[PATCH v11 00/33] Introduce the Counter character device interface

[PATCH v11 00/33] Introduce the Counter character device interface

[William Breathitt Gray]

Changes in v11:
 - Migrated Intel QEP to new interface
 - Context adjustments made for documentation

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_v11

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 (33):
  docs: counter: Consolidate Counter sysfs attributes documentation
  docs: counter: Fix spelling
  counter: 104-quad-8: Remove pointless comment
  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: interrupt-cnt: Add const qualifier for functions_list array
  counter: microchip-tcb-capture: Add const qualifier for functions_list
    array
  counter: stm32-lptimer-cnt: Add const qualifier for functions_list
    array
  counter: stm32-timer-cnt: 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: interrupt-cnt: Add const qualifier for actions_list array
  counter: microchip-tcb-capture: Add const qualifier for actions_list
    array
  counter: stm32-lptimer-cnt: Add const qualifier for actions_list array
  counter: stm32-timer-cnt: 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
  tools/counter: Create Counter tools
  counter: Implement signalZ_action_component_id sysfs attribute
  counter: Implement *_component_id 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   |  112 +-
 .../ABI/testing/sysfs-bus-counter-104-quad-8  |   61 -
 .../ABI/testing/sysfs-bus-counter-ftm-quaddec |   16 -
 Documentation/driver-api/generic-counter.rst  |  368 +++-
 .../userspace-api/ioctl/ioctl-number.rst      |    1 +
 MAINTAINERS                                   |    7 +-
 drivers/counter/104-quad-8.c                  |  739 ++++----
 drivers/counter/Kconfig                       |    6 +-
 drivers/counter/Makefile                      |    1 +
 drivers/counter/counter-chrdev.c              |  486 ++++++
 drivers/counter/counter-chrdev.h              |   14 +
 drivers/counter/counter-core.c                |  192 +++
 drivers/counter/counter-sysfs.c               |  953 +++++++++++
 drivers/counter/counter-sysfs.h               |   13 +
 drivers/counter/counter.c                     | 1496 -----------------
 drivers/counter/ftm-quaddec.c                 |   61 +-
 drivers/counter/intel-qep.c                   |  150 +-
 drivers/counter/interrupt-cnt.c               |   75 +-
 drivers/counter/microchip-tcb-capture.c       |  105 +-
 drivers/counter/stm32-lptimer-cnt.c           |  176 +-
 drivers/counter/stm32-timer-cnt.c             |  149 +-
 drivers/counter/ti-eqep.c                     |  221 +--
 include/linux/counter.h                       |  716 ++++----
 include/linux/counter_enum.h                  |   45 -
 include/uapi/linux/counter.h                  |  133 ++
 tools/Makefile                                |   13 +-
 tools/counter/Build                           |    1 +
 tools/counter/Makefile                        |   53 +
 tools/counter/counter_example.c               |   95 ++
 29 files changed, 3586 insertions(+), 2872 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
 create mode 100644 tools/counter/Build
 create mode 100644 tools/counter/Makefile
 create mode 100644 tools/counter/counter_example.c

-- 
2.32.0


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[PATCH v11 01/33] 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>
Reviewed-by: David Lechner <david@lechnology.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 e9d9e50f03be..20fe5afd4f9e 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
@@ -224,11 +234,45 @@ 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
@@ -237,3 +281,31 @@ 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 e679d422b472..8fa9202610c5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -299,7 +299,6 @@ 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
@@ -4675,7 +4674,7 @@ 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
@@ -7087,7 +7086,6 @@ 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
 
-- 
2.32.0


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Re: [PATCH v11 01/33] docs: counter: Consolidate Counter sysfs attributes documentation

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:04 +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.
> 
> Cc: Patrick Havelange <patrick.havelange@essensium.com>
> Reviewed-by: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to see if they find anything that we missed.

Thanks,

Jonathan

> ---
>  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 e9d9e50f03be..20fe5afd4f9e 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
> @@ -224,11 +234,45 @@ 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
> @@ -237,3 +281,31 @@ 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 e679d422b472..8fa9202610c5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -299,7 +299,6 @@ 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
> @@ -4675,7 +4674,7 @@ 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
> @@ -7087,7 +7086,6 @@ 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
>  


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[PATCH v11 02/33] docs: counter: Fix spelling

[William Breathitt Gray]

"Miscellaneous" is the correct spelling.

Reviewed-by: David Lechner <david@lechnology.com>
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":
-- 
2.32.0


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Re: [PATCH v11 02/33] docs: counter: Fix spelling

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:05 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> "Miscellaneous" is the correct spelling.
> 
> Reviewed-by: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.
> ---
>  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":


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[PATCH v11 03/33] counter: 104-quad-8: Remove pointless comment

[William Breathitt Gray]

It is obvious that devm_counter_register() is used to register a Counter
device, so a comment stating such is pointless here.

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

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 9691f8612be8..4bb9abffae48 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -1082,7 +1082,6 @@ static int quad8_probe(struct device *dev, unsigned int id)
 	/* Enable all counters */
 	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
 
-	/* Register Counter device */
 	return devm_counter_register(dev, &priv->counter);
 }
 
-- 
2.32.0


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Re: [PATCH v11 03/33] counter: 104-quad-8: Remove pointless comment

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:06 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> It is obvious that devm_counter_register() is used to register a Counter
> device, so a comment stating such is pointless here.
> 
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.
> ---
>  drivers/counter/104-quad-8.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 9691f8612be8..4bb9abffae48 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -1082,7 +1082,6 @@ static int quad8_probe(struct device *dev, unsigned int id)
>  	/* Enable all counters */
>  	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
>  
> -	/* Register Counter device */
>  	return devm_counter_register(dev, &priv->counter);
>  }
>  


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[PATCH v11 04/33] 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")
Acked-by: 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 4bb9abffae48..233a3acc1377 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,
-- 
2.32.0


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Re: [PATCH v11 04/33] counter: 104-quad-8: Return error when invalid mode during ceiling_write

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:07 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> 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")
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

We seem to have some inconsistency in the driver about whether
we hold the priv->lock when calling quad8_preset_register_set()

Can we look to make that consistent?

> ---
>  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 4bb9abffae48..233a3acc1377 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);

Probably swap this line and the next one...]

>  		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,


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Re: [PATCH v11 04/33] counter: 104-quad-8: Return error when invalid mode during ceiling_write

[William Breathitt Gray]

[-- Attachment #1.1: Type: text/plain, Size: 1927 bytes --]

On Wed, Jun 09, 2021 at 04:12:36PM +0100, Jonathan Cameron wrote:
> On Wed,  9 Jun 2021 10:31:07 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> 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")
> > Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> 
> We seem to have some inconsistency in the driver about whether
> we hold the priv->lock when calling quad8_preset_register_set()
> 
> Can we look to make that consistent?

We do need to hold the lock when calling quad8_preset_register_set()
lest priv->preset goes out of sync with the device state.

Syed, if you have no objections I'll adjust this in the next version.

William Breathitt Gray

> > ---
> >  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 4bb9abffae48..233a3acc1377 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);
> 
> Probably swap this line and the next one...]
> 
> >  		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,
> 

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

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[PATCH v11 05/33] 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.

Acked-by: 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 233a3acc1377..0fd61cc82d30 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
-- 
2.32.0


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Re: [PATCH v11 05/33] counter: 104-quad-8: Annotate hardware config module parameter

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:08 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> 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.
> 
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
As this has no dependency on patch 4, I've applied it.

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to poke at it.

Thanks,

Jonathan

> ---
>  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 233a3acc1377..0fd61cc82d30 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


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[PATCH v11 06/33] 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.

Acked-by: 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 0fd61cc82d30..51fba8cf9c2a 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;
-- 
2.32.0


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Re: [PATCH v11 06/33] counter: 104-quad-8: Add const qualifiers for quad8_preset_register_set

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:09 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> Add some safety by qualifying the quad8_preset_register_set() function
> parameters as const.
> 
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied
(no clash with patch 4)
> ---
>  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 0fd61cc82d30..51fba8cf9c2a 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;


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[PATCH v11 07/33] 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_count_functions_list to match functions_list.

Acked-by: 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 51fba8cf9c2a..ae89ad7a91c6 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_count_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,
-- 
2.32.0


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Re: [PATCH v11 07/33] counter: 104-quad-8: Add const qualifier for functions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:10 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_count functions_list member expects a const enum
> counter_count_function array. This patch adds the const qualifier to the
> quad8_count_functions_list to match functions_list.
> 
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied,
> ---
>  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 51fba8cf9c2a..ae89ad7a91c6 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_count_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,


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[PATCH v11 08/33] counter: interrupt-cnt: 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
interrupt__cnt_functions to match functions_list.

Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/interrupt-cnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
index a99ee7996977..827d785e19b4 100644
--- a/drivers/counter/interrupt-cnt.c
+++ b/drivers/counter/interrupt-cnt.c
@@ -112,7 +112,7 @@ static int interrupt_cnt_write(struct counter_device *counter,
 	return 0;
 }
 
-static enum counter_count_function interrupt_cnt_functions[] = {
+static const enum counter_count_function interrupt_cnt_functions[] = {
 	COUNTER_COUNT_FUNCTION_INCREASE,
 };
 
-- 
2.32.0


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Re: [PATCH v11 08/33] counter: interrupt-cnt: Add const qualifier for functions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:11 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_count functions_list member expects a const enum
> counter_count_function array. This patch adds the const qualifier to the
> interrupt__cnt_functions to match functions_list.
> 
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied
> ---
>  drivers/counter/interrupt-cnt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
> index a99ee7996977..827d785e19b4 100644
> --- a/drivers/counter/interrupt-cnt.c
> +++ b/drivers/counter/interrupt-cnt.c
> @@ -112,7 +112,7 @@ static int interrupt_cnt_write(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static enum counter_count_function interrupt_cnt_functions[] = {
> +static const enum counter_count_function interrupt_cnt_functions[] = {
>  	COUNTER_COUNT_FUNCTION_INCREASE,
>  };
>  


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[PATCH v11 09/33] counter: microchip-tcb-capture: 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
mchp_tc_count_functions to match functions_list.

Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/microchip-tcb-capture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 710acc0a3704..cabcfebfc799 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -37,7 +37,7 @@ enum mchp_tc_count_function {
 	MCHP_TC_FUNCTION_QUADRATURE,
 };
 
-static enum counter_count_function mchp_tc_count_functions[] = {
+static const 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,
 };
-- 
2.32.0


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Re: [PATCH v11 09/33] counter: microchip-tcb-capture: Add const qualifier for functions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:12 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_count functions_list member expects a const enum
> counter_count_function array. This patch adds the const qualifier to the
> mchp_tc_count_functions to match functions_list.
> 
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.

> ---
>  drivers/counter/microchip-tcb-capture.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
> index 710acc0a3704..cabcfebfc799 100644
> --- a/drivers/counter/microchip-tcb-capture.c
> +++ b/drivers/counter/microchip-tcb-capture.c
> @@ -37,7 +37,7 @@ enum mchp_tc_count_function {
>  	MCHP_TC_FUNCTION_QUADRATURE,
>  };
>  
> -static enum counter_count_function mchp_tc_count_functions[] = {
> +static const 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,
>  };


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[PATCH v11 10/33] counter: stm32-lptimer-cnt: 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
stm32_lptim_cnt_functions to match functions_list.

Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/stm32-lptimer-cnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 937439635d53..0f7d3f1ec1b6 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -134,7 +134,7 @@ enum stm32_lptim_cnt_function {
 	STM32_LPTIM_ENCODER_BOTH_EDGE,
 };
 
-static enum counter_count_function stm32_lptim_cnt_functions[] = {
+static const 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,
 };
-- 
2.32.0


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Re: [PATCH v11 10/33] counter: stm32-lptimer-cnt: Add const qualifier for functions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:13 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_count functions_list member expects a const enum
> counter_count_function array. This patch adds the const qualifier to the
> stm32_lptim_cnt_functions to match functions_list.
> 
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.

btw a different reasoning for all of these is that static const is
read only and will let linker and compiler do various tricks that it can't
do otherwise.

Jonathan

> ---
>  drivers/counter/stm32-lptimer-cnt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index 937439635d53..0f7d3f1ec1b6 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -134,7 +134,7 @@ enum stm32_lptim_cnt_function {
>  	STM32_LPTIM_ENCODER_BOTH_EDGE,
>  };
>  
> -static enum counter_count_function stm32_lptim_cnt_functions[] = {
> +static const 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,
>  };


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[PATCH v11 11/33] counter: stm32-timer-cnt: 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
stm32_count_functions to match functions_list.

Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/stm32-timer-cnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 75bc401fdd18..0c18573a7837 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -50,7 +50,7 @@ enum stm32_count_function {
 	STM32_COUNT_ENCODER_MODE_3,
 };
 
-static enum counter_count_function stm32_count_functions[] = {
+static const enum counter_count_function stm32_count_functions[] = {
 	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_COUNT_FUNCTION_INCREASE,
 	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
 	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
-- 
2.32.0


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Re: [PATCH v11 11/33] counter: stm32-timer-cnt: Add const qualifier for functions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:14 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_count functions_list member expects a const enum
> counter_count_function array. This patch adds the const qualifier to the
> stm32_count_functions to match functions_list.
> 
> Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied. Thanks
> ---
>  drivers/counter/stm32-timer-cnt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> index 75bc401fdd18..0c18573a7837 100644
> --- a/drivers/counter/stm32-timer-cnt.c
> +++ b/drivers/counter/stm32-timer-cnt.c
> @@ -50,7 +50,7 @@ enum stm32_count_function {
>  	STM32_COUNT_ENCODER_MODE_3,
>  };
>  
> -static enum counter_count_function stm32_count_functions[] = {
> +static const enum counter_count_function stm32_count_functions[] = {
>  	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_COUNT_FUNCTION_INCREASE,
>  	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
>  	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,


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[PATCH v11 12/33] 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.

Acked-by: 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 ae89ad7a91c6..09d779544969 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,
-- 
2.32.0


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Re: [PATCH v11 12/33] counter: 104-quad-8: Add const qualifier for actions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:15 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> 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.
> 
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied

Thanks,
> ---
>  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 ae89ad7a91c6..09d779544969 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,


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[PATCH v11 13/33] 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
 };
-- 
2.32.0


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Re: [PATCH v11 13/33] counter: ftm-quaddec: Add const qualifier for actions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:16 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> 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>
Applied.

Thanks,

Jonathan

> ---
>  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
>  };


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[PATCH v11 14/33] counter: interrupt-cnt: 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
interrupt_cnt_synapse_actionss to match actions_list.

Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/interrupt-cnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
index 827d785e19b4..0e07607f2cd3 100644
--- a/drivers/counter/interrupt-cnt.c
+++ b/drivers/counter/interrupt-cnt.c
@@ -77,7 +77,7 @@ static const struct counter_count_ext interrupt_cnt_ext[] = {
 	},
 };
 
-static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
+static const enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 };
 
-- 
2.32.0


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Re: [PATCH v11 14/33] counter: interrupt-cnt: Add const qualifier for actions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:17 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_synapse actions_list member expects a const enum
> counter_synapse_action array. This patch adds the const qualifier to the
> interrupt_cnt_synapse_actionss to match actions_list.
> 
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Naming looks unusual...

> ---
>  drivers/counter/interrupt-cnt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
> index 827d785e19b4..0e07607f2cd3 100644
> --- a/drivers/counter/interrupt-cnt.c
> +++ b/drivers/counter/interrupt-cnt.c
> @@ -77,7 +77,7 @@ static const struct counter_count_ext interrupt_cnt_ext[] = {
>  	},
>  };
>  
> -static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
> +static const enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {

actions?

Perhaps good to fix that whilst we are here.

>  	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
>  };
>  


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Re: [PATCH v11 14/33] counter: interrupt-cnt: Add const qualifier for actions_list array

[William Breathitt Gray]

[-- Attachment #1.1: Type: text/plain, Size: 1434 bytes --]

On Wed, Jun 09, 2021 at 04:29:42PM +0100, Jonathan Cameron wrote:
> On Wed,  9 Jun 2021 10:31:17 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > The struct counter_synapse actions_list member expects a const enum
> > counter_synapse_action array. This patch adds the const qualifier to the
> > interrupt_cnt_synapse_actionss to match actions_list.
> > 
> > Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> Naming looks unusual...
> 
> > ---
> >  drivers/counter/interrupt-cnt.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
> > index 827d785e19b4..0e07607f2cd3 100644
> > --- a/drivers/counter/interrupt-cnt.c
> > +++ b/drivers/counter/interrupt-cnt.c
> > @@ -77,7 +77,7 @@ static const struct counter_count_ext interrupt_cnt_ext[] = {
> >  	},
> >  };
> >  
> > -static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
> > +static const enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
> 
> actions?
> 
> Perhaps good to fix that whilst we are here.
> 
> >  	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> >  };
> >  

Hi Oleksij,

Would you take a look at this driver and let us know whether the two 's'
at the end of this symbol is intentional?

Thanks,

William Breathitt Gray

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[PATCH v11 15/33] counter: microchip-tcb-capture: 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
mchp_tc_synapse_actions to match actions_list.

Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/microchip-tcb-capture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index cabcfebfc799..51b8af80f98b 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -49,7 +49,7 @@ enum mchp_tc_synapse_action {
 	MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE
 };
 
-static enum counter_synapse_action mchp_tc_synapse_actions[] = {
+static const 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,
-- 
2.32.0


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Re: [PATCH v11 15/33] counter: microchip-tcb-capture: Add const qualifier for actions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:18 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_synapse actions_list member expects a const enum
> counter_synapse_action array. This patch adds the const qualifier to the
> mchp_tc_synapse_actions to match actions_list.
> 
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.
Thanks
> ---
>  drivers/counter/microchip-tcb-capture.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
> index cabcfebfc799..51b8af80f98b 100644
> --- a/drivers/counter/microchip-tcb-capture.c
> +++ b/drivers/counter/microchip-tcb-capture.c
> @@ -49,7 +49,7 @@ enum mchp_tc_synapse_action {
>  	MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE
>  };
>  
> -static enum counter_synapse_action mchp_tc_synapse_actions[] = {
> +static const 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,


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[PATCH v11 16/33] counter: stm32-lptimer-cnt: 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
stm32_lptim_cnt_synapse_actions to match actions_list.

Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/stm32-lptimer-cnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 0f7d3f1ec1b6..c19d998df5ba 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -146,7 +146,7 @@ enum stm32_lptim_synapse_action {
 	STM32_LPTIM_SYNAPSE_ACTION_NONE,
 };
 
-static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
+static const enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
 	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
 	[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 	[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
-- 
2.32.0


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Re: [PATCH v11 16/33] counter: stm32-lptimer-cnt: Add const qualifier for actions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:19 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_synapse actions_list member expects a const enum
> counter_synapse_action array. This patch adds the const qualifier to the
> stm32_lptim_cnt_synapse_actions to match actions_list.
> 
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.

