTER_FUNCTION_QUADRATURE_X4,
+	COUNTER_FUNCTION_PULSE_DIRECTION,
+	COUNTER_FUNCTION_INCREASE,
+	COUNTER_FUNCTION_DECREASE,
 };
 
 static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
-	[TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES]	= COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
-	[TI_EQEP_SYNAPSE_ACTION_RISING_EDGE]	= COUNTER_SYNAPSE_ACTION_RISING_EDGE,
-	[TI_EQEP_SYNAPSE_ACTION_NONE]		= COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_NONE,
 };
 
 static struct counter_synapse ti_eqep_position_synapses[] = {
diff --git a/include/linux/counter.h b/include/linux/counter.h
index d16ce2819b48..76b0b06dd5db 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -6,42 +6,184 @@
 #ifndef _COUNTER_H_
 #define _COUNTER_H_
 
-#include <linux/counter_enum.h>
 #include <linux/device.h>
+#include <linux/kernel.h>
 #include <linux/types.h>
 
+struct counter_device;
+struct counter_count;
+struct counter_synapse;
+struct counter_signal;
+
+enum counter_comp_type {
+	COUNTER_COMP_U8,
+	COUNTER_COMP_U64,
+	COUNTER_COMP_BOOL,
+	COUNTER_COMP_SIGNAL_LEVEL,
+	COUNTER_COMP_FUNCTION,
+	COUNTER_COMP_SYNAPSE_ACTION,
+	COUNTER_COMP_ENUM,
+	COUNTER_COMP_COUNT_DIRECTION,
+	COUNTER_COMP_COUNT_MODE,
+};
+
+enum counter_scope {
+	COUNTER_SCOPE_DEVICE,
+	COUNTER_SCOPE_SIGNAL,
+	COUNTER_SCOPE_COUNT,
+};
+
 enum counter_count_direction {
-	COUNTER_COUNT_DIRECTION_FORWARD = 0,
-	COUNTER_COUNT_DIRECTION_BACKWARD
+	COUNTER_COUNT_DIRECTION_FORWARD,
+	COUNTER_COUNT_DIRECTION_BACKWARD,
 };
-extern const char *const counter_count_direction_str[2];
 
 enum counter_count_mode {
-	COUNTER_COUNT_MODE_NORMAL = 0,
+	COUNTER_COUNT_MODE_NORMAL,
 	COUNTER_COUNT_MODE_RANGE_LIMIT,
 	COUNTER_COUNT_MODE_NON_RECYCLE,
-	COUNTER_COUNT_MODE_MODULO_N
+	COUNTER_COUNT_MODE_MODULO_N,
 };
-extern const char *const counter_count_mode_str[4];
 
-struct counter_device;
-struct counter_signal;
+enum counter_function {
+	COUNTER_FUNCTION_INCREASE,
+	COUNTER_FUNCTION_DECREASE,
+	COUNTER_FUNCTION_PULSE_DIRECTION,
+	COUNTER_FUNCTION_QUADRATURE_X1_A,
+	COUNTER_FUNCTION_QUADRATURE_X1_B,
+	COUNTER_FUNCTION_QUADRATURE_X2_A,
+	COUNTER_FUNCTION_QUADRATURE_X2_B,
+	COUNTER_FUNCTION_QUADRATURE_X4,
+};
+
+enum counter_signal_level {
+	COUNTER_SIGNAL_LEVEL_LOW,
+	COUNTER_SIGNAL_LEVEL_HIGH,
+};
+
+enum counter_synapse_action {
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+};
 
 /**
- * struct counter_signal_ext - Counter Signal extensions
- * @name:	attribute name
- * @read:	read callback for this attribute; may be NULL
- * @write:	write callback for this attribute; may be NULL
- * @priv:	data private to the driver
+ * struct counter_comp - Counter component node
+ * @type:		Counter component data type
+ * @name:		device-specific component name
+ * @priv:		component-relevant data
+ * @action_read		Synapse action mode read callback. The read value of the
+ *			respective Synapse action mode should be passed back via
+ *			the action parameter.
+ * @device_u8_read	Device u8 component read callback. The read value of the
+ *			respective Device u8 component should be passed back via
+ *			the val parameter.
+ * @count_u8_read	Count u8 component read callback. The read value of the
+ *			respective Count u8 component should be passed back via
+ *			the val parameter.
+ * @signal_u8_read	Signal u8 component read callback. The read value of the
+ *			respective Signal u8 component should be passed back via
+ *			the val parameter.
+ * @device_u32_read	Device u32 component read callback. The read value of
+ *			the respective Device u32 component should be passed
+ *			back via the val parameter.
+ * @count_u32_read	Count u32 component read callback. The read value of the
+ *			respective Count u32 component should be passed back via
+ *			the val parameter.
+ * @signal_u32_read	Signal u32 component read callback. The read value of
+ *			the respective Signal u32 component should be passed
+ *			back via the val parameter.
+ * @device_u64_read	Device u64 component read callback. The read value of
+ *			the respective Device u64 component should be passed
+ *			back via the val parameter.
+ * @count_u64_read	Count u64 component read callback. The read value of the
+ *			respective Count u64 component should be passed back via
+ *			the val parameter.
+ * @signal_u64_read	Signal u64 component read callback. The read value of
+ *			the respective Signal u64 component should be passed
+ *			back via the val parameter.
+ * @action_write	Synapse action mode write callback. The write value of
+ *			the respective Synapse action mode is passed via the
+ *			action parameter.
+ * @device_u8_write	Device u8 component write callback. The write value of
+ *			the respective Device u8 component is passed via the val
+ *			parameter.
+ * @count_u8_write	Count u8 component write callback. The write value of
+ *			the respective Count u8 component is passed via the val
+ *			parameter.
+ * @signal_u8_write	Signal u8 component write callback. The write value of
+ *			the respective Signal u8 component is passed via the val
+ *			parameter.
+ * @device_u32_write	Device u32 component write callback. The write value of
+ *			the respective Device u32 component is passed via the
+ *			val parameter.
+ * @count_u32_write	Count u32 component write callback. The write value of
+ *			the respective Count u32 component is passed via the val
+ *			parameter.
+ * @signal_u32_write	Signal u32 component write callback. The write value of
+ *			the respective Signal u32 component is passed via the
+ *			val parameter.
+ * @device_u64_write	Device u64 component write callback. The write value of
+ *			the respective Device u64 component is passed via the
+ *			val parameter.
+ * @count_u64_write	Count u64 component write callback. The write value of
+ *			the respective Count u64 component is passed via the val
+ *			parameter.
+ * @signal_u64_write	Signal u64 component write callback. The write value of
+ *			the respective Signal u64 component is passed via the
+ *			val parameter.
  */
-struct counter_signal_ext {
+struct counter_comp {
+	enum counter_comp_type type;
 	const char *name;
-	ssize_t (*read)(struct counter_device *counter,
-			struct counter_signal *signal, void *priv, char *buf);
-	ssize_t (*write)(struct counter_device *counter,
-			 struct counter_signal *signal, void *priv,
-			 const char *buf, size_t len);
 	void *priv;
+	union {
+		int (*action_read)(struct counter_device *counter,
+				   struct counter_count *count,
+				   struct counter_synapse *synapse,
+				   enum counter_synapse_action *action);
+		int (*device_u8_read)(struct counter_device *counter, u8 *val);
+		int (*count_u8_read)(struct counter_device *counter,
+				     struct counter_count *count, u8 *val);
+		int (*signal_u8_read)(struct counter_device *counter,
+				      struct counter_signal *signal, u8 *val);
+		int (*device_u32_read)(struct counter_device *counter,
+				       u32 *val);
+		int (*count_u32_read)(struct counter_device *counter,
+				      struct counter_count *count, u32 *val);
+		int (*signal_u32_read)(struct counter_device *counter,
+				       struct counter_signal *signal, u32 *val);
+		int (*device_u64_read)(struct counter_device *counter,
+				       u64 *val);
+		int (*count_u64_read)(struct counter_device *counter,
+				      struct counter_count *count, u64 *val);
+		int (*signal_u64_read)(struct counter_device *counter,
+				       struct counter_signal *signal, u64 *val);
+	};
+	union {
+		int (*action_write)(struct counter_device *counter,
+				    struct counter_count *count,
+				    struct counter_synapse *synapse,
+				    enum counter_synapse_action action);
+		int (*device_u8_write)(struct counter_device *counter, u8 val);
+		int (*count_u8_write)(struct counter_device *counter,
+				      struct counter_count *count, u8 val);
+		int (*signal_u8_write)(struct counter_device *counter,
+				       struct counter_signal *signal, u8 val);
+		int (*device_u32_write)(struct counter_device *counter,
+					u32 val);
+		int (*count_u32_write)(struct counter_device *counter,
+				       struct counter_count *count, u32 val);
+		int (*signal_u32_write)(struct counter_device *counter,
+					struct counter_signal *signal, u32 val);
+		int (*device_u64_write)(struct counter_device *counter,
+					u64 val);
+		int (*count_u64_write)(struct counter_device *counter,
+				       struct counter_count *count, u64 val);
+		int (*signal_u64_write)(struct counter_device *counter,
+					struct counter_signal *signal, u64 val);
+	};
 };
 
 /**
@@ -57,122 +199,23 @@ struct counter_signal {
 	int id;
 	const char *name;
 
-	const struct counter_signal_ext *ext;
+	struct counter_comp *ext;
 	size_t num_ext;
-
-	void *priv;
-};
-
-/**
- * struct counter_signal_enum_ext - Signal enum extension attribute
- * @items:	Array of strings
- * @num_items:	Number of items specified in @items
- * @set:	Set callback function; may be NULL
- * @get:	Get callback function; may be NULL
- *
- * The counter_signal_enum_ext structure can be used to implement enum style
- * Signal extension attributes. Enum style attributes are those which have a set
- * of strings that map to unsigned integer values. The Generic Counter Signal
- * enum extension helper code takes care of mapping between value and string, as
- * well as generating a "_available" file which contains a list of all available
- * items. The get callback is used to query the currently active item; the index
- * of the item within the respective items array is returned via the 'item'
- * parameter. The set callback is called when the attribute is updated; the
- * 'item' parameter contains the index of the newly activated item within the
- * respective items array.
- */
-struct counter_signal_enum_ext {
-	const char * const *items;
-	size_t num_items;
-	int (*get)(struct counter_device *counter,
-		   struct counter_signal *signal, size_t *item);
-	int (*set)(struct counter_device *counter,
-		   struct counter_signal *signal, size_t item);
-};
-
-/**
- * COUNTER_SIGNAL_ENUM() - Initialize Signal enum extension
- * @_name:	Attribute name
- * @_e:		Pointer to a counter_signal_enum_ext structure
- *
- * This should usually be used together with COUNTER_SIGNAL_ENUM_AVAILABLE()
- */
-#define COUNTER_SIGNAL_ENUM(_name, _e) \
-{ \
-	.name = (_name), \
-	.read = counter_signal_enum_read, \
-	.write = counter_signal_enum_write, \
-	.priv = (_e) \
-}
-
-/**
- * COUNTER_SIGNAL_ENUM_AVAILABLE() - Initialize Signal enum available extension
- * @_name:	Attribute name ("_available" will be appended to the name)
- * @_e:		Pointer to a counter_signal_enum_ext structure
- *
- * Creates a read only attribute that lists all the available enum items in a
- * newline separated list. This should usually be used together with
- * COUNTER_SIGNAL_ENUM()
- */
-#define COUNTER_SIGNAL_ENUM_AVAILABLE(_name, _e) \
-{ \
-	.name = (_name "_available"), \
-	.read = counter_signal_enum_available_read, \
-	.priv = (_e) \
-}
-
-enum counter_synapse_action {
-	COUNTER_SYNAPSE_ACTION_NONE = 0,
-	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
-	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
-	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };
 
 /**
  * struct counter_synapse - Counter Synapse node
- * @action:		index of current action mode
  * @actions_list:	array of available action modes
  * @num_actions:	number of action modes specified in @actions_list
  * @signal:		pointer to associated signal
  */
 struct counter_synapse {
-	size_t action;
 	const enum counter_synapse_action *actions_list;
 	size_t num_actions;
 
 	struct counter_signal *signal;
 };
 
-struct counter_count;
-
-/**
- * struct counter_count_ext - Counter Count extension
- * @name:	attribute name
- * @read:	read callback for this attribute; may be NULL
- * @write:	write callback for this attribute; may be NULL
- * @priv:	data private to the driver
- */
-struct counter_count_ext {
-	const char *name;
-	ssize_t (*read)(struct counter_device *counter,
-			struct counter_count *count, void *priv, char *buf);
-	ssize_t (*write)(struct counter_device *counter,
-			 struct counter_count *count, void *priv,
-			 const char *buf, size_t len);
-	void *priv;
-};
-
-enum counter_function {
-	COUNTER_FUNCTION_INCREASE = 0,
-	COUNTER_FUNCTION_DECREASE,
-	COUNTER_FUNCTION_PULSE_DIRECTION,
-	COUNTER_FUNCTION_QUADRATURE_X1_A,
-	COUNTER_FUNCTION_QUADRATURE_X1_B,
-	COUNTER_FUNCTION_QUADRATURE_X2_A,
-	COUNTER_FUNCTION_QUADRATURE_X2_B,
-	COUNTER_FUNCTION_QUADRATURE_X4
-};
-
 /**
  * struct counter_count - Counter Count node
  * @id:			unique ID used to identify Count
@@ -191,108 +234,14 @@ struct counter_count {
 	int id;
 	const char *name;
 
-	size_t function;
 	const enum counter_function *functions_list;
 	size_t num_functions;
 
 	struct counter_synapse *synapses;
 	size_t num_synapses;
 
-	const struct counter_count_ext *ext;
+	struct counter_comp *ext;
 	size_t num_ext;
-
-	void *priv;
-};
-
-/**
- * struct counter_count_enum_ext - Count enum extension attribute
- * @items:	Array of strings
- * @num_items:	Number of items specified in @items
- * @set:	Set callback function; may be NULL
- * @get:	Get callback function; may be NULL
- *
- * The counter_count_enum_ext structure can be used to implement enum style
- * Count extension attributes. Enum style attributes are those which have a set
- * of strings that map to unsigned integer values. The Generic Counter Count
- * enum extension helper code takes care of mapping between value and string, as
- * well as generating a "_available" file which contains a list of all available
- * items. The get callback is used to query the currently active item; the index
- * of the item within the respective items array is returned via the 'item'
- * parameter. The set callback is called when the attribute is updated; the
- * 'item' parameter contains the index of the newly activated item within the
- * respective items array.
- */
-struct counter_count_enum_ext {
-	const char * const *items;
-	size_t num_items;
-	int (*get)(struct counter_device *counter, struct counter_count *count,
-		   size_t *item);
-	int (*set)(struct counter_device *counter, struct counter_count *count,
-		   size_t item);
-};
-
-/**
- * COUNTER_COUNT_ENUM() - Initialize Count enum extension
- * @_name:	Attribute name
- * @_e:		Pointer to a counter_count_enum_ext structure
- *
- * This should usually be used together with COUNTER_COUNT_ENUM_AVAILABLE()
- */
-#define COUNTER_COUNT_ENUM(_name, _e) \
-{ \
-	.name = (_name), \
-	.read = counter_count_enum_read, \
-	.write = counter_count_enum_write, \
-	.priv = (_e) \
-}
-
-/**
- * COUNTER_COUNT_ENUM_AVAILABLE() - Initialize Count enum available extension
- * @_name:	Attribute name ("_available" will be appended to the name)
- * @_e:		Pointer to a counter_count_enum_ext structure
- *
- * Creates a read only attribute that lists all the available enum items in a
- * newline separated list. This should usually be used together with
- * COUNTER_COUNT_ENUM()
- */
-#define COUNTER_COUNT_ENUM_AVAILABLE(_name, _e) \
-{ \
-	.name = (_name "_available"), \
-	.read = counter_count_enum_available_read, \
-	.priv = (_e) \
-}
-
-/**
- * struct counter_device_attr_group - internal container for attribute group
- * @attr_group:	Counter sysfs attributes group
- * @attr_list:	list to keep track of created Counter sysfs attributes
- * @num_attr:	number of Counter sysfs attributes
- */
-struct counter_device_attr_group {
-	struct attribute_group attr_group;
-	struct list_head attr_list;
-	size_t num_attr;
-};
-
-/**
- * struct counter_device_state - internal state container for a Counter device
- * @id:			unique ID used to identify the Counter
- * @dev:		internal device structure
- * @groups_list:	attribute groups list (for Signals, Counts, and ext)
- * @num_groups:		number of attribute groups containers
- * @groups:		Counter sysfs attribute groups (to populate @dev.groups)
- */
-struct counter_device_state {
-	int id;
-	struct device dev;
-	struct counter_device_attr_group *groups_list;
-	size_t num_groups;
-	const struct attribute_group **groups;
-};
-
-enum counter_signal_level {
-	COUNTER_SIGNAL_LEVEL_LOW,
-	COUNTER_SIGNAL_LEVEL_HIGH,
 };
 
 /**
@@ -326,97 +275,29 @@ struct counter_ops {
 			   struct counter_signal *signal,
 			   enum counter_signal_level *level);
 	int (*count_read)(struct counter_device *counter,
-			  struct counter_count *count, unsigned long *val);
+			  struct counter_count *count, u64 *value);
 	int (*count_write)(struct counter_device *counter,
-			   struct counter_count *count, unsigned long val);
-	int (*function_get)(struct counter_device *counter,
-			    struct counter_count *count, size_t *function);
-	int (*function_set)(struct counter_device *counter,
-			    struct counter_count *count, size_t function);
-	int (*action_get)(struct counter_device *counter,
-			  struct counter_count *count,
-			  struct counter_synapse *synapse, size_t *action);
-	int (*action_set)(struct counter_device *counter,
-			  struct counter_count *count,
-			  struct counter_synapse *synapse, size_t action);
-};
-
-/**
- * struct counter_device_ext - Counter device extension
- * @name:	attribute name
- * @read:	read callback for this attribute; may be NULL
- * @write:	write callback for this attribute; may be NULL
- * @priv:	data private to the driver
- */
-struct counter_device_ext {
-	const char *name;
-	ssize_t (*read)(struct counter_device *counter, void *priv, char *buf);
-	ssize_t (*write)(struct counter_device *counter, void *priv,
-			 const char *buf, size_t len);
-	void *priv;
+			   struct counter_count *count, u64 value);
+	int (*function_read)(struct counter_device *counter,
+			     struct counter_count *count,
+			     enum counter_function *function);
+	int (*function_write)(struct counter_device *counter,
+			      struct counter_count *count,
+			      enum counter_function function);
+	int (*action_read)(struct counter_device *counter,
+			   struct counter_count *count,
+			   struct counter_synapse *synapse,
+			   enum counter_synapse_action *action);
+	int (*action_write)(struct counter_device *counter,
+			    struct counter_count *count,
+			    struct counter_synapse *synapse,
+			    enum counter_synapse_action action);
 };
 
-/**
- * struct counter_device_enum_ext - Counter enum extension attribute
- * @items:	Array of strings
- * @num_items:	Number of items specified in @items
- * @set:	Set callback function; may be NULL
- * @get:	Get callback function; may be NULL
- *
- * The counter_device_enum_ext structure can be used to implement enum style
- * Counter extension attributes. Enum style attributes are those which have a
- * set of strings that map to unsigned integer values. The Generic Counter enum
- * extension helper code takes care of mapping between value and string, as well
- * as generating a "_available" file which contains a list of all available
- * items. The get callback is used to query the currently active item; the index
- * of the item within the respective items array is returned via the 'item'
- * parameter. The set callback is called when the attribute is updated; the
- * 'item' parameter contains the index of the newly activated item within the
- * respective items array.
- */
-struct counter_device_enum_ext {
-	const char * const *items;
-	size_t num_items;
-	int (*get)(struct counter_device *counter, size_t *item);
-	int (*set)(struct counter_device *counter, size_t item);
-};
-
-/**
- * COUNTER_DEVICE_ENUM() - Initialize Counter enum extension
- * @_name:	Attribute name
- * @_e:		Pointer to a counter_device_enum_ext structure
- *
- * This should usually be used together with COUNTER_DEVICE_ENUM_AVAILABLE()
- */
-#define COUNTER_DEVICE_ENUM(_name, _e) \
-{ \
-	.name = (_name), \
-	.read = counter_device_enum_read, \
-	.write = counter_device_enum_write, \
-	.priv = (_e) \
-}
-
-/**
- * COUNTER_DEVICE_ENUM_AVAILABLE() - Initialize Counter enum available extension
- * @_name:	Attribute name ("_available" will be appended to the name)
- * @_e:		Pointer to a counter_device_enum_ext structure
- *
- * Creates a read only attribute that lists all the available enum items in a
- * newline separated list. This should usually be used together with
- * COUNTER_DEVICE_ENUM()
- */
-#define COUNTER_DEVICE_ENUM_AVAILABLE(_name, _e) \
-{ \
-	.name = (_name "_available"), \
-	.read = counter_device_enum_available_read, \
-	.priv = (_e) \
-}
-
 /**
  * struct counter_device - Counter data structure
  * @name:		name of the device as it appears in the datasheet
  * @parent:		optional parent device providing the counters
- * @device_state:	internal device state container
  * @ops:		callbacks from driver
  * @signals:		array of Signals
  * @num_signals:	number of Signals specified in @signals
@@ -425,11 +306,12 @@ struct counter_device_enum_ext {
  * @ext:		optional array of Counter device extensions
  * @num_ext:		number of Counter device extensions specified in @ext
  * @priv:		optional private data supplied by driver
+ * @id:			unique ID used to identify the Counter
+ * @dev:		internal device structure
  */
 struct counter_device {
 	const char *name;
 	struct device *parent;
-	struct counter_device_state *device_state;
 
 	const struct counter_ops *ops;
 
@@ -438,17 +320,160 @@ struct counter_device {
 	struct counter_count *counts;
 	size_t num_counts;
 
-	const struct counter_device_ext *ext;
+	struct counter_comp *ext;
 	size_t num_ext;
 
 	void *priv;
+
+	int id;
+	struct device dev;
 };
 
 int counter_register(struct counter_device *const counter);
 void counter_unregister(struct counter_device *const counter);
 int devm_counter_register(struct device *dev,
 			  struct counter_device *const counter);
-void devm_counter_unregister(struct device *dev,
-			     struct counter_device *const counter);
+
+#define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_U8, \
+	.name = (_name), \
+	.device_u8_read = (_read), \
+	.device_u8_write = (_write), \
+}
+#define COUNTER_COMP_COUNT_U8(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_U8, \
+	.name = (_name), \
+	.count_u8_read = (_read), \
+	.count_u8_write = (_write), \
+}
+#define COUNTER_COMP_SIGNAL_U8(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_U8, \
+	.name = (_name), \
+	.signal_u8_read = (_read), \
+	.signal_u8_write = (_write), \
+}
+
+#define COUNTER_COMP_DEVICE_U64(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_U64, \
+	.name = (_name), \
+	.device_u64_read = (_read), \
+	.device_u64_write = (_write), \
+}
+#define COUNTER_COMP_COUNT_U64(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_U64, \
+	.name = (_name), \
+	.count_u64_read = (_read), \
+	.count_u64_write = (_write), \
+}
+#define COUNTER_COMP_SIGNAL_U64(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_U64, \
+	.name = (_name), \
+	.signal_u64_read = (_read), \
+	.signal_u64_write = (_write), \
+}
+
+#define COUNTER_COMP_DEVICE_BOOL(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_BOOL, \
+	.name = (_name), \
+	.device_u8_read = (_read), \
+	.device_u8_write = (_write), \
+}
+#define COUNTER_COMP_COUNT_BOOL(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_BOOL, \
+	.name = (_name), \
+	.count_u8_read = (_read), \
+	.count_u8_write = (_write), \
+}
+#define COUNTER_COMP_SIGNAL_BOOL(_name, _read, _write) \
+{ \
+	.type = COUNTER_COMP_BOOL, \
+	.name = (_name), \
+	.signal_u8_read = (_read), \
+	.signal_u8_write = (_write), \
+}
+
+struct counter_available {
+	union {
+		const u32 *enums;
+		const char *const *strs;
+	};
+	size_t num_items;
+};
+
+#define DEFINE_COUNTER_AVAILABLE(_name, _enums) \
+	struct counter_available _name = { \
+		.enums = (_enums), \
+		.num_items = ARRAY_SIZE(_enums), \
+	}
+
+#define DEFINE_COUNTER_ENUM(_name, _strs) \
+	struct counter_available _name = { \
+		.strs = (_strs), \
+		.num_items = ARRAY_SIZE(_strs), \
+	}
+
+#define COUNTER_COMP_DEVICE_ENUM(_name, _get, _set, _available) \
+{ \
+	.type = COUNTER_COMP_ENUM, \
+	.name = (_name), \
+	.device_u32_read = (_get), \
+	.device_u32_write = (_set), \
+	.priv = &(_available), \
+}
+#define COUNTER_COMP_COUNT_ENUM(_name, _get, _set, _available) \
+{ \
+	.type = COUNTER_COMP_ENUM, \
+	.name = (_name), \
+	.count_u32_read = (_get), \
+	.count_u32_write = (_set), \
+	.priv = &(_available), \
+}
+#define COUNTER_COMP_SIGNAL_ENUM(_name, _get, _set, _available) \
+{ \
+	.type = COUNTER_COMP_ENUM, \
+	.name = (_name), \
+	.signal_u32_read = (_get), \
+	.signal_u32_write = (_set), \
+	.priv = &(_available), \
+}
+
+#define COUNTER_COMP_CEILING(_read, _write) \
+	COUNTER_COMP_COUNT_U64("ceiling", _read, _write)
+
+#define COUNTER_COMP_COUNT_MODE(_read, _write, _available) \
+{ \
+	.type = COUNTER_COMP_COUNT_MODE, \
+	.name = "count_mode", \
+	.count_u32_read = (_read), \
+	.count_u32_write = (_write), \
+	.priv = &(_available), \
+}
+
+#define COUNTER_COMP_DIRECTION(_read) \
+{ \
+	.type = COUNTER_COMP_COUNT_DIRECTION, \
+	.name = "direction", \
+	.count_u32_read = (_read), \
+}
+
+#define COUNTER_COMP_ENABLE(_read, _write) \
+	COUNTER_COMP_COUNT_BOOL("enable", _read, _write)
+
+#define COUNTER_COMP_FLOOR(_read, _write) \
+	COUNTER_COMP_COUNT_U64("floor", _read, _write)
+
+#define COUNTER_COMP_PRESET(_read, _write) \
+	COUNTER_COMP_COUNT_U64("preset", _read, _write)
+
+#define COUNTER_COMP_PRESET_ENABLE(_read, _write) \
+	COUNTER_COMP_COUNT_BOOL("preset_enable", _read, _write)
 
 #endif /* _COUNTER_H_ */
diff --git a/include/linux/counter_enum.h b/include/linux/counter_enum.h
deleted file mode 100644
index 9f917298a88f..000000000000
--- a/include/linux/counter_enum.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Counter interface enum functions
- * Copyright (C) 2018 William Breathitt Gray
- */
-#ifndef _COUNTER_ENUM_H_
-#define _COUNTER_ENUM_H_
-
-#include <linux/types.h>
-
-struct counter_device;
-struct counter_signal;
-struct counter_count;
-
-ssize_t counter_signal_enum_read(struct counter_device *counter,
-				 struct counter_signal *signal, void *priv,
-				 char *buf);
-ssize_t counter_signal_enum_write(struct counter_device *counter,
-				  struct counter_signal *signal, void *priv,
-				  const char *buf, size_t len);
-
-ssize_t counter_signal_enum_available_read(struct counter_device *counter,
-					   struct counter_signal *signal,
-					   void *priv, char *buf);
-
-ssize_t counter_count_enum_read(struct counter_device *counter,
-				struct counter_count *count, void *priv,
-				char *buf);
-ssize_t counter_count_enum_write(struct counter_device *counter,
-				 struct counter_count *count, void *priv,
-				 const char *buf, size_t len);
-
-ssize_t counter_count_enum_available_read(struct counter_device *counter,
-					  struct counter_count *count,
-					  void *priv, char *buf);
-
-ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
-				 char *buf);
-ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
-				  const char *buf, size_t len);
-
-ssize_t counter_device_enum_available_read(struct counter_device *counter,
-					   void *priv, char *buf);
-
-#endif /* _COUNTER_ENUM_H_ */
-- 
2.30.0

Re: [PATCH v8 13/22] counter: Internalize sysfs interface code

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:37 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> This is a reimplementation of the Generic Counter driver interface.
> There are no modifications to the Counter subsystem userspace interface,
> so existing userspace applications should continue to run seamlessly.
> 
> The purpose of this patch is to internalize the sysfs interface code
> among the various counter drivers into a shared module. Counter drivers
> pass and take data natively (i.e. u8, u64, etc.) and the shared counter
> module handles the translation between the sysfs interface and the
> device drivers. This guarantees a standard userspace interface for all
> counter drivers, and helps generalize the Generic Counter driver ABI in
> order to support the Generic Counter chrdev interface (introduced in a
> subsequent patch) without significant changes to the existing counter
> drivers.
> 
> Note, Counter device registration is the same as before: drivers
> populate a struct counter_device with components and callbacks, then
> pass the structure to the devm_counter_register function. However,
> what's different now is how the Counter subsystem code handles this
> registration internally.
> 
> Whereas before callbacks would interact directly with sysfs data, this
> interaction is now abstracted and instead callbacks interact with native
> C data types. The counter_comp structure forms the basis for Counter
> extensions.
> 
> The counter-sysfs.c file contains the code to parse through the
> counter_device structure and register the requested components and
> extensions. Attributes are created and populated based on type, with
> respective translation functions to handle the mapping between sysfs and
> the counter driver callbacks.
> 
> The translation performed for each attribute is straightforward: the
> attribute type and data is parsed from the counter_attribute structure,
> the respective counter driver read/write callback is called, and sysfs
> I/O is handled before or after the driver read/write function is called.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: David Lechner <david@lechnology.com>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

A few minor comments inline.