Thanks,

J
> ---
>  drivers/counter/stm32-lptimer-cnt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index 0f7d3f1ec1b6..c19d998df5ba 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -146,7 +146,7 @@ enum stm32_lptim_synapse_action {
>  	STM32_LPTIM_SYNAPSE_ACTION_NONE,
>  };
>  
> -static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
> +static const enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
>  	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
>  	[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
>  	[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,


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[PATCH v11 17/33] counter: stm32-timer-cnt: 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
stm32_synapse_actions to match actions_list.

Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/stm32-timer-cnt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 0c18573a7837..603b30ada839 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -267,7 +267,7 @@ enum stm32_synapse_action {
 	STM32_SYNAPSE_ACTION_BOTH_EDGES
 };
 
-static enum counter_synapse_action stm32_synapse_actions[] = {
+static const 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
 };
-- 
2.32.0


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Re: [PATCH v11 17/33] counter: stm32-timer-cnt: Add const qualifier for actions_list array

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:20 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> The struct counter_synapse actions_list member expects a const enum
> counter_synapse_action array. This patch adds the const qualifier to the
> stm32_synapse_actions to match actions_list.
> 
> Cc: Benjamin Gaignard <benjamin.gaignard@st.com>
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Applied.

> ---
>  drivers/counter/stm32-timer-cnt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> index 0c18573a7837..603b30ada839 100644
> --- a/drivers/counter/stm32-timer-cnt.c
> +++ b/drivers/counter/stm32-timer-cnt.c
> @@ -267,7 +267,7 @@ enum stm32_synapse_action {
>  	STM32_SYNAPSE_ACTION_BOTH_EDGES
>  };
>  
> -static enum counter_synapse_action stm32_synapse_actions[] = {
> +static const 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
>  };


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[PATCH v11 18/33] 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: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: David Lechner <david@lechnology.com>
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c            | 20 +++++++----
 drivers/counter/microchip-tcb-capture.c |  6 ++++
 drivers/counter/stm32-lptimer-cnt.c     | 10 +++---
 drivers/counter/ti-eqep.c               | 45 +++++++++++--------------
 4 files changed, 46 insertions(+), 35 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 09d779544969..b7d6c1c43655 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;
 		}
 	}
 
@@ -349,7 +353,7 @@ static int quad8_action_get(struct counter_device *counter,
 	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
 		if (synapse->signal->id == signal_a_id)
 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
-		break;
+		return 0;
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
 		if (synapse->signal->id == signal_a_id) {
 			quad8_direction_get(counter, count, &direction);
@@ -359,17 +363,18 @@ static int quad8_action_get(struct counter_device *counter,
 			else
 				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
 		}
-		break;
+		return 0;
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
 		if (synapse->signal->id == signal_a_id)
 			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
-		break;
+		return 0;
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
 		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
-		break;
+		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return 0;
 }
 
 static const struct counter_ops quad8_ops = {
@@ -529,6 +534,9 @@ 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 51b8af80f98b..0c9a61962911 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 c19d998df5ba..78f383b77bd2 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/ti-eqep.c b/drivers/counter/ti-eqep.c
index 65df9ef5b5bc..878725c2f010 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -157,44 +157,39 @@ static int ti_eqep_action_get(struct counter_device *counter,
 		 * QEPA and QEPB trigger QCLK.
 		 */
 		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
-		break;
+		return 0;
 	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
 		/* 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;
-			break;
-		default:
+		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB)
 			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
-			break;
-		}
-		break;
+		else
+			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+		return 0;
 	case TI_EQEP_COUNT_FUNC_UP_COUNT:
 	case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
 		/* In up/down-count modes only QEPA is counted and QEPB is not
 		 * used.
 		 */
-		switch (synapse->signal->id) {
-		case TI_EQEP_SIGNAL_QEPA:
-			err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
-			if (err)
-				return err;
-
-			if (qdecctl & QDECCTL_XCR)
-				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
-			else
-				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
-			break;
-		default:
+		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB) {
 			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
-			break;
+			return 0;
 		}
-		break;
-	}
 
-	return 0;
+		err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
+		if (err)
+			return err;
+
+		if (qdecctl & QDECCTL_XCR)
+			*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
+		else
+			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
+	}
 }
 
 static const struct counter_ops ti_eqep_counter_ops = {
-- 
2.32.0


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Re: [PATCH v11 18/33] counter: Return error code on invalid modes

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:21 +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.
> 
> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: David Lechner <david@lechnology.com>
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

Hi,

I've been lazy and not looked at these in sufficient depth before now :(

There are a few cases in here that I think could be handled more
elegantly and in a fashion more likely to expose potential bugs
if enums change number of entries in future etc.

I've very keen on a compiler being able to see when we have a
switch on an enum.

Jonathan


> ---
>  drivers/counter/104-quad-8.c            | 20 +++++++----
>  drivers/counter/microchip-tcb-capture.c |  6 ++++
>  drivers/counter/stm32-lptimer-cnt.c     | 10 +++---
>  drivers/counter/ti-eqep.c               | 45 +++++++++++--------------
>  4 files changed, 46 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 09d779544969..b7d6c1c43655 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;
>  		}
>  	}
>  
> @@ -349,7 +353,7 @@ static int quad8_action_get(struct counter_device *counter,
>  	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
>  		if (synapse->signal->id == signal_a_id)
>  			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
> -		break;
> +		return 0;
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
>  		if (synapse->signal->id == signal_a_id) {
>  			quad8_direction_get(counter, count, &direction);
> @@ -359,17 +363,18 @@ static int quad8_action_get(struct counter_device *counter,
>  			else
>  				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
>  		}
> -		break;
> +		return 0;
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
>  		if (synapse->signal->id == signal_a_id)
>  			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
> -		break;
> +		return 0;
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
>  		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
> -		break;
> +		return 0;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
>  	}
> -
> -	return 0;
>  }
>  
>  static const struct counter_ops quad8_ops = {
> @@ -529,6 +534,9 @@ 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 51b8af80f98b..0c9a61962911 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 c19d998df5ba..78f383b77bd2 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;

In this particular case we are already exhaustive.  So we should have neither default
nor ideally the return below.  

If we have a local variable of the relevant enum type, then I think the compiler
should be able to tell this is exhaustive and usefully it will then issue
a warning should the enum gain more entries in future.

>  	}
> -
> -	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:

Same in this path.

> +		/* 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/ti-eqep.c b/drivers/counter/ti-eqep.c
> index 65df9ef5b5bc..878725c2f010 100644
> --- a/drivers/counter/ti-eqep.c
> +++ b/drivers/counter/ti-eqep.c
> @@ -157,44 +157,39 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  		 * QEPA and QEPB trigger QCLK.
>  		 */
>  		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> -		break;
> +		return 0;
>  	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
>  		/* In direction-count mode only rising edge of QEPA is counted
>  		 * and QEPB gives direction.
>  		 */
> -		switch (synapse->signal->id) {
I'd rather see this as

case TI_EQEP_SIGNAL_QEPA:
caes TI_EQEP_SIGNAL_QEPB:

To make it clear what the two cases are.  Then we don't need the default
assuming the type is right so the compiler should be able to see
that we have been exhaustive.


> -		case TI_EQEP_SIGNAL_QEPA:
> -			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> -			break;
> -		default:
> +		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB)
>  			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
> -			break;
> -		}
> -		break;
> +		else
> +			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> +		return 0;
>  	case TI_EQEP_COUNT_FUNC_UP_COUNT:
>  	case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
>  		/* In up/down-count modes only QEPA is counted and QEPB is not
>  		 * used.
>  		 */
> -		switch (synapse->signal->id) {
> -		case TI_EQEP_SIGNAL_QEPA:
> -			err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
> -			if (err)
> -				return err;
> -
> -			if (qdecctl & QDECCTL_XCR)
> -				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> -			else
> -				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> -			break;
> -		default:
> +		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB) {
>  			*action = TI_EQEP_SYNAPSE_ACTION_NONE;

Same as above

> -			break;
> +			return 0;
>  		}
> -		break;
> -	}
>  
> -	return 0;
> +		err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
> +		if (err)
> +			return err;
> +
> +		if (qdecctl & QDECCTL_XCR)
> +			*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> +		else
> +			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> +		return 0;
> +	default:
> +		/* should never reach this path */
> +		return -EINVAL;
> +	}
>  }
>  
>  static const struct counter_ops ti_eqep_counter_ops = {


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Re: [PATCH v11 18/33] counter: Return error code on invalid modes

[William Breathitt Gray]

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On Wed, Jun 09, 2021 at 04:47:31PM +0100, Jonathan Cameron wrote:
> On Wed,  9 Jun 2021 10:31:21 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> > diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> > index c19d998df5ba..78f383b77bd2 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;
> 
> In this particular case we are already exhaustive.  So we should have neither default
> nor ideally the return below.  
> 
> If we have a local variable of the relevant enum type, then I think the compiler
> should be able to tell this is exhaustive and usefully it will then issue
> a warning should the enum gain more entries in future.

I tried using a local variable of type enum stm32_lptim_cnt_function,
but unfortunately the compiler is not able to tell this is exhaustive --
I think it's because 'function' is of type enum counter_function which
can theoretically have a value outside enum stm32_lptim_cnt_function.

> 
> >  	}
> > -
> > -	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:
> 
> Same in this path.
> 
> > +		/* 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/ti-eqep.c b/drivers/counter/ti-eqep.c
> > index 65df9ef5b5bc..878725c2f010 100644
> > --- a/drivers/counter/ti-eqep.c
> > +++ b/drivers/counter/ti-eqep.c
> > @@ -157,44 +157,39 @@ static int ti_eqep_action_get(struct counter_device *counter,
> >  		 * QEPA and QEPB trigger QCLK.
> >  		 */
> >  		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> > -		break;
> > +		return 0;
> >  	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
> >  		/* In direction-count mode only rising edge of QEPA is counted
> >  		 * and QEPB gives direction.
> >  		 */
> > -		switch (synapse->signal->id) {
> I'd rather see this as
> 
> case TI_EQEP_SIGNAL_QEPA:
> caes TI_EQEP_SIGNAL_QEPB:
> 
> To make it clear what the two cases are.  Then we don't need the default
> assuming the type is right so the compiler should be able to see
> that we have been exhaustive.

I can refactor this back to a switch statement as you suggest, but we'll
need the default case for the same reason as mentioned above.

William Breathitt Gray

> 
> > -		case TI_EQEP_SIGNAL_QEPA:
> > -			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> > -			break;
> > -		default:
> > +		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB)
> >  			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
> > -			break;
> > -		}
> > -		break;
> > +		else
> > +			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> > +		return 0;
> >  	case TI_EQEP_COUNT_FUNC_UP_COUNT:
> >  	case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
> >  		/* In up/down-count modes only QEPA is counted and QEPB is not
> >  		 * used.
> >  		 */
> > -		switch (synapse->signal->id) {
> > -		case TI_EQEP_SIGNAL_QEPA:
> > -			err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
> > -			if (err)
> > -				return err;
> > -
> > -			if (qdecctl & QDECCTL_XCR)
> > -				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> > -			else
> > -				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> > -			break;
> > -		default:
> > +		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB) {
> >  			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
> 
> Same as above
> 
> > -			break;
> > +			return 0;
> >  		}
> > -		break;
> > -	}
> >  
> > -	return 0;
> > +		err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
> > +		if (err)
> > +			return err;
> > +
> > +		if (qdecctl & QDECCTL_XCR)
> > +			*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> > +		else
> > +			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> > +		return 0;
> > +	default:
> > +		/* should never reach this path */
> > +		return -EINVAL;
> > +	}
> >  }
> >  
> >  static const struct counter_ops ti_eqep_counter_ops = {
> 

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[PATCH v11 19/33] 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: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Reviewed-by: David Lechner <david@lechnology.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c        | 6 +++---
 drivers/counter/intel-qep.c         | 2 +-
 drivers/counter/interrupt-cnt.c     | 3 +++
 drivers/counter/stm32-lptimer-cnt.c | 2 +-
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index b7d6c1c43655..0409b1771fd9 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);
 
@@ -669,7 +669,7 @@ 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);
 
@@ -714,7 +714,7 @@ 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/intel-qep.c b/drivers/counter/intel-qep.c
index ab10ba33f46a..7b4eb8ff8348 100644
--- a/drivers/counter/intel-qep.c
+++ b/drivers/counter/intel-qep.c
@@ -320,7 +320,7 @@ static ssize_t spike_filter_ns_write(struct counter_device *counter,
 	}
 
 	if (length > INTEL_QEPFLT_MAX_COUNT(length))
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&qep->lock);
 	if (qep->enabled) {
diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
index 0e07607f2cd3..f27dea317965 100644
--- a/drivers/counter/interrupt-cnt.c
+++ b/drivers/counter/interrupt-cnt.c
@@ -107,6 +107,9 @@ static int interrupt_cnt_write(struct counter_device *counter,
 {
 	struct interrupt_cnt_priv *priv = counter->priv;
 
+	if (val != (typeof(priv->count.counter))val)
+		return -ERANGE;
+
 	atomic_set(&priv->count, val);
 
 	return 0;
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 78f383b77bd2..49aeb9e393f3 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;
 
-- 
2.32.0


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[PATCH v11 20/33] 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: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Reviewed-by: David Lechner <david@lechnology.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/interrupt-cnt.c         |  4 ++--
 drivers/counter/microchip-tcb-capture.c |  4 ++--
 include/linux/counter.h                 | 12 ++++++------
 5 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 0409b1771fd9..fb0f021c0751 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/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
index f27dea317965..cce579c1c6ae 100644
--- a/drivers/counter/interrupt-cnt.c
+++ b/drivers/counter/interrupt-cnt.c
@@ -130,7 +130,7 @@ static int interrupt_cnt_function_get(struct counter_device *counter,
 
 static int interrupt_cnt_signal_read(struct counter_device *counter,
 				     struct counter_signal *signal,
-				     enum counter_signal_value *val)
+				     enum counter_signal_level *level)
 {
 	struct interrupt_cnt_priv *priv = counter->priv;
 	int ret;
@@ -142,7 +142,7 @@ static int interrupt_cnt_signal_read(struct counter_device *counter,
 	if (ret < 0)
 		return ret;
 
-	*val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+	*level = ret ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 
 	return 0;
 }
diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 0c9a61962911..6be3adf74114 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,
-- 
2.32.0


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[PATCH v11 21/33] 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.

Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: David Lechner <david@lechnology.com>
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c            | 10 +++----
 drivers/counter/counter.c               | 38 ++++++++++++-------------
 drivers/counter/ftm-quaddec.c           |  5 ++--
 drivers/counter/intel-qep.c             |  4 +--
 drivers/counter/interrupt-cnt.c         |  4 +--
 drivers/counter/microchip-tcb-capture.c |  4 +--
 drivers/counter/stm32-lptimer-cnt.c     |  6 ++--
 drivers/counter/stm32-timer-cnt.c       | 10 +++----
 drivers/counter/ti-eqep.c               | 10 +++----
 include/linux/counter.h                 | 20 ++++++-------
 10 files changed, 55 insertions(+), 56 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index fb0f021c0751..5a49ace2d4a6 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -194,11 +194,11 @@ enum quad8_count_function {
 	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
 };
 
-static const enum counter_count_function quad8_count_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_count_functions_list[] = {
+	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_FUNCTION_PULSE_DIRECTION,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_FUNCTION_QUADRATURE_X1_A,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 static int quad8_function_get(struct counter_device *counter,
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..53c15f84909b 100644
--- a/drivers/counter/ftm-quaddec.c
+++ b/drivers/counter/ftm-quaddec.c
@@ -171,9 +171,8 @@ enum ftm_quaddec_count_function {
 	FTM_QUADDEC_COUNT_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_count_functions[] = {
+	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 static int ftm_quaddec_count_read(struct counter_device *counter,
diff --git a/drivers/counter/intel-qep.c b/drivers/counter/intel-qep.c
index 7b4eb8ff8348..51f16ed1a7a0 100644
--- a/drivers/counter/intel-qep.c
+++ b/drivers/counter/intel-qep.c
@@ -127,8 +127,8 @@ static int intel_qep_count_read(struct counter_device *counter,
 	return 0;
 }
 
-static const enum counter_count_function intel_qep_count_functions[] = {
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+static const enum counter_function intel_qep_count_functions[] = {
+	COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 static int intel_qep_function_get(struct counter_device *counter,
diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
index cce579c1c6ae..3dbb8acc67eb 100644
--- a/drivers/counter/interrupt-cnt.c
+++ b/drivers/counter/interrupt-cnt.c
@@ -115,8 +115,8 @@ static int interrupt_cnt_write(struct counter_device *counter,
 	return 0;
 }
 
-static const enum counter_count_function interrupt_cnt_functions[] = {
-	COUNTER_COUNT_FUNCTION_INCREASE,
+static const enum counter_function interrupt_cnt_functions[] = {
+	COUNTER_FUNCTION_INCREASE,
 };
 
 static int interrupt_cnt_function_get(struct counter_device *counter,
diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 6be3adf74114..4c57d43e7d66 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -38,8 +38,8 @@ enum mchp_tc_count_function {
 };
 
 static const 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,
+	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_FUNCTION_INCREASE,
+	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 enum mchp_tc_synapse_action {
diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
index 49aeb9e393f3..13656957c45f 100644
--- a/drivers/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -134,9 +134,9 @@ enum stm32_lptim_cnt_function {
 	STM32_LPTIM_ENCODER_BOTH_EDGE,
 };
 
-static const 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 const enum counter_function stm32_lptim_cnt_functions[] = {
+	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_FUNCTION_INCREASE,
+	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 enum stm32_lptim_synapse_action {
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 603b30ada839..3fb0debd7425 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -50,11 +50,11 @@ enum stm32_count_function {
 	STM32_COUNT_ENCODER_MODE_3,
 };
 
-static const enum counter_count_function stm32_count_functions[] = {
-	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_COUNT_FUNCTION_INCREASE,
-	[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 const enum counter_function stm32_count_functions[] = {
+	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_FUNCTION_INCREASE,
+	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_FUNCTION_QUADRATURE_X2_B,
+	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 static int stm32_count_read(struct counter_device *counter,
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
index 878725c2f010..04be25ebf4a4 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -284,11 +284,11 @@ 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_COUNT_FUNC_QUAD_COUNT]	= COUNTER_FUNCTION_QUADRATURE_X4,
+	[TI_EQEP_COUNT_FUNC_DIR_COUNT]	= COUNTER_FUNCTION_PULSE_DIRECTION,
+	[TI_EQEP_COUNT_FUNC_UP_COUNT]	= COUNTER_FUNCTION_INCREASE,
+	[TI_EQEP_COUNT_FUNC_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;
-- 
2.32.0


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[PATCH v11 23/33] 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 e7dd6ea01c8a..407661c6feb0 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -41,6 +41,9 @@ 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 567471818ec3..e7fd6d81a929 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
-- 
2.32.0


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Re: [PATCH v11 23/33] counter: Update counter.h comments to reflect sysfs internalization

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:26 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> 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>

I'd rather see anything in here that isn't just tidy up moved back to the
earlier patches.