This set is still huge, so I've only looked at the core code
for this version.  Hopefully driver maintainers will do the thorough
review of how it effects the individual drivers!

Jonathan

> ---
>  MAINTAINERS                             |    1 -
>  drivers/counter/104-quad-8.c            |  449 +++----
>  drivers/counter/Makefile                |    1 +
>  drivers/counter/counter-core.c          |  153 +++
>  drivers/counter/counter-sysfs.c         |  833 +++++++++++++
>  drivers/counter/counter-sysfs.h         |   13 +
>  drivers/counter/counter.c               | 1496 -----------------------
>  drivers/counter/ftm-quaddec.c           |   56 +-
>  drivers/counter/microchip-tcb-capture.c |   87 +-
>  drivers/counter/stm32-lptimer-cnt.c     |  164 ++-
>  drivers/counter/stm32-timer-cnt.c       |  142 +--
>  drivers/counter/ti-eqep.c               |  211 ++--
>  include/linux/counter.h                 |  631 +++++-----
>  include/linux/counter_enum.h            |   45 -
>  14 files changed, 1816 insertions(+), 2466 deletions(-)
>  create mode 100644 drivers/counter/counter-core.c
>  create mode 100644 drivers/counter/counter-sysfs.c
>  create mode 100644 drivers/counter/counter-sysfs.h
>  delete mode 100644 drivers/counter/counter.c
>  delete mode 100644 include/linux/counter_enum.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d858582c917b..94a19606d947 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4543,7 +4543,6 @@ F:	Documentation/ABI/testing/sysfs-bus-counter
>  F:	Documentation/driver-api/generic-counter.rst
>  F:	drivers/counter/
>  F:	include/linux/counter.h
> -F:	include/linux/counter_enum.h
>  
>  CPMAC ETHERNET DRIVER
>  M:	Florian Fainelli <f.fainelli@gmail.com>
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index eca3f6482719..41fdbd228be3 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -116,7 +116,7 @@ static int quad8_signal_read(struct counter_device *counter,
...

> diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
> new file mode 100644
> index 000000000000..52513a213cc5
> --- /dev/null
> +++ b/drivers/counter/counter-sysfs.c
> @@ -0,0 +1,833 @@

...

> +
> +static ssize_t counter_comp_u8_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	int err;
> +	u8 data = 0;
> +
> +	switch (a->scope) {
> +	case COUNTER_SCOPE_DEVICE:
> +		err = a->comp.device_u8_read(counter, &data);
> +		break;
> +	case COUNTER_SCOPE_SIGNAL:
> +		err = a->comp.signal_u8_read(counter, a->parent, &data);
> +		break;
> +	case COUNTER_SCOPE_COUNT:
> +		err = a->comp.count_u8_read(counter, a->parent, &data);
> +		break;

I'd add a default in here just to make it obvious anything else is
an error.  Same in other similar cases that follow.

> +	}
> +	if (err < 0)
> +		return err;
> +
> +	if (a->comp.type == COUNTER_COMP_BOOL)
> +		data = !!data;
> +
> +	return sprintf(buf, "%u\n", (unsigned int)data);
> +}
> +


...

> +
> +static int counter_name_attr_create(struct device *const dev,
> +				    struct counter_attribute_group *const group,
> +				    const char *const name)
> +{
> +	struct counter_attribute *counter_attr;
> +
> +	/* Allocate Counter attribute */
> +	counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
> +	if (!counter_attr)
> +		return -ENOMEM;
> +
> +	/* Configure Counter attribute */
> +	counter_attr->comp.name = name;
> +
> +	/* Configure device attribute */
> +	sysfs_attr_init(&counter_attr->dev_attr.attr);
> +	counter_attr->dev_attr.attr.name = "name";
> +	counter_attr->dev_attr.attr.mode = 0444;
> +	counter_attr->dev_attr.show = counter_comp_name_show;
> +
> +	/* Store list node */
> +	list_add(&counter_attr->l, &group->attr_list);
> +	group->num_attr++;
> +
> +	return 0;
> +}

Trivial but one too many blank lines.

> +
> +
> +static struct counter_comp counter_signal_comp = {
> +	.type = COUNTER_COMP_SIGNAL_LEVEL,
> +	.name = "signal",
> +};

...


>  static struct counter_synapse ti_eqep_position_synapses[] = {
> diff --git a/include/linux/counter.h b/include/linux/counter.h
> index d16ce2819b48..76b0b06dd5db 100644
> --- a/include/linux/counter.h
> +++ b/include/linux/counter.h
> @@ -6,42 +6,184 @@
>  #ifndef _COUNTER_H_
>  #define _COUNTER_H_
>  
...

Re: [PATCH v8 13/22] counter: Internalize sysfs interface code

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> This is a reimplementation of the Generic Counter driver interface.
> There are no modifications to the Counter subsystem userspace interface,
> so existing userspace applications should continue to run seamlessly.
> 
> The purpose of this patch is to internalize the sysfs interface code
> among the various counter drivers into a shared module. Counter drivers
> pass and take data natively (i.e. u8, u64, etc.) and the shared counter
> module handles the translation between the sysfs interface and the
> device drivers. This guarantees a standard userspace interface for all
> counter drivers, and helps generalize the Generic Counter driver ABI in
> order to support the Generic Counter chrdev interface (introduced in a
> subsequent patch) without significant changes to the existing counter
> drivers.
> 
> Note, Counter device registration is the same as before: drivers
> populate a struct counter_device with components and callbacks, then
> pass the structure to the devm_counter_register function. However,
> what's different now is how the Counter subsystem code handles this
> registration internally.
> 
> Whereas before callbacks would interact directly with sysfs data, this
> interaction is now abstracted and instead callbacks interact with native
> C data types. The counter_comp structure forms the basis for Counter
> extensions.
> 
> The counter-sysfs.c file contains the code to parse through the
> counter_device structure and register the requested components and
> extensions. Attributes are created and populated based on type, with
> respective translation functions to handle the mapping between sysfs and
> the counter driver callbacks.
> 
> The translation performed for each attribute is straightforward: the
> attribute type and data is parsed from the counter_attribute structure,
> the respective counter driver read/write callback is called, and sysfs
> I/O is handled before or after the driver read/write function is called.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: David Lechner <david@lechnology.com>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

For TI eQEP bits...

Reviewed-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>

[PATCH v8 14/22] counter: Update counter.h comments to reflect sysfs internalization

[William Breathitt Gray]

The Counter subsystem architecture and driver implementations have
changed in order to handle Counter sysfs interactions in a more
consistent way. This patch updates the Generic Counter interface
header file comments to reflect the changes.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/counter-core.c |  3 ++
 include/linux/counter.h        | 72 +++++++++++++++-------------------
 2 files changed, 35 insertions(+), 40 deletions(-)

diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
index 1577a6562cad..bcf672e1fc0d 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -40,6 +40,9 @@ static struct bus_type counter_bus_type = {
  * This function registers a Counter to the system. A sysfs "counter" directory
  * will be created and populated with sysfs attributes correlating with the
  * Counter Signals, Synapses, and Counts respectively.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
  */
 int counter_register(struct counter_device *const counter)
 {
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 76b0b06dd5db..2f01e1fec857 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -188,12 +188,10 @@ struct counter_comp {
 
 /**
  * struct counter_signal - Counter Signal node
- * @id:		unique ID used to identify signal
- * @name:	device-specific Signal name; ideally, this should match the name
- *		as it appears in the datasheet documentation
- * @ext:	optional array of Counter Signal extensions
- * @num_ext:	number of Counter Signal extensions specified in @ext
- * @priv:	optional private data supplied by driver
+ * @id:		unique ID used to identify the Signal
+ * @name:	device-specific Signal name
+ * @ext:	optional array of Signal extensions
+ * @num_ext:	number of Signal extensions specified in @ext
  */
 struct counter_signal {
 	int id;
@@ -207,7 +205,7 @@ struct counter_signal {
  * struct counter_synapse - Counter Synapse node
  * @actions_list:	array of available action modes
  * @num_actions:	number of action modes specified in @actions_list
- * @signal:		pointer to associated signal
+ * @signal:		pointer to the associated Signal
  */
 struct counter_synapse {
 	const enum counter_synapse_action *actions_list;
@@ -218,17 +216,14 @@ struct counter_synapse {
 
 /**
  * struct counter_count - Counter Count node
- * @id:			unique ID used to identify Count
- * @name:		device-specific Count name; ideally, this should match
- *			the name as it appears in the datasheet documentation
- * @function:		index of current function mode
- * @functions_list:	array available function modes
+ * @id:			unique ID used to identify the Count
+ * @name:		device-specific Count name
+ * @functions_list:	array of available function modes
  * @num_functions:	number of function modes specified in @functions_list
- * @synapses:		array of synapses for initialization
- * @num_synapses:	number of synapses specified in @synapses
- * @ext:		optional array of Counter Count extensions
- * @num_ext:		number of Counter Count extensions specified in @ext
- * @priv:		optional private data supplied by driver
+ * @synapses:		array of Synapses for initialization
+ * @num_synapses:	number of Synapses specified in @synapses
+ * @ext:		optional array of Count extensions
+ * @num_ext:		number of Count extensions specified in @ext
  */
 struct counter_count {
 	int id;
@@ -246,29 +241,26 @@ struct counter_count {
 
 /**
  * struct counter_ops - Callbacks from driver
- * @signal_read:	optional read callback for Signal attribute. The read
- *			level of the respective Signal should be passed back via
- *			the level parameter.
- * @count_read:		optional read callback for Count attribute. The read
- *			value of the respective Count should be passed back via
- *			the val parameter.
- * @count_write:	optional write callback for Count attribute. The write
- *			value for the respective Count is passed in via the val
+ * @signal_read:	read callback for Signals. The read level of the
+ *			respective Signal should be passed back via the level
+ *			parameter.
+ * @count_read:		read callback for Counts. The read value of the
+ *			respective Count should be passed back via the value
  *			parameter.
- * @function_get:	function to get the current count function mode. Returns
- *			0 on success and negative error code on error. The index
- *			of the respective Count's returned function mode should
- *			be passed back via the function parameter.
- * @function_set:	function to set the count function mode. function is the
- *			index of the requested function mode from the respective
- *			Count's functions_list array.
- * @action_get:		function to get the current action mode. Returns 0 on
- *			success and negative error code on error. The index of
- *			the respective Synapse's returned action mode should be
- *			passed back via the action parameter.
- * @action_set:		function to set the action mode. action is the index of
- *			the requested action mode from the respective Synapse's
- *			actions_list array.
+ * @count_write:	write callback for Counts. The write value for the
+ *			respective Count is passed in via the value parameter.
+ * @function_read:	read callback the Count function modes. The read
+ *			function mode of the respective Count should be passed
+ *			back via the function parameter.
+ * @function_write:	write callback for Count function modes. The function
+ *			mode to write for the respective Count is passed in via
+ *			the function parameter.
+ * @action_read:	read callback the Synapse action modes. The read action
+ *			mode of the respective Synapse should be passed back via
+ *			the action parameter.
+ * @action_write:	write callback for Synapse action modes. The action mode
+ *			to write for the respective Synapse is passed in via the
+ *			action parameter.
  */
 struct counter_ops {
 	int (*signal_read)(struct counter_device *counter,
@@ -296,7 +288,7 @@ struct counter_ops {
 
 /**
  * struct counter_device - Counter data structure
- * @name:		name of the device as it appears in the datasheet
+ * @name:		name of the device
  * @parent:		optional parent device providing the counters
  * @ops:		callbacks from driver
  * @signals:		array of Signals
-- 
2.30.0

[PATCH v8 15/22] docs: counter: Update to reflect sysfs internalization

[William Breathitt Gray]

The Counter subsystem architecture and driver implementations have
changed in order to handle Counter sysfs interactions in a more
consistent way. This patch updates the Generic Counter interface
documentation to reflect the changes.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-counter  |   9 +-
 Documentation/driver-api/generic-counter.rst | 243 ++++++++++++++-----
 2 files changed, 185 insertions(+), 67 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 29f54484183f..6353f0a2f8f8 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -277,7 +277,14 @@ What:		/sys/bus/counter/devices/counterX/signalY/signal
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
 Description:
-		Signal data of Signal Y represented as a string.
+		Signal level state of Signal Y. The following signal level
+		states are available:
+
+		low:
+			Low level state.
+
+		high:
+			High level state.
 
 What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
 KernelVersion:	5.2
diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index 64fe7db080e5..f6397218aa4c 100644
--- a/Documentation/driver-api/generic-counter.rst
+++ b/Documentation/driver-api/generic-counter.rst
@@ -250,8 +250,8 @@ for defining a counter device.
 .. kernel-doc:: drivers/counter/counter.c
    :export:
 
-Implementation
-==============
+Driver Implementation
+=====================
 
 To support a counter device, a driver must first allocate the available
 Counter Signals via counter_signal structures. These Signals should
@@ -267,25 +267,61 @@ respective counter_count structure. These counter_count structures are
 set to the counts array member of an allocated counter_device structure
 before the Counter is registered to the system.
 
-Driver callbacks should be provided to the counter_device structure via
-a constant counter_ops structure in order to communicate with the
-device: to read and write various Signals and Counts, and to set and get
-the "action mode" and "function mode" for various Synapses and Counts
-respectively.
+Driver callbacks must be provided to the counter_device structure in
+order to communicate with the device: to read and write various Signals
+and Counts, and to set and get the "action mode" and "function mode" for
+various Synapses and Counts respectively.
 
 A defined counter_device structure may be registered to the system by
 passing it to the counter_register function, and unregistered by passing
 it to the counter_unregister function. Similarly, the
-devm_counter_register and devm_counter_unregister functions may be used
-if device memory-managed registration is desired.
-
-Extension sysfs attributes can be created for auxiliary functionality
-and data by passing in defined counter_device_ext, counter_count_ext,
-and counter_signal_ext structures. In these cases, the
-counter_device_ext structure is used for global/miscellaneous exposure
-and configuration of the respective Counter device, while the
-counter_count_ext and counter_signal_ext structures allow for auxiliary
-exposure and configuration of a specific Count or Signal respectively.
+devm_counter_register function may be used if device memory-managed
+registration is desired.
+
+The struct counter_comp structure is used to define counter extensions
+for Signals, Synapses, and Counts.
+
+The "type" member specifies the type of high-level data (e.g. BOOL,
+COUNT_DIRECTION, etc.) handled by this extension. The "``*_read``" and
+"``*_write``" members can then be set by the counter device driver with
+callbacks to handle that data using native C data types (i.e. u8, u64,
+etc.).
+
+Convenience macros such as ``COUNTER_COMP_COUNT_U64`` are provided for
+use by driver authors. In particular, driver authors are expected to use
+the provided macros for standard Counter subsystem attributes in order
+to maintain a consistent interface for userspace. For example, a counter
+device driver may define several standard attributes like so::
+
+        struct counter_comp count_ext[] = {
+                COUNTER_COMP_DIRECTION(count_direction_read),
+                COUNTER_COMP_ENABLE(count_enable_read, count_enable_write),
+                COUNTER_COMP_CEILING(count_ceiling_read, count_ceiling_write),
+        };
+
+This makes it simple to see, add, and modify the attributes that are
+supported by this driver ("direction", "enable", and "ceiling") and to
+maintain this code without getting lost in a web of struct braces.
+
+Callbacks must match the function type expected for the respective
+component or extension. These function types are defined in the struct
+counter_comp structure as the "``*_read``" and "``*_write``" union
+members.
+
+The corresponding callback prototypes for the extensions mentioned in
+the previous example above would be::
+
+        int count_direction_read(struct counter_device *counter,
+                                 struct counter_count *count,
+                                 enum counter_count_direction *direction);
+        int count_enable_read(struct counter_device *counter,
+                              struct counter_count *count, u8 *enable);
+        int count_enable_write(struct counter_device *counter,
+                               struct counter_count *count, u8 enable);
+        int count_ceiling_read(struct counter_device *counter,
+                               struct counter_count *count, u64 *ceiling);
+        int count_ceiling_write(struct counter_device *counter,
+                                struct counter_count *count, u64 ceiling);
 
 Determining the type of extension to create is a matter of scope.
 
@@ -313,52 +349,127 @@ Determining the type of extension to create is a matter of scope.
   chip overheated via a device extension called "error_overtemp":
   /sys/bus/counter/devices/counterX/error_overtemp
 