> ---
>  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 e7dd6ea01c8a..407661c6feb0 100644
> --- a/drivers/counter/counter-core.c
> +++ b/drivers/counter/counter-core.c
> @@ -41,6 +41,9 @@ 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 567471818ec3..e7fd6d81a929 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

I'm not keen on having a stage between patches where there
area things documented that don't exist. (e.g. priv)

>   */
>  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


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[PATCH v11 24/33] 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 20fe5afd4f9e..dee79b606847 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -286,7 +286,14 @@ 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.
-- 
2.32.0


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[PATCH v11 25/33] 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.

Reviewed-by: David Lechner <david@lechnology.com>
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 0acde40d682c..7e2ddf74bd7b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4678,6 +4678,7 @@ 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
 
 CP2615 I2C DRIVER
 M:	Bence Csókás <bence98@sch.bme.hu>
diff --git a/include/linux/counter.h b/include/linux/counter.h
index e7fd6d81a929..eee85db8e332 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_ */
-- 
2.32.0


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[PATCH v11 26/33] 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 | 482 +++++++++++++++++++++++++++++++
 drivers/counter/counter-chrdev.h |  14 +
 drivers/counter/counter-core.c   |  44 ++-
 include/linux/counter.h          |  45 +++
 include/uapi/linux/counter.h     |  77 +++++
 6 files changed, 658 insertions(+), 6 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 1ab7e087fdc2..8fde6c100ebc 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_INTERRUPT_CNT)		+= interrupt-cnt.o
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
new file mode 100644
index 000000000000..d5f92b2d3bb4
--- /dev/null
+++ b/drivers/counter/counter-chrdev.c
@@ -0,0 +1,482 @@
+// 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/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fs.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;
+
+	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);
+
+	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:
+		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);
+
+		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)
+{
+	/* Initialize Counter events lists */
+	INIT_LIST_HEAD(&counter->events_list);
+	INIT_LIST_HEAD(&counter->next_events_list);
+	spin_lock_init(&counter->events_list_lock);
+	init_waitqueue_head(&counter->events_wait);
+	mutex_init(&counter->events_lock);
+
+	/* Initialize character device */
+	cdev_init(&counter->chrdev, &counter_fops);
+
+	/* Allocate Counter events queue */
+	return kfifo_alloc(&counter->events, 64, GFP_ATOMIC);
+}
+
+void counter_chrdev_remove(struct counter_device *const counter)
+{
+	kfifo_free(&counter->events);
+}
+
+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 */
+	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:
+	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..5529d16703c4
--- /dev/null
+++ b/drivers/counter/counter-chrdev.h
@@ -0,0 +1,14 @@
+/* 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>
+
+int counter_chrdev_add(struct counter_device *const counter);
+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 407661c6feb0..91af3f8a5df8 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -3,14 +3,20 @@
  * Generic Counter interface
  * Copyright (C) 2020 William Breathitt Gray
  */
+#include <linux/cdev.h>
 #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/kdev_t.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 */
@@ -34,6 +40,8 @@ static struct bus_type counter_bus_type = {
 	.dev_name = "counter",
 };
 
+static dev_t counter_devt;
+
 /**
  * counter_register - register Counter to the system
  * @counter:	pointer to Counter to register
@@ -60,6 +68,7 @@ int counter_register(struct counter_device *const counter)
 	dev->id = id;
 	dev->type = &counter_device_type;
 	dev->bus = &counter_bus_type;
+	dev->devt = MKDEV(MAJOR(counter_devt), id);
 	if (counter->parent) {
 		dev->parent = counter->parent;
 		dev->of_node = counter->parent->of_node;
@@ -67,18 +76,25 @@ 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);
+	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);
+	err = cdev_device_add(&counter->chrdev, 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;
@@ -96,7 +112,8 @@ void counter_unregister(struct counter_device *const counter)
 	if (!counter)
 		return;
 
-	device_unregister(&counter->dev);
+	cdev_device_del(&counter->chrdev, &counter->dev);
+	put_device(&counter->dev);
 }
 EXPORT_SYMBOL_GPL(counter_unregister);
 
@@ -140,13 +157,30 @@ 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 eee85db8e332..3f0bbe4ff702 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);
 };
 
 /**
@@ -259,6 +288,13 @@ struct counter_ops {
  * @num_ext:		number of Counter device extensions specified in @ext
  * @priv:		optional private data supplied by driver
  * @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;
@@ -277,12 +313,21 @@ struct counter_device {
 	void *priv;
 
 	struct device dev;
+	struct cdev chrdev;
+	struct list_head events_list;
+	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..e55dfc9de887 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 +26,70 @@ 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 ID (matching the ID suffix of the respective parent sysfs
+ *          path as described by the ABI documentation file
+ *          Documentation/ABI/testing/sysfs-bus-counter; e.g. if the component
+ *          attribute path is /sys/bus/counter/devices/counter4/count2/count,
+ *          the parent is count2 and thus parent ID is 2)
+ * @id: component ID (matching the ID provided by the respective *_component_id
+ *      sysfs attribute of the desired component; for example, if the component
+ *      attribute path is /sys/bus/counter/devices/counter4/count2/ceiling, the
+ *      respective /sys/bus/counter/devices/counter4/count2/ceiling_component_id
+ *      attribute will provide the necessary component ID)
+ * )
+ */
+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,
-- 
2.32.0


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Re: [PATCH v11 26/33] counter: Add character device interface

[Dan Carpenter]

On Wed, Jun 09, 2021 at 10:31:29AM +0900, William Breathitt Gray wrote:
> +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;
> +

The caller should be holding the counter->events_list_lock lock but it's
not.


> +	/* 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;
> +
> +	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);
> +
> +	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};

Always use = {};.  It's the new hotness, and it avoids a Sparse warning
for using 0 instead of NULL.  #IDidNotTest #CouldBeWrongAboutSparse

> +	size_t parent, id;
> +	struct counter_comp *ext;
> +	size_t num_ext;
> +	int err;
> +

regards,
dan carpenter


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Re: [PATCH v11 26/33] counter: Add character device interface

[William Breathitt Gray]

[-- Attachment #1.1: Type: text/plain, Size: 3509 bytes --]

On Wed, Jun 09, 2021 at 11:07:08AM +0300, Dan Carpenter wrote:
> On Wed, Jun 09, 2021 at 10:31:29AM +0900, William Breathitt Gray wrote:
> > +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;
> > +
> 
> The caller should be holding the counter->events_list_lock lock but it's
> not.

Hi Dan,

The counter_set_event_node() function doesn't access or modify
counter->events_list (it works on counter->next_events_list) so holding
the counter->events_list_lock here isn't necessary.

> > +	/* 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;
> > +
> > +	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);
> > +
> > +	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};
> 
> Always use = {};.  It's the new hotness, and it avoids a Sparse warning
> for using 0 instead of NULL.  #IDidNotTest #CouldBeWrongAboutSparse

Thanks for the heads-up! I think this is the only patch where I have
this, so I'll hold off submitting a v12 for just this change unless
something else comes up with this patchset (I can fix this spare warning
in a subsequent patch).

William Breathitt Gray

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Re: [PATCH v11 26/33] counter: Add character device interface

[Dan Carpenter]

On Wed, Jun 09, 2021 at 05:28:10PM +0900, William Breathitt Gray wrote:
> On Wed, Jun 09, 2021 at 11:07:08AM +0300, Dan Carpenter wrote:
> > On Wed, Jun 09, 2021 at 10:31:29AM +0900, William Breathitt Gray wrote:
> > > +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;
> > > +
> > 
> > The caller should be holding the counter->events_list_lock lock but it's
> > not.
> 
> Hi Dan,
> 
> The counter_set_event_node() function doesn't access or modify
> counter->events_list (it works on counter->next_events_list) so holding
> the counter->events_list_lock here isn't necessary.
> 

There needs to be some sort of locking or this function can race with
itself.  (Two threads add the same event at exactly the same time).  It
looks like it can also race with counter_disable_events() leading to a
use after free.

> > > +	/* 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);

Btw, say we decided that we can add/remove events locklessly, then these
GFP_ATOMICs can be changed to GFP_KERNEL.

> > > +		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;
> > > +}

regards,
dan carpenter


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Re: [PATCH v11 26/33] counter: Add character device interface

[William Breathitt Gray]

[-- Attachment #1.1: Type: text/plain, Size: 2018 bytes --]

On Wed, Jun 09, 2021 at 11:59:38AM +0300, Dan Carpenter wrote:
> On Wed, Jun 09, 2021 at 05:28:10PM +0900, William Breathitt Gray wrote:
> > On Wed, Jun 09, 2021 at 11:07:08AM +0300, Dan Carpenter wrote:
> > > On Wed, Jun 09, 2021 at 10:31:29AM +0900, William Breathitt Gray wrote:
> > > > +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;
> > > > +
> > > 
> > > The caller should be holding the counter->events_list_lock lock but it's
> > > not.
> > 
> > Hi Dan,
> > 
> > The counter_set_event_node() function doesn't access or modify
> > counter->events_list (it works on counter->next_events_list) so holding
> > the counter->events_list_lock here isn't necessary.
> > 
> 
> There needs to be some sort of locking or this function can race with
> itself.  (Two threads add the same event at exactly the same time).  It
> looks like it can also race with counter_disable_events() leading to a
> use after free.

All right, I'll add in a lock to protect this function so it doesn't
race with itself nor counter_disable_events().

> > > > +	/* 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);
> 
> Btw, say we decided that we can add/remove events locklessly, then these
> GFP_ATOMICs can be changed to GFP_KERNEL.

Because I'll be using a lock I'll keep these as GFP_ATOMICs afterall.

Thanks,

William Breathitt Gray

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[PATCH v11 27/33] 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  | 185 ++++++++++++++----
 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 2 files changed, 145 insertions(+), 41 deletions(-)

diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index f6397218aa4c..62a702e7f994 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 +467,112 @@ 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.
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 9bfc2b510c64..cad12ae3f945 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
-- 
2.32.0


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[PATCH v11 28/33] tools/counter: Create Counter tools

[William Breathitt Gray]

This creates an example Counter program under tools/counter/*
to exemplify the Counter character device interface.

Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 MAINTAINERS                     |  1 +
 tools/Makefile                  | 13 ++---
 tools/counter/Build             |  1 +
 tools/counter/Makefile          | 53 ++++++++++++++++++
 tools/counter/counter_example.c | 95 +++++++++++++++++++++++++++++++++
 5 files changed, 157 insertions(+), 6 deletions(-)
 create mode 100644 tools/counter/Build
 create mode 100644 tools/counter/Makefile
 create mode 100644 tools/counter/counter_example.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 7e2ddf74bd7b..9e2a0c5637ba 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4679,6 +4679,7 @@ F:	Documentation/driver-api/generic-counter.rst
 F:	drivers/counter/
 F:	include/linux/counter.h
 F:	include/uapi/linux/counter.h
+F:	tools/counter/
 
 CP2615 I2C DRIVER
 M:	Bence Csókás <bence98@sch.bme.hu>
diff --git a/tools/Makefile b/tools/Makefile
index 7e9d34ddd74c..4c26400ffc03 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -12,6 +12,7 @@ help:
 	@echo '  acpi                   - ACPI tools'
 	@echo '  bpf                    - misc BPF tools'
 	@echo '  cgroup                 - cgroup tools'
+	@echo '  counter                - Counter tools'
 	@echo '  cpupower               - a tool for all things x86 CPU power'
 	@echo '  debugging              - tools for debugging'
 	@echo '  firewire               - the userspace part of nosy, an IEEE-1394 traffic sniffer'
@@ -65,7 +66,7 @@ acpi: FORCE
 cpupower: FORCE
 	$(call descend,power/$@)
 
-cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
+cgroup counter firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
 	$(call descend,$@)
 
 bpf/%: FORCE
@@ -100,7 +101,7 @@ freefall: FORCE
 kvm_stat: FORCE
 	$(call descend,kvm/$@)
 
-all: acpi cgroup cpupower gpio hv firewire liblockdep \
+all: acpi cgroup counter cpupower gpio hv firewire liblockdep \
 		perf selftests bootconfig spi turbostat usb \
 		virtio vm bpf x86_energy_perf_policy \
 		tmon freefall iio objtool kvm_stat wmi \
@@ -112,7 +113,7 @@ acpi_install:
 cpupower_install:
 	$(call descend,power/$(@:_install=),install)
 
-cgroup_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
+cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
 	$(call descend,$(@:_install=),install)
 
 liblockdep_install:
@@ -133,7 +134,7 @@ freefall_install:
 kvm_stat_install:
 	$(call descend,kvm/$(@:_install=),install)
 
-install: acpi_install cgroup_install cpupower_install gpio_install \
+install: acpi_install cgroup_install counter_install cpupower_install gpio_install \
 		hv_install firewire_install iio_install liblockdep_install \
 		perf_install selftests_install turbostat_install usb_install \
 		virtio_install vm_install bpf_install x86_energy_perf_policy_install \
@@ -147,7 +148,7 @@ acpi_clean:
 cpupower_clean:
 	$(call descend,power/cpupower,clean)
 
-cgroup_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
+cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
 	$(call descend,$(@:_clean=),clean)
 
 liblockdep_clean:
@@ -181,7 +182,7 @@ freefall_clean:
 build_clean:
 	$(call descend,build,clean)
 
-clean: acpi_clean cgroup_clean cpupower_clean hv_clean firewire_clean \
+clean: acpi_clean cgroup_clean counter_clean cpupower_clean hv_clean firewire_clean \
 		perf_clean selftests_clean turbostat_clean bootconfig_clean spi_clean usb_clean virtio_clean \
 		vm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
 		freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean \
diff --git a/tools/counter/Build b/tools/counter/Build
new file mode 100644
index 000000000000..33f4a51d715e
--- /dev/null
+++ b/tools/counter/Build
@@ -0,0 +1 @@
+counter_example-y += counter_example.o
diff --git a/tools/counter/Makefile b/tools/counter/Makefile
new file mode 100644
index 000000000000..5ebc195fd9c0
--- /dev/null
+++ b/tools/counter/Makefile
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../scripts/Makefile.include
+
+bindir ?= /usr/bin
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+# Do not use make's built-in rules
+# (this improves performance and avoids hard-to-debug behaviour);
+MAKEFLAGS += -r
+
+override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
+
+ALL_TARGETS := counter_example
+ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))
+
+all: $(ALL_PROGRAMS)
+
+export srctree OUTPUT CC LD CFLAGS
+include $(srctree)/tools/build/Makefile.include
+
+#
+# We need the following to be outside of kernel tree
+#
+$(OUTPUT)include/linux/counter.h: ../../include/uapi/linux/counter.h
+	mkdir -p $(OUTPUT)include/linux 2>&1 || true
+	ln -sf $(CURDIR)/../../include/uapi/linux/counter.h $@
+
+prepare: $(OUTPUT)include/linux/counter.h
+
+COUNTER_EXAMPLE := $(OUTPUT)counter_example.o
+$(COUNTER_EXAMPLE): prepare FORCE
+	$(Q)$(MAKE) $(build)=counter_example
+$(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+clean:
+	rm -f $(ALL_PROGRAMS)
+	rm -rf $(OUTPUT)include/linux/counter.h
+	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+
+install: $(ALL_PROGRAMS)
+	install -d -m 755 $(DESTDIR)$(bindir);		\
+	for program in $(ALL_PROGRAMS); do		\
+		install $$program $(DESTDIR)$(bindir);	\
+	done
+
+FORCE:
+
+.PHONY: all install clean FORCE prepare
diff --git a/tools/counter/counter_example.c b/tools/counter/counter_example.c
new file mode 100644
index 000000000000..71dfec673c11
--- /dev/null
+++ b/tools/counter/counter_example.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Counter - example userspace application
+ *
+ * The userspace application opens /dev/counter0, configures the
+ * COUNTER_EVENT_INDEX event channel 0 to gather Count 0 count and Count
+ * 1 count, and prints out the data as it becomes available on the
+ * character device node.
+ *
+ * Copyright (C) 2021 William Breathitt Gray
+ */
+#include <errno.h>
+#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 data: Count 0 count */
+		.component.type = COUNTER_COMPONENT_COUNT,
+		.component.scope = COUNTER_SCOPE_COUNT,
+		.component.parent = 0,
+		/* Event type: Index */
+		.event = COUNTER_EVENT_INDEX,
+		/* Device event channel 0 */
+		.channel = 0,
+	},
+	{
+		/* Component data: Count 1 count */
+		.component.type = COUNTER_COMPONENT_COUNT,
+		.component.scope = COUNTER_SCOPE_COUNT,
+		.component.parent = 1,
+		/* Event type: Index */
+		.event = COUNTER_EVENT_INDEX,
+		/* Device event channel 0 */
+		.channel = 0,
+	},
+};
+
+int main(void)
+{
+	int fd;
+	int ret;
+	struct counter_event event_data[2];
+
+	fd = open("/dev/counter0", O_RDWR);
+	if (fd == -1) {
+		perror("Unable to open /dev/counter0");
+		return -errno;
+	}
+
+	ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
+	if (ret == -1) {
+		perror("Error adding watches[0]");
+		return -errno;
+	}
+	ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
+	if (ret == -1) {
+		perror("Error adding watches[1]");
+		return -errno;
+	}
+	ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
+	if (ret == -1) {
+		perror("Error enabling events");
+		return -errno;
+	}
+
+	for (;;) {
+		ret = read(fd, event_data, sizeof(event_data));
+		if (ret == -1) {
+			perror("Failed to read event data");
+			return -errno;
+		}
+
+		if (ret != sizeof(event_data)) {
+			fprintf(stderr, "Failed to read event data\n");
+			return -EIO;
+		}
+
+		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;
+}
-- 
2.32.0


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[PATCH v11 29/33] counter: Implement signalZ_action_component_id sysfs attribute

[William Breathitt Gray]

The Generic Counter chrdev interface expects users to supply component
IDs in order to select Synapses for requests. In order for users to know
what component ID belongs to which Synapse this information must be
exposed. The signalZ_action_component_id attribute provides a way for
users to discover what component ID belongs to the respective Synapse.

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 |  7 ++++
 drivers/counter/counter-sysfs.c             | 45 +++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index dee79b606847..9809d8a47431 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -203,6 +203,13 @@ Description:
 		both edges:
 			Any state transition.
 