-Architecture
-============
-
-When the Generic Counter interface counter module is loaded, the
-counter_init function is called which registers a bus_type named
-"counter" to the system. Subsequently, when the module is unloaded, the
-counter_exit function is called which unregisters the bus_type named
-"counter" from the system.
-
-Counter devices are registered to the system via the counter_register
-function, and later removed via the counter_unregister function. The
-counter_register function establishes a unique ID for the Counter
-device and creates a respective sysfs directory, where X is the
-mentioned unique ID:
-
-    /sys/bus/counter/devices/counterX
-
-Sysfs attributes are created within the counterX directory to expose
-functionality, configurations, and data relating to the Counts, Signals,
-and Synapses of the Counter device, as well as options and information
-for the Counter device itself.
-
-Each Signal has a directory created to house its relevant sysfs
-attributes, where Y is the unique ID of the respective Signal:
-
-    /sys/bus/counter/devices/counterX/signalY
-
-Similarly, each Count has a directory created to house its relevant
-sysfs attributes, where Y is the unique ID of the respective Count:
-
-    /sys/bus/counter/devices/counterX/countY
-
-For a more detailed breakdown of the available Generic Counter interface
-sysfs attributes, please refer to the
-Documentation/ABI/testing/sysfs-bus-counter file.
-
-The Signals and Counts associated with the Counter device are registered
-to the system as well by the counter_register function. The
-signal_read/signal_write driver callbacks are associated with their
-respective Signal attributes, while the count_read/count_write and
-function_get/function_set driver callbacks are associated with their
-respective Count attributes; similarly, the same is true for the
-action_get/action_set driver callbacks and their respective Synapse
-attributes. If a driver callback is left undefined, then the respective
-read/write permission is left disabled for the relevant attributes.
-
-Similarly, extension sysfs attributes are created for the defined
-counter_device_ext, counter_count_ext, and counter_signal_ext
-structures that are passed in.
+Subsystem Architecture
+======================
+
+Counter drivers pass and take data natively (i.e. ``u8``, ``u64``, etc.)
+and the shared counter module handles the translation between the sysfs
+interface. This guarantees a standard userspace interface for all
+counter drivers, and enables a Generic Counter chrdev interface via a
+generalized device driver ABI.
+
+A high-level view of how a count value is passed down from a counter
+driver is exemplified by the following. The driver callbacks are first
+registered to the Counter core component for use by the Counter
+userspace interface components::
+
+        Driver callbacks registration:
+        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+                        +----------------------------+
+                        | Counter device driver      |
+                        +----------------------------+
+                        | Processes data from device |
+                        +----------------------------+
+                                |
+                         -------------------
+                        / driver callbacks /
+                        -------------------
+                                |
+                                V
+                        +----------------------+
+                        | Counter core         |
+                        +----------------------+
+                        | Routes device driver |
+                        | callbacks to the     |
+                        | userspace interfaces |
+                        +----------------------+
+                                |
+                         -------------------
+                        / driver callbacks /
+                        -------------------
+                                |
+                +---------------+
+                |
+                V
+        +--------------------+
+        | Counter sysfs      |
+        +--------------------+
+        | Translates to the  |
+        | standard Counter   |
+        | sysfs output       |
+        +--------------------+
+
+Thereafter, data can be transferred directly between the Counter device
+driver and Counter userspace interface::
+
+        Count data request:
+        ~~~~~~~~~~~~~~~~~~~
+                         ----------------------
+                        / Counter device       \
+                        +----------------------+
+                        | Count register: 0x28 |
+                        +----------------------+
+                                |
+                         -----------------
+                        / raw count data /
+                        -----------------
+                                |
+                                V
+                        +----------------------------+
+                        | Counter device driver      |
+                        +----------------------------+
+                        | Processes data from device |
+                        |----------------------------|
+                        | Type: u64                  |
+                        | Value: 42                  |
+                        +----------------------------+
+                                |
+                         ----------
+                        / u64     /
+                        ----------
+                                |
+                +---------------+
+                |
+                V
+        +--------------------+
+        | Counter sysfs      |
+        +--------------------+
+        | Translates to the  |
+        | standard Counter   |
+        | sysfs output       |
+        |--------------------|
+        | Type: const char * |
+        | Value: "42"        |
+        +--------------------+
+                |
+         ---------------
+        / const char * /
+        ---------------
+                |
+                V
+        +--------------------------------------------------+
+        | `/sys/bus/counter/devices/counterX/countY/count` |
+        +--------------------------------------------------+
+        \ Count: "42"                                      /
+         --------------------------------------------------
+
+There are three primary components involved:
+
+Counter device driver
+---------------------
+Communicates with the hardware device to read/write data; e.g. counter
+drivers for quadrature encoders, timers, etc.
+
+Counter core
+------------
+Registers the counter device driver to the system so that the respective
+callbacks are called during userspace interaction.
+
+Counter sysfs
+-------------
+Translates counter data to the standard Counter sysfs interface format
+and vice versa.
+
+Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
+for a detailed breakdown of the available Generic Counter interface
+sysfs attributes.
-- 
2.30.0

[PATCH v8 16/22] counter: Move counter enums to uapi header

[William Breathitt Gray]

This is in preparation for a subsequent patch implementing a character
device interface for the Counter subsystem.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 MAINTAINERS                  |  1 +
 include/linux/counter.h      | 42 +--------------------------
 include/uapi/linux/counter.h | 56 ++++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 41 deletions(-)
 create mode 100644 include/uapi/linux/counter.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 94a19606d947..5392112b3f19 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4543,6 +4543,7 @@ F:	Documentation/ABI/testing/sysfs-bus-counter
 F:	Documentation/driver-api/generic-counter.rst
 F:	drivers/counter/
 F:	include/linux/counter.h
+F:	include/uapi/linux/counter.h
 
 CPMAC ETHERNET DRIVER
 M:	Florian Fainelli <f.fainelli@gmail.com>
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 2f01e1fec857..2d544f58a79c 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -9,6 +9,7 @@
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
+#include <uapi/linux/counter.h>
 
 struct counter_device;
 struct counter_count;
@@ -27,47 +28,6 @@ enum counter_comp_type {
 	COUNTER_COMP_COUNT_MODE,
 };
 
-enum counter_scope {
-	COUNTER_SCOPE_DEVICE,
-	COUNTER_SCOPE_SIGNAL,
-	COUNTER_SCOPE_COUNT,
-};
-
-enum counter_count_direction {
-	COUNTER_COUNT_DIRECTION_FORWARD,
-	COUNTER_COUNT_DIRECTION_BACKWARD,
-};
-
-enum counter_count_mode {
-	COUNTER_COUNT_MODE_NORMAL,
-	COUNTER_COUNT_MODE_RANGE_LIMIT,
-	COUNTER_COUNT_MODE_NON_RECYCLE,
-	COUNTER_COUNT_MODE_MODULO_N,
-};
-
-enum counter_function {
-	COUNTER_FUNCTION_INCREASE,
-	COUNTER_FUNCTION_DECREASE,
-	COUNTER_FUNCTION_PULSE_DIRECTION,
-	COUNTER_FUNCTION_QUADRATURE_X1_A,
-	COUNTER_FUNCTION_QUADRATURE_X1_B,
-	COUNTER_FUNCTION_QUADRATURE_X2_A,
-	COUNTER_FUNCTION_QUADRATURE_X2_B,
-	COUNTER_FUNCTION_QUADRATURE_X4,
-};
-
-enum counter_signal_level {
-	COUNTER_SIGNAL_LEVEL_LOW,
-	COUNTER_SIGNAL_LEVEL_HIGH,
-};
-
-enum counter_synapse_action {
-	COUNTER_SYNAPSE_ACTION_NONE,
-	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
-	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
-	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
-};
-
 /**
  * struct counter_comp - Counter component node
  * @type:		Counter component data type
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
new file mode 100644
index 000000000000..6113938a6044
--- /dev/null
+++ b/include/uapi/linux/counter.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Userspace ABI for Counter character devices
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _UAPI_COUNTER_H_
+#define _UAPI_COUNTER_H_
+
+/* Component scope definitions */
+enum counter_scope {
+	COUNTER_SCOPE_DEVICE,
+	COUNTER_SCOPE_SIGNAL,
+	COUNTER_SCOPE_COUNT,
+};
+
+/* Count direction values */
+enum counter_count_direction {
+	COUNTER_COUNT_DIRECTION_FORWARD,
+	COUNTER_COUNT_DIRECTION_BACKWARD,
+};
+
+/* Count mode values */
+enum counter_count_mode {
+	COUNTER_COUNT_MODE_NORMAL,
+	COUNTER_COUNT_MODE_RANGE_LIMIT,
+	COUNTER_COUNT_MODE_NON_RECYCLE,
+	COUNTER_COUNT_MODE_MODULO_N,
+};
+
+/* Count function values */
+enum counter_function {
+	COUNTER_FUNCTION_INCREASE,
+	COUNTER_FUNCTION_DECREASE,
+	COUNTER_FUNCTION_PULSE_DIRECTION,
+	COUNTER_FUNCTION_QUADRATURE_X1_A,
+	COUNTER_FUNCTION_QUADRATURE_X1_B,
+	COUNTER_FUNCTION_QUADRATURE_X2_A,
+	COUNTER_FUNCTION_QUADRATURE_X2_B,
+	COUNTER_FUNCTION_QUADRATURE_X4,
+};
+
+/* Signal values */
+enum counter_signal_level {
+	COUNTER_SIGNAL_LEVEL_LOW,
+	COUNTER_SIGNAL_LEVEL_HIGH,
+};
+
+/* Action mode values */
+enum counter_synapse_action {
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+};
+
+#endif /* _UAPI_COUNTER_H_ */
-- 
2.30.0

Re: [PATCH v8 16/22] counter: Move counter enums to uapi header

[David Lechner]

On 2/12/21 6:13 AM, William Breathitt Gray wrote:
> This is in preparation for a subsequent patch implementing a character
> device interface for the Counter subsystem.
> 
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---

Reviewed-by: David Lechner <david@lechnology.com>

[PATCH v8 17/22] counter: Add character device interface

[William Breathitt Gray]

This patch introduces a character device interface for the Counter
subsystem. Device data is exposed through standard character device read
operations. Device data is gathered when a Counter event is pushed by
the respective Counter device driver. Configuration is handled via ioctl
operations on the respective Counter character device node.

Cc: David Lechner <david@lechnology.com>
Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/Makefile         |   2 +-
 drivers/counter/counter-chrdev.c | 496 +++++++++++++++++++++++++++++++
 drivers/counter/counter-chrdev.h |  16 +
 drivers/counter/counter-core.c   |  37 ++-
 include/linux/counter.h          |  45 +++
 include/uapi/linux/counter.h     |  70 +++++
 6 files changed, 661 insertions(+), 5 deletions(-)
 create mode 100644 drivers/counter/counter-chrdev.c
 create mode 100644 drivers/counter/counter-chrdev.h

diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index cbe1d06af6a9..c4870eb5b1dd 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -4,7 +4,7 @@
 #
 
 obj-$(CONFIG_COUNTER) += counter.o
-counter-y := counter-core.o counter-sysfs.o
+counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
 
 obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
 obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
new file mode 100644
index 000000000000..16f02df7f73d
--- /dev/null
+++ b/drivers/counter/counter-chrdev.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter character device interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+
+#include <linux/cdev.h>
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/kdev_t.h>
+#include <linux/kfifo.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/nospec.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/uaccess.h>
+
+#include "counter-chrdev.h"
+
+struct counter_comp_node {
+	struct list_head l;
+	struct counter_component component;
+	struct counter_comp comp;
+	void *parent;
+};
+
+static ssize_t counter_chrdev_read(struct file *filp, char __user *buf,
+				   size_t len, loff_t *f_ps)
+{
+	struct counter_device *const counter = filp->private_data;
+	int err;
+	unsigned int copied;
+
+	if (len < sizeof(struct counter_event))
+		return -EINVAL;
+
+	do {
+		if (kfifo_is_empty(&counter->events)) {
+			if (filp->f_flags & O_NONBLOCK)
+				return -EAGAIN;
+
+			err = wait_event_interruptible(counter->events_wait,
+					!kfifo_is_empty(&counter->events));
+			if (err < 0)
+				return err;
+		}
+
+		if (mutex_lock_interruptible(&counter->events_lock))
+			return -ERESTARTSYS;
+		err = kfifo_to_user(&counter->events, buf, len, &copied);
+		mutex_unlock(&counter->events_lock);
+		if (err < 0)
+			return err;
+	} while (!copied);
+
+	return copied;
+}
+
+static __poll_t counter_chrdev_poll(struct file *filp,
+				    struct poll_table_struct *pollt)
+{
+	struct counter_device *const counter = filp->private_data;
+	__poll_t events = 0;
+
+	poll_wait(filp, &counter->events_wait, pollt);
+
+	if (!kfifo_is_empty(&counter->events))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+static void counter_events_list_free(struct list_head *const events_list)
+{
+	struct counter_event_node *p, *n;
+	struct counter_comp_node *q, *o;
+
+	list_for_each_entry_safe(p, n, events_list, l) {
+		/* Free associated component nodes */
+		list_for_each_entry_safe(q, o, &p->comp_list, l) {
+			list_del(&q->l);
+			kfree(q);
+		}
+
+		/* Free event node */
+		list_del(&p->l);
+		kfree(p);
+	}
+}
+
+static int counter_set_event_node(struct counter_device *const counter,
+				  struct counter_watch *const watch,
+				  const struct counter_comp_node *const cfg)
+{
+	struct counter_event_node *event_node;
+	struct counter_comp_node *comp_node;
+
+	/* Search for event in the list */
+	list_for_each_entry(event_node, &counter->next_events_list, l)
+		if (event_node->event == watch->event &&
+		    event_node->channel == watch->channel)
+			break;
+
+	/* If event is not already in the list */
+	if (&event_node->l == &counter->next_events_list) {
+		/* Allocate new event node */
+		event_node = kmalloc(sizeof(*event_node), GFP_ATOMIC);
+		if (!event_node)
+			return -ENOMEM;
+
+		/* Configure event node and add to the list */
+		event_node->event = watch->event;
+		event_node->channel = watch->channel;
+		INIT_LIST_HEAD(&event_node->comp_list);
+		list_add(&event_node->l, &counter->next_events_list);
+	}
+
+	/* Check if component watch has already been set before */
+	list_for_each_entry(comp_node, &event_node->comp_list, l)
+		if (comp_node->parent == cfg->parent &&
+		    comp_node->comp.count_u8_read == cfg->comp.count_u8_read)
+			return -EINVAL;
+
+	/* Allocate component node */
+	comp_node = kmalloc(sizeof(*comp_node), GFP_ATOMIC);
+	if (!comp_node) {
+		/* Free event node if no one else is watching */
+		if (list_empty(&event_node->comp_list)) {
+			list_del(&event_node->l);
+			kfree(event_node);
+		}
+		return -ENOMEM;
+	}
+	*comp_node = *cfg;
+
+	/* Add component node to event node */
+	list_add_tail(&comp_node->l, &event_node->comp_list);
+
+	return 0;
+}
+
+static int counter_disable_events(struct counter_device *const counter)
+{
+	unsigned long flags;
+	int err = 0;
+
+	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
+
+	counter_events_list_free(&counter->events_list);
+
+	if (counter->ops->events_configure)
+		err = counter->ops->events_configure(counter);
+
+	raw_spin_unlock_irqrestore(&counter->events_list_lock, flags);
+
+	counter_events_list_free(&counter->next_events_list);
+
+	return err;
+}
+
+static int counter_add_watch(struct counter_device *const counter,
+			     const unsigned long arg)
+{
+	void __user *const uwatch = (void __user *)arg;
+	struct counter_watch watch;
+	struct counter_comp_node comp_node = {0};
+	size_t parent, id;
+	struct counter_comp *ext;
+	size_t num_ext;
+	int err;
+
+	if (copy_from_user(&watch, uwatch, sizeof(watch)))
+		return -EFAULT;
+
+	if (watch.component.type == COUNTER_COMPONENT_NONE)
+		goto no_component;
+
+	parent = watch.component.parent;
+
+	/* Configure parent component info for comp node */
+	switch (watch.component.scope) {
+	case COUNTER_SCOPE_DEVICE:
+		ext = counter->ext;
+		num_ext = counter->num_ext;
+		break;
+	case COUNTER_SCOPE_SIGNAL:
+		if (parent >= counter->num_signals)
+			return -EINVAL;
+		parent = array_index_nospec(parent, counter->num_signals);
+
+		comp_node.parent = counter->signals + parent;
+
+		ext = counter->signals[parent].ext;
+		num_ext = counter->signals[parent].num_ext;
+		break;
+	case COUNTER_SCOPE_COUNT:
+		if (parent >= counter->num_counts)
+			return -EINVAL;
+		parent = array_index_nospec(parent, counter->num_counts);
+
+		comp_node.parent = counter->counts + parent;
+
+		ext = counter->counts[parent].ext;
+		num_ext = counter->counts[parent].num_ext;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	id = watch.component.id;
+
+	/* Configure component info for comp node */
+	switch (watch.component.type) {
+	case COUNTER_COMPONENT_SIGNAL:
+		if (watch.component.scope != COUNTER_SCOPE_SIGNAL)
+			return -EINVAL;
+
+		comp_node.comp.type = COUNTER_COMP_SIGNAL_LEVEL;
+		comp_node.comp.signal_u32_read = counter->ops->signal_read;
+		break;
+	case COUNTER_COMPONENT_COUNT:
+		if (watch.component.scope != COUNTER_SCOPE_COUNT)
+			return -EINVAL;
+
+		comp_node.comp.type = COUNTER_COMP_U64;
+		comp_node.comp.count_u64_read = counter->ops->count_read;
+		break;
+	case COUNTER_COMPONENT_FUNCTION:
+		if (watch.component.scope != COUNTER_SCOPE_COUNT)
+			return -EINVAL;
+
+		comp_node.comp.type = COUNTER_COMP_FUNCTION;
+		comp_node.comp.count_u32_read = counter->ops->function_read;
+		break;
+	case COUNTER_COMPONENT_SYNAPSE_ACTION:
+		if (watch.component.scope != COUNTER_SCOPE_COUNT)
+			return -EINVAL;
+		if (id >= counter->counts[parent].num_synapses)
+			return -EINVAL;
+		id = array_index_nospec(id, counter->counts[parent].num_synapses);
+
+		comp_node.comp.type = COUNTER_COMP_SYNAPSE_ACTION;
+		comp_node.comp.action_read = counter->ops->action_read;
+		comp_node.comp.priv = counter->counts[parent].synapses + id;
+		break;
+	case COUNTER_COMPONENT_EXTENSION:
+		if (id >= num_ext)
+			return -EINVAL;
+		id = array_index_nospec(id, num_ext);
+
+		comp_node.comp = ext[id];
+		break;
+	default:
+		return -EINVAL;
+	}
+	/* Check if any read callback is set; this is part of a union */
+	if (!comp_node.comp.count_u8_read)
+		return -EOPNOTSUPP;
+
+no_component:
+	if (counter->ops->watch_validate) {
+		err = counter->ops->watch_validate(counter, &watch);
+		if (err < 0)
+			return err;
+	}
+
+	comp_node.component = watch.component;
+
+	return counter_set_event_node(counter, &watch, &comp_node);
+}
+
+static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd,
+				 unsigned long arg)
+{
+	struct counter_device *const counter = filp->private_data;
+	unsigned long flags;
+	int err = 0;
+
+	switch (cmd) {
+	case COUNTER_ADD_WATCH_IOCTL:
+		return counter_add_watch(counter, arg);
+	case COUNTER_ENABLE_EVENTS_IOCTL:
+		raw_spin_lock_irqsave(&counter->events_list_lock, flags);
+
+		counter_events_list_free(&counter->events_list);
+		list_replace_init(&counter->next_events_list,
+				  &counter->events_list);
+
+		if (counter->ops->events_configure)
+			err = counter->ops->events_configure(counter);
+
+		raw_spin_unlock_irqrestore(&counter->events_list_lock, flags);
+		return err;
+	case COUNTER_DISABLE_EVENTS_IOCTL:
+		return counter_disable_events(counter);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static int counter_chrdev_open(struct inode *inode, struct file *filp)
+{
+	struct counter_device *const counter = container_of(inode->i_cdev,
+							    typeof(*counter),
+							    chrdev);
+
+	get_device(&counter->dev);
+	filp->private_data = counter;
+
+	return nonseekable_open(inode, filp);
+}
+
+static int counter_chrdev_release(struct inode *inode, struct file *filp)
+{
+	struct counter_device *const counter = filp->private_data;
+	int err;
+
+	err = counter_disable_events(counter);
+	if (err < 0)
+		return err;
+
+	put_device(&counter->dev);
+
+	return 0;
+}
+
+static const struct file_operations counter_fops = {
+	.llseek = no_llseek,
+	.read = counter_chrdev_read,
+	.poll = counter_chrdev_poll,
+	.unlocked_ioctl = counter_chrdev_ioctl,
+	.open = counter_chrdev_open,
+	.release = counter_chrdev_release,
+};
+
+int counter_chrdev_add(struct counter_device *const counter,
+		       const dev_t counter_devt)
+{
+	struct device *const dev = &counter->dev;
+	struct cdev *const chrdev = &counter->chrdev;
+	int err;
+
+	/* Initialize Counter events lists */
+	INIT_LIST_HEAD(&counter->events_list);
+	INIT_LIST_HEAD(&counter->next_events_list);
+	raw_spin_lock_init(&counter->events_list_lock);
+
+	/* Initialize Counter events queue */
+	err = kfifo_alloc(&counter->events, 64, GFP_ATOMIC);
+	if (err)
+		return err;
+	init_waitqueue_head(&counter->events_wait);
+	mutex_init(&counter->events_lock);
+
+	/* Initialize character device */
+	cdev_init(chrdev, &counter_fops);
+	dev->devt = MKDEV(MAJOR(counter_devt), counter->id);
+	cdev_set_parent(chrdev, &dev->kobj);
+
+	return cdev_add(chrdev, dev->devt, 1);
+}
+
+void counter_chrdev_remove(struct counter_device *const counter)
+{
+	kfifo_free(&counter->events);
+	cdev_del(&counter->chrdev);
+}
+
+static int counter_get_data(struct counter_device *const counter,
+			    const struct counter_comp_node *const comp_node,
+			    u64 *const value)
+{
+	const struct counter_comp *const comp = &comp_node->comp;
+	void *const parent = comp_node->parent;
+	u8 value_u8 = 0;
+	u32 value_u32 = 0;
+	int ret;
+
+	if (comp_node->component.type == COUNTER_COMPONENT_NONE)
+		return 0;
+
+	switch (comp->type) {
+	case COUNTER_COMP_U8:
+	case COUNTER_COMP_BOOL:
+		switch (comp_node->component.scope) {
+		case COUNTER_SCOPE_DEVICE:
+			ret = comp->device_u8_read(counter, &value_u8);
+			break;
+		case COUNTER_SCOPE_SIGNAL:
+			ret = comp->signal_u8_read(counter, parent, &value_u8);
+			break;
+		case COUNTER_SCOPE_COUNT:
+			ret = comp->count_u8_read(counter, parent, &value_u8);
+			break;
+		}
+		*value = value_u8;
+		return ret;
+	case COUNTER_COMP_SIGNAL_LEVEL:
+	case COUNTER_COMP_FUNCTION:
+	case COUNTER_COMP_ENUM:
+	case COUNTER_COMP_COUNT_DIRECTION:
+	case COUNTER_COMP_COUNT_MODE:
+		switch (comp_node->component.scope) {
+		case COUNTER_SCOPE_DEVICE:
+			ret = comp->device_u32_read(counter, &value_u32);
+			break;
+		case COUNTER_SCOPE_SIGNAL:
+			ret = comp->signal_u32_read(counter, parent,
+						    &value_u32);
+			break;
+		case COUNTER_SCOPE_COUNT:
+			ret = comp->count_u32_read(counter, parent, &value_u32);
+			break;
+		}
+		*value = value_u32;
+		return ret;
+	case COUNTER_COMP_U64:
+		switch (comp_node->component.scope) {
+		case COUNTER_SCOPE_DEVICE:
+			return comp->device_u64_read(counter, value);
+		case COUNTER_SCOPE_SIGNAL:
+			return comp->signal_u64_read(counter, parent, value);
+		case COUNTER_SCOPE_COUNT:
+			return comp->count_u64_read(counter, parent, value);
+		default:
+			return -EINVAL;
+		}
+	case COUNTER_COMP_SYNAPSE_ACTION:
+		ret = comp->action_read(counter, parent, comp->priv,
+					&value_u32);
+		*value = value_u32;
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+/**
+ * counter_push_event - queue event for userspace reading
+ * @counter:	pointer to Counter structure
+ * @event:	triggered event
+ * @channel:	event channel
+ *
+ * Note: If no one is watching for the respective event, it is silently
+ * discarded.
+ */
+void counter_push_event(struct counter_device *const counter, const u8 event,
+			const u8 channel)
+{
+	struct counter_event ev = {0};
+	unsigned int copied = 0;
+	unsigned long flags;
+	struct counter_event_node *event_node;
+	struct counter_comp_node *comp_node;
+
+	ev.timestamp = ktime_get_ns();
+	ev.watch.event = event;
+	ev.watch.channel = channel;
+
+	/* Could be in an interrupt context, so use a raw spin lock */
+	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
+
+	/* Search for event in the list */
+	list_for_each_entry(event_node, &counter->events_list, l)
+		if (event_node->event == event &&
+		    event_node->channel == channel)
+			break;
+
+	/* If event is not in the list */
+	if (&event_node->l == &counter->events_list)
+		goto exit_early;
+
+	/* Read and queue relevant comp for userspace */
+	list_for_each_entry(comp_node, &event_node->comp_list, l) {
+		ev.watch.component = comp_node->component;
+		ev.status = -counter_get_data(counter, comp_node, &ev.value);
+
+		copied += kfifo_in(&counter->events, &ev, 1);
+	}
+
+	if (copied)
+		wake_up_poll(&counter->events_wait, EPOLLIN);
+
+exit_early:
+	raw_spin_unlock_irqrestore(&counter->events_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(counter_push_event);
diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
new file mode 100644
index 000000000000..cf5a318fe540
--- /dev/null
+++ b/drivers/counter/counter-chrdev.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Counter character device interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#ifndef _COUNTER_CHRDEV_H_
+#define _COUNTER_CHRDEV_H_
+
+#include <linux/counter.h>
+#include <linux/types.h>
+
+int counter_chrdev_add(struct counter_device *const counter,
+		       const dev_t counter_devt);
+void counter_chrdev_remove(struct counter_device *const counter);
+
+#endif /* _COUNTER_CHRDEV_H_ */
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
index bcf672e1fc0d..c137fcb97d9c 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -5,12 +5,16 @@
  */
 #include <linux/counter.h>
 #include <linux/device.h>
+#include <linux/device/bus.h>
 #include <linux/export.h>
+#include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/idr.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/types.h>
 
+#include "counter-chrdev.h"
 #include "counter-sysfs.h"
 
 /* Provides a unique ID for each counter device */
@@ -33,6 +37,8 @@ static struct bus_type counter_bus_type = {
 	.name = "counter"
 };
 
+static dev_t counter_devt;
+
 /**
  * counter_register - register Counter to the system
  * @counter:	pointer to Counter to register
@@ -54,7 +60,6 @@ int counter_register(struct counter_device *const counter)
 	if (counter->id < 0)
 		return counter->id;
 
-	/* Configure device structure for Counter */
 	dev->type = &counter_device_type;
 	dev->bus = &counter_bus_type;
 	if (counter->parent) {
@@ -65,18 +70,25 @@ int counter_register(struct counter_device *const counter)
 	device_initialize(dev);
 	dev_set_drvdata(dev, counter);
 
+	/* Add Counter character device */
+	err = counter_chrdev_add(counter, counter_devt);
+	if (err < 0)
+		goto err_free_id;
+
 	/* Add Counter sysfs attributes */
 	err = counter_sysfs_add(counter);
 	if (err < 0)
-		goto err_free_id;
+		goto err_remove_chrdev;
 
 	/* Add device to system */
 	err = device_add(dev);
 	if (err < 0)
-		goto err_free_id;
+		goto err_remove_chrdev;
 
 	return 0;
 
+err_remove_chrdev:
+	counter_chrdev_remove(counter);
 err_free_id:
 	put_device(dev);
 	return err;
@@ -138,13 +150,30 @@ int devm_counter_register(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_counter_register);
 
+#define COUNTER_DEV_MAX 256
+
 static int __init counter_init(void)
 {
-	return bus_register(&counter_bus_type);
+	int err;
+
+	err = bus_register(&counter_bus_type);
+	if (err < 0)
+		return err;
+
+	err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
+	if (err < 0)
+		goto err_unregister_bus;
+
+	return 0;
+
+err_unregister_bus:
+	bus_unregister(&counter_bus_type);
+	return err;
 }
 
 static void __exit counter_exit(void)
 {
+	unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
 	bus_unregister(&counter_bus_type);
 }
 
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 2d544f58a79c..af896143d533 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -6,9 +6,14 @@
 #ifndef _COUNTER_H_
 #define _COUNTER_H_
 
+#include <linux/cdev.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/mutex.h>
+#include <linux/spinlock_types.h>
 #include <linux/types.h>
+#include <linux/wait.h>
 #include <uapi/linux/counter.h>
 
 struct counter_device;
@@ -199,6 +204,20 @@ struct counter_count {
 	size_t num_ext;
 };
 
+/**
+ * struct counter_event_node - Counter Event node
+ * @l:		list of current watching Counter events
+ * @event:	event that triggers
+ * @channel:	event channel
+ * @comp_list:	list of components to watch when event triggers
+ */
+struct counter_event_node {
+	struct list_head l;
+	u8 event;
+	u8 channel;
+	struct list_head comp_list;
+};
+
 /**
  * struct counter_ops - Callbacks from driver
  * @signal_read:	read callback for Signals. The read level of the
@@ -221,6 +240,13 @@ struct counter_count {
  * @action_write:	write callback for Synapse action modes. The action mode
  *			to write for the respective Synapse is passed in via the
  *			action parameter.
+ * @events_configure:	write callback to configure events. The list of struct
+ *			counter_event_node may be accessed via the events_list
+ *			member of the counter parameter.
+ * @watch_validate:	callback to validate a watch. The Counter component
+ *			watch configuration is passed in via the watch
+ *			parameter. A return value of 0 indicates a valid Counter
+ *			component watch configuration.
  */
 struct counter_ops {
 	int (*signal_read)(struct counter_device *counter,
@@ -244,6 +270,9 @@ struct counter_ops {
 			    struct counter_count *count,
 			    struct counter_synapse *synapse,
 			    enum counter_synapse_action action);
+	int (*events_configure)(struct counter_device *counter);
+	int (*watch_validate)(struct counter_device *counter,
+			      const struct counter_watch *watch);
 };
 
 /**
@@ -260,6 +289,13 @@ struct counter_ops {
  * @priv:		optional private data supplied by driver
  * @id:			unique ID used to identify the Counter
  * @dev:		internal device structure
+ * @chrdev:		internal character device structure
+ * @events_list:	list of current watching Counter events
+ * @events_list_lock:	lock to protect Counter events list operations
+ * @next_events_list:	list of next watching Counter events
+ * @events:		queue of detected Counter events
+ * @events_wait:	wait queue to allow blocking reads of Counter events
+ * @events_lock:	lock to protect Counter events queue read operations
  */
 struct counter_device {
 	const char *name;
@@ -279,12 +315,21 @@ struct counter_device {
 
 	int id;
 	struct device dev;
+	struct cdev chrdev;
+	struct list_head events_list;
+	raw_spinlock_t events_list_lock;
+	struct list_head next_events_list;
+	DECLARE_KFIFO_PTR(events, struct counter_event);
+	wait_queue_head_t events_wait;
+	struct mutex events_lock;
 };
 
 int counter_register(struct counter_device *const counter);
 void counter_unregister(struct counter_device *const counter);
 int devm_counter_register(struct device *dev,
 			  struct counter_device *const counter);
+void counter_push_event(struct counter_device *const counter, const u8 event,
+			const u8 channel);
 
 #define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \
 { \
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
index 6113938a6044..3d647a5383b8 100644
--- a/include/uapi/linux/counter.h
+++ b/include/uapi/linux/counter.h
@@ -6,6 +6,19 @@
 #ifndef _UAPI_COUNTER_H_
 #define _UAPI_COUNTER_H_
 
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/* Component type definitions */
+enum counter_component_type {
+	COUNTER_COMPONENT_NONE,
+	COUNTER_COMPONENT_SIGNAL,
+	COUNTER_COMPONENT_COUNT,
+	COUNTER_COMPONENT_FUNCTION,
+	COUNTER_COMPONENT_SYNAPSE_ACTION,
+	COUNTER_COMPONENT_EXTENSION,
+};
+
 /* Component scope definitions */
 enum counter_scope {
 	COUNTER_SCOPE_DEVICE,
@@ -13,6 +26,63 @@ enum counter_scope {
 	COUNTER_SCOPE_COUNT,
 };
 
+/**
+ * struct counter_component - Counter component identification
+ * @type: component type (one of enum counter_component_type)
+ * @scope: component scope (one of enum counter_scope)
+ * @parent: parent component ID (matching the Y/Z suffix of the respective sysfs
+ *	    path as described in Documentation/ABI/testing/sysfs-bus-counter)
+ * @id: component ID (matching the Y/Z suffix of the respective sysfs path as
+ *	described in Documentation/ABI/testing/sysfs-bus-counter)
+ */
+struct counter_component {
+	__u8 type;
+	__u8 scope;
+	__u8 parent;
+	__u8 id;
+};
+
+/* Event type definitions */
+enum counter_event_type {
+	COUNTER_EVENT_OVERFLOW,
+	COUNTER_EVENT_UNDERFLOW,
+	COUNTER_EVENT_OVERFLOW_UNDERFLOW,
+	COUNTER_EVENT_THRESHOLD,
+	COUNTER_EVENT_INDEX,
+};
+
+/**
+ * struct counter_watch - Counter component watch configuration
+ * @component: component to watch when event triggers
+ * @event: event that triggers (one of enum counter_event_type)
+ * @channel: event channel (typically 0 unless the device supports concurrent
+ *	     events of the same type)
+ */
+struct counter_watch {
+	struct counter_component component;
+	__u8 event;
+	__u8 channel;
+};
+
+/* ioctl commands */
+#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch)
+#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01)
+#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02)
+
+/**
+ * struct counter_event - Counter event data
+ * @timestamp: best estimate of time of event occurrence, in nanoseconds
+ * @value: component value
+ * @watch: component watch configuration
+ * @status: return status (system error number)
+ */
+struct counter_event {
+	__aligned_u64 timestamp;
+	__aligned_u64 value;
+	struct counter_watch watch;
+	__u8 status;
+};
+
 /* Count direction values */
 enum counter_count_direction {
 	COUNTER_COUNT_DIRECTION_FORWARD,
-- 
2.30.0

Re: [PATCH v8 17/22] counter: Add character device interface

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:41 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> This patch introduces a character device interface for the Counter
> subsystem. Device data is exposed through standard character device read
> operations. Device data is gathered when a Counter event is pushed by
> the respective Counter device driver. Configuration is handled via ioctl
> operations on the respective Counter character device node.
> 
> Cc: David Lechner <david@lechnology.com>
> Cc: Gwendal Grignou <gwendal@chromium.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

Hi William,

A few minor comments.  Mostly seems to have come together well and
makes sense to me.

Jonathan

> ---
>  drivers/counter/Makefile         |   2 +-
>  drivers/counter/counter-chrdev.c | 496 +++++++++++++++++++++++++++++++
>  drivers/counter/counter-chrdev.h |  16 +
>  drivers/counter/counter-core.c   |  37 ++-
>  include/linux/counter.h          |  45 +++
>  include/uapi/linux/counter.h     |  70 +++++
>  6 files changed, 661 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/counter/counter-chrdev.c
>  create mode 100644 drivers/counter/counter-chrdev.h
> 

...

> diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> index bcf672e1fc0d..c137fcb97d9c 100644
> --- a/drivers/counter/counter-core.c
> +++ b/drivers/counter/counter-core.c
> @@ -5,12 +5,16 @@
>   */
>  #include <linux/counter.h>
>  #include <linux/device.h>
> +#include <linux/device/bus.h>
>  #include <linux/export.h>
> +#include <linux/fs.h>
>  #include <linux/gfp.h>
>  #include <linux/idr.h>
>  #include <linux/init.h>
>  #include <linux/module.h>
> +#include <linux/types.h>
>  
> +#include "counter-chrdev.h"
>  #include "counter-sysfs.h"
>  
>  /* Provides a unique ID for each counter device */
> @@ -33,6 +37,8 @@ static struct bus_type counter_bus_type = {
>  	.name = "counter"
>  };
>  
> +static dev_t counter_devt;
> +
>  /**
>   * counter_register - register Counter to the system
>   * @counter:	pointer to Counter to register
> @@ -54,7 +60,6 @@ int counter_register(struct counter_device *const counter)
>  	if (counter->id < 0)
>  		return counter->id;
>  
> -	/* Configure device structure for Counter */

Not sure why this comment gets removed here.

>  	dev->type = &counter_device_type;
>  	dev->bus = &counter_bus_type;
>  	if (counter->parent) {
> @@ -65,18 +70,25 @@ int counter_register(struct counter_device *const counter)
>  	device_initialize(dev);
>  	dev_set_drvdata(dev, counter);
>  
> +	/* Add Counter character device */
> +	err = counter_chrdev_add(counter, counter_devt);
> +	if (err < 0)
> +		goto err_free_id;
> +
>  	/* Add Counter sysfs attributes */
>  	err = counter_sysfs_add(counter);
>  	if (err < 0)
> -		goto err_free_id;
> +		goto err_remove_chrdev;
>  
>  	/* Add device to system */
>  	err = device_add(dev);
>  	if (err < 0)
> -		goto err_free_id;
> +		goto err_remove_chrdev;

It might be worth thinking about using cdev_device_add()
though will require a slightly different order of adding.


>  
>  	return 0;
>  
> +err_remove_chrdev:
> +	counter_chrdev_remove(counter);
>  err_free_id:
>  	put_device(dev);
>  	return err;
> @@ -138,13 +150,30 @@ int devm_counter_register(struct device *dev,
>  }
>  EXPORT_SYMBOL_GPL(devm_counter_register);
>  
> +#define COUNTER_DEV_MAX 256
> +
>  static int __init counter_init(void)
>  {
> -	return bus_register(&counter_bus_type);
> +	int err;
> +
> +	err = bus_register(&counter_bus_type);
> +	if (err < 0)
> +		return err;
> +
> +	err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
> +	if (err < 0)
> +		goto err_unregister_bus;
> +
> +	return 0;
> +
> +err_unregister_bus:
> +	bus_unregister(&counter_bus_type);
> +	return err;
>  }
>  
>  static void __exit counter_exit(void)
>  {
> +	unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
>  	bus_unregister(&counter_bus_type);
>  }
>  

...

> diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
> index 6113938a6044..3d647a5383b8 100644
> --- a/include/uapi/linux/counter.h
> +++ b/include/uapi/linux/counter.h
> @@ -6,6 +6,19 @@
>  #ifndef _UAPI_COUNTER_H_
>  #define _UAPI_COUNTER_H_
>  
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +/* Component type definitions */
> +enum counter_component_type {
> +	COUNTER_COMPONENT_NONE,
> +	COUNTER_COMPONENT_SIGNAL,
> +	COUNTER_COMPONENT_COUNT,
> +	COUNTER_COMPONENT_FUNCTION,
> +	COUNTER_COMPONENT_SYNAPSE_ACTION,
> +	COUNTER_COMPONENT_EXTENSION,
> +};
> +
>  /* Component scope definitions */
>  enum counter_scope {
>  	COUNTER_SCOPE_DEVICE,
> @@ -13,6 +26,63 @@ enum counter_scope {
>  	COUNTER_SCOPE_COUNT,
>  };
>  
> +/**
> + * struct counter_component - Counter component identification
> + * @type: component type (one of enum counter_component_type)
> + * @scope: component scope (one of enum counter_scope)
> + * @parent: parent component ID (matching the Y/Z suffix of the respective sysfs
> + *	    path as described in Documentation/ABI/testing/sysfs-bus-counter)

Probably good to give an example here as well as the cross reference.

> + * @id: component ID (matching the Y/Z suffix of the respective sysfs path as
> + *	described in Documentation/ABI/testing/sysfs-bus-counter)
> + */
> +struct counter_component {
> +	__u8 type;
> +	__u8 scope;
> +	__u8 parent;
> +	__u8 id;
> +};
> +
> +/* Event type definitions */
> +enum counter_event_type {
> +	COUNTER_EVENT_OVERFLOW,
> +	COUNTER_EVENT_UNDERFLOW,
> +	COUNTER_EVENT_OVERFLOW_UNDERFLOW,
> +	COUNTER_EVENT_THRESHOLD,
> +	COUNTER_EVENT_INDEX,
> +};
> +
> +/**
> + * struct counter_watch - Counter component watch configuration
> + * @component: component to watch when event triggers
> + * @event: event that triggers (one of enum counter_event_type)
> + * @channel: event channel (typically 0 unless the device supports concurrent
> + *	     events of the same type)
> + */
> +struct counter_watch {
> +	struct counter_component component;
> +	__u8 event;
> +	__u8 channel;
> +};
> +
> +/* ioctl commands */
> +#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch)
> +#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01)
> +#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02)
> +
> +/**
> + * struct counter_event - Counter event data
> + * @timestamp: best estimate of time of event occurrence, in nanoseconds
> + * @value: component value
> + * @watch: component watch configuration
> + * @status: return status (system error number)
> + */
> +struct counter_event {
> +	__aligned_u64 timestamp;
> +	__aligned_u64 value;
> +	struct counter_watch watch;
> +	__u8 status;
> +};
> +
>  /* Count direction values */
>  enum counter_count_direction {
>  	COUNTER_COUNT_DIRECTION_FORWARD,

Re: [PATCH v8 17/22] counter: Add character device interface

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 6051 bytes --]

On Sun, Feb 14, 2021 at 06:06:12PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:41 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > This patch introduces a character device interface for the Counter
> > subsystem. Device data is exposed through standard character device read
> > operations. Device data is gathered when a Counter event is pushed by
> > the respective Counter device driver. Configuration is handled via ioctl
> > operations on the respective Counter character device node.
> > 
> > Cc: David Lechner <david@lechnology.com>
> > Cc: Gwendal Grignou <gwendal@chromium.org>
> > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> 
> Hi William,
> 
> A few minor comments.  Mostly seems to have come together well and
> makes sense to me.
> 
> Jonathan
> 
> > ---
> >  drivers/counter/Makefile         |   2 +-
> >  drivers/counter/counter-chrdev.c | 496 +++++++++++++++++++++++++++++++
> >  drivers/counter/counter-chrdev.h |  16 +
> >  drivers/counter/counter-core.c   |  37 ++-
> >  include/linux/counter.h          |  45 +++
> >  include/uapi/linux/counter.h     |  70 +++++
> >  6 files changed, 661 insertions(+), 5 deletions(-)
> >  create mode 100644 drivers/counter/counter-chrdev.c
> >  create mode 100644 drivers/counter/counter-chrdev.h
> > 
> 
> ...
> 
> > diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> > index bcf672e1fc0d..c137fcb97d9c 100644
> > --- a/drivers/counter/counter-core.c
> > +++ b/drivers/counter/counter-core.c
> > @@ -5,12 +5,16 @@
> >   */
> >  #include <linux/counter.h>
> >  #include <linux/device.h>
> > +#include <linux/device/bus.h>
> >  #include <linux/export.h>
> > +#include <linux/fs.h>
> >  #include <linux/gfp.h>
> >  #include <linux/idr.h>
> >  #include <linux/init.h>
> >  #include <linux/module.h>
> > +#include <linux/types.h>
> >  
> > +#include "counter-chrdev.h"
> >  #include "counter-sysfs.h"
> >  
> >  /* Provides a unique ID for each counter device */
> > @@ -33,6 +37,8 @@ static struct bus_type counter_bus_type = {
> >  	.name = "counter"
> >  };
> >  
> > +static dev_t counter_devt;
> > +
> >  /**
> >   * counter_register - register Counter to the system
> >   * @counter:	pointer to Counter to register
> > @@ -54,7 +60,6 @@ int counter_register(struct counter_device *const counter)
> >  	if (counter->id < 0)
> >  		return counter->id;
> >  
> > -	/* Configure device structure for Counter */
> 
> Not sure why this comment gets removed here.

This comment wasn't suppose to be removed. I'll revert this.

> >  	dev->type = &counter_device_type;
> >  	dev->bus = &counter_bus_type;
> >  	if (counter->parent) {
> > @@ -65,18 +70,25 @@ int counter_register(struct counter_device *const counter)
> >  	device_initialize(dev);
> >  	dev_set_drvdata(dev, counter);
> >  
> > +	/* Add Counter character device */
> > +	err = counter_chrdev_add(counter, counter_devt);
> > +	if (err < 0)
> > +		goto err_free_id;
> > +
> >  	/* Add Counter sysfs attributes */
> >  	err = counter_sysfs_add(counter);
> >  	if (err < 0)
> > -		goto err_free_id;
> > +		goto err_remove_chrdev;
> >  
> >  	/* Add device to system */
> >  	err = device_add(dev);
> >  	if (err < 0)
> > -		goto err_free_id;
> > +		goto err_remove_chrdev;
> 
> It might be worth thinking about using cdev_device_add()
> though will require a slightly different order of adding.

I think using cdev_device_add() should be possible. I'll adjust
counter_chrdev_add() accordingly to account for this.
 
> >  
> >  	return 0;
> >  
> > +err_remove_chrdev:
> > +	counter_chrdev_remove(counter);
> >  err_free_id:
> >  	put_device(dev);
> >  	return err;
> > @@ -138,13 +150,30 @@ int devm_counter_register(struct device *dev,
> >  }
> >  EXPORT_SYMBOL_GPL(devm_counter_register);
> >  
> > +#define COUNTER_DEV_MAX 256
> > +
> >  static int __init counter_init(void)
> >  {
> > -	return bus_register(&counter_bus_type);
> > +	int err;
> > +
> > +	err = bus_register(&counter_bus_type);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
> > +	if (err < 0)
> > +		goto err_unregister_bus;
> > +
> > +	return 0;
> > +
> > +err_unregister_bus:
> > +	bus_unregister(&counter_bus_type);
> > +	return err;
> >  }
> >  
> >  static void __exit counter_exit(void)
> >  {
> > +	unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
> >  	bus_unregister(&counter_bus_type);
> >  }
> >  
> 
> ...
> 
> > diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
> > index 6113938a6044..3d647a5383b8 100644
> > --- a/include/uapi/linux/counter.h
> > +++ b/include/uapi/linux/counter.h
> > @@ -6,6 +6,19 @@
> >  #ifndef _UAPI_COUNTER_H_
> >  #define _UAPI_COUNTER_H_
> >  
> > +#include <linux/ioctl.h>
> > +#include <linux/types.h>
> > +
> > +/* Component type definitions */
> > +enum counter_component_type {
> > +	COUNTER_COMPONENT_NONE,
> > +	COUNTER_COMPONENT_SIGNAL,
> > +	COUNTER_COMPONENT_COUNT,
> > +	COUNTER_COMPONENT_FUNCTION,
> > +	COUNTER_COMPONENT_SYNAPSE_ACTION,
> > +	COUNTER_COMPONENT_EXTENSION,
> > +};
> > +
> >  /* Component scope definitions */
> >  enum counter_scope {
> >  	COUNTER_SCOPE_DEVICE,
> > @@ -13,6 +26,63 @@ enum counter_scope {
> >  	COUNTER_SCOPE_COUNT,
> >  };
> >  
> > +/**
> > + * struct counter_component - Counter component identification
> > + * @type: component type (one of enum counter_component_type)
> > + * @scope: component scope (one of enum counter_scope)
> > + * @parent: parent component ID (matching the Y/Z suffix of the respective sysfs
> > + *	    path as described in Documentation/ABI/testing/sysfs-bus-counter)
> 
> Probably good to give an example here as well as the cross reference.

Ack.

William Breathitt Gray

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Re: [PATCH v8 17/22] counter: Add character device interface

[Oleksij Rempel]

Hi William,

On Fri, Feb 12, 2021 at 09:13:41PM +0900, William Breathitt Gray wrote:
> This patch introduces a character device interface for the Counter
> subsystem. Device data is exposed through standard character device read
> operations. Device data is gathered when a Counter event is pushed by
> the respective Counter device driver. Configuration is handled via ioctl
> operations on the respective Counter character device node.

.....

> +/**
> + * counter_push_event - queue event for userspace reading
> + * @counter:	pointer to Counter structure
> + * @event:	triggered event
> + * @channel:	event channel
> + *
> + * Note: If no one is watching for the respective event, it is silently
> + * discarded.
> + */
> +void counter_push_event(struct counter_device *const counter, const u8 event,
> +			const u8 channel)
> +{
> +	struct counter_event ev = {0};
> +	unsigned int copied = 0;
> +	unsigned long flags;
> +	struct counter_event_node *event_node;
> +	struct counter_comp_node *comp_node;
> +
> +	ev.timestamp = ktime_get_ns();
> +	ev.watch.event = event;
> +	ev.watch.channel = channel;
> +
> +	/* Could be in an interrupt context, so use a raw spin lock */
> +	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> +	/* Search for event in the list */
> +	list_for_each_entry(event_node, &counter->events_list, l)
> +		if (event_node->event == event &&
> +		    event_node->channel == channel)
> +			break;
> +
> +	/* If event is not in the list */
> +	if (&event_node->l == &counter->events_list)
> +		goto exit_early;

To cover my "interrupt-counter" use case, I added following line here to
convert the tail drop fifo to the head drop fifo:

+       list_for_each_entry(comp_node, &event_node->comp_list, l)
+               to_copy += sizeof(ev);
+
+       while (kfifo_avail(&counter->events) < to_copy)
+               kfifo_skip(&counter->events);

May be it make sense to make it optional and integrate in to you patches
before it goes mainline?

Regards,
Oleksij
-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH v8 17/22] counter: Add character device interface

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 3058 bytes --]

On Mon, Feb 15, 2021 at 10:24:12AM +0100, Oleksij Rempel wrote:
> Hi William,
> 
> On Fri, Feb 12, 2021 at 09:13:41PM +0900, William Breathitt Gray wrote:
> > This patch introduces a character device interface for the Counter
> > subsystem. Device data is exposed through standard character device read
> > operations. Device data is gathered when a Counter event is pushed by
> > the respective Counter device driver. Configuration is handled via ioctl
> > operations on the respective Counter character device node.
> 
> .....
> 
> > +/**
> > + * counter_push_event - queue event for userspace reading
> > + * @counter:	pointer to Counter structure
> > + * @event:	triggered event
> > + * @channel:	event channel
> > + *
> > + * Note: If no one is watching for the respective event, it is silently
> > + * discarded.
> > + */
> > +void counter_push_event(struct counter_device *const counter, const u8 event,
> > +			const u8 channel)
> > +{
> > +	struct counter_event ev = {0};
> > +	unsigned int copied = 0;
> > +	unsigned long flags;
> > +	struct counter_event_node *event_node;
> > +	struct counter_comp_node *comp_node;
> > +
> > +	ev.timestamp = ktime_get_ns();
> > +	ev.watch.event = event;
> > +	ev.watch.channel = channel;
> > +
> > +	/* Could be in an interrupt context, so use a raw spin lock */
> > +	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
> > +
> > +	/* Search for event in the list */
> > +	list_for_each_entry(event_node, &counter->events_list, l)
> > +		if (event_node->event == event &&
> > +		    event_node->channel == channel)
> > +			break;
> > +
> > +	/* If event is not in the list */
> > +	if (&event_node->l == &counter->events_list)
> > +		goto exit_early;
> 
> To cover my "interrupt-counter" use case, I added following line here to
> convert the tail drop fifo to the head drop fifo:
> 
> +       list_for_each_entry(comp_node, &event_node->comp_list, l)
> +               to_copy += sizeof(ev);
> +
> +       while (kfifo_avail(&counter->events) < to_copy)
> +               kfifo_skip(&counter->events);
> 
> May be it make sense to make it optional and integrate in to you patches
> before it goes mainline?
> 
> Regards,
> Oleksij
> -- 
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Hello Oleksij,

I appreciate your suggestion, and I'm excited about your
interrupt-counter driver -- it looks like the Counter character device
interface will be central for that driver. However, I want to hold off
on adding further functionality to this patchset so that we can stablize
it enough to merge.

Once the Counter character device interface is merged, please send your
changes again as a patch and we can review it further then.

Thank you,

William Breathitt Gray

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[PATCH v8 18/22] docs: counter: Document character device interface

[William Breathitt Gray]

This patch adds high-level documentation about the Counter subsystem
character device interface.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 Documentation/driver-api/generic-counter.rst  | 243 +++++++++++++++---
 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 2 files changed, 203 insertions(+), 41 deletions(-)

diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index f6397218aa4c..3be109dc81bb 100644
--- a/Documentation/driver-api/generic-counter.rst
+++ b/Documentation/driver-api/generic-counter.rst
@@ -223,19 +223,6 @@ whether an input line is differential or single-ended) and instead focus
 on the core idea of what the data and process represent (e.g. position
 as interpreted from quadrature encoding data).
 
-Userspace Interface
-===================
-
-Several sysfs attributes are generated by the Generic Counter interface,
-and reside under the /sys/bus/counter/devices/counterX directory, where
-counterX refers to the respective counter device. Please see
-Documentation/ABI/testing/sysfs-bus-counter for detailed
-information on each Generic Counter interface sysfs attribute.
-
-Through these sysfs attributes, programs and scripts may interact with
-the Generic Counter paradigm Counts, Signals, and Synapses of respective
-counter devices.
-
 Driver API
 ==========
 
@@ -388,16 +375,16 @@ userspace interface components::
                         / driver callbacks /
                         -------------------
                                 |
-                +---------------+
-                |
-                V
-        +--------------------+
-        | Counter sysfs      |
-        +--------------------+
-        | Translates to the  |
-        | standard Counter   |
-        | sysfs output       |
-        +--------------------+
+                +---------------+---------------+
+                |                               |
+                V                               V
+        +--------------------+          +---------------------+
+        | Counter sysfs      |          | Counter chrdev      |
+        +--------------------+          +---------------------+
+        | Translates to the  |          | Translates to the   |
+        | standard Counter   |          | standard Counter    |
+        | sysfs output       |          | character device    |
+        +--------------------+          +---------------------+
 
 Thereafter, data can be transferred directly between the Counter device
 driver and Counter userspace interface::
@@ -428,23 +415,30 @@ driver and Counter userspace interface::
                         / u64     /
                         ----------
                                 |
-                +---------------+
-                |
-                V
-        +--------------------+
-        | Counter sysfs      |
-        +--------------------+
-        | Translates to the  |
-        | standard Counter   |
-        | sysfs output       |
-        |--------------------|
-        | Type: const char * |
-        | Value: "42"        |
-        +--------------------+
-                |
-         ---------------
-        / const char * /
-        ---------------
+                +---------------+---------------+
+                |                               |
+                V                               V
+        +--------------------+          +---------------------+
+        | Counter sysfs      |          | Counter chrdev      |
+        +--------------------+          +---------------------+
+        | Translates to the  |          | Translates to the   |
+        | standard Counter   |          | standard Counter    |
+        | sysfs output       |          | character device    |
+        |--------------------|          |---------------------|
+        | Type: const char * |          | Type: u64           |
+        | Value: "42"        |          | Value: 42           |
+        +--------------------+          +---------------------+
+                |                               |
+         ---------------                 -----------------------
+        / const char * /                / struct counter_event /
+        ---------------                 -----------------------
+                |                               |
+                |                               V
+                |                       +-----------+
+                |                       | read      |
+                |                       +-----------+
+                |                       \ Count: 42 /
+                |                        -----------
                 |
                 V
         +--------------------------------------------------+
@@ -453,7 +447,7 @@ driver and Counter userspace interface::
         \ Count: "42"                                      /
          --------------------------------------------------
 
-There are three primary components involved:
+There are four primary components involved:
 
 Counter device driver
 ---------------------
@@ -473,3 +467,170 @@ and vice versa.
 Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
 for a detailed breakdown of the available Generic Counter interface
 sysfs attributes.
+
+Counter chrdev
+--------------
+Translates counter data to the standard Counter character device; data
+is transferred via standard character device read calls, while Counter
+events are configured via ioctl calls.
+
+Sysfs Interface
+===============
+
+Several sysfs attributes are generated by the Generic Counter interface,
+and reside under the ``/sys/bus/counter/devices/counterX`` directory,
+where ``X`` is to the respective counter device id. Please see
+``Documentation/ABI/testing/sysfs-bus-counter`` for detailed information
+on each Generic Counter interface sysfs attribute.
+
+Through these sysfs attributes, programs and scripts may interact with
+the Generic Counter paradigm Counts, Signals, and Synapses of respective
+counter devices.
+
+Counter Character Device
+========================
+
+Counter character device nodes are created under the ``/dev`` directory
+as ``counterX``, where ``X`` is the respective counter device id.
+Defines for the standard Counter data types are exposed via the
+userspace ``include/uapi/linux/counter.h`` file.
+
+Counter events
+--------------
+Counter device drivers can support Counter events by utilizing the
+``counter_push_event`` function::
+
+        void counter_push_event(struct counter_device *const counter, const u8 event,
+                                const u8 channel);
+
+The event id is specified by the ``event`` parameter; the event channel
+id is specified by the ``channel`` parameter. When this function is
+called, the Counter data associated with the respective event is
+gathered, and a ``struct counter_event`` is generated for each datum and
+pushed to userspace.
+
+Counter events can be configured by users to report various Counter
+data of interest. This can be conceptualized as a list of Counter
+component read calls to perform. For example::
+
+        +~~~~~~~~~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~~~~~+
+        | COUNTER_EVENT_OVERFLOW | COUNTER_EVENT_INDEX    |
+        +~~~~~~~~~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~~~~~+
+        | Channel 0              | Channel 0              |
+        +------------------------+------------------------+
+        | * Count 0              | * Signal 0             |
+        | * Count 1              | * Signal 0 Extension 0 |
+        | * Signal 3             | * Extension 4          |
+        | * Count 4 Extension 2  +------------------------+
+        | * Signal 5 Extension 0 | Channel 1              |
+        |                        +------------------------+
+        |                        | * Signal 4             |
+        |                        | * Signal 4 Extension 0 |
+        |                        | * Count 7              |
+        +------------------------+------------------------+
+
+When ``counter_push_event(counter, COUNTER_EVENT_INDEX, 1)`` is called
+for example, it will go down the list for the ``COUNTER_EVENT_INDEX``
+event channel 1 and execute the read callbacks for Signal 4, Signal 4
+Extension 0, and Count 4 -- the data returned for each is pushed to a
+kfifo as a ``struct counter_event``, which userspace can retrieve via a
+standard read operation on the respective character device node.
+
+Userspace
+---------
+Userspace applications can configure Counter events via ioctl operations
+on the Counter character device node. There following ioctl codes are
+supported and provided by the ``linux/counter.h`` userspace header file:
+
+* COUNTER_ADD_WATCH_IOCTL:
+  Queues a Counter watch for the specified event. The queued watches
+  will not be applied until ``COUNTER_ENABLE_EVENTS_IOCTL`` is called.
+
+* COUNTER_ENABLE_EVENTS_IOCTL:
+  Enables monitoring the events specified by the Counter watches that
+  were queued by ``COUNTER_ADD_WATCH_IOCTL``. If events are already
+  enabled, the new set of watches replaces the old one. Calling this
+  ioctl also has the effect of clearing the queue of watches added by
+  ``COUNTER_ADD_WATCH_IOCTL``.
+
+* COUNTER_DISABLE_EVENTS_IOCTL:
+  Stops monitoring the previously enabled events.
+
+To configure events to gather Counter data, users first populate a
+``struct counter_watch`` with the relevant event id, event channel id,
+and the information for the desired Counter component from which to
+read, and then pass it via the ``COUNTER_ADD_WATCH_IOCTL`` ioctl
+command.
+
+Note that an event can be watched without gathering Counter data by
+setting the ``component.type`` member equal to
+``COUNTER_COMPONENT_NONE``. With this configuration the Counter
+character device will simply populate the event timestamps for those
+respective ``struct counter_event`` elements and ignore the component
+value.
+
+The ``COUNTER_ADD_WATCH_IOCTL`` command will buffer these Counter
+watches. When ready, the ``COUNTER_ENABLE_EVENTS_IOCTL`` ioctl command
+may be used to activate these Counter watches.
+
+Userspace applications can then execute a ``read`` operation (optionally
+calling ``poll`` first) on the Counter character device node to retrieve
+``struct counter_event`` elements with the desired data.
+
+For example, the following userspace code opens ``/dev/counter0``,
+configures the ``COUNTER_EVENT_INDEX`` event channel 0 to gather Count 0
+and Count 1, and prints out the data as it becomes available on the
+character device node::
+
+        #include <fcntl.h>
+        #include <linux/counter.h>
+        #include <stdio.h>
+        #include <string.h>
+        #include <sys/ioctl.h>
+        #include <unistd.h>
+
+        struct counter_watch watches[2] = {
+                {
+                        .component.type = COUNTER_COMPONENT_COUNT,
+                        .component.scope = COUNTER_SCOPE_COUNT,
+                        .component.parent = 0,
+                        .event = COUNTER_EVENT_INDEX,
+                        .channel = 0,
+                },
+                {
+                        .component.type = COUNTER_COMPONENT_COUNT,
+                        .component.scope = COUNTER_SCOPE_COUNT,
+                        .component.parent = 1,
+                        .event = COUNTER_EVENT_INDEX,
+                        .channel = 0,
+                },
+        };
+
+        int main(void)
+        {
+                int fd;
+                struct counter_event event_data[2];
+
+                fd = open("/dev/counter0", O_RDWR);
+
+                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
+                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
+                ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
+
+                for (;;) {
+                        read(fd, event_data, sizeof(event_data));
+
+                        printf("Timestamp 0: %llu\tCount 0: %llu\n"
+                               "Error Message 0: %s\n"
+                               "Timestamp 1: %llu\tCount 1: %llu\n"
+                               "Error Message 1: %s\n",
+                               (unsigned long long)event_data[0].timestamp,
+                               (unsigned long long)event_data[0].value,
+                               strerror(event_data[0].status),
+                               (unsigned long long)event_data[1].timestamp,
+                               (unsigned long long)event_data[1].value,
+                               strerror(event_data[1].status));
+                }
+
+                return 0;
+        }
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index a4c75a28c839..8ddca931ec4e 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -88,6 +88,7 @@ Code  Seq#    Include File                                           Comments
                                                                      <http://infiniband.sourceforge.net/>
 0x20  all    drivers/cdrom/cm206.h
 0x22  all    scsi/sg.h
+0x3E  00-0F  linux/counter.h                                         <mailto:linux-iio@vger.kernel.org>
 '!'   00-1F  uapi/linux/seccomp.h
 '#'   00-3F                                                          IEEE 1394 Subsystem
                                                                      Block for the entire subsystem
-- 
2.30.0

Re: [PATCH v8 18/22] docs: counter: Document character device interface

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:42 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> This patch adds high-level documentation about the Counter subsystem
> character device interface.
> 
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>  Documentation/driver-api/generic-counter.rst  | 243 +++++++++++++++---
>  .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>  2 files changed, 203 insertions(+), 41 deletions(-)
> 
> diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
> index f6397218aa4c..3be109dc81bb 100644
> --- a/Documentation/driver-api/generic-counter.rst
> +++ b/Documentation/driver-api/generic-counter.rst
> @@ -223,19 +223,6 @@ whether an input line is differential or single-ended) and instead focus
>  on the core idea of what the data and process represent (e.g. position
>  as interpreted from quadrature encoding data).
>  
> -Userspace Interface
> -===================
> -
> -Several sysfs attributes are generated by the Generic Counter interface,
> -and reside under the /sys/bus/counter/devices/counterX directory, where
> -counterX refers to the respective counter device. Please see
> -Documentation/ABI/testing/sysfs-bus-counter for detailed
> -information on each Generic Counter interface sysfs attribute.
> -
> -Through these sysfs attributes, programs and scripts may interact with
> -the Generic Counter paradigm Counts, Signals, and Synapses of respective
> -counter devices.
> -
>  Driver API
>  ==========
>  
> @@ -388,16 +375,16 @@ userspace interface components::
>                          / driver callbacks /
>                          -------------------
>                                  |
> -                +---------------+
> -                |
> -                V
> -        +--------------------+
> -        | Counter sysfs      |
> -        +--------------------+
> -        | Translates to the  |
> -        | standard Counter   |
> -        | sysfs output       |
> -        +--------------------+
> +                +---------------+---------------+
> +                |                               |
> +                V                               V
> +        +--------------------+          +---------------------+
> +        | Counter sysfs      |          | Counter chrdev      |
> +        +--------------------+          +---------------------+
> +        | Translates to the  |          | Translates to the   |
> +        | standard Counter   |          | standard Counter    |
> +        | sysfs output       |          | character device    |
> +        +--------------------+          +---------------------+
>  
>  Thereafter, data can be transferred directly between the Counter device
>  driver and Counter userspace interface::
> @@ -428,23 +415,30 @@ driver and Counter userspace interface::
>                          / u64     /
>                          ----------
>                                  |
> -                +---------------+
> -                |
> -                V
> -        +--------------------+
> -        | Counter sysfs      |
> -        +--------------------+
> -        | Translates to the  |
> -        | standard Counter   |
> -        | sysfs output       |
> -        |--------------------|
> -        | Type: const char * |
> -        | Value: "42"        |
> -        +--------------------+
> -                |
> -         ---------------
> -        / const char * /
> -        ---------------
> +                +---------------+---------------+
> +                |                               |
> +                V                               V
> +        +--------------------+          +---------------------+
> +        | Counter sysfs      |          | Counter chrdev      |
> +        +--------------------+          +---------------------+
> +        | Translates to the  |          | Translates to the   |
> +        | standard Counter   |          | standard Counter    |
> +        | sysfs output       |          | character device    |
> +        |--------------------|          |---------------------|
> +        | Type: const char * |          | Type: u64           |
> +        | Value: "42"        |          | Value: 42           |
> +        +--------------------+          +---------------------+
> +                |                               |
> +         ---------------                 -----------------------
> +        / const char * /                / struct counter_event /
> +        ---------------                 -----------------------
> +                |                               |
> +                |                               V
> +                |                       +-----------+
> +                |                       | read      |
> +                |                       +-----------+
> +                |                       \ Count: 42 /
> +                |                        -----------
>                  |
>                  V
>          +--------------------------------------------------+
> @@ -453,7 +447,7 @@ driver and Counter userspace interface::
>          \ Count: "42"                                      /
>           --------------------------------------------------
>  
> -There are three primary components involved:
> +There are four primary components involved:
>  
>  Counter device driver
>  ---------------------
> @@ -473,3 +467,170 @@ and vice versa.