+What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
+KernelVersion:	5.15
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Read-only attribute that indicates the component ID of the
+		respective Synapse of Count Y for Signal Z.
+
 What:		/sys/bus/counter/devices/counterX/countY/spike_filter_ns
 KernelVersion:	5.14
 Contact:	linux-iio@vger.kernel.org
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 07588130600a..bb49a10f160b 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -533,6 +533,46 @@ static int counter_name_attr_create(struct device *const dev,
 	return 0;
 }
 
+static ssize_t counter_comp_id_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	const size_t id = (size_t)to_counter_attribute(attr)->comp.priv;
+
+	return sprintf(buf, "%zu\n", id);
+}
+
+static int counter_comp_id_attr_create(struct device *const dev,
+				       struct counter_attribute_group *const group,
+				       const char *name, const size_t id)
+{
+	struct counter_attribute *counter_attr;
+
+	/* Allocate Counter attribute */
+	counter_attr = devm_kzalloc(dev, sizeof(*counter_attr), GFP_KERNEL);
+	if (!counter_attr)
+		return -ENOMEM;
+
+	/* Generate component ID name */
+	name = devm_kasprintf(dev, GFP_KERNEL, "%s_component_id", name);
+	if (!name)
+		return -ENOMEM;
+
+	/* Configure Counter attribute */
+	counter_attr->comp.priv = (void *)id;
+
+	/* 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_id_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",
@@ -627,6 +667,11 @@ static int counter_sysfs_synapses_add(struct counter_device *const counter,
 					  COUNTER_SCOPE_COUNT, count);
 		if (err < 0)
 			return err;
+
+		/* Create Synapse component ID attribute */
+		err = counter_comp_id_attr_create(dev, group, comp.name, i);
+		if (err < 0)
+			return err;
 	}
 
 	return 0;
-- 
2.32.0


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[PATCH v11 30/33] counter: Implement *_component_id sysfs attributes

[William Breathitt Gray]

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

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 | 16 ++++++++++-
 drivers/counter/counter-sysfs.c             | 30 ++++++++++++++++-----
 2 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 9809d8a47431..e0e99adb0ecc 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -203,12 +203,26 @@ Description:
 		both edges:
 			Any state transition.
 
+What:		/sys/bus/counter/devices/counterX/countY/ceiling_component_id
+What:		/sys/bus/counter/devices/counterX/countY/floor_component_id
+What:		/sys/bus/counter/devices/counterX/countY/count_mode_component_id
+What:		/sys/bus/counter/devices/counterX/countY/direction_component_id
+What:		/sys/bus/counter/devices/counterX/countY/enable_component_id
+What:		/sys/bus/counter/devices/counterX/countY/error_noise_component_id
+What:		/sys/bus/counter/devices/counterX/countY/prescaler_component_id
+What:		/sys/bus/counter/devices/counterX/countY/preset_component_id
+What:		/sys/bus/counter/devices/counterX/countY/preset_enable_component_id
 What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
+What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id
 KernelVersion:	5.15
 Contact:	linux-iio@vger.kernel.org
 Description:
 		Read-only attribute that indicates the component ID of the
-		respective Synapse of Count Y for Signal Z.
+		respective extension or Synapse.
 
 What:		/sys/bus/counter/devices/counterX/countY/spike_filter_ns
 KernelVersion:	5.14
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index bb49a10f160b..eb1505bfbd89 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -587,6 +587,7 @@ 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;
@@ -602,8 +603,13 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
 
 	/* 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_comp_id_attr_create(dev, group, ext->name, i);
 		if (err < 0)
 			return err;
 	}
@@ -694,6 +700,7 @@ 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;
@@ -718,8 +725,13 @@ 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_comp_id_attr_create(dev, group, ext->name, i);
 		if (err < 0)
 			return err;
 	}
@@ -783,6 +795,7 @@ 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);
@@ -815,8 +828,13 @@ 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_comp_id_attr_create(dev, group, ext->name, i);
 		if (err < 0)
 			return err;
 	}
-- 
2.32.0


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[PATCH v11 31/33] 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            |  4 ++
 drivers/counter/counter-sysfs.c             | 44 +++++++++++++++++++++
 include/linux/counter.h                     |  2 +
 4 files changed, 58 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index e0e99adb0ecc..84ebb1ed28ed 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -233,6 +233,14 @@ Description:
 		shorter or equal to configured value are ignored. Value 0 means
 		filter is disabled.
 
+What:		/sys/bus/counter/devices/counterX/events_queue_size
+KernelVersion:	5.15
+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 d5f92b2d3bb4..d9f123ca0ed6 100644
--- a/drivers/counter/counter-chrdev.c
+++ b/drivers/counter/counter-chrdev.c
@@ -311,6 +311,9 @@ static int counter_chrdev_open(struct inode *inode, struct file *filp)
 							    typeof(*counter),
 							    chrdev);
 
+	if (!mutex_trylock(&counter->chrdev_lock))
+		return -EBUSY;
+
 	get_device(&counter->dev);
 	filp->private_data = counter;
 
@@ -327,6 +330,7 @@ static int counter_chrdev_release(struct inode *inode, struct file *filp)
 		return err;
 
 	put_device(&counter->dev);
+	mutex_unlock(&counter->chrdev_lock);
 
 	return 0;
 }
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index eb1505bfbd89..bf038eff4587 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -8,7 +8,9 @@
 #include <linux/err.h>
 #include <linux/gfp.h>
 #include <linux/kernel.h>
+#include <linux/kfifo.h>
 #include <linux/list.h>
+#include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/sysfs.h>
 #include <linux/types.h>
@@ -782,12 +784,48 @@ 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 = kfifo_size(&counter->events);
+	return 0;
+}
+
+static int counter_events_queue_size_write(struct counter_device *counter,
+					   u64 val)
+{
+	int err;
+	DECLARE_KFIFO_PTR(events, struct counter_event);
+
+	/* Verify chrdev is not currently being used */
+	if (!mutex_trylock(&counter->chrdev_lock))
+		return -EBUSY;
+
+	/* Allocate new events queue */
+	err = kfifo_alloc(&events, val, GFP_ATOMIC);
+	if (err)
+		return err;
+
+	/* Swap in new events queue */
+	kfifo_free(&counter->events);
+	counter->events.kfifo = events.kfifo;
+
+	mutex_unlock(&counter->chrdev_lock);
+
+	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 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)
 {
@@ -826,6 +864,12 @@ 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;
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 3f0bbe4ff702..854fcaf49c32 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -289,6 +289,7 @@ struct counter_ops {
  * @priv:		optional private data supplied by driver
  * @dev:		internal device structure
  * @chrdev:		internal character device structure
+ * @chrdev_lock:	lock to limit chrdev to a single open at a time
  * @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
@@ -314,6 +315,7 @@ struct counter_device {
 
 	struct device dev;
 	struct cdev chrdev;
+	struct mutex chrdev_lock;
 	struct list_head events_list;
 	spinlock_t events_list_lock;
 	struct list_head next_events_list;
-- 
2.32.0


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[PATCH v11 32/33] 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.

Acked-by: 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 eb7d63769f4c..d46b8101f207 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:		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
@@ -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;
+	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);
+	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);
+	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);
+	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);
+	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);
+	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);
+	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);
+	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);
+			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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -405,9 +411,10 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	idr_cfg |= priv->synchronous_mode[channel_id];
 
@@ -416,7 +423,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -445,15 +452,16 @@ 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);
+	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);
+		spin_unlock_irqrestore(&priv->lock, irqflags);
 		return -EINVAL;
 	}
 
@@ -462,7 +470,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -509,6 +517,7 @@ 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) {
@@ -529,7 +538,7 @@ static int quad8_count_mode_write(struct counter_device *counter,
 		return -EINVAL;
 	}
 
-	mutex_lock(&priv->lock);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->count_mode[count->id] = count_mode;
 
@@ -543,7 +552,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -563,9 +572,10 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->ab_enable[count->id] = enable;
 
@@ -574,7 +584,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -625,16 +635,17 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	quad8_preset_register_set(priv, count->id, preset);
 
-	mutex_unlock(&priv->lock);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -643,8 +654,9 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	/* Range Limit and Modulo-N count modes use preset value as ceiling */
 	switch (priv->count_mode[count->id]) {
@@ -658,7 +670,7 @@ static int quad8_count_ceiling_read(struct counter_device *counter,
 		break;
 	}
 
-	mutex_unlock(&priv->lock);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -667,23 +679,24 @@ 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);
+	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);
+		spin_unlock_irqrestore(&priv->lock, irqflags);
 		quad8_preset_register_set(priv, count->id, ceiling);
 		return 0;
 	}
 
-	mutex_unlock(&priv->lock);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return -EINVAL;
 }
@@ -705,12 +718,13 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->preset_enable[count->id] = preset_enable;
 
@@ -719,7 +733,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -730,22 +744,23 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	disabled = !(priv->cable_fault_enable & BIT(channel_id));
 
 	if (disabled) {
-		mutex_unlock(&priv->lock);
+		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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	/* Mask respective channel and invert logic */
 	*cable_fault = !(status & BIT(channel_id));
@@ -771,9 +786,10 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	if (enable)
 		priv->cable_fault_enable |= BIT(channel_id);
@@ -785,7 +801,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -808,8 +824,9 @@ 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);
+	spin_lock_irqsave(&priv->lock, irqflags);
 
 	priv->fck_prescaler[channel_id] = prescaler;
 
@@ -821,7 +838,7 @@ 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);
+	spin_unlock_irqrestore(&priv->lock, irqflags);
 
 	return 0;
 }
@@ -990,8 +1007,7 @@ static int quad8_probe(struct device *dev, unsigned int id)
 	priv->counter.priv = priv;
 	priv->base = base[id];
 
-	/* Initialize mutex */
-	mutex_init(&priv->lock);
+	spin_lock_init(&priv->lock);
 
 	/* Reset all counters and disable interrupt function */
 	outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
-- 
2.32.0


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[PATCH v11 33/33] 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.

Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/counter/104-quad-8.c | 167 +++++++++++++++++++++++++++++++++--
 drivers/counter/Kconfig      |   6 +-
 2 files changed, 164 insertions(+), 9 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index d46b8101f207..09b0b0ba8fe7 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>
@@ -25,6 +26,10 @@ 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
 
 /**
@@ -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
@@ -378,13 +389,103 @@ static int quad8_action_read(struct counter_device *counter,
 	}
 }
 
+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;
+
+	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);
+
+	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[] = {
@@ -579,7 +680,8 @@ 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);
@@ -728,7 +830,8 @@ 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);
@@ -980,11 +1083,54 @@ 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",
@@ -1009,6 +1155,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
 
 	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 */
@@ -1035,11 +1183,18 @@ 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;
 
 	return devm_counter_register(dev, &priv->counter);
 }
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index d5d2540b30c2..3dcdb681c4e4 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 INTERRUPT_CNT
 	tristate "Interrupt counter driver"
-- 
2.32.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v11 33/33] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:36 +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.
> 
> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

I've taken a look at the remainder of the patches I haven't commented
on an I think they are all fine.

Of course good to get more eyes on this if possible though
and perhaps a few more reviews of the interfaces at least from
the various counter driver maintainers.

Thanks,

Jonathan

> ---
>  drivers/counter/104-quad-8.c | 167 +++++++++++++++++++++++++++++++++--
>  drivers/counter/Kconfig      |   6 +-
>  2 files changed, 164 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index d46b8101f207..09b0b0ba8fe7 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>
> @@ -25,6 +26,10 @@ 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
>  
>  /**
> @@ -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
> @@ -378,13 +389,103 @@ static int quad8_action_read(struct counter_device *counter,
>  	}
>  }
>  
> +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;
> +
> +	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);
> +
> +	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[] = {
> @@ -579,7 +680,8 @@ 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);
> @@ -728,7 +830,8 @@ 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);
> @@ -980,11 +1083,54 @@ 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",
> @@ -1009,6 +1155,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
>  
>  	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 */
> @@ -1035,11 +1183,18 @@ 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;
>  
>  	return devm_counter_register(dev, &priv->counter);
>  }
> diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
> index d5d2540b30c2..3dcdb681c4e4 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 INTERRUPT_CNT
>  	tristate "Interrupt counter driver"


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Re: [PATCH v11 00/33] Introduce the Counter character device interface

[Jonathan Cameron]

On Wed,  9 Jun 2021 10:31:03 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:

> Changes in v11:
>  - Migrated Intel QEP to new interface
>  - Context adjustments made for documentation
> 
> 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_v11
> 
> 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.

Let us aim to do that in the interests of cutting down on the volume for future
versions!

However, it is made tricky by the fact patch 22 hasn't made it to me or
lore.kernel.org.  Could you send that one again.  Hopefully the in-reply-to
will ensure it's correctly threaded.

Jonathan


> 
> 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 (33):
>   docs: counter: Consolidate Counter sysfs attributes documentation
>   docs: counter: Fix spelling
>   counter: 104-quad-8: Remove pointless comment
>   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: interrupt-cnt: Add const qualifier for functions_list array
>   counter: microchip-tcb-capture: Add const qualifier for functions_list
>     array
>   counter: stm32-lptimer-cnt: Add const qualifier for functions_list
>     array
>   counter: stm32-timer-cnt: 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: interrupt-cnt: Add const qualifier for actions_list array
>   counter: microchip-tcb-capture: Add const qualifier for actions_list
>     array
>   counter: stm32-lptimer-cnt: Add const qualifier for actions_list array
>   counter: stm32-timer-cnt: 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
>   tools/counter: Create Counter tools
>   counter: Implement signalZ_action_component_id sysfs attribute
>   counter: Implement *_component_id 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   |  112 +-
>  .../ABI/testing/sysfs-bus-counter-104-quad-8  |   61 -
>  .../ABI/testing/sysfs-bus-counter-ftm-quaddec |   16 -
>  Documentation/driver-api/generic-counter.rst  |  368 +++-
>  .../userspace-api/ioctl/ioctl-number.rst      |    1 +
>  MAINTAINERS                                   |    7 +-
>  drivers/counter/104-quad-8.c                  |  739 ++++----
>  drivers/counter/Kconfig                       |    6 +-
>  drivers/counter/Makefile                      |    1 +
>  drivers/counter/counter-chrdev.c              |  486 ++++++
>  drivers/counter/counter-chrdev.h              |   14 +
>  drivers/counter/counter-core.c                |  192 +++
>  drivers/counter/counter-sysfs.c               |  953 +++++++++++
>  drivers/counter/counter-sysfs.h               |   13 +
>  drivers/counter/counter.c                     | 1496 -----------------
>  drivers/counter/ftm-quaddec.c                 |   61 +-
>  drivers/counter/intel-qep.c                   |  150 +-
>  drivers/counter/interrupt-cnt.c               |   75 +-
>  drivers/counter/microchip-tcb-capture.c       |  105 +-
>  drivers/counter/stm32-lptimer-cnt.c           |  176 +-
>  drivers/counter/stm32-timer-cnt.c             |  149 +-
>  drivers/counter/ti-eqep.c                     |  221 +--
>  include/linux/counter.h                       |  716 ++++----
>  include/linux/counter_enum.h                  |   45 -
>  include/uapi/linux/counter.h                  |  133 ++
>  tools/Makefile                                |   13 +-
>  tools/counter/Build                           |    1 +
>  tools/counter/Makefile                        |   53 +
>  tools/counter/counter_example.c               |   95 ++
>  29 files changed, 3586 insertions(+), 2872 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
>  create mode 100644 tools/counter/Build
>  create mode 100644 tools/counter/Makefile
>  create mode 100644 tools/counter/counter_example.c
> 


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Re: [PATCH v11 00/33] Introduce the Counter character device interface

[William Breathitt Gray]

[-- Attachment #1.1: Type: text/plain, Size: 1790 bytes --]

On Wed, Jun 09, 2021 at 02:59:51PM +0100, Jonathan Cameron wrote:
> On Wed,  9 Jun 2021 10:31:03 +0900
> William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> 
> > Changes in v11:
> >  - Migrated Intel QEP to new interface
> >  - Context adjustments made for documentation
> > 
> > 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_v11
> > 
> > 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.
> 
> Let us aim to do that in the interests of cutting down on the volume for future
> versions!
> 
> However, it is made tricky by the fact patch 22 hasn't made it to me or
> lore.kernel.org.  Could you send that one again.  Hopefully the in-reply-to
> will ensure it's correctly threaded.
> 
> Jonathan

I think patch 22 just took a while to be processed by the servers
because of its size; I went ahead and submitted a RESEND of it
regardless just in case. You should be able to access both on
lore.kernel.org:

https://lore.kernel.org/lkml/87dec6c889e40068ed27cbb3e66a6376856e2267.1623201082.git.vilhelm.gray@gmail.com/
https://lore.kernel.org/lkml/20210609141145.Ci-kBe7zxq4hPKS98nEi0JK7WOv0DHLOIm8pmrIDvVY@z/

Let me know if you encounter any other problems.

William Breathitt Gray

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[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

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Re: [RESEND PATCH v11 22/33] counter: Internalize sysfs interface code

[Jonathan Cameron]

On Wed,  9 Jun 2021 23:11:45 +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: Jarkko Nikula <jarkko.nikula@linux.intel.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: Dan Carpenter <dan.carpenter@oracle.com>
> Reviewed-by: David Lechner <david@lechnology.com>
> Tested-by: David Lechner <david@lechnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>

Given you will probably do a v12 anyway, a few comments inline.

Jonathan

> ---
>  MAINTAINERS                             |    1 -
>  drivers/counter/104-quad-8.c            |  449 +++----
>  drivers/counter/Makefile                |    1 +
>  drivers/counter/counter-core.c          |  155 +++
>  drivers/counter/counter-sysfs.c         |  846 +++++++++++++
>  drivers/counter/counter-sysfs.h         |   13 +
>  drivers/counter/counter.c               | 1496 -----------------------
>  drivers/counter/ftm-quaddec.c           |   56 +-
>  drivers/counter/intel-qep.c             |  144 +--
>  drivers/counter/interrupt-cnt.c         |   62 +-
>  drivers/counter/microchip-tcb-capture.c |   93 +-
>  drivers/counter/stm32-lptimer-cnt.c     |  162 ++-
>  drivers/counter/stm32-timer-cnt.c       |  147 +--
>  drivers/counter/ti-eqep.c               |  180 +--
>  include/linux/counter.h                 |  629 +++++-----
>  include/linux/counter_enum.h            |   45 -
>  16 files changed, 1918 insertions(+), 2561 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/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> new file mode 100644
> index 000000000000..e7dd6ea01c8a
> --- /dev/null
> +++ b/drivers/counter/counter-core.c
> @@ -0,0 +1,155 @@
> +// 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);
> +

...
> +int counter_register(struct counter_device *const counter)
> +{
> +	struct device *const dev = &counter->dev;
> +	int id;
> +	int err;
> +
> +	/* Acquire unique ID */
> +	id = ida_alloc(&counter_ida, GFP_KERNEL);
> +	if (id < 0)
> +		return id;
> +
> +	/* Configure device structure for Counter */
> +	dev->id = id;
> +	dev->type = &counter_device_type;
> +	dev->bus = &counter_bus_type;
> +	if (counter->parent) {
> +		dev->parent = counter->parent;
> +		dev->of_node = counter->parent->of_node;
> +	}
> +	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.

If we are being fussy. This isn't necessarily true. If the reference goes
down to 0 it will be freed, but in theory that could happen later than
this call.  I'm guessing we will have get_device() calls once the
chrdev is in place.

> + */
> +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;

If you look at how devm_iio_device_register() is now done in
the togreg branch of iio.git, you'll see it now just uses
devm_add_action_or_reset() internally.  I think you could do something similar
here and reduce boilerplate a little.

> +
> +	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..07588130600a
> --- /dev/null
> +++ b/drivers/counter/counter-sysfs.c
> @@ -0,0 +1,846 @@
> +// 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"
> +

...

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