>  Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
>  for a detailed breakdown of the available Generic Counter interface
>  sysfs attributes.
> +
> +Counter chrdev
> +--------------
> +Translates counter data to the standard Counter character device; data
> +is transferred via standard character device read calls, while Counter
> +events are configured via ioctl calls.
> +
> +Sysfs Interface
> +===============
> +
> +Several sysfs attributes are generated by the Generic Counter interface,
> +and reside under the ``/sys/bus/counter/devices/counterX`` directory,
> +where ``X`` is to the respective counter device id. Please see
> +``Documentation/ABI/testing/sysfs-bus-counter`` for detailed information
> +on each Generic Counter interface sysfs attribute.
> +
> +Through these sysfs attributes, programs and scripts may interact with
> +the Generic Counter paradigm Counts, Signals, and Synapses of respective
> +counter devices.
> +
> +Counter Character Device
> +========================
> +
> +Counter character device nodes are created under the ``/dev`` directory
> +as ``counterX``, where ``X`` is the respective counter device id.
> +Defines for the standard Counter data types are exposed via the
> +userspace ``include/uapi/linux/counter.h`` file.
> +
> +Counter events
> +--------------
> +Counter device drivers can support Counter events by utilizing the
> +``counter_push_event`` function::
> +
> +        void counter_push_event(struct counter_device *const counter, const u8 event,
> +                                const u8 channel);
> +
> +The event id is specified by the ``event`` parameter; the event channel
> +id is specified by the ``channel`` parameter. When this function is
> +called, the Counter data associated with the respective event is
> +gathered, and a ``struct counter_event`` is generated for each datum and
> +pushed to userspace.
> +
> +Counter events can be configured by users to report various Counter
> +data of interest. This can be conceptualized as a list of Counter
> +component read calls to perform. For example::
> +
> +        +~~~~~~~~~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~~~~~+
> +        | COUNTER_EVENT_OVERFLOW | COUNTER_EVENT_INDEX    |
> +        +~~~~~~~~~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~~~~~+
> +        | Channel 0              | Channel 0              |
> +        +------------------------+------------------------+
> +        | * Count 0              | * Signal 0             |
> +        | * Count 1              | * Signal 0 Extension 0 |
> +        | * Signal 3             | * Extension 4          |
> +        | * Count 4 Extension 2  +------------------------+
> +        | * Signal 5 Extension 0 | Channel 1              |
> +        |                        +------------------------+
> +        |                        | * Signal 4             |
> +        |                        | * Signal 4 Extension 0 |
> +        |                        | * Count 7              |
> +        +------------------------+------------------------+
> +
> +When ``counter_push_event(counter, COUNTER_EVENT_INDEX, 1)`` is called
> +for example, it will go down the list for the ``COUNTER_EVENT_INDEX``
> +event channel 1 and execute the read callbacks for Signal 4, Signal 4
> +Extension 0, and Count 4 -- the data returned for each is pushed to a
> +kfifo as a ``struct counter_event``, which userspace can retrieve via a
> +standard read operation on the respective character device node.
> +
> +Userspace
> +---------
> +Userspace applications can configure Counter events via ioctl operations
> +on the Counter character device node. There following ioctl codes are
> +supported and provided by the ``linux/counter.h`` userspace header file:
> +
> +* COUNTER_ADD_WATCH_IOCTL:
> +  Queues a Counter watch for the specified event. The queued watches
> +  will not be applied until ``COUNTER_ENABLE_EVENTS_IOCTL`` is called.
> +
> +* COUNTER_ENABLE_EVENTS_IOCTL:
> +  Enables monitoring the events specified by the Counter watches that
> +  were queued by ``COUNTER_ADD_WATCH_IOCTL``. If events are already
> +  enabled, the new set of watches replaces the old one. Calling this
> +  ioctl also has the effect of clearing the queue of watches added by
> +  ``COUNTER_ADD_WATCH_IOCTL``.
> +
> +* COUNTER_DISABLE_EVENTS_IOCTL:
> +  Stops monitoring the previously enabled events.

Is there a way to remove a watch? 

> +
> +To configure events to gather Counter data, users first populate a
> +``struct counter_watch`` with the relevant event id, event channel id,
> +and the information for the desired Counter component from which to
> +read, and then pass it via the ``COUNTER_ADD_WATCH_IOCTL`` ioctl
> +command.
> +
> +Note that an event can be watched without gathering Counter data by
> +setting the ``component.type`` member equal to
> +``COUNTER_COMPONENT_NONE``. With this configuration the Counter
> +character device will simply populate the event timestamps for those
> +respective ``struct counter_event`` elements and ignore the component
> +value.
> +
> +The ``COUNTER_ADD_WATCH_IOCTL`` command will buffer these Counter
> +watches. When ready, the ``COUNTER_ENABLE_EVENTS_IOCTL`` ioctl command
> +may be used to activate these Counter watches.
> +
> +Userspace applications can then execute a ``read`` operation (optionally
> +calling ``poll`` first) on the Counter character device node to retrieve
> +``struct counter_event`` elements with the desired data.
> +
> +For example, the following userspace code opens ``/dev/counter0``,
> +configures the ``COUNTER_EVENT_INDEX`` event channel 0 to gather Count 0
> +and Count 1, and prints out the data as it becomes available on the
> +character device node::
> +

Consider adding an example program under tools/

> +        #include <fcntl.h>
> +        #include <linux/counter.h>
> +        #include <stdio.h>
> +        #include <string.h>
> +        #include <sys/ioctl.h>
> +        #include <unistd.h>
> +
> +        struct counter_watch watches[2] = {
> +                {
> +                        .component.type = COUNTER_COMPONENT_COUNT,
> +                        .component.scope = COUNTER_SCOPE_COUNT,
> +                        .component.parent = 0,

Good to add comments on what these elements actually are?

> +                        .event = COUNTER_EVENT_INDEX,
> +                        .channel = 0,
> +                },
> +                {
> +                        .component.type = COUNTER_COMPONENT_COUNT,
> +                        .component.scope = COUNTER_SCOPE_COUNT,
> +                        .component.parent = 1,
> +                        .event = COUNTER_EVENT_INDEX,
> +                        .channel = 0,
> +                },
> +        };
> +
> +        int main(void)
> +        {
> +                int fd;
> +                struct counter_event event_data[2];
> +
> +                fd = open("/dev/counter0", O_RDWR);
> +
> +                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
> +                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
> +                ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
> +
> +                for (;;) {
> +                        read(fd, event_data, sizeof(event_data));
> +
> +                        printf("Timestamp 0: %llu\tCount 0: %llu\n"
> +                               "Error Message 0: %s\n"
> +                               "Timestamp 1: %llu\tCount 1: %llu\n"
> +                               "Error Message 1: %s\n",
> +                               (unsigned long long)event_data[0].timestamp,
> +                               (unsigned long long)event_data[0].value,
> +                               strerror(event_data[0].status),
> +                               (unsigned long long)event_data[1].timestamp,
> +                               (unsigned long long)event_data[1].value,
> +                               strerror(event_data[1].status));
> +                }
> +
> +                return 0;
> +        }
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index a4c75a28c839..8ddca931ec4e 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -88,6 +88,7 @@ Code  Seq#    Include File                                           Comments
>                                                                       <http://infiniband.sourceforge.net/>
>  0x20  all    drivers/cdrom/cm206.h
>  0x22  all    scsi/sg.h
> +0x3E  00-0F  linux/counter.h                                         <mailto:linux-iio@vger.kernel.org>
>  '!'   00-1F  uapi/linux/seccomp.h
>  '#'   00-3F                                                          IEEE 1394 Subsystem
>                                                                       Block for the entire subsystem

Re: [PATCH v8 18/22] docs: counter: Document character device interface

[Pavel Machek]

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Hi!

> > +* COUNTER_ENABLE_EVENTS_IOCTL:
> > +  Enables monitoring the events specified by the Counter watches that
> > +  were queued by ``COUNTER_ADD_WATCH_IOCTL``. If events are already
> > +  enabled, the new set of watches replaces the old one. Calling this
> > +  ioctl also has the effect of clearing the queue of watches added by
> > +  ``COUNTER_ADD_WATCH_IOCTL``.
> > +
> > +* COUNTER_DISABLE_EVENTS_IOCTL:
> > +  Stops monitoring the previously enabled events.
> 
> Is there a way to remove a watch? 

Is there a way to eat all kernel memory and crash the system by adding
too many watches?

> > +For example, the following userspace code opens ``/dev/counter0``,
> > +configures the ``COUNTER_EVENT_INDEX`` event channel 0 to gather Count 0
> > +and Count 1, and prints out the data as it becomes available on the
> > +character device node::
> > +
> 
> Consider adding an example program under tools/
> 
> > +        #include <fcntl.h>
> > +        #include <linux/counter.h>
> > +        #include <stdio.h>
> > +        #include <string.h>
> > +        #include <sys/ioctl.h>
> > +        #include <unistd.h>
> > +
> > +        struct counter_watch watches[2] = {
> > +                {
> > +                        .component.type = COUNTER_COMPONENT_COUNT,
> > +                        .component.scope = COUNTER_SCOPE_COUNT,
> > +                        .component.parent = 0,
> 
> Good to add comments on what these elements actually are?

> > +                fd = open("/dev/counter0", O_RDWR);
> > +
> > +                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
> > +                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
> > +                ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);

> > +                for (;;) {
> > +                        read(fd, event_data, sizeof(event_data));

If this goes to tools it really should have error handling and
handling of short read.

Best regards,
							Pavel

-- 
http://www.livejournal.com/~pavelmachek

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Re: [PATCH v8 18/22] docs: counter: Document character device interface

[William Breathitt Gray]

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On Mon, Feb 22, 2021 at 11:11:33AM +0100, Pavel Machek wrote:
> Hi!
> 
> > > +* COUNTER_ENABLE_EVENTS_IOCTL:
> > > +  Enables monitoring the events specified by the Counter watches that
> > > +  were queued by ``COUNTER_ADD_WATCH_IOCTL``. If events are already
> > > +  enabled, the new set of watches replaces the old one. Calling this
> > > +  ioctl also has the effect of clearing the queue of watches added by
> > > +  ``COUNTER_ADD_WATCH_IOCTL``.
> > > +
> > > +* COUNTER_DISABLE_EVENTS_IOCTL:
> > > +  Stops monitoring the previously enabled events.
> > 
> > Is there a way to remove a watch? 
> 
> Is there a way to eat all kernel memory and crash the system by adding
> too many watches?

There can only ever be as many watches as there are Counter components
for the respective Counter device. This is enforced by
counter_set_event_node() which checks whether a particular watch has
been created before and returns an EINVAL if it so has.

> > > +For example, the following userspace code opens ``/dev/counter0``,
> > > +configures the ``COUNTER_EVENT_INDEX`` event channel 0 to gather Count 0
> > > +and Count 1, and prints out the data as it becomes available on the
> > > +character device node::
> > > +
> > 
> > Consider adding an example program under tools/
> > 
> > > +        #include <fcntl.h>
> > > +        #include <linux/counter.h>
> > > +        #include <stdio.h>
> > > +        #include <string.h>
> > > +        #include <sys/ioctl.h>
> > > +        #include <unistd.h>
> > > +
> > > +        struct counter_watch watches[2] = {
> > > +                {
> > > +                        .component.type = COUNTER_COMPONENT_COUNT,
> > > +                        .component.scope = COUNTER_SCOPE_COUNT,
> > > +                        .component.parent = 0,
> > 
> > Good to add comments on what these elements actually are?
> 
> > > +                fd = open("/dev/counter0", O_RDWR);
> > > +
> > > +                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
> > > +                ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
> > > +                ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
> 
> > > +                for (;;) {
> > > +                        read(fd, event_data, sizeof(event_data));
> 
> If this goes to tools it really should have error handling and
> handling of short read.
> 
> Best regards,
> 							Pavel
> 
> -- 
> http://www.livejournal.com/~pavelmachek

Ack. I'll improve the error handling for this.

William Breathitt Gray

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Re: [PATCH v8 18/22] docs: counter: Document character device interface

[William Breathitt Gray]

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On Sun, Feb 14, 2021 at 05:48:19PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:42 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > This patch adds high-level documentation about the Counter subsystem
> > character device interface.
> > 
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> >  Documentation/driver-api/generic-counter.rst  | 243 +++++++++++++++---
> >  .../userspace-api/ioctl/ioctl-number.rst      |   1 +
> >  2 files changed, 203 insertions(+), 41 deletions(-)
> > 
> > diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
> > index f6397218aa4c..3be109dc81bb 100644
> > --- a/Documentation/driver-api/generic-counter.rst
> > +++ b/Documentation/driver-api/generic-counter.rst
> > @@ -223,19 +223,6 @@ whether an input line is differential or single-ended) and instead focus
> >  on the core idea of what the data and process represent (e.g. position
> >  as interpreted from quadrature encoding data).
> >  
> > -Userspace Interface
> > -===================
> > -
> > -Several sysfs attributes are generated by the Generic Counter interface,
> > -and reside under the /sys/bus/counter/devices/counterX directory, where
> > -counterX refers to the respective counter device. Please see
> > -Documentation/ABI/testing/sysfs-bus-counter for detailed
> > -information on each Generic Counter interface sysfs attribute.
> > -
> > -Through these sysfs attributes, programs and scripts may interact with
> > -the Generic Counter paradigm Counts, Signals, and Synapses of respective
> > -counter devices.
> > -
> >  Driver API
> >  ==========
> >  
> > @@ -388,16 +375,16 @@ userspace interface components::
> >                          / driver callbacks /
> >                          -------------------
> >                                  |
> > -                +---------------+
> > -                |
> > -                V
> > -        +--------------------+
> > -        | Counter sysfs      |
> > -        +--------------------+
> > -        | Translates to the  |
> > -        | standard Counter   |
> > -        | sysfs output       |
> > -        +--------------------+
> > +                +---------------+---------------+
> > +                |                               |
> > +                V                               V
> > +        +--------------------+          +---------------------+
> > +        | Counter sysfs      |          | Counter chrdev      |
> > +        +--------------------+          +---------------------+
> > +        | Translates to the  |          | Translates to the   |
> > +        | standard Counter   |          | standard Counter    |
> > +        | sysfs output       |          | character device    |
> > +        +--------------------+          +---------------------+
> >  
> >  Thereafter, data can be transferred directly between the Counter device
> >  driver and Counter userspace interface::
> > @@ -428,23 +415,30 @@ driver and Counter userspace interface::
> >                          / u64     /
> >                          ----------
> >                                  |
> > -                +---------------+
> > -                |
> > -                V
> > -        +--------------------+
> > -        | Counter sysfs      |
> > -        +--------------------+
> > -        | Translates to the  |
> > -        | standard Counter   |
> > -        | sysfs output       |
> > -        |--------------------|
> > -        | Type: const char * |
> > -        | Value: "42"        |
> > -        +--------------------+
> > -                |
> > -         ---------------
> > -        / const char * /
> > -        ---------------
> > +                +---------------+---------------+
> > +                |                               |
> > +                V                               V
> > +        +--------------------+          +---------------------+
> > +        | Counter sysfs      |          | Counter chrdev      |
> > +        +--------------------+          +---------------------+
> > +        | Translates to the  |          | Translates to the   |
> > +        | standard Counter   |          | standard Counter    |
> > +        | sysfs output       |          | character device    |
> > +        |--------------------|          |---------------------|
> > +        | Type: const char * |          | Type: u64           |
> > +        | Value: "42"        |          | Value: 42           |
> > +        +--------------------+          +---------------------+
> > +                |                               |
> > +         ---------------                 -----------------------
> > +        / const char * /                / struct counter_event /
> > +        ---------------                 -----------------------
> > +                |                               |
> > +                |                               V
> > +                |                       +-----------+
> > +                |                       | read      |
> > +                |                       +-----------+
> > +                |                       \ Count: 42 /
> > +                |                        -----------
> >                  |
> >                  V
> >          +--------------------------------------------------+
> > @@ -453,7 +447,7 @@ driver and Counter userspace interface::
> >          \ Count: "42"                                      /
> >           --------------------------------------------------
> >  
> > -There are three primary components involved:
> > +There are four primary components involved:
> >  
> >  Counter device driver
> >  ---------------------
> > @@ -473,3 +467,170 @@ and vice versa.
> >  Please refer to the ``Documentation/ABI/testing/sysfs-bus-counter`` file
> >  for a detailed breakdown of the available Generic Counter interface
> >  sysfs attributes.
> > +
> > +Counter chrdev
> > +--------------
> > +Translates counter data to the standard Counter character device; data
> > +is transferred via standard character device read calls, while Counter
> > +events are configured via ioctl calls.
> > +
> > +Sysfs Interface
> > +===============
> > +
> > +Several sysfs attributes are generated by the Generic Counter interface,
> > +and reside under the ``/sys/bus/counter/devices/counterX`` directory,
> > +where ``X`` is to the respective counter device id. Please see
> > +``Documentation/ABI/testing/sysfs-bus-counter`` for detailed information
> > +on each Generic Counter interface sysfs attribute.
> > +
> > +Through these sysfs attributes, programs and scripts may interact with
> > +the Generic Counter paradigm Counts, Signals, and Synapses of respective
> > +counter devices.
> > +
> > +Counter Character Device
> > +========================
> > +
> > +Counter character device nodes are created under the ``/dev`` directory
> > +as ``counterX``, where ``X`` is the respective counter device id.
> > +Defines for the standard Counter data types are exposed via the
> > +userspace ``include/uapi/linux/counter.h`` file.
> > +
> > +Counter events
> > +--------------
> > +Counter device drivers can support Counter events by utilizing the
> > +``counter_push_event`` function::
> > +
> > +        void counter_push_event(struct counter_device *const counter, const u8 event,
> > +                                const u8 channel);
> > +
> > +The event id is specified by the ``event`` parameter; the event channel
> > +id is specified by the ``channel`` parameter. When this function is
> > +called, the Counter data associated with the respective event is
> > +gathered, and a ``struct counter_event`` is generated for each datum and
> > +pushed to userspace.
> > +
> > +Counter events can be configured by users to report various Counter
> > +data of interest. This can be conceptualized as a list of Counter
> > +component read calls to perform. For example::
> > +
> > +        +~~~~~~~~~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~~~~~+
> > +        | COUNTER_EVENT_OVERFLOW | COUNTER_EVENT_INDEX    |
> > +        +~~~~~~~~~~~~~~~~~~~~~~~~+~~~~~~~~~~~~~~~~~~~~~~~~+
> > +        | Channel 0              | Channel 0              |
> > +        +------------------------+------------------------+
> > +        | * Count 0              | * Signal 0             |
> > +        | * Count 1              | * Signal 0 Extension 0 |
> > +        | * Signal 3             | * Extension 4          |
> > +        | * Count 4 Extension 2  +------------------------+
> > +        | * Signal 5 Extension 0 | Channel 1              |
> > +        |                        +------------------------+
> > +        |                        | * Signal 4             |
> > +        |                        | * Signal 4 Extension 0 |
> > +        |                        | * Count 7              |
> > +        +------------------------+------------------------+
> > +
> > +When ``counter_push_event(counter, COUNTER_EVENT_INDEX, 1)`` is called
> > +for example, it will go down the list for the ``COUNTER_EVENT_INDEX``
> > +event channel 1 and execute the read callbacks for Signal 4, Signal 4
> > +Extension 0, and Count 4 -- the data returned for each is pushed to a
> > +kfifo as a ``struct counter_event``, which userspace can retrieve via a
> > +standard read operation on the respective character device node.
> > +
> > +Userspace
> > +---------
> > +Userspace applications can configure Counter events via ioctl operations
> > +on the Counter character device node. There following ioctl codes are
> > +supported and provided by the ``linux/counter.h`` userspace header file:
> > +
> > +* COUNTER_ADD_WATCH_IOCTL:
> > +  Queues a Counter watch for the specified event. The queued watches
> > +  will not be applied until ``COUNTER_ENABLE_EVENTS_IOCTL`` is called.
> > +
> > +* COUNTER_ENABLE_EVENTS_IOCTL:
> > +  Enables monitoring the events specified by the Counter watches that
> > +  were queued by ``COUNTER_ADD_WATCH_IOCTL``. If events are already
> > +  enabled, the new set of watches replaces the old one. Calling this
> > +  ioctl also has the effect of clearing the queue of watches added by
> > +  ``COUNTER_ADD_WATCH_IOCTL``.
> > +
> > +* COUNTER_DISABLE_EVENTS_IOCTL:
> > +  Stops monitoring the previously enabled events.
> 
> Is there a way to remove a watch? 

Both COUNTER_ENABLE_EVENTS_IOCTL and COUNTER_DISABLE_EVENTS_IOCTL remove
the watches -- the only difference is that COUNTER_ENABLE_EVENTS_IOCTL
will also swap in a new set of watches. The watches are also removed if
a user closes the cdev.

If you mean whether there is a way to selectively remove a single watch,
then the process for that would be to generate a new set of watches
using COUNTER_ADD_WATCH_IOCTL and then swap them in by using
COUNTER_ENABLE_EVENTS_IOCTL. This swap happens atomically so there's no
risk of missing an event. The user should already know the current
configuration of watches because they are the ones who added them after
opening the cdev, so we don't need to worry about dealing with an old
unknown watch configuration created by someone else.

> > +
> > +To configure events to gather Counter data, users first populate a
> > +``struct counter_watch`` with the relevant event id, event channel id,
> > +and the information for the desired Counter component from which to
> > +read, and then pass it via the ``COUNTER_ADD_WATCH_IOCTL`` ioctl
> > +command.
> > +
> > +Note that an event can be watched without gathering Counter data by
> > +setting the ``component.type`` member equal to
> > +``COUNTER_COMPONENT_NONE``. With this configuration the Counter
> > +character device will simply populate the event timestamps for those
> > +respective ``struct counter_event`` elements and ignore the component
> > +value.
> > +
> > +The ``COUNTER_ADD_WATCH_IOCTL`` command will buffer these Counter
> > +watches. When ready, the ``COUNTER_ENABLE_EVENTS_IOCTL`` ioctl command
> > +may be used to activate these Counter watches.
> > +
> > +Userspace applications can then execute a ``read`` operation (optionally
> > +calling ``poll`` first) on the Counter character device node to retrieve
> > +``struct counter_event`` elements with the desired data.
> > +
> > +For example, the following userspace code opens ``/dev/counter0``,
> > +configures the ``COUNTER_EVENT_INDEX`` event channel 0 to gather Count 0
> > +and Count 1, and prints out the data as it becomes available on the
> > +character device node::
> > +
> 
> Consider adding an example program under tools/

I can put this example program we have here below under tools/. I'd like
to create a more general Counter test program in the future, but I think
it will be a more involved project to undertake right now given the
differences between the possible configurations available and possible
for the Counter drivers we have.

> > +        #include <fcntl.h>
> > +        #include <linux/counter.h>
> > +        #include <stdio.h>
> > +        #include <string.h>
> > +        #include <sys/ioctl.h>
> > +        #include <unistd.h>
> > +
> > +        struct counter_watch watches[2] = {
> > +                {
> > +                        .component.type = COUNTER_COMPONENT_COUNT,
> > +                        .component.scope = COUNTER_SCOPE_COUNT,
> > +                        .component.parent = 0,
> 
> Good to add comments on what these elements actually are?

Ack.

William Breathitt Gray

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[PATCH v8 19/22] counter: Implement extension*_name sysfs attributes

[William Breathitt Gray]

The Generic Counter chrdev interface expects users to supply extension
IDs in order to select extensions for requests. In order for users to
know what extension ID belongs to which extension this information must
be exposed. The extension*_name attribute provides a way for users to
discover what extension ID belongs to which extension by reading the
respective extension name for an extension ID.

Cc: David Lechner <david@lechnology.com>
Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-counter |  9 ++++
 drivers/counter/counter-sysfs.c             | 51 +++++++++++++++++----
 2 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 6353f0a2f8f8..847e96f19d19 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -100,6 +100,15 @@ Description:
 		Read-only attribute that indicates whether excessive noise is
 		present at the channel Y counter inputs.
 
+What:		/sys/bus/counter/devices/counterX/countY/extensionZ_name
+What:		/sys/bus/counter/devices/counterX/extensionZ_name
+What:		/sys/bus/counter/devices/counterX/signalY/extensionZ_name
+KernelVersion:	5.13
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Read-only attribute that indicates the component name of
+		Extension Z.
+
 What:		/sys/bus/counter/devices/counterX/countY/function
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 52513a213cc5..0cb3dba950bc 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -494,6 +494,7 @@ static ssize_t counter_comp_name_show(struct device *dev,
 
 static int counter_name_attr_create(struct device *const dev,
 				    struct counter_attribute_group *const group,
+				    const char *const attr_name,
 				    const char *const name)
 {
 	struct counter_attribute *counter_attr;
@@ -508,7 +509,7 @@ static int counter_name_attr_create(struct device *const dev,
 
 	/* Configure device attribute */
 	sysfs_attr_init(&counter_attr->dev_attr.attr);
-	counter_attr->dev_attr.attr.name = "name";
+	counter_attr->dev_attr.attr.name = attr_name;
 	counter_attr->dev_attr.attr.mode = 0444;
 	counter_attr->dev_attr.show = counter_comp_name_show;
 
@@ -519,6 +520,18 @@ static int counter_name_attr_create(struct device *const dev,
 	return 0;
 }
 
+static int counter_ext_name_attr_create(struct device *const dev,
+	struct counter_attribute_group *const group, const size_t i,
+	const char *const name)
+{
+	const char *attr_name;
+
+	attr_name = devm_kasprintf(dev, GFP_KERNEL, "extension%zu_name", i);
+	if (!attr_name)
+		return -ENOMEM;
+
+	return counter_name_attr_create(dev, group, attr_name, name);
+}
 
 static struct counter_comp counter_signal_comp = {
 	.type = COUNTER_COMP_SIGNAL_LEVEL,
@@ -534,6 +547,7 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
 	int err;
 	struct counter_comp comp;
 	size_t i;
+	struct counter_comp *ext;
 
 	/* Create main Signal attribute */
 	comp = counter_signal_comp;
@@ -543,14 +557,19 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
 		return err;
 
 	/* Create Signal name attribute */
-	err = counter_name_attr_create(dev, group, signal->name);
+	err = counter_name_attr_create(dev, group, "name", signal->name);
 	if (err < 0)
 		return err;
 
 	/* Create an attribute for each extension */
 	for (i = 0; i < signal->num_ext; i++) {
-		err = counter_attr_create(dev, group, signal->ext + i, scope,
-					  signal);
+		ext = signal->ext + i;
+
+		err = counter_attr_create(dev, group, ext, scope, signal);
+		if (err < 0)
+			return err;
+
+		err = counter_ext_name_attr_create(dev, group, i, ext->name);
 		if (err < 0)
 			return err;
 	}
@@ -636,6 +655,7 @@ static int counter_count_attrs_create(struct counter_device *const counter,
 	int err;
 	struct counter_comp comp;
 	size_t i;
+	struct counter_comp *ext;
 
 	/* Create main Count attribute */
 	comp = counter_count_comp;
@@ -646,7 +666,7 @@ static int counter_count_attrs_create(struct counter_device *const counter,
 		return err;
 
 	/* Create Count name attribute */
-	err = counter_name_attr_create(dev, group, count->name);
+	err = counter_name_attr_create(dev, group, "name", count->name);
 	if (err < 0)
 		return err;
 
@@ -660,8 +680,13 @@ static int counter_count_attrs_create(struct counter_device *const counter,
 
 	/* Create an attribute for each extension */
 	for (i = 0; i < count->num_ext; i++) {
-		err = counter_attr_create(dev, group, count->ext + i, scope,
-					  count);
+		ext = count->ext + i;
+
+		err = counter_attr_create(dev, group, ext, scope, count);
+		if (err < 0)
+			return err;
+
+		err = counter_ext_name_attr_create(dev, group, i, ext->name);
 		if (err < 0)
 			return err;
 	}
@@ -725,6 +750,7 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
 	struct device *const dev = &counter->dev;
 	int err;
 	size_t i;
+	struct counter_comp *ext;
 
 	/* Add Signals sysfs attributes */
 	err = counter_sysfs_signals_add(counter, group);
@@ -739,7 +765,7 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
 	group += counter->num_counts;
 
 	/* Create name attribute */
-	err = counter_name_attr_create(dev, group, counter->name);
+	err = counter_name_attr_create(dev, group, "name", counter->name);
 	if (err < 0)
 		return err;
 
@@ -757,8 +783,13 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
 
 	/* Create an attribute for each extension */
 	for (i = 0; i < counter->num_ext; i++) {
-		err = counter_attr_create(dev, group, counter->ext + i, scope,
-					  NULL);
+		ext = counter->ext + i;
+
+		err = counter_attr_create(dev, group, ext, scope, NULL);
+		if (err < 0)
+			return err;
+
+		err = counter_ext_name_attr_create(dev, group, i, ext->name);
 		if (err < 0)
 			return err;
 	}
-- 
2.30.0

Re: [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:43 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The Generic Counter chrdev interface expects users to supply extension
> IDs in order to select extensions for requests. In order for users to
> know what extension ID belongs to which extension this information must
> be exposed. The extension*_name attribute provides a way for users to
> discover what extension ID belongs to which extension by reading the
> respective extension name for an extension ID.
> 
> Cc: David Lechner <david@lechnology.com>
> Cc: Gwendal Grignou <gwendal@chromium.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-counter |  9 ++++
>  drivers/counter/counter-sysfs.c             | 51 +++++++++++++++++----
>  2 files changed, 50 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> index 6353f0a2f8f8..847e96f19d19 100644
> --- a/Documentation/ABI/testing/sysfs-bus-counter
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -100,6 +100,15 @@ Description:
>  		Read-only attribute that indicates whether excessive noise is
>  		present at the channel Y counter inputs.
>  
> +What:		/sys/bus/counter/devices/counterX/countY/extensionZ_name
> +What:		/sys/bus/counter/devices/counterX/extensionZ_name
> +What:		/sys/bus/counter/devices/counterX/signalY/extensionZ_name
> +KernelVersion:	5.13
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Read-only attribute that indicates the component name of
> +		Extension Z.

Good to say what form this takes.

> +

Re: [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes

[William Breathitt Gray]

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On Sun, Feb 14, 2021 at 06:09:13PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:43 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > The Generic Counter chrdev interface expects users to supply extension
> > IDs in order to select extensions for requests. In order for users to
> > know what extension ID belongs to which extension this information must
> > be exposed. The extension*_name attribute provides a way for users to
> > discover what extension ID belongs to which extension by reading the
> > respective extension name for an extension ID.
> > 
> > Cc: David Lechner <david@lechnology.com>
> > Cc: Gwendal Grignou <gwendal@chromium.org>
> > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-counter |  9 ++++
> >  drivers/counter/counter-sysfs.c             | 51 +++++++++++++++++----
> >  2 files changed, 50 insertions(+), 10 deletions(-)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > index 6353f0a2f8f8..847e96f19d19 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > @@ -100,6 +100,15 @@ Description:
> >  		Read-only attribute that indicates whether excessive noise is
> >  		present at the channel Y counter inputs.
> >  
> > +What:		/sys/bus/counter/devices/counterX/countY/extensionZ_name
> > +What:		/sys/bus/counter/devices/counterX/extensionZ_name
> > +What:		/sys/bus/counter/devices/counterX/signalY/extensionZ_name
> > +KernelVersion:	5.13
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Read-only attribute that indicates the component name of
> > +		Extension Z.
> 
> Good to say what form this takes.

Do you mean a description like this: "Read-only string attribute that
indicates the component name of Extension Z"?

William Breathitt Gray

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Re: [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes

[Jonathan Cameron]

On Fri, 19 Feb 2021 17:51:37 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> On Sun, Feb 14, 2021 at 06:09:13PM +0000, Jonathan Cameron wrote:
> > On Fri, 12 Feb 2021 21:13:43 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >   
> > > The Generic Counter chrdev interface expects users to supply extension
> > > IDs in order to select extensions for requests. In order for users to
> > > know what extension ID belongs to which extension this information must
> > > be exposed. The extension*_name attribute provides a way for users to
> > > discover what extension ID belongs to which extension by reading the
> > > respective extension name for an extension ID.
> > > 
> > > Cc: David Lechner <david@lechnology.com>
> > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > ---
> > >  Documentation/ABI/testing/sysfs-bus-counter |  9 ++++
> > >  drivers/counter/counter-sysfs.c             | 51 +++++++++++++++++----
> > >  2 files changed, 50 insertions(+), 10 deletions(-)
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > index 6353f0a2f8f8..847e96f19d19 100644
> > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > @@ -100,6 +100,15 @@ Description:
> > >  		Read-only attribute that indicates whether excessive noise is
> > >  		present at the channel Y counter inputs.
> > >  
> > > +What:		/sys/bus/counter/devices/counterX/countY/extensionZ_name
> > > +What:		/sys/bus/counter/devices/counterX/extensionZ_name
> > > +What:		/sys/bus/counter/devices/counterX/signalY/extensionZ_name
> > > +KernelVersion:	5.13
> > > +Contact:	linux-iio@vger.kernel.org
> > > +Description:
> > > +		Read-only attribute that indicates the component name of
> > > +		Extension Z.  
> > 
> > Good to say what form this takes.  
> 
> Do you mean a description like this: "Read-only string attribute that
> indicates the component name of Extension Z"?

My expectation would be that the possible strings are tightly constrained
(perhaps via review). So I'd like to see what they are and a brief description
of what each one means.

Jonathan

> 
> William Breathitt Gray

Re: [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes

[William Breathitt Gray]

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On Sun, Feb 21, 2021 at 02:05:07PM +0000, Jonathan Cameron wrote:
> On Fri, 19 Feb 2021 17:51:37 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > On Sun, Feb 14, 2021 at 06:09:13PM +0000, Jonathan Cameron wrote:
> > > On Fri, 12 Feb 2021 21:13:43 +0900
> > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > >   
> > > > The Generic Counter chrdev interface expects users to supply extension
> > > > IDs in order to select extensions for requests. In order for users to
> > > > know what extension ID belongs to which extension this information must
> > > > be exposed. The extension*_name attribute provides a way for users to
> > > > discover what extension ID belongs to which extension by reading the
> > > > respective extension name for an extension ID.
> > > > 
> > > > Cc: David Lechner <david@lechnology.com>
> > > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > > ---
> > > >  Documentation/ABI/testing/sysfs-bus-counter |  9 ++++
> > > >  drivers/counter/counter-sysfs.c             | 51 +++++++++++++++++----
> > > >  2 files changed, 50 insertions(+), 10 deletions(-)
> > > > 
> > > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > > index 6353f0a2f8f8..847e96f19d19 100644
> > > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > > @@ -100,6 +100,15 @@ Description:
> > > >  		Read-only attribute that indicates whether excessive noise is
> > > >  		present at the channel Y counter inputs.
> > > >  
> > > > +What:		/sys/bus/counter/devices/counterX/countY/extensionZ_name
> > > > +What:		/sys/bus/counter/devices/counterX/extensionZ_name
> > > > +What:		/sys/bus/counter/devices/counterX/signalY/extensionZ_name
> > > > +KernelVersion:	5.13
> > > > +Contact:	linux-iio@vger.kernel.org
> > > > +Description:
> > > > +		Read-only attribute that indicates the component name of
> > > > +		Extension Z.  
> > > 
> > > Good to say what form this takes.  
> > 
> > Do you mean a description like this: "Read-only string attribute that
> > indicates the component name of Extension Z"?
> 
> My expectation would be that the possible strings are tightly constrained
> (perhaps via review). So I'd like to see what they are and a brief description
> of what each one means.
> 
> Jonathan

Okay I see what you mean now. These names will match the sysfs attribute
filenames. So for example, if Extension 9 of Count 2 of Counter device
is /sys/bus/counter/devices/counter4/count2/ceiling, then the attribute
/sys/bus/counter/devices/counter4/count2/extension9_name will hold a
value of "ceiling".

The idea is that the user walks down through each extension*_name to
find sysfs attribute name for the Extension that they want. When they
find the desired Extension name in say sysfs attribute extension9_name,
then they know 9 is the ID number for that Extension.

There is an alternative design I was considering: instead of
extension*_name attributes, we could have each Extension sysfs attribute
have a matching *_extension_id attribute which provides the respective
Extension ID. So for example, using the same Extension as before:
/sys/bus/counter/devices/counter4/count2/ceiling_extension_id will hold
a value of 9.

Do you think this alternative design would be more intuitive to users?

William Breathitt Gray

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Re: [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes

[Jonathan Cameron]

On Fri, 26 Feb 2021 08:32:59 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> On Sun, Feb 21, 2021 at 02:05:07PM +0000, Jonathan Cameron wrote:
> > On Fri, 19 Feb 2021 17:51:37 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >   
> > > On Sun, Feb 14, 2021 at 06:09:13PM +0000, Jonathan Cameron wrote:  
> > > > On Fri, 12 Feb 2021 21:13:43 +0900
> > > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > > >     
> > > > > The Generic Counter chrdev interface expects users to supply extension
> > > > > IDs in order to select extensions for requests. In order for users to
> > > > > know what extension ID belongs to which extension this information must
> > > > > be exposed. The extension*_name attribute provides a way for users to
> > > > > discover what extension ID belongs to which extension by reading the
> > > > > respective extension name for an extension ID.
> > > > > 
> > > > > Cc: David Lechner <david@lechnology.com>
> > > > > Cc: Gwendal Grignou <gwendal@chromium.org>
> > > > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > > > ---
> > > > >  Documentation/ABI/testing/sysfs-bus-counter |  9 ++++
> > > > >  drivers/counter/counter-sysfs.c             | 51 +++++++++++++++++----
> > > > >  2 files changed, 50 insertions(+), 10 deletions(-)
> > > > > 
> > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > > > index 6353f0a2f8f8..847e96f19d19 100644
> > > > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > > > @@ -100,6 +100,15 @@ Description:
> > > > >  		Read-only attribute that indicates whether excessive noise is
> > > > >  		present at the channel Y counter inputs.
> > > > >  
> > > > > +What:		/sys/bus/counter/devices/counterX/countY/extensionZ_name
> > > > > +What:		/sys/bus/counter/devices/counterX/extensionZ_name
> > > > > +What:		/sys/bus/counter/devices/counterX/signalY/extensionZ_name
> > > > > +KernelVersion:	5.13
> > > > > +Contact:	linux-iio@vger.kernel.org
> > > > > +Description:
> > > > > +		Read-only attribute that indicates the component name of
> > > > > +		Extension Z.    
> > > > 
> > > > Good to say what form this takes.    
> > > 
> > > Do you mean a description like this: "Read-only string attribute that
> > > indicates the component name of Extension Z"?  
> > 
> > My expectation would be that the possible strings are tightly constrained
> > (perhaps via review). So I'd like to see what they are and a brief description
> > of what each one means.
> > 
> > Jonathan  
> 
> Okay I see what you mean now. These names will match the sysfs attribute
> filenames. So for example, if Extension 9 of Count 2 of Counter device
> is /sys/bus/counter/devices/counter4/count2/ceiling, then the attribute
> /sys/bus/counter/devices/counter4/count2/extension9_name will hold a
> value of "ceiling".
> 
> The idea is that the user walks down through each extension*_name to
> find sysfs attribute name for the Extension that they want. When they
> find the desired Extension name in say sysfs attribute extension9_name,
> then they know 9 is the ID number for that Extension.
> 
> There is an alternative design I was considering: instead of
> extension*_name attributes, we could have each Extension sysfs attribute
> have a matching *_extension_id attribute which provides the respective
> Extension ID. So for example, using the same Extension as before:
> /sys/bus/counter/devices/counter4/count2/ceiling_extension_id will hold
> a value of 9.
> 
> Do you think this alternative design would be more intuitive to users?
It feels like the user is going to start from what they want to enable
then get the ID from that.   With the current way around they'll have
to search the extensionX_name files to find it, rather than a direct
look up.  So immediate thought is this second way would be easier to
use, but perhaps others think differently.

Jonathan

> 
> William Breathitt Gray

[PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[William Breathitt Gray]

The events_queue_size sysfs attribute provides a way for users to
dynamically configure the Counter events queue size for the Counter
character device interface. The size is in number of struct
counter_event data structures. The number of elements will be rounded-up
to a power of 2 due to a requirement of the kfifo_alloc function called
during reallocation of the queue.

Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
 drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
 drivers/counter/counter-chrdev.h            |  2 ++
 drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
 4 files changed, 58 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 847e96f19d19..f6cb2a8b08a7 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -212,6 +212,14 @@ Description:
 		both edges:
 			Any state transition.
 
+What:		/sys/bus/counter/devices/counterX/events_queue_size
+KernelVersion:	5.13
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Size of the Counter events queue in number of struct
+		counter_event data structures. The number of elements will be
+		rounded-up to a power of 2.
+
 What:		/sys/bus/counter/devices/counterX/name
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
index 16f02df7f73d..53eea894e13f 100644
--- a/drivers/counter/counter-chrdev.c
+++ b/drivers/counter/counter-chrdev.c
@@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
 	cdev_del(&counter->chrdev);
 }
 
+int counter_chrdev_realloc_queue(struct counter_device *const counter,
+				 size_t queue_size)
+{
+	int err;
+	DECLARE_KFIFO_PTR(events, struct counter_event);
+	unsigned long flags;
+
+	/* Allocate new events queue */
+	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);
+	if (err)
+		return err;
+
+	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
+
+	/* Swap in new events queue */
+	kfifo_free(&counter->events);
+	counter->events.kfifo = events.kfifo;
+
+	raw_spin_unlock_irqrestore(&counter->events_list_lock, flags);
+
+	return 0;
+}
+
 static int counter_get_data(struct counter_device *const counter,
 			    const struct counter_comp_node *const comp_node,
 			    u64 *const value)
diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
index cf5a318fe540..ff7fb0191852 100644
--- a/drivers/counter/counter-chrdev.h
+++ b/drivers/counter/counter-chrdev.h
@@ -12,5 +12,7 @@
 int counter_chrdev_add(struct counter_device *const counter,
 		       const dev_t counter_devt);
 void counter_chrdev_remove(struct counter_device *const counter);
+int counter_chrdev_realloc_queue(struct counter_device *const counter,
+				 size_t queue_size);
 
 #endif /* _COUNTER_CHRDEV_H_ */
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 0cb3dba950bc..9abc821a3871 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -13,6 +13,7 @@
 #include <linux/sysfs.h>
 #include <linux/types.h>
 
+#include "counter-chrdev.h"
 #include "counter-sysfs.h"
 
 /**
@@ -737,12 +738,30 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val)
 	return 0;
 }
 
+static int counter_events_queue_size_read(struct counter_device *counter,
+					  u64 *val)
+{
+	*val = counter->events.kfifo.mask + 1;
+	return 0;
+}
+
+static int counter_events_queue_size_write(struct counter_device *counter,
+					   u64 val)
+{
+	return counter_chrdev_realloc_queue(counter, val);
+}
+
 static struct counter_comp counter_num_signals_comp =
 	COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL);
 
 static struct counter_comp counter_num_counts_comp =
 	COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL);
 
+static struct counter_comp counter_events_queue_size_comp =
+	COUNTER_COMP_DEVICE_U64("events_queue_size",
+				counter_events_queue_size_read,
+				counter_events_queue_size_write);
+
 static int counter_sysfs_attr_add(struct counter_device *const counter,
 				  struct counter_attribute_group *group)
 {
@@ -781,6 +800,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
 	if (err < 0)
 		return err;
 
+	/* Create num_counts attribute */
+	err = counter_attr_create(dev, group, &counter_events_queue_size_comp,
+				  scope, NULL);
+	if (err < 0)
+		return err;
+
 	/* Create an attribute for each extension */
 	for (i = 0; i < counter->num_ext; i++) {
 		ext = counter->ext + i;
-- 
2.30.0

Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:44 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The events_queue_size sysfs attribute provides a way for users to
> dynamically configure the Counter events queue size for the Counter
> character device interface. The size is in number of struct
> counter_event data structures. The number of elements will be rounded-up
> to a power of 2 due to a requirement of the kfifo_alloc function called
> during reallocation of the queue.
> 
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
>  drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
>  drivers/counter/counter-chrdev.h            |  2 ++
>  drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
>  4 files changed, 58 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> index 847e96f19d19..f6cb2a8b08a7 100644
> --- a/Documentation/ABI/testing/sysfs-bus-counter
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -212,6 +212,14 @@ Description:
>  		both edges:
>  			Any state transition.
>  
> +What:		/sys/bus/counter/devices/counterX/events_queue_size
> +KernelVersion:	5.13
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Size of the Counter events queue in number of struct
> +		counter_event data structures. The number of elements will be
> +		rounded-up to a power of 2.
> +
>  What:		/sys/bus/counter/devices/counterX/name
>  KernelVersion:	5.2
>  Contact:	linux-iio@vger.kernel.org
> diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> index 16f02df7f73d..53eea894e13f 100644
> --- a/drivers/counter/counter-chrdev.c
> +++ b/drivers/counter/counter-chrdev.c
> @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
>  	cdev_del(&counter->chrdev);
>  }
>  
> +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> +				 size_t queue_size)
> +{
> +	int err;
> +	DECLARE_KFIFO_PTR(events, struct counter_event);
> +	unsigned long flags;
> +
> +	/* Allocate new events queue */
> +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);

Is there any potential for losing events?

> +	if (err)
> +		return err;
> +
> +	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> +	/* Swap in new events queue */
> +	kfifo_free(&counter->events);
> +	counter->events.kfifo = events.kfifo;
> +
> +	raw_spin_unlock_irqrestore(&counter->events_list_lock, flags);
> +
> +	return 0;
> +}
> +
>  static int counter_get_data(struct counter_device *const counter,
>  			    const struct counter_comp_node *const comp_node,
>  			    u64 *const value)
> diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
> index cf5a318fe540..ff7fb0191852 100644
> --- a/drivers/counter/counter-chrdev.h
> +++ b/drivers/counter/counter-chrdev.h
> @@ -12,5 +12,7 @@
>  int counter_chrdev_add(struct counter_device *const counter,
>  		       const dev_t counter_devt);
>  void counter_chrdev_remove(struct counter_device *const counter);
> +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> +				 size_t queue_size);
>  
>  #endif /* _COUNTER_CHRDEV_H_ */
> diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
> index 0cb3dba950bc..9abc821a3871 100644
> --- a/drivers/counter/counter-sysfs.c
> +++ b/drivers/counter/counter-sysfs.c
> @@ -13,6 +13,7 @@
>  #include <linux/sysfs.h>
>  #include <linux/types.h>
>  
> +#include "counter-chrdev.h"
>  #include "counter-sysfs.h"
>  
>  /**
> @@ -737,12 +738,30 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val)
>  	return 0;
>  }
>  
> +static int counter_events_queue_size_read(struct counter_device *counter,
> +					  u64 *val)
> +{
> +	*val = counter->events.kfifo.mask + 1;

kfifo_size() rather than open coding it?

> +	return 0;
> +}
> +
> +static int counter_events_queue_size_write(struct counter_device *counter,
> +					   u64 val)
> +{
> +	return counter_chrdev_realloc_queue(counter, val);
> +}
> +
>  static struct counter_comp counter_num_signals_comp =
>  	COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL);
>  
>  static struct counter_comp counter_num_counts_comp =
>  	COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL);
>  
> +static struct counter_comp counter_events_queue_size_comp =
> +	COUNTER_COMP_DEVICE_U64("events_queue_size",
> +				counter_events_queue_size_read,
> +				counter_events_queue_size_write);
> +
>  static int counter_sysfs_attr_add(struct counter_device *const counter,
>  				  struct counter_attribute_group *group)
>  {
> @@ -781,6 +800,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
>  	if (err < 0)
>  		return err;
>  
> +	/* Create num_counts attribute */
> +	err = counter_attr_create(dev, group, &counter_events_queue_size_comp,
> +				  scope, NULL);
> +	if (err < 0)
> +		return err;
> +
>  	/* Create an attribute for each extension */
>  	for (i = 0; i < counter->num_ext; i++) {
>  		ext = counter->ext + i;

Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 6471 bytes --]

On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:44 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > The events_queue_size sysfs attribute provides a way for users to
> > dynamically configure the Counter events queue size for the Counter
> > character device interface. The size is in number of struct
> > counter_event data structures. The number of elements will be rounded-up
> > to a power of 2 due to a requirement of the kfifo_alloc function called
> > during reallocation of the queue.
> > 
> > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
> >  drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
> >  drivers/counter/counter-chrdev.h            |  2 ++
> >  drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
> >  4 files changed, 58 insertions(+)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > index 847e96f19d19..f6cb2a8b08a7 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > @@ -212,6 +212,14 @@ Description:
> >  		both edges:
> >  			Any state transition.
> >  
> > +What:		/sys/bus/counter/devices/counterX/events_queue_size
> > +KernelVersion:	5.13
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Size of the Counter events queue in number of struct
> > +		counter_event data structures. The number of elements will be
> > +		rounded-up to a power of 2.
> > +
> >  What:		/sys/bus/counter/devices/counterX/name
> >  KernelVersion:	5.2
> >  Contact:	linux-iio@vger.kernel.org
> > diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> > index 16f02df7f73d..53eea894e13f 100644
> > --- a/drivers/counter/counter-chrdev.c
> > +++ b/drivers/counter/counter-chrdev.c
> > @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
> >  	cdev_del(&counter->chrdev);
> >  }
> >  
> > +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> > +				 size_t queue_size)
> > +{
> > +	int err;
> > +	DECLARE_KFIFO_PTR(events, struct counter_event);
> > +	unsigned long flags;
> > +
> > +	/* Allocate new events queue */
> > +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);
> 
> Is there any potential for losing events?

We take the events_list_lock down below so we're safe against missing an
event, but past events currently unread in the queue will be lost.

Shortening the size of the queue is inherently a destructive process if
we have more events in the current queue than can fit in the new queue.
Because we a liable to lose some events in such a case, I think it's
best to keep the behavior of this reallocation consistent and have it
provide a fresh empty queue every time, as opposed to sometimes dropping
events and sometimes not.

I also suspect an actual user would be setting the size of their queue
to the required amount before they begin watching events, rather than
adjusting it sporadically during a live operation.

> > +	if (err)
> > +		return err;
> > +
> > +	raw_spin_lock_irqsave(&counter->events_list_lock, flags);
> > +
> > +	/* Swap in new events queue */
> > +	kfifo_free(&counter->events);
> > +	counter->events.kfifo = events.kfifo;
> > +
> > +	raw_spin_unlock_irqrestore(&counter->events_list_lock, flags);
> > +
> > +	return 0;
> > +}
> > +
> >  static int counter_get_data(struct counter_device *const counter,
> >  			    const struct counter_comp_node *const comp_node,
> >  			    u64 *const value)
> > diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h
> > index cf5a318fe540..ff7fb0191852 100644
> > --- a/drivers/counter/counter-chrdev.h
> > +++ b/drivers/counter/counter-chrdev.h
> > @@ -12,5 +12,7 @@
> >  int counter_chrdev_add(struct counter_device *const counter,
> >  		       const dev_t counter_devt);
> >  void counter_chrdev_remove(struct counter_device *const counter);
> > +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> > +				 size_t queue_size);
> >  
> >  #endif /* _COUNTER_CHRDEV_H_ */
> > diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
> > index 0cb3dba950bc..9abc821a3871 100644
> > --- a/drivers/counter/counter-sysfs.c
> > +++ b/drivers/counter/counter-sysfs.c
> > @@ -13,6 +13,7 @@
> >  #include <linux/sysfs.h>
> >  #include <linux/types.h>
> >  
> > +#include "counter-chrdev.h"
> >  #include "counter-sysfs.h"
> >  
> >  /**
> > @@ -737,12 +738,30 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val)
> >  	return 0;
> >  }
> >  
> > +static int counter_events_queue_size_read(struct counter_device *counter,
> > +					  u64 *val)
> > +{
> > +	*val = counter->events.kfifo.mask + 1;
> 
> kfifo_size() rather than open coding it?

Ack.

William Breathitt Gray

> > +	return 0;
> > +}
> > +
> > +static int counter_events_queue_size_write(struct counter_device *counter,
> > +					   u64 val)
> > +{
> > +	return counter_chrdev_realloc_queue(counter, val);
> > +}
> > +
> >  static struct counter_comp counter_num_signals_comp =
> >  	COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL);
> >  
> >  static struct counter_comp counter_num_counts_comp =
> >  	COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL);
> >  
> > +static struct counter_comp counter_events_queue_size_comp =
> > +	COUNTER_COMP_DEVICE_U64("events_queue_size",
> > +				counter_events_queue_size_read,
> > +				counter_events_queue_size_write);
> > +
> >  static int counter_sysfs_attr_add(struct counter_device *const counter,
> >  				  struct counter_attribute_group *group)
> >  {
> > @@ -781,6 +800,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
> >  	if (err < 0)
> >  		return err;
> >  
> > +	/* Create num_counts attribute */
> > +	err = counter_attr_create(dev, group, &counter_events_queue_size_comp,
> > +				  scope, NULL);
> > +	if (err < 0)
> > +		return err;
> > +
> >  	/* Create an attribute for each extension */
> >  	for (i = 0; i < counter->num_ext; i++) {
> >  		ext = counter->ext + i;
> 

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Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[Jonathan Cameron]

On Thu, 18 Feb 2021 19:32:16 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:
> > On Fri, 12 Feb 2021 21:13:44 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >   
> > > The events_queue_size sysfs attribute provides a way for users to
> > > dynamically configure the Counter events queue size for the Counter
> > > character device interface. The size is in number of struct
> > > counter_event data structures. The number of elements will be rounded-up
> > > to a power of 2 due to a requirement of the kfifo_alloc function called
> > > during reallocation of the queue.
> > > 
> > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > ---
> > >  Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
> > >  drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
> > >  drivers/counter/counter-chrdev.h            |  2 ++
> > >  drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
> > >  4 files changed, 58 insertions(+)
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > index 847e96f19d19..f6cb2a8b08a7 100644
> > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > @@ -212,6 +212,14 @@ Description:
> > >  		both edges:
> > >  			Any state transition.
> > >  
> > > +What:		/sys/bus/counter/devices/counterX/events_queue_size
> > > +KernelVersion:	5.13
> > > +Contact:	linux-iio@vger.kernel.org
> > > +Description:
> > > +		Size of the Counter events queue in number of struct
> > > +		counter_event data structures. The number of elements will be
> > > +		rounded-up to a power of 2.
> > > +
> > >  What:		/sys/bus/counter/devices/counterX/name
> > >  KernelVersion:	5.2
> > >  Contact:	linux-iio@vger.kernel.org
> > > diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> > > index 16f02df7f73d..53eea894e13f 100644
> > > --- a/drivers/counter/counter-chrdev.c
> > > +++ b/drivers/counter/counter-chrdev.c
> > > @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
> > >  	cdev_del(&counter->chrdev);
> > >  }
> > >  
> > > +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> > > +				 size_t queue_size)
> > > +{
> > > +	int err;
> > > +	DECLARE_KFIFO_PTR(events, struct counter_event);
> > > +	unsigned long flags;
> > > +
> > > +	/* Allocate new events queue */
> > > +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);  
> > 
> > Is there any potential for losing events?  
> 
> We take the events_list_lock down below so we're safe against missing an
> event, but past events currently unread in the queue will be lost.
> 
> Shortening the size of the queue is inherently a destructive process if
> we have more events in the current queue than can fit in the new queue.
> Because we a liable to lose some events in such a case, I think it's
> best to keep the behavior of this reallocation consistent and have it
> provide a fresh empty queue every time, as opposed to sometimes dropping
> events and sometimes not.
> 
> I also suspect an actual user would be setting the size of their queue
> to the required amount before they begin watching events, rather than
> adjusting it sporadically during a live operation.
>

Absolutely agree.   As such I wonder if you are better off enforcing this
behaviour?  If the cdev is open for reading, don't allow the fifo to be
resized. 

Jonathan

Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 4356 bytes --]

On Sun, Feb 21, 2021 at 03:51:40PM +0000, Jonathan Cameron wrote:
> On Thu, 18 Feb 2021 19:32:16 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:
> > > On Fri, 12 Feb 2021 21:13:44 +0900
> > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > >   
> > > > The events_queue_size sysfs attribute provides a way for users to
> > > > dynamically configure the Counter events queue size for the Counter
> > > > character device interface. The size is in number of struct
> > > > counter_event data structures. The number of elements will be rounded-up
> > > > to a power of 2 due to a requirement of the kfifo_alloc function called
> > > > during reallocation of the queue.
> > > > 
> > > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > > ---
> > > >  Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
> > > >  drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
> > > >  drivers/counter/counter-chrdev.h            |  2 ++
> > > >  drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
> > > >  4 files changed, 58 insertions(+)
> > > > 
> > > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > > index 847e96f19d19..f6cb2a8b08a7 100644
> > > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > > @@ -212,6 +212,14 @@ Description:
> > > >  		both edges:
> > > >  			Any state transition.
> > > >  
> > > > +What:		/sys/bus/counter/devices/counterX/events_queue_size
> > > > +KernelVersion:	5.13
> > > > +Contact:	linux-iio@vger.kernel.org
> > > > +Description:
> > > > +		Size of the Counter events queue in number of struct
> > > > +		counter_event data structures. The number of elements will be
> > > > +		rounded-up to a power of 2.
> > > > +
> > > >  What:		/sys/bus/counter/devices/counterX/name
> > > >  KernelVersion:	5.2
> > > >  Contact:	linux-iio@vger.kernel.org
> > > > diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> > > > index 16f02df7f73d..53eea894e13f 100644
> > > > --- a/drivers/counter/counter-chrdev.c
> > > > +++ b/drivers/counter/counter-chrdev.c
> > > > @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
> > > >  	cdev_del(&counter->chrdev);
> > > >  }
> > > >  
> > > > +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> > > > +				 size_t queue_size)
> > > > +{
> > > > +	int err;
> > > > +	DECLARE_KFIFO_PTR(events, struct counter_event);
> > > > +	unsigned long flags;
> > > > +
> > > > +	/* Allocate new events queue */
> > > > +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);  
> > > 
> > > Is there any potential for losing events?  
> > 
> > We take the events_list_lock down below so we're safe against missing an
> > event, but past events currently unread in the queue will be lost.
> > 
> > Shortening the size of the queue is inherently a destructive process if
> > we have more events in the current queue than can fit in the new queue.
> > Because we a liable to lose some events in such a case, I think it's
> > best to keep the behavior of this reallocation consistent and have it
> > provide a fresh empty queue every time, as opposed to sometimes dropping
> > events and sometimes not.
> > 
> > I also suspect an actual user would be setting the size of their queue
> > to the required amount before they begin watching events, rather than
> > adjusting it sporadically during a live operation.
> >
> 
> Absolutely agree.   As such I wonder if you are better off enforcing this
> behaviour?  If the cdev is open for reading, don't allow the fifo to be
> resized. 
> 
> Jonathan

I can't really think of a good reason not to, so let's enforce it: if
the cdev is open, then we'll return an EINVAL if the user attempts to
resize the queue.

What is a good way to check for this condition? Should I just call
kref_read() and see if it's greater than 1? For example, in
counter_chrdev_realloc_queue():

	if (kref_read(&counter->dev.kobj.kref) > 1)
		return -EINVAL;

William Breathitt Gray

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Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[David Lechner]

On 2/25/21 6:03 PM, William Breathitt Gray wrote:
> On Sun, Feb 21, 2021 at 03:51:40PM +0000, Jonathan Cameron wrote:
>> On Thu, 18 Feb 2021 19:32:16 +0900
>> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
>>
>>> On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:
>>>> On Fri, 12 Feb 2021 21:13:44 +0900
>>>> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
>>>>    
>>>>> The events_queue_size sysfs attribute provides a way for users to
>>>>> dynamically configure the Counter events queue size for the Counter
>>>>> character device interface. The size is in number of struct
>>>>> counter_event data structures. The number of elements will be rounded-up
>>>>> to a power of 2 due to a requirement of the kfifo_alloc function called
>>>>> during reallocation of the queue.
>>>>>
>>>>> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
>>>>> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
>>>>> ---
>>>>>   Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
>>>>>   drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
>>>>>   drivers/counter/counter-chrdev.h            |  2 ++
>>>>>   drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
>>>>>   4 files changed, 58 insertions(+)
>>>>>
>>>>> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
>>>>> index 847e96f19d19..f6cb2a8b08a7 100644
>>>>> --- a/Documentation/ABI/testing/sysfs-bus-counter
>>>>> +++ b/Documentation/ABI/testing/sysfs-bus-counter
>>>>> @@ -212,6 +212,14 @@ Description:
>>>>>   		both edges:
>>>>>   			Any state transition.
>>>>>   
>>>>> +What:		/sys/bus/counter/devices/counterX/events_queue_size
>>>>> +KernelVersion:	5.13
>>>>> +Contact:	linux-iio@vger.kernel.org
>>>>> +Description:
>>>>> +		Size of the Counter events queue in number of struct
>>>>> +		counter_event data structures. The number of elements will be
>>>>> +		rounded-up to a power of 2.
>>>>> +
>>>>>   What:		/sys/bus/counter/devices/counterX/name
>>>>>   KernelVersion:	5.2
>>>>>   Contact:	linux-iio@vger.kernel.org
>>>>> diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
>>>>> index 16f02df7f73d..53eea894e13f 100644
>>>>> --- a/drivers/counter/counter-chrdev.c
>>>>> +++ b/drivers/counter/counter-chrdev.c
>>>>> @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
>>>>>   	cdev_del(&counter->chrdev);
>>>>>   }
>>>>>   
>>>>> +int counter_chrdev_realloc_queue(struct counter_device *const counter,
>>>>> +				 size_t queue_size)
>>>>> +{
>>>>> +	int err;
>>>>> +	DECLARE_KFIFO_PTR(events, struct counter_event);
>>>>> +	unsigned long flags;
>>>>> +
>>>>> +	/* Allocate new events queue */
>>>>> +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);
>>>>
>>>> Is there any potential for losing events?
>>>
>>> We take the events_list_lock down below so we're safe against missing an
>>> event, but past events currently unread in the queue will be lost.
>>>
>>> Shortening the size of the queue is inherently a destructive process if
>>> we have more events in the current queue than can fit in the new queue.
>>> Because we a liable to lose some events in such a case, I think it's
>>> best to keep the behavior of this reallocation consistent and have it
>>> provide a fresh empty queue every time, as opposed to sometimes dropping
>>> events and sometimes not.
>>>
>>> I also suspect an actual user would be setting the size of their queue
>>> to the required amount before they begin watching events, rather than
>>> adjusting it sporadically during a live operation.
>>>
>>
>> Absolutely agree.   As such I wonder if you are better off enforcing this
>> behaviour?  If the cdev is open for reading, don't allow the fifo to be
>> resized.
>>
>> Jonathan
> 
> I can't really think of a good reason not to, so let's enforce it: if
> the cdev is open, then we'll return an EINVAL if the user attempts to
> resize the queue.
> 
> What is a good way to check for this condition? Should I just call
> kref_read() and see if it's greater than 1? For example, in
> counter_chrdev_realloc_queue():
> 
> 	if (kref_read(&counter->dev.kobj.kref) > 1)
> 		return -EINVAL;
> 
> William Breathitt Gray
> 

Wouldn't EBUSY make more sense?

Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 4807 bytes --]

On Fri, Feb 26, 2021 at 06:14:12PM -0600, David Lechner wrote:
> On 2/25/21 6:03 PM, William Breathitt Gray wrote:
> > On Sun, Feb 21, 2021 at 03:51:40PM +0000, Jonathan Cameron wrote:
> >> On Thu, 18 Feb 2021 19:32:16 +0900
> >> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >>
> >>> On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:
> >>>> On Fri, 12 Feb 2021 21:13:44 +0900
> >>>> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >>>>    
> >>>>> The events_queue_size sysfs attribute provides a way for users to
> >>>>> dynamically configure the Counter events queue size for the Counter
> >>>>> character device interface. The size is in number of struct
> >>>>> counter_event data structures. The number of elements will be rounded-up
> >>>>> to a power of 2 due to a requirement of the kfifo_alloc function called
> >>>>> during reallocation of the queue.
> >>>>>
> >>>>> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> >>>>> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> >>>>> ---
> >>>>>   Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
> >>>>>   drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
> >>>>>   drivers/counter/counter-chrdev.h            |  2 ++
> >>>>>   drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
> >>>>>   4 files changed, 58 insertions(+)
> >>>>>
> >>>>> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> >>>>> index 847e96f19d19..f6cb2a8b08a7 100644
> >>>>> --- a/Documentation/ABI/testing/sysfs-bus-counter
> >>>>> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> >>>>> @@ -212,6 +212,14 @@ Description:
> >>>>>   		both edges:
> >>>>>   			Any state transition.
> >>>>>   
> >>>>> +What:		/sys/bus/counter/devices/counterX/events_queue_size
> >>>>> +KernelVersion:	5.13
> >>>>> +Contact:	linux-iio@vger.kernel.org
> >>>>> +Description:
> >>>>> +		Size of the Counter events queue in number of struct
> >>>>> +		counter_event data structures. The number of elements will be
> >>>>> +		rounded-up to a power of 2.
> >>>>> +
> >>>>>   What:		/sys/bus/counter/devices/counterX/name
> >>>>>   KernelVersion:	5.2
> >>>>>   Contact:	linux-iio@vger.kernel.org
> >>>>> diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> >>>>> index 16f02df7f73d..53eea894e13f 100644
> >>>>> --- a/drivers/counter/counter-chrdev.c
> >>>>> +++ b/drivers/counter/counter-chrdev.c
> >>>>> @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
> >>>>>   	cdev_del(&counter->chrdev);
> >>>>>   }
> >>>>>   
> >>>>> +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> >>>>> +				 size_t queue_size)
> >>>>> +{
> >>>>> +	int err;
> >>>>> +	DECLARE_KFIFO_PTR(events, struct counter_event);
> >>>>> +	unsigned long flags;
> >>>>> +
> >>>>> +	/* Allocate new events queue */
> >>>>> +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);
> >>>>
> >>>> Is there any potential for losing events?
> >>>
> >>> We take the events_list_lock down below so we're safe against missing an
> >>> event, but past events currently unread in the queue will be lost.
> >>>
> >>> Shortening the size of the queue is inherently a destructive process if
> >>> we have more events in the current queue than can fit in the new queue.
> >>> Because we a liable to lose some events in such a case, I think it's
> >>> best to keep the behavior of this reallocation consistent and have it
> >>> provide a fresh empty queue every time, as opposed to sometimes dropping
> >>> events and sometimes not.
> >>>
> >>> I also suspect an actual user would be setting the size of their queue
> >>> to the required amount before they begin watching events, rather than
> >>> adjusting it sporadically during a live operation.
> >>>
> >>
> >> Absolutely agree.   As such I wonder if you are better off enforcing this
> >> behaviour?  If the cdev is open for reading, don't allow the fifo to be
> >> resized.
> >>
> >> Jonathan
> > 
> > I can't really think of a good reason not to, so let's enforce it: if
> > the cdev is open, then we'll return an EINVAL if the user attempts to
> > resize the queue.
> > 
> > What is a good way to check for this condition? Should I just call
> > kref_read() and see if it's greater than 1? For example, in
> > counter_chrdev_realloc_queue():
> > 
> > 	if (kref_read(&counter->dev.kobj.kref) > 1)
> > 		return -EINVAL;
> > 
> > William Breathitt Gray
> > 
> 
> Wouldn't EBUSY make more sense?

Yes, EBUSY would be better here because the operation isn't necessarily
invalid, just unavailable because someone else has the cdev open.

William Breathitt Gray

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Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[Jonathan Cameron]

On Fri, 26 Feb 2021 09:03:48 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> On Sun, Feb 21, 2021 at 03:51:40PM +0000, Jonathan Cameron wrote:
> > On Thu, 18 Feb 2021 19:32:16 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >   
> > > On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:  
> > > > On Fri, 12 Feb 2021 21:13:44 +0900
> > > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > > >     
> > > > > The events_queue_size sysfs attribute provides a way for users to
> > > > > dynamically configure the Counter events queue size for the Counter
> > > > > character device interface. The size is in number of struct
> > > > > counter_event data structures. The number of elements will be rounded-up
> > > > > to a power of 2 due to a requirement of the kfifo_alloc function called
> > > > > during reallocation of the queue.
> > > > > 
> > > > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > > > ---
> > > > >  Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
> > > > >  drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
> > > > >  drivers/counter/counter-chrdev.h            |  2 ++
> > > > >  drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
> > > > >  4 files changed, 58 insertions(+)
> > > > > 
> > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > > > index 847e96f19d19..f6cb2a8b08a7 100644
> > > > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > > > @@ -212,6 +212,14 @@ Description:
> > > > >  		both edges:
> > > > >  			Any state transition.
> > > > >  
> > > > > +What:		/sys/bus/counter/devices/counterX/events_queue_size
> > > > > +KernelVersion:	5.13
> > > > > +Contact:	linux-iio@vger.kernel.org
> > > > > +Description:
> > > > > +		Size of the Counter events queue in number of struct
> > > > > +		counter_event data structures. The number of elements will be
> > > > > +		rounded-up to a power of 2.
> > > > > +
> > > > >  What:		/sys/bus/counter/devices/counterX/name
> > > > >  KernelVersion:	5.2
> > > > >  Contact:	linux-iio@vger.kernel.org
> > > > > diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> > > > > index 16f02df7f73d..53eea894e13f 100644
> > > > > --- a/drivers/counter/counter-chrdev.c
> > > > > +++ b/drivers/counter/counter-chrdev.c
> > > > > @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
> > > > >  	cdev_del(&counter->chrdev);
> > > > >  }
> > > > >  
> > > > > +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> > > > > +				 size_t queue_size)
> > > > > +{
> > > > > +	int err;
> > > > > +	DECLARE_KFIFO_PTR(events, struct counter_event);
> > > > > +	unsigned long flags;
> > > > > +
> > > > > +	/* Allocate new events queue */
> > > > > +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);    
> > > > 
> > > > Is there any potential for losing events?    
> > > 
> > > We take the events_list_lock down below so we're safe against missing an
> > > event, but past events currently unread in the queue will be lost.
> > > 
> > > Shortening the size of the queue is inherently a destructive process if
> > > we have more events in the current queue than can fit in the new queue.
> > > Because we a liable to lose some events in such a case, I think it's
> > > best to keep the behavior of this reallocation consistent and have it
> > > provide a fresh empty queue every time, as opposed to sometimes dropping
> > > events and sometimes not.
> > > 
> > > I also suspect an actual user would be setting the size of their queue
> > > to the required amount before they begin watching events, rather than
> > > adjusting it sporadically during a live operation.
> > >  
> > 
> > Absolutely agree.   As such I wonder if you are better off enforcing this
> > behaviour?  If the cdev is open for reading, don't allow the fifo to be
> > resized. 
> > 
> > Jonathan  
> 
> I can't really think of a good reason not to, so let's enforce it: if
> the cdev is open, then we'll return an EINVAL if the user attempts to
> resize the queue.
> 
> What is a good way to check for this condition? Should I just call
> kref_read() and see if it's greater than 1? For example, in
> counter_chrdev_realloc_queue():
> 
> 	if (kref_read(&counter->dev.kobj.kref) > 1)
> 		return -EINVAL;
In theory at least you might want the kobj.kref to be incremented
for other reasons than just open.   So to keep different concepts
separate, perhaps it's worth a separate variable somewhere to
track whether the file is open currently.

However, it's reasonable (I think) to assume the kref will have a
minimum value if open, so perhaps what you suggest works fine.

Jonathan

> 
> William Breathitt Gray

Re: [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 5616 bytes --]

On Sat, Feb 27, 2021 at 03:18:47PM +0000, Jonathan Cameron wrote:
> On Fri, 26 Feb 2021 09:03:48 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > On Sun, Feb 21, 2021 at 03:51:40PM +0000, Jonathan Cameron wrote:
> > > On Thu, 18 Feb 2021 19:32:16 +0900
> > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > >   
> > > > On Sun, Feb 14, 2021 at 06:11:46PM +0000, Jonathan Cameron wrote:  
> > > > > On Fri, 12 Feb 2021 21:13:44 +0900
> > > > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > > > >     
> > > > > > The events_queue_size sysfs attribute provides a way for users to
> > > > > > dynamically configure the Counter events queue size for the Counter
> > > > > > character device interface. The size is in number of struct
> > > > > > counter_event data structures. The number of elements will be rounded-up
> > > > > > to a power of 2 due to a requirement of the kfifo_alloc function called
> > > > > > during reallocation of the queue.
> > > > > > 
> > > > > > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > > > > > ---
> > > > > >  Documentation/ABI/testing/sysfs-bus-counter |  8 +++++++
> > > > > >  drivers/counter/counter-chrdev.c            | 23 +++++++++++++++++++
> > > > > >  drivers/counter/counter-chrdev.h            |  2 ++
> > > > > >  drivers/counter/counter-sysfs.c             | 25 +++++++++++++++++++++
> > > > > >  4 files changed, 58 insertions(+)
> > > > > > 
> > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > > > > index 847e96f19d19..f6cb2a8b08a7 100644
> > > > > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > > > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > > > > @@ -212,6 +212,14 @@ Description:
> > > > > >  		both edges:
> > > > > >  			Any state transition.
> > > > > >  
> > > > > > +What:		/sys/bus/counter/devices/counterX/events_queue_size
> > > > > > +KernelVersion:	5.13
> > > > > > +Contact:	linux-iio@vger.kernel.org
> > > > > > +Description:
> > > > > > +		Size of the Counter events queue in number of struct
> > > > > > +		counter_event data structures. The number of elements will be
> > > > > > +		rounded-up to a power of 2.
> > > > > > +
> > > > > >  What:		/sys/bus/counter/devices/counterX/name
> > > > > >  KernelVersion:	5.2
> > > > > >  Contact:	linux-iio@vger.kernel.org
> > > > > > diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
> > > > > > index 16f02df7f73d..53eea894e13f 100644
> > > > > > --- a/drivers/counter/counter-chrdev.c
> > > > > > +++ b/drivers/counter/counter-chrdev.c
> > > > > > @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter)
> > > > > >  	cdev_del(&counter->chrdev);
> > > > > >  }
> > > > > >  
> > > > > > +int counter_chrdev_realloc_queue(struct counter_device *const counter,
> > > > > > +				 size_t queue_size)
> > > > > > +{
> > > > > > +	int err;
> > > > > > +	DECLARE_KFIFO_PTR(events, struct counter_event);
> > > > > > +	unsigned long flags;
> > > > > > +
> > > > > > +	/* Allocate new events queue */
> > > > > > +	err = kfifo_alloc(&events, queue_size, GFP_ATOMIC);    
> > > > > 
> > > > > Is there any potential for losing events?    
> > > > 
> > > > We take the events_list_lock down below so we're safe against missing an
> > > > event, but past events currently unread in the queue will be lost.
> > > > 
> > > > Shortening the size of the queue is inherently a destructive process if
> > > > we have more events in the current queue than can fit in the new queue.
> > > > Because we a liable to lose some events in such a case, I think it's
> > > > best to keep the behavior of this reallocation consistent and have it
> > > > provide a fresh empty queue every time, as opposed to sometimes dropping
> > > > events and sometimes not.
> > > > 
> > > > I also suspect an actual user would be setting the size of their queue
> > > > to the required amount before they begin watching events, rather than
> > > > adjusting it sporadically during a live operation.
> > > >  
> > > 
> > > Absolutely agree.   As such I wonder if you are better off enforcing this
> > > behaviour?  If the cdev is open for reading, don't allow the fifo to be
> > > resized. 
> > > 
> > > Jonathan  
> > 
> > I can't really think of a good reason not to, so let's enforce it: if
> > the cdev is open, then we'll return an EINVAL if the user attempts to
> > resize the queue.
> > 
> > What is a good way to check for this condition? Should I just call
> > kref_read() and see if it's greater than 1? For example, in
> > counter_chrdev_realloc_queue():
> > 
> > 	if (kref_read(&counter->dev.kobj.kref) > 1)
> > 		return -EINVAL;
> In theory at least you might want the kobj.kref to be incremented
> for other reasons than just open.   So to keep different concepts
> separate, perhaps it's worth a separate variable somewhere to
> track whether the file is open currently.
> 
> However, it's reasonable (I think) to assume the kref will have a
> minimum value if open, so perhaps what you suggest works fine.
> 
> Jonathan

I noticed an open() operation could occur right after this check, so
we'll need a mutex here to ensure the the queue size is not modified
during use. Because of that, I'll create a separate variable to track
this and use a mutex_trylock() instead of the kref to test whether to
return -EBUSY.

William Breathitt Gray

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[PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock

[William Breathitt Gray]

This patch replaces the mutex I/O lock with a spinlock. This is in
preparation for a subsequent patch adding IRQ support for 104-QUAD-8
devices; we can't sleep in an interrupt context, so we'll need to use a
spinlock instead.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 90 +++++++++++++++++++++---------------
 1 file changed, 53 insertions(+), 37 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 41fdbd228be3..2b47f9991acc 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
+#include <linux/spinlock.h>
 
 #define QUAD8_EXTENT 32
 
@@ -28,6 +29,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
 
 /**
  * struct quad8 - device private data structure
+ * @lock:		synchronization lock to prevent I/O race conditions
  * @counter:		instance of the counter_device
  * @fck_prescaler:	array of filter clock prescaler configurations
  * @preset:		array of preset values
@@ -42,7 +44,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
  * @base:		base port address of the device
  */
 struct quad8 {
-	struct mutex lock;
+	raw_spinlock_t lock;
 	struct counter_device counter;
 	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
 	unsigned int preset[QUAD8_NUM_COUNTERS];
@@ -123,6 +125,7 @@ static int quad8_count_read(struct counter_device *counter,
 	unsigned int flags;
 	unsigned int borrow;
 	unsigned int carry;
+	unsigned long irqflags;
 	int i;
 
 	flags = inb(base_offset + 1);
@@ -132,7 +135,7 @@ static int quad8_count_read(struct counter_device *counter,
 	/* Borrow XOR Carry effectively doubles count range */
 	*val = (unsigned long)(borrow ^ carry) << 24;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	/* Reset Byte Pointer; transfer Counter to Output Latch */
 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
@@ -141,7 +144,7 @@ static int quad8_count_read(struct counter_device *counter,
 	for (i = 0; i < 3; i++)
 		*val |= (unsigned long)inb(base_offset) << (8 * i);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -151,13 +154,14 @@ static int quad8_count_write(struct counter_device *counter,
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id;
+	unsigned long irqflags;
 	int i;
 
 	/* Only 24-bit values are supported */
 	if (val > 0xFFFFFF)
 		return -ERANGE;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	/* Reset Byte Pointer */
 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
@@ -182,7 +186,7 @@ static int quad8_count_write(struct counter_device *counter,
 	/* Reset Error flag */
 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -200,8 +204,9 @@ static int quad8_function_read(struct counter_device *counter,
 {
 	struct quad8 *const priv = counter->priv;
 	const int id = count->id;
+	unsigned long irqflags;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	if (priv->quadrature_mode[id])
 		switch (priv->quadrature_scale[id]) {
@@ -218,7 +223,7 @@ static int quad8_function_read(struct counter_device *counter,
 	else
 		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -233,10 +238,11 @@ static int quad8_function_write(struct counter_device *counter,
 	unsigned int *const scale = priv->quadrature_scale + id;
 	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
 	const int base_offset = priv->base + 2 * id + 1;
+	unsigned long irqflags;
 	unsigned int mode_cfg;
 	unsigned int idr_cfg;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	mode_cfg = priv->count_mode[id] << 1;
 	idr_cfg = priv->index_polarity[id] << 1;
@@ -271,7 +277,7 @@ static int quad8_function_write(struct counter_device *counter,
 			break;
 		default:
 			/* should never reach this path */
-			mutex_unlock(&priv->lock);
+			raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 			return -EINVAL;
 		}
 	}
@@ -279,7 +285,7 @@ static int quad8_function_write(struct counter_device *counter,
 	/* Load mode configuration to Counter Mode Register */
 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -407,9 +413,10 @@ static int quad8_index_polarity_set(struct counter_device *counter,
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id - 16;
 	const int base_offset = priv->base + 2 * channel_id + 1;
+	unsigned long irqflags;
 	unsigned int idr_cfg = index_polarity << 1;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	idr_cfg |= priv->synchronous_mode[channel_id];
 
@@ -418,7 +425,7 @@ static int quad8_index_polarity_set(struct counter_device *counter,
 	/* Load Index Control configuration to Index Control Register */
 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -447,15 +454,16 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id - 16;
 	const int base_offset = priv->base + 2 * channel_id + 1;
+	unsigned long irqflags;
 	unsigned int idr_cfg = synchronous_mode;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	idr_cfg |= priv->index_polarity[channel_id] << 1;
 
 	/* Index function must be non-synchronous in non-quadrature mode */
 	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
-		mutex_unlock(&priv->lock);
+		raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 		return -EINVAL;
 	}
 
@@ -464,7 +472,7 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
 	/* Load Index Control configuration to Index Control Register */
 	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -511,6 +519,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
 	unsigned int count_mode;
 	unsigned int mode_cfg;
 	const int base_offset = priv->base + 2 * count->id + 1;
+	unsigned long irqflags;
 
 	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
 	switch (cnt_mode) {
@@ -531,7 +540,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
 		return -EINVAL;
 	}
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->count_mode[count->id] = count_mode;
 
@@ -545,7 +554,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
 	/* Load mode configuration to Counter Mode Register */
 	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -565,9 +574,10 @@ static int quad8_count_enable_write(struct counter_device *counter,
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id;
+	unsigned long irqflags;
 	unsigned int ior_cfg;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->ab_enable[count->id] = enable;
 
@@ -576,7 +586,7 @@ static int quad8_count_enable_write(struct counter_device *counter,
 	/* Load I/O control configuration */
 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -627,16 +637,17 @@ static int quad8_count_preset_write(struct counter_device *counter,
 				    struct counter_count *count, u64 preset)
 {
 	struct quad8 *const priv = counter->priv;
+	unsigned long irqflags;
 
 	/* Only 24-bit values are supported */
 	if (preset > 0xFFFFFF)
 		return -ERANGE;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	quad8_preset_register_set(priv, count->id, preset);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -645,8 +656,9 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
 				    struct counter_count *count, u64 *ceiling)
 {
 	struct quad8 *const priv = counter->priv;
+	unsigned long irqflags;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
 	switch (priv->count_mode[count->id]) {
@@ -660,7 +672,7 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
 		break;
 	}
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -669,23 +681,24 @@ static int quad8_count_ceiling_write(struct counter_device *counter,
 				     struct counter_count *count, u64 ceiling)
 {
 	struct quad8 *const priv = counter->priv;
+	unsigned long irqflags;
 
 	/* Only 24-bit values are supported */
 	if (ceiling > 0xFFFFFF)
 		return -ERANGE;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
 	switch (priv->count_mode[count->id]) {
 	case 1:
 	case 3:
-		mutex_unlock(&priv->lock);
+		raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 		quad8_preset_register_set(priv, count->id, ceiling);
 		return 0;
 	}
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return -EINVAL;
 }
@@ -707,12 +720,13 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
 {
 	struct quad8 *const priv = counter->priv;
 	const int base_offset = priv->base + 2 * count->id + 1;
+	unsigned long irqflags;
 	unsigned int ior_cfg;
 
 	/* Preset enable is active low in Input/Output Control register */
 	preset_enable = !preset_enable;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->preset_enable[count->id] = preset_enable;
 
@@ -721,7 +735,7 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
 	/* Load I/O control configuration to Input / Output Control Register */
 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -732,22 +746,23 @@ static int quad8_signal_cable_fault_read(struct counter_device *counter,
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
+	unsigned long irqflags;
 	bool disabled;
 	unsigned int status;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
 
 	if (disabled) {
-		mutex_unlock(&priv->lock);
+		raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 		return -EINVAL;
 	}
 
 	/* Logic 0 = cable fault */
 	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	/* Mask respective channel and invert logic */
 	*cable_fault = !(status & BIT(channel_id));
@@ -773,9 +788,10 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
 {
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
+	unsigned long irqflags;
 	unsigned int cable_fault_enable;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	if (enable)
 		priv->cable_fault_enable |= BIT(channel_id);
@@ -787,7 +803,7 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
 
 	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -810,8 +826,9 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
 	struct quad8 *const priv = counter->priv;
 	const size_t channel_id = signal->id / 2;
 	const int base_offset = priv->base + 2 * channel_id;
+	unsigned long irqflags;
 
-	mutex_lock(&priv->lock);
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->fck_prescaler[channel_id] = prescaler;
 
@@ -823,7 +840,7 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
 	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
 	     base_offset + 1);
 
-	mutex_unlock(&priv->lock);
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -992,8 +1009,7 @@ static int quad8_probe(struct device *dev, unsigned int id)
 	priv->counter.priv = priv;
 	priv->base = base[id];
 
-	/* Initialize mutex */
-	mutex_init(&priv->lock);
+	raw_spin_lock_init(&priv->lock);
 
 	/* Reset all counters and disable interrupt function */
 	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
-- 
2.30.0

Re: [PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:45 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> This patch replaces the mutex I/O lock with a spinlock. This is in
> preparation for a subsequent patch adding IRQ support for 104-QUAD-8
> devices; we can't sleep in an interrupt context, so we'll need to use a
> spinlock instead.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

Why do these need to be raw_spin_locks?
Normally only need to do that if in code related to interrupt chips etc,
not their use.

Jonathan

> ---
>  drivers/counter/104-quad-8.c | 90 +++++++++++++++++++++---------------
>  1 file changed, 53 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 41fdbd228be3..2b47f9991acc 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -16,6 +16,7 @@
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/types.h>
> +#include <linux/spinlock.h>
>  
>  #define QUAD8_EXTENT 32
>  
> @@ -28,6 +29,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
>  
>  /**
>   * struct quad8 - device private data structure
> + * @lock:		synchronization lock to prevent I/O race conditions
>   * @counter:		instance of the counter_device
>   * @fck_prescaler:	array of filter clock prescaler configurations
>   * @preset:		array of preset values
> @@ -42,7 +44,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
>   * @base:		base port address of the device
>   */
>  struct quad8 {
> -	struct mutex lock;
> +	raw_spinlock_t lock;
>  	struct counter_device counter;
>  	unsigned int fck_prescaler[QUAD8_NUM_COUNTERS];
>  	unsigned int preset[QUAD8_NUM_COUNTERS];
> @@ -123,6 +125,7 @@ static int quad8_count_read(struct counter_device *counter,
>  	unsigned int flags;
>  	unsigned int borrow;
>  	unsigned int carry;
> +	unsigned long irqflags;
>  	int i;
>  
>  	flags = inb(base_offset + 1);
> @@ -132,7 +135,7 @@ static int quad8_count_read(struct counter_device *counter,
>  	/* Borrow XOR Carry effectively doubles count range */
>  	*val = (unsigned long)(borrow ^ carry) << 24;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	/* Reset Byte Pointer; transfer Counter to Output Latch */
>  	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT,
> @@ -141,7 +144,7 @@ static int quad8_count_read(struct counter_device *counter,
>  	for (i = 0; i < 3; i++)
>  		*val |= (unsigned long)inb(base_offset) << (8 * i);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -151,13 +154,14 @@ static int quad8_count_write(struct counter_device *counter,
>  {
>  	struct quad8 *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id;
> +	unsigned long irqflags;
>  	int i;
>  
>  	/* Only 24-bit values are supported */
>  	if (val > 0xFFFFFF)
>  		return -ERANGE;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	/* Reset Byte Pointer */
>  	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1);
> @@ -182,7 +186,7 @@ static int quad8_count_write(struct counter_device *counter,
>  	/* Reset Error flag */
>  	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -200,8 +204,9 @@ static int quad8_function_read(struct counter_device *counter,
>  {
>  	struct quad8 *const priv = counter->priv;
>  	const int id = count->id;
> +	unsigned long irqflags;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	if (priv->quadrature_mode[id])
>  		switch (priv->quadrature_scale[id]) {
> @@ -218,7 +223,7 @@ static int quad8_function_read(struct counter_device *counter,
>  	else
>  		*function = COUNTER_FUNCTION_PULSE_DIRECTION;
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -233,10 +238,11 @@ static int quad8_function_write(struct counter_device *counter,
>  	unsigned int *const scale = priv->quadrature_scale + id;
>  	unsigned int *const synchronous_mode = priv->synchronous_mode + id;
>  	const int base_offset = priv->base + 2 * id + 1;
> +	unsigned long irqflags;
>  	unsigned int mode_cfg;
>  	unsigned int idr_cfg;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	mode_cfg = priv->count_mode[id] << 1;
>  	idr_cfg = priv->index_polarity[id] << 1;
> @@ -271,7 +277,7 @@ static int quad8_function_write(struct counter_device *counter,
>  			break;
>  		default:
>  			/* should never reach this path */
> -			mutex_unlock(&priv->lock);
> +			raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  			return -EINVAL;
>  		}
>  	}
> @@ -279,7 +285,7 @@ static int quad8_function_write(struct counter_device *counter,
>  	/* Load mode configuration to Counter Mode Register */
>  	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -407,9 +413,10 @@ static int quad8_index_polarity_set(struct counter_device *counter,
>  	struct quad8 *const priv = counter->priv;
>  	const size_t channel_id = signal->id - 16;
>  	const int base_offset = priv->base + 2 * channel_id + 1;
> +	unsigned long irqflags;
>  	unsigned int idr_cfg = index_polarity << 1;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	idr_cfg |= priv->synchronous_mode[channel_id];
>  
> @@ -418,7 +425,7 @@ static int quad8_index_polarity_set(struct counter_device *counter,
>  	/* Load Index Control configuration to Index Control Register */
>  	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -447,15 +454,16 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
>  	struct quad8 *const priv = counter->priv;
>  	const size_t channel_id = signal->id - 16;
>  	const int base_offset = priv->base + 2 * channel_id + 1;
> +	unsigned long irqflags;
>  	unsigned int idr_cfg = synchronous_mode;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	idr_cfg |= priv->index_polarity[channel_id] << 1;
>  
>  	/* Index function must be non-synchronous in non-quadrature mode */
>  	if (synchronous_mode && !priv->quadrature_mode[channel_id]) {
> -		mutex_unlock(&priv->lock);
> +		raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  		return -EINVAL;
>  	}
>  
> @@ -464,7 +472,7 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
>  	/* Load Index Control configuration to Index Control Register */
>  	outb(QUAD8_CTR_IDR | idr_cfg, base_offset);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -511,6 +519,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
>  	unsigned int count_mode;
>  	unsigned int mode_cfg;
>  	const int base_offset = priv->base + 2 * count->id + 1;
> +	unsigned long irqflags;
>  
>  	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
>  	switch (cnt_mode) {
> @@ -531,7 +540,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
>  		return -EINVAL;
>  	}
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	priv->count_mode[count->id] = count_mode;
>  
> @@ -545,7 +554,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
>  	/* Load mode configuration to Counter Mode Register */
>  	outb(QUAD8_CTR_CMR | mode_cfg, base_offset);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -565,9 +574,10 @@ static int quad8_count_enable_write(struct counter_device *counter,
>  {
>  	struct quad8 *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id;
> +	unsigned long irqflags;
>  	unsigned int ior_cfg;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	priv->ab_enable[count->id] = enable;
>  
> @@ -576,7 +586,7 @@ static int quad8_count_enable_write(struct counter_device *counter,
>  	/* Load I/O control configuration */
>  	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -627,16 +637,17 @@ static int quad8_count_preset_write(struct counter_device *counter,
>  				    struct counter_count *count, u64 preset)
>  {
>  	struct quad8 *const priv = counter->priv;
> +	unsigned long irqflags;
>  
>  	/* Only 24-bit values are supported */
>  	if (preset > 0xFFFFFF)
>  		return -ERANGE;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	quad8_preset_register_set(priv, count->id, preset);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -645,8 +656,9 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
>  				    struct counter_count *count, u64 *ceiling)
>  {
>  	struct quad8 *const priv = counter->priv;
> +	unsigned long irqflags;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	/* Range Limit and Modulo-N count modes use preset value as ceiling */
>  	switch (priv->count_mode[count->id]) {
> @@ -660,7 +672,7 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
>  		break;
>  	}
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -669,23 +681,24 @@ static int quad8_count_ceiling_write(struct counter_device *counter,
>  				     struct counter_count *count, u64 ceiling)
>  {
>  	struct quad8 *const priv = counter->priv;
> +	unsigned long irqflags;
>  
>  	/* Only 24-bit values are supported */
>  	if (ceiling > 0xFFFFFF)
>  		return -ERANGE;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	/* Range Limit and Modulo-N count modes use preset value as ceiling */
>  	switch (priv->count_mode[count->id]) {
>  	case 1:
>  	case 3:
> -		mutex_unlock(&priv->lock);
> +		raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  		quad8_preset_register_set(priv, count->id, ceiling);
>  		return 0;
>  	}
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return -EINVAL;
>  }
> @@ -707,12 +720,13 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
>  {
>  	struct quad8 *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id + 1;
> +	unsigned long irqflags;
>  	unsigned int ior_cfg;
>  
>  	/* Preset enable is active low in Input/Output Control register */
>  	preset_enable = !preset_enable;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	priv->preset_enable[count->id] = preset_enable;
>  
> @@ -721,7 +735,7 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
>  	/* Load I/O control configuration to Input / Output Control Register */
>  	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -732,22 +746,23 @@ static int quad8_signal_cable_fault_read(struct counter_device *counter,
>  {
>  	struct quad8 *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
> +	unsigned long irqflags;
>  	bool disabled;
>  	unsigned int status;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	disabled = !(priv->cable_fault_enable & BIT(channel_id));
>  
>  	if (disabled) {
> -		mutex_unlock(&priv->lock);
> +		raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  		return -EINVAL;
>  	}
>  
>  	/* Logic 0 = cable fault */
>  	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	/* Mask respective channel and invert logic */
>  	*cable_fault = !(status & BIT(channel_id));
> @@ -773,9 +788,10 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
>  {
>  	struct quad8 *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
> +	unsigned long irqflags;
>  	unsigned int cable_fault_enable;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	if (enable)
>  		priv->cable_fault_enable |= BIT(channel_id);
> @@ -787,7 +803,7 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
>  
>  	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -810,8 +826,9 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
>  	struct quad8 *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
>  	const int base_offset = priv->base + 2 * channel_id;
> +	unsigned long irqflags;
>  
> -	mutex_lock(&priv->lock);
> +	raw_spin_lock_irqsave(&priv->lock, irqflags);
>  
>  	priv->fck_prescaler[channel_id] = prescaler;
>  
> @@ -823,7 +840,7 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
>  	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
>  	     base_offset + 1);
>  
> -	mutex_unlock(&priv->lock);
> +	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
>  
>  	return 0;
>  }
> @@ -992,8 +1009,7 @@ static int quad8_probe(struct device *dev, unsigned int id)
>  	priv->counter.priv = priv;
>  	priv->base = base[id];
>  
> -	/* Initialize mutex */
> -	mutex_init(&priv->lock);
> +	raw_spin_lock_init(&priv->lock);
>  
>  	/* Reset all counters and disable interrupt function */
>  	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);

Re: [PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock

[William Breathitt Gray]

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On Sun, Feb 14, 2021 at 06:19:46PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:45 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > This patch replaces the mutex I/O lock with a spinlock. This is in
> > preparation for a subsequent patch adding IRQ support for 104-QUAD-8
> > devices; we can't sleep in an interrupt context, so we'll need to use a
> > spinlock instead.
> > 
> > Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> 
> Why do these need to be raw_spin_locks?
> Normally only need to do that if in code related to interrupt chips etc,
> not their use.
> 
> Jonathan

This lock can be taken in an interrupt context in a subsequent patch:
counter_push_event() called by quad8_irq_handler() can end up calling
the Counter component callbacks which take this lock. We can't use a
mutex nor a regular spinlock because those can sleep on RT setups [1]
which would result in a deadlock due to the interrupt context here -- so
therefore we're left with using raw_spin_lock.

[1] https://lwn.net/Articles/367219/

William Breathitt Gray

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Re: [PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock

[Jonathan Cameron]

On Tue, 16 Feb 2021 11:16:03 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> On Sun, Feb 14, 2021 at 06:19:46PM +0000, Jonathan Cameron wrote:
> > On Fri, 12 Feb 2021 21:13:45 +0900
> > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> >   
> > > This patch replaces the mutex I/O lock with a spinlock. This is in
> > > preparation for a subsequent patch adding IRQ support for 104-QUAD-8
> > > devices; we can't sleep in an interrupt context, so we'll need to use a
> > > spinlock instead.
> > > 
> > > Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>  
> > 
> > Why do these need to be raw_spin_locks?
> > Normally only need to do that if in code related to interrupt chips etc,
> > not their use.
> > 
> > Jonathan  
> 
> This lock can be taken in an interrupt context in a subsequent patch:
> counter_push_event() called by quad8_irq_handler() can end up calling
> the Counter component callbacks which take this lock. We can't use a
> mutex nor a regular spinlock because those can sleep on RT setups [1]

But on RT setups the interrupts become threads and are preemptable etc,
so that shouldn't matter.  There are a few corner cases that cause
trouble, but in most normal drivers you should be fine with a
spin_lock.

Jonathan


> which would result in a deadlock due to the interrupt context here -- so
> therefore we're left with using raw_spin_lock.
> 
> [1] https://lwn.net/Articles/367219/
> 
> William Breathitt Gray

Re: [PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 1950 bytes --]

On Tue, Feb 16, 2021 at 07:27:20PM +0000, Jonathan Cameron wrote:
> On Tue, 16 Feb 2021 11:16:03 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > On Sun, Feb 14, 2021 at 06:19:46PM +0000, Jonathan Cameron wrote:
> > > On Fri, 12 Feb 2021 21:13:45 +0900
> > > William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > >   
> > > > This patch replaces the mutex I/O lock with a spinlock. This is in
> > > > preparation for a subsequent patch adding IRQ support for 104-QUAD-8
> > > > devices; we can't sleep in an interrupt context, so we'll need to use a
> > > > spinlock instead.
> > > > 
> > > > Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>  
> > > 
> > > Why do these need to be raw_spin_locks?
> > > Normally only need to do that if in code related to interrupt chips etc,
> > > not their use.
> > > 
> > > Jonathan  
> > 
> > This lock can be taken in an interrupt context in a subsequent patch:
> > counter_push_event() called by quad8_irq_handler() can end up calling
> > the Counter component callbacks which take this lock. We can't use a
> > mutex nor a regular spinlock because those can sleep on RT setups [1]
> 
> But on RT setups the interrupts become threads and are preemptable etc,
> so that shouldn't matter.  There are a few corner cases that cause
> trouble, but in most normal drivers you should be fine with a
> spin_lock.
> 
> Jonathan

Thinking this over again I realize you're probably right. A simple
spin_lock should be fine for these drivers, so I'll switch over to that
instead of the raw_spin_lock for this driver and the Counter interface
code.

William Breathitt Gray

> > which would result in a deadlock due to the interrupt context here -- so
> > therefore we're left with using raw_spin_lock.
> > 
> > [1] https://lwn.net/Articles/367219/
> > 
> > William Breathitt Gray
> 

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[PATCH v8 22/22] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8

[William Breathitt Gray]

The LSI/CSI LS7266R1 chip provides programmable output via the FLG pins.
When interrupts are enabled on the ACCES 104-QUAD-8, they occur whenever
FLG1 is active. Four functions are available for the FLG1 signal: Carry,
Compare, Carry-Borrow, and Index.

	Carry:
		Interrupt generated on active low Carry signal. Carry
		signal toggles every time the respective channel's
		counter overflows.

	Compare:
		Interrupt generated on active low Compare signal.
		Compare signal toggles every time respective channel's
		preset register is equal to the respective channel's
		counter.

	Carry-Borrow:
		Interrupt generated on active low Carry signal and
		active low Borrow signal. Carry signal toggles every
		time the respective channel's counter overflows. Borrow
		signal toggles every time the respective channel's
		counter underflows.

	Index:
		Interrupt generated on active high Index signal.

These four functions correspond respectivefly to the following four
Counter event types: COUNTER_EVENT_OVERFLOW, COUNTER_EVENT_THRESHOLD,
COUNTER_EVENT_OVERFLOW_UNDERFLOW, and COUNTER_EVENT_INDEX. Interrupts
push Counter events to event channel X, where 'X' is the respective
channel whose FLG1 activated.

This patch adds IRQ support for the ACCES 104-QUAD-8. The interrupt line
numbers for the devices may be configured via the irq array module
parameter.

Cc: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 170 +++++++++++++++++++++++++++++++++--
 drivers/counter/Kconfig      |   6 +-
 2 files changed, 165 insertions(+), 11 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 2b47f9991acc..45090cd9f813 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -11,6 +11,7 @@
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
+#include <linux/interrupt.h>
 #include <linux/isa.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -25,11 +26,15 @@ static unsigned int num_quad8;
 module_param_hw_array(base, uint, ioport, &num_quad8, 0);
 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
 
+static unsigned int irq[max_num_isa_dev(QUAD8_EXTENT)];
+module_param_hw_array(irq, uint, irq, NULL, 0);
+MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
+
 #define QUAD8_NUM_COUNTERS 8
 
 /**
  * struct quad8 - device private data structure
- * @lock:		synchronization lock to prevent I/O race conditions
+ * @lock:		lock to prevent clobbering device states during R/W ops
  * @counter:		instance of the counter_device
  * @fck_prescaler:	array of filter clock prescaler configurations
  * @preset:		array of preset values
@@ -38,6 +43,8 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
  * @quadrature_scale:	array of quadrature mode scale configurations
  * @ab_enable:		array of A and B inputs enable configurations
  * @preset_enable:	array of set_to_preset_on_index attribute configurations
+ * @irq_trigger:	array of current IRQ trigger function configurations
+ * @next_irq_trigger:	array of next IRQ trigger function configurations
  * @synchronous_mode:	array of index function synchronous mode configurations
  * @index_polarity:	array of index function polarity configurations
  * @cable_fault_enable:	differential encoder cable status enable configurations
@@ -53,13 +60,17 @@ struct quad8 {
 	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
 	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
 	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
+	unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
+	unsigned int next_irq_trigger[QUAD8_NUM_COUNTERS];
 	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
 	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
 	unsigned int cable_fault_enable;
 	unsigned int base;
 };
 
+#define QUAD8_REG_INTERRUPT_STATUS 0x10
 #define QUAD8_REG_CHAN_OP 0x11
+#define QUAD8_REG_INDEX_INTERRUPT 0x12
 #define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
 #define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
 /* Borrow Toggle flip-flop */
@@ -92,8 +103,8 @@ struct quad8 {
 #define QUAD8_RLD_CNTR_OUT 0x10
 /* Transfer Preset Register LSB to FCK Prescaler */
 #define QUAD8_RLD_PRESET_PSC 0x18
-#define QUAD8_CHAN_OP_ENABLE_COUNTERS 0x00
 #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
+#define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
 #define QUAD8_CMR_QUADRATURE_X1 0x08
 #define QUAD8_CMR_QUADRATURE_X2 0x10
 #define QUAD8_CMR_QUADRATURE_X4 0x18
@@ -380,13 +391,103 @@ static int quad8_action_read(struct counter_device *counter,
 	return 0;
 }
 
+enum {
+	QUAD8_EVENT_NONE = -1,
+	QUAD8_EVENT_CARRY = 0,
+	QUAD8_EVENT_COMPARE = 1,
+	QUAD8_EVENT_CARRY_BORROW = 2,
+	QUAD8_EVENT_INDEX = 3,
+};
+
+static int quad8_events_configure(struct counter_device *counter)
+{
+	struct quad8 *const priv = counter->priv;
+	unsigned long irq_enabled = 0;
+	unsigned long irqflags;
+	size_t channel;
+	unsigned long ior_cfg;
+	unsigned long base_offset;
+
+	raw_spin_lock_irqsave(&priv->lock, irqflags);
+
+	/* Enable interrupts for the requested channels, disable for the rest */
+	for (channel = 0; channel < QUAD8_NUM_COUNTERS; channel++) {
+		if (priv->next_irq_trigger[channel] == QUAD8_EVENT_NONE)
+			continue;
+
+		if (priv->irq_trigger[channel] != priv->next_irq_trigger[channel]) {
+			/* Save new IRQ function configuration */
+			priv->irq_trigger[channel] = priv->next_irq_trigger[channel];
+
+			/* Load configuration to I/O Control Register */
+			ior_cfg = priv->ab_enable[channel] |
+				  priv->preset_enable[channel] << 1 |
+				  priv->irq_trigger[channel] << 3;
+			base_offset = priv->base + 2 * channel + 1;
+			outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
+		}
+
+		/* Reset next IRQ trigger function configuration */
+		priv->next_irq_trigger[channel] = QUAD8_EVENT_NONE;
+
+		/* Enable IRQ line */
+		irq_enabled |= BIT(channel);
+	}
+
+	outb(irq_enabled, priv->base + QUAD8_REG_INDEX_INTERRUPT);
+
+	raw_spin_unlock_irqrestore(&priv->lock, irqflags);
+
+	return 0;
+}
+
+static int quad8_watch_validate(struct counter_device *counter,
+				const struct counter_watch *watch)
+{
+	struct quad8 *const priv = counter->priv;
+
+	if (watch->channel > QUAD8_NUM_COUNTERS - 1)
+		return -EINVAL;
+
+	switch (watch->event) {
+	case COUNTER_EVENT_OVERFLOW:
+		if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+			priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_CARRY;
+		else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_CARRY)
+			return -EINVAL;
+		return 0;
+	case COUNTER_EVENT_THRESHOLD:
+		if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+			priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_COMPARE;
+		else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_COMPARE)
+			return -EINVAL;
+		return 0;
+	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
+		if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+			priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_CARRY_BORROW;
+		else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_CARRY_BORROW)
+			return -EINVAL;
+		return 0;
+	case COUNTER_EVENT_INDEX:
+		if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
+			priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_INDEX;
+		else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_INDEX)
+			return -EINVAL;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct counter_ops quad8_ops = {
 	.signal_read = quad8_signal_read,
 	.count_read = quad8_count_read,
 	.count_write = quad8_count_write,
 	.function_read = quad8_function_read,
 	.function_write = quad8_function_write,
-	.action_read = quad8_action_read
+	.action_read = quad8_action_read,
+	.events_configure = quad8_events_configure,
+	.watch_validate = quad8_watch_validate,
 };
 
 static const char *const quad8_index_polarity_modes[] = {
@@ -581,7 +682,8 @@ static int quad8_count_enable_write(struct counter_device *counter,
 
 	priv->ab_enable[count->id] = enable;
 
-	ior_cfg = enable | priv->preset_enable[count->id] << 1;
+	ior_cfg = enable | priv->preset_enable[count->id] << 1 |
+		  priv->irq_trigger[count->id] << 3;
 
 	/* Load I/O control configuration */
 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
@@ -730,7 +832,8 @@ static int quad8_count_preset_enable_write(struct counter_device *counter,
 
 	priv->preset_enable[count->id] = preset_enable;
 
-	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1;
+	ior_cfg = priv->ab_enable[count->id] | preset_enable << 1 |
+		  priv->irq_trigger[count->id] << 3;
 
 	/* Load I/O control configuration to Input / Output Control Register */
 	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
@@ -982,11 +1085,54 @@ static struct counter_count quad8_counts[] = {
 	QUAD8_COUNT(7, "Channel 8 Count")
 };
 
+static irqreturn_t quad8_irq_handler(int irq, void *private)
+{
+	struct quad8 *const priv = private;
+	const unsigned long base = priv->base;
+	unsigned long irq_status;
+	unsigned long channel;
+	u8 event;
+
+	irq_status = inb(base + QUAD8_REG_INTERRUPT_STATUS);
+	if (!irq_status)
+		return IRQ_NONE;
+
+	for_each_set_bit(channel, &irq_status, QUAD8_NUM_COUNTERS) {
+		switch (priv->irq_trigger[channel]) {
+		case QUAD8_EVENT_CARRY:
+			event = COUNTER_EVENT_OVERFLOW;
+				break;
+		case QUAD8_EVENT_COMPARE:
+			event = COUNTER_EVENT_THRESHOLD;
+				break;
+		case QUAD8_EVENT_CARRY_BORROW:
+			event = COUNTER_EVENT_OVERFLOW_UNDERFLOW;
+				break;
+		case QUAD8_EVENT_INDEX:
+			event = COUNTER_EVENT_INDEX;
+				break;
+		default:
+			/* should never reach this path */
+			WARN_ONCE(true, "invalid interrupt trigger function %u configured for channel %lu\n",
+				  priv->irq_trigger[channel], channel);
+			continue;
+		}
+
+		counter_push_event(&priv->counter, event, channel);
+	}
+
+	/* Clear pending interrupts on device */
+	outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base + QUAD8_REG_CHAN_OP);
+
+	return IRQ_HANDLED;
+}
+
 static int quad8_probe(struct device *dev, unsigned int id)
 {
 	struct quad8 *priv;
 	int i, j;
 	unsigned int base_offset;
+	int err;
 
 	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
@@ -1011,6 +1157,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
 
 	raw_spin_lock_init(&priv->lock);
 
+	/* Reset Index/Interrupt Register */
+	outb(0x00, base[id] + QUAD8_REG_INDEX_INTERRUPT);
 	/* Reset all counters and disable interrupt function */
 	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
 	/* Set initial configuration for all counters */
@@ -1037,13 +1185,19 @@ static int quad8_probe(struct device *dev, unsigned int id)
 		outb(QUAD8_CTR_IOR, base_offset + 1);
 		/* Disable index function; negative index polarity */
 		outb(QUAD8_CTR_IDR, base_offset + 1);
+		/* Initialize next IRQ trigger function configuration */
+		priv->next_irq_trigger[i] = QUAD8_EVENT_NONE;
 	}
 	/* Disable Differential Encoder Cable Status for all channels */
 	outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
-	/* Enable all counters */
-	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
+	/* Enable all counters and enable interrupt function */
+	outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
+
+	err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
+			       priv->counter.name, priv);
+	if (err)
+		return err;
 
-	/* Register Counter device */
 	return devm_counter_register(dev, &priv->counter);
 }
 
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 1391e8ea64fe..b0f8fef18b51 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -23,11 +23,11 @@ config 104_QUAD_8
 	  A counter's respective error flag may be cleared by performing a write
 	  operation on the respective count value attribute. Although the
 	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
-	  set, either directly or via the counter's preset attribute. Interrupts
-	  are not supported by this driver.
+	  set, either directly or via the counter's preset attribute.
 
 	  The base port addresses for the devices may be configured via the base
-	  array module parameter.
+	  array module parameter. The interrupt line numbers for the devices may
+	  be configured via the irq array module parameter.
 
 config STM32_TIMER_CNT
 	tristate "STM32 Timer encoder counter driver"
-- 
2.30.0

Re: [PATCH v8 22/22] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8

[Jonathan Cameron]

On Fri, 12 Feb 2021 21:13:46 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The LSI/CSI LS7266R1 chip provides programmable output via the FLG pins.
> When interrupts are enabled on the ACCES 104-QUAD-8, they occur whenever
> FLG1 is active. Four functions are available for the FLG1 signal: Carry,
> Compare, Carry-Borrow, and Index.
> 
> 	Carry:
> 		Interrupt generated on active low Carry signal. Carry
> 		signal toggles every time the respective channel's
> 		counter overflows.
> 
> 	Compare:
> 		Interrupt generated on active low Compare signal.
> 		Compare signal toggles every time respective channel's
> 		preset register is equal to the respective channel's
> 		counter.
> 
> 	Carry-Borrow:
> 		Interrupt generated on active low Carry signal and
> 		active low Borrow signal. Carry signal toggles every
> 		time the respective channel's counter overflows. Borrow
> 		signal toggles every time the respective channel's
> 		counter underflows.
> 
> 	Index:
> 		Interrupt generated on active high Index signal.
> 
> These four functions correspond respectivefly to the following four
> Counter event types: COUNTER_EVENT_OVERFLOW, COUNTER_EVENT_THRESHOLD,
> COUNTER_EVENT_OVERFLOW_UNDERFLOW, and COUNTER_EVENT_INDEX. Interrupts
> push Counter events to event channel X, where 'X' is the respective
> channel whose FLG1 activated.
> 
> This patch adds IRQ support for the ACCES 104-QUAD-8. The interrupt line
> numbers for the devices may be configured via the irq array module
> parameter.
> 
> Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

A few minor bits inline.

Jonathan

> ---
>  drivers/counter/104-quad-8.c | 170 +++++++++++++++++++++++++++++++++--
>  drivers/counter/Kconfig      |   6 +-
>  2 files changed, 165 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 2b47f9991acc..45090cd9f813 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -11,6 +11,7 @@
>  #include <linux/errno.h>
>  #include <linux/io.h>
>  #include <linux/ioport.h>
> +#include <linux/interrupt.h>
>  #include <linux/isa.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> @@ -25,11 +26,15 @@ static unsigned int num_quad8;
>  module_param_hw_array(base, uint, ioport, &num_quad8, 0);
>  MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
>  
> +static unsigned int irq[max_num_isa_dev(QUAD8_EXTENT)];
> +module_param_hw_array(irq, uint, irq, NULL, 0);
> +MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
> +
>  #define QUAD8_NUM_COUNTERS 8
>  
>  /**
>   * struct quad8 - device private data structure
> - * @lock:		synchronization lock to prevent I/O race conditions
> + * @lock:		lock to prevent clobbering device states during R/W ops
>   * @counter:		instance of the counter_device
>   * @fck_prescaler:	array of filter clock prescaler configurations
>   * @preset:		array of preset values
> @@ -38,6 +43,8 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
>   * @quadrature_scale:	array of quadrature mode scale configurations
>   * @ab_enable:		array of A and B inputs enable configurations
>   * @preset_enable:	array of set_to_preset_on_index attribute configurations
> + * @irq_trigger:	array of current IRQ trigger function configurations
> + * @next_irq_trigger:	array of next IRQ trigger function configurations
>   * @synchronous_mode:	array of index function synchronous mode configurations
>   * @index_polarity:	array of index function polarity configurations
>   * @cable_fault_enable:	differential encoder cable status enable configurations
> @@ -53,13 +60,17 @@ struct quad8 {
>  	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
>  	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
>  	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
> +	unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
> +	unsigned int next_irq_trigger[QUAD8_NUM_COUNTERS];
>  	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
>  	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
>  	unsigned int cable_fault_enable;
>  	unsigned int base;
>  };
>  
> +#define QUAD8_REG_INTERRUPT_STATUS 0x10
>  #define QUAD8_REG_CHAN_OP 0x11
> +#define QUAD8_REG_INDEX_INTERRUPT 0x12
>  #define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
>  #define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
>  /* Borrow Toggle flip-flop */
> @@ -92,8 +103,8 @@ struct quad8 {
>  #define QUAD8_RLD_CNTR_OUT 0x10
>  /* Transfer Preset Register LSB to FCK Prescaler */
>  #define QUAD8_RLD_PRESET_PSC 0x18
> -#define QUAD8_CHAN_OP_ENABLE_COUNTERS 0x00

This seems like an unrelated change...

>  #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
> +#define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
>  #define QUAD8_CMR_QUADRATURE_X1 0x08
>  #define QUAD8_CMR_QUADRATURE_X2 0x10
>  #define QUAD8_CMR_QUADRATURE_X4 0x18
> @@ -380,13 +391,103 @@ static int quad8_action_read(struct counter_device *counter,
>  	return 0;
>  }

...

>  static int quad8_probe(struct device *dev, unsigned int id)
>  {
>  	struct quad8 *priv;
>  	int i, j;
>  	unsigned int base_offset;
> +	int err;
>  
>  	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
>  		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
> @@ -1011,6 +1157,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
>  
>  	raw_spin_lock_init(&priv->lock);
>  
> +	/* Reset Index/Interrupt Register */
> +	outb(0x00, base[id] + QUAD8_REG_INDEX_INTERRUPT);
>  	/* Reset all counters and disable interrupt function */
>  	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
>  	/* Set initial configuration for all counters */
> @@ -1037,13 +1185,19 @@ static int quad8_probe(struct device *dev, unsigned int id)
>  		outb(QUAD8_CTR_IOR, base_offset + 1);
>  		/* Disable index function; negative index polarity */
>  		outb(QUAD8_CTR_IDR, base_offset + 1);
> +		/* Initialize next IRQ trigger function configuration */
> +		priv->next_irq_trigger[i] = QUAD8_EVENT_NONE;
>  	}
>  	/* Disable Differential Encoder Cable Status for all channels */
>  	outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
> -	/* Enable all counters */
> -	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
> +	/* Enable all counters and enable interrupt function */
> +	outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
> +
> +	err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
> +			       priv->counter.name, priv);
> +	if (err)
> +		return err;
>  
> -	/* Register Counter device */

Whilst I would agree with removing this comment as being pointless
as it's obvious, it doesn't really belong in this patch.

>  	return devm_counter_register(dev, &priv->counter);
>  }
>  
> diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
> index 1391e8ea64fe..b0f8fef18b51 100644
> --- a/drivers/counter/Kconfig
> +++ b/drivers/counter/Kconfig
> @@ -23,11 +23,11 @@ config 104_QUAD_8
>  	  A counter's respective error flag may be cleared by performing a write
>  	  operation on the respective count value attribute. Although the
>  	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
> -	  set, either directly or via the counter's preset attribute. Interrupts
> -	  are not supported by this driver.
> +	  set, either directly or via the counter's preset attribute.
>  
>  	  The base port addresses for the devices may be configured via the base
> -	  array module parameter.
> +	  array module parameter. The interrupt line numbers for the devices may
> +	  be configured via the irq array module parameter.
>  
>  config STM32_TIMER_CNT
>  	tristate "STM32 Timer encoder counter driver"

Re: [PATCH v8 22/22] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8

[William Breathitt Gray]

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On Sun, Feb 14, 2021 at 06:24:59PM +0000, Jonathan Cameron wrote:
> On Fri, 12 Feb 2021 21:13:46 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > The LSI/CSI LS7266R1 chip provides programmable output via the FLG pins.
> > When interrupts are enabled on the ACCES 104-QUAD-8, they occur whenever
> > FLG1 is active. Four functions are available for the FLG1 signal: Carry,
> > Compare, Carry-Borrow, and Index.
> > 
> > 	Carry:
> > 		Interrupt generated on active low Carry signal. Carry
> > 		signal toggles every time the respective channel's
> > 		counter overflows.
> > 
> > 	Compare:
> > 		Interrupt generated on active low Compare signal.
> > 		Compare signal toggles every time respective channel's
> > 		preset register is equal to the respective channel's
> > 		counter.
> > 
> > 	Carry-Borrow:
> > 		Interrupt generated on active low Carry signal and
> > 		active low Borrow signal. Carry signal toggles every
> > 		time the respective channel's counter overflows. Borrow
> > 		signal toggles every time the respective channel's
> > 		counter underflows.
> > 
> > 	Index:
> > 		Interrupt generated on active high Index signal.
> > 
> > These four functions correspond respectivefly to the following four
> > Counter event types: COUNTER_EVENT_OVERFLOW, COUNTER_EVENT_THRESHOLD,
> > COUNTER_EVENT_OVERFLOW_UNDERFLOW, and COUNTER_EVENT_INDEX. Interrupts
> > push Counter events to event channel X, where 'X' is the respective
> > channel whose FLG1 activated.
> > 
> > This patch adds IRQ support for the ACCES 104-QUAD-8. The interrupt line
> > numbers for the devices may be configured via the irq array module
> > parameter.
> > 
> > Cc: Syed Nayyar Waris <syednwaris@gmail.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> 
> A few minor bits inline.
> 
> Jonathan
> 
> > ---
> >  drivers/counter/104-quad-8.c | 170 +++++++++++++++++++++++++++++++++--
> >  drivers/counter/Kconfig      |   6 +-
> >  2 files changed, 165 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> > index 2b47f9991acc..45090cd9f813 100644
> > --- a/drivers/counter/104-quad-8.c
> > +++ b/drivers/counter/104-quad-8.c
> > @@ -11,6 +11,7 @@
> >  #include <linux/errno.h>
> >  #include <linux/io.h>
> >  #include <linux/ioport.h>
> > +#include <linux/interrupt.h>
> >  #include <linux/isa.h>
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> > @@ -25,11 +26,15 @@ static unsigned int num_quad8;
> >  module_param_hw_array(base, uint, ioport, &num_quad8, 0);
> >  MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
> >  
> > +static unsigned int irq[max_num_isa_dev(QUAD8_EXTENT)];
> > +module_param_hw_array(irq, uint, irq, NULL, 0);
> > +MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
> > +
> >  #define QUAD8_NUM_COUNTERS 8
> >  
> >  /**
> >   * struct quad8 - device private data structure
> > - * @lock:		synchronization lock to prevent I/O race conditions
> > + * @lock:		lock to prevent clobbering device states during R/W ops
> >   * @counter:		instance of the counter_device
> >   * @fck_prescaler:	array of filter clock prescaler configurations
> >   * @preset:		array of preset values
> > @@ -38,6 +43,8 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
> >   * @quadrature_scale:	array of quadrature mode scale configurations
> >   * @ab_enable:		array of A and B inputs enable configurations
> >   * @preset_enable:	array of set_to_preset_on_index attribute configurations
> > + * @irq_trigger:	array of current IRQ trigger function configurations
> > + * @next_irq_trigger:	array of next IRQ trigger function configurations
> >   * @synchronous_mode:	array of index function synchronous mode configurations
> >   * @index_polarity:	array of index function polarity configurations
> >   * @cable_fault_enable:	differential encoder cable status enable configurations
> > @@ -53,13 +60,17 @@ struct quad8 {
> >  	unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
> >  	unsigned int ab_enable[QUAD8_NUM_COUNTERS];
> >  	unsigned int preset_enable[QUAD8_NUM_COUNTERS];
> > +	unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
> > +	unsigned int next_irq_trigger[QUAD8_NUM_COUNTERS];
> >  	unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
> >  	unsigned int index_polarity[QUAD8_NUM_COUNTERS];
> >  	unsigned int cable_fault_enable;
> >  	unsigned int base;
> >  };
> >  
> > +#define QUAD8_REG_INTERRUPT_STATUS 0x10
> >  #define QUAD8_REG_CHAN_OP 0x11
> > +#define QUAD8_REG_INDEX_INTERRUPT 0x12
> >  #define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
> >  #define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
> >  /* Borrow Toggle flip-flop */
> > @@ -92,8 +103,8 @@ struct quad8 {
> >  #define QUAD8_RLD_CNTR_OUT 0x10
> >  /* Transfer Preset Register LSB to FCK Prescaler */
> >  #define QUAD8_RLD_PRESET_PSC 0x18
> > -#define QUAD8_CHAN_OP_ENABLE_COUNTERS 0x00
> 
> This seems like an unrelated change...

This register has a bit to enable the interrupt functions in addition to
the counters. When I first introduced these macro defines, I ignored
mentioning the interrupt functionality because we weren't supporting IRQ
at the time. The change in this patch here is actually a rename of this
register configuration with the new respective bit now properly enabled:
QUAD8_CHAN_OP_ENABLE_COUNTERS -> QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC.

> >  #define QUAD8_CHAN_OP_RESET_COUNTERS 0x01
> > +#define QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC 0x04
> >  #define QUAD8_CMR_QUADRATURE_X1 0x08
> >  #define QUAD8_CMR_QUADRATURE_X2 0x10
> >  #define QUAD8_CMR_QUADRATURE_X4 0x18
> > @@ -380,13 +391,103 @@ static int quad8_action_read(struct counter_device *counter,
> >  	return 0;
> >  }
> 
> ...
> 
> >  static int quad8_probe(struct device *dev, unsigned int id)
> >  {
> >  	struct quad8 *priv;
> >  	int i, j;
> >  	unsigned int base_offset;
> > +	int err;
> >  
> >  	if (!devm_request_region(dev, base[id], QUAD8_EXTENT, dev_name(dev))) {
> >  		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
> > @@ -1011,6 +1157,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
> >  
> >  	raw_spin_lock_init(&priv->lock);
> >  
> > +	/* Reset Index/Interrupt Register */
> > +	outb(0x00, base[id] + QUAD8_REG_INDEX_INTERRUPT);
> >  	/* Reset all counters and disable interrupt function */
> >  	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
> >  	/* Set initial configuration for all counters */
> > @@ -1037,13 +1185,19 @@ static int quad8_probe(struct device *dev, unsigned int id)
> >  		outb(QUAD8_CTR_IOR, base_offset + 1);
> >  		/* Disable index function; negative index polarity */
> >  		outb(QUAD8_CTR_IDR, base_offset + 1);
> > +		/* Initialize next IRQ trigger function configuration */
> > +		priv->next_irq_trigger[i] = QUAD8_EVENT_NONE;
> >  	}
> >  	/* Disable Differential Encoder Cable Status for all channels */
> >  	outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
> > -	/* Enable all counters */
> > -	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
> > +	/* Enable all counters and enable interrupt function */
> > +	outb(QUAD8_CHAN_OP_ENABLE_INTERRUPT_FUNC, base[id] + QUAD8_REG_CHAN_OP);
> > +
> > +	err = devm_request_irq(dev, irq[id], quad8_irq_handler, IRQF_SHARED,
> > +			       priv->counter.name, priv);
> > +	if (err)
> > +		return err;
> >  
> > -	/* Register Counter device */
> 
> Whilst I would agree with removing this comment as being pointless
> as it's obvious, it doesn't really belong in this patch.

I'll move this to its own patch.

William Breathitt Gray

> >  	return devm_counter_register(dev, &priv->counter);
> >  }
> >  
> > diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
> > index 1391e8ea64fe..b0f8fef18b51 100644
> > --- a/drivers/counter/Kconfig
> > +++ b/drivers/counter/Kconfig
> > @@ -23,11 +23,11 @@ config 104_QUAD_8
> >  	  A counter's respective error flag may be cleared by performing a write
> >  	  operation on the respective count value attribute. Although the
> >  	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
> > -	  set, either directly or via the counter's preset attribute. Interrupts
> > -	  are not supported by this driver.
> > +	  set, either directly or via the counter's preset attribute.
> >  
> >  	  The base port addresses for the devices may be configured via the base
> > -	  array module parameter.
> > +	  array module parameter. The interrupt line numbers for the devices may
> > +	  be configured via the irq array module parameter.
> >  
> >  config STM32_TIMER_CNT
> >  	tristate "STM32 Timer encoder counter driver"
> 

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