* [PATCH v7 0/3] Runtime Interpreter Power Sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Quite a big redesign of the feature - both structures and code have been
simplified and should be easier to read and understand, data duplication is
avoided, and much less memory allocations take place at runtime. Usage
interface is also simpler and IMHO more logical.
What happened is that platform_power_seq and power_seq have been merged,
and so power sequences declared as platform data are used "as-is". The
"build" step is not needed anymore - resources are allocated when a
power sequence is added into a set.
There is still one design flaw that I would like to solve: sequences are
still tied to a device, i.e. if you have two devices that use the same
powering scheme, you have to declare two identical power sequences and assign
each of these to one device. It would be much more flexible if sequences could
be shared across devices. The problem is that the resources structure,
references by steps, cannot be shared. Actually we could share it by having
a linked list of devices and resolved resources in the resource structure and
thus share power sequences over devices. That would work for regulator and
PWM resources, which have a get_regulator/pwm(dev, id) function that could
return a different resource depending on the device that is passed.
But there is no similar get_gpio() function for GPIOs which number is directly
specified in the resource, and I don't know if such a function would make
sense otherwise. Opinions on the subject are welcome.
Alexandre Courbot (3):
Runtime Interpreted Power Sequences
pwm_backlight: use power sequences
tegra: ventana: add PWM backlight to device tree
.../devicetree/bindings/power/power_seq.txt | 121 +++++++
.../bindings/video/backlight/pwm-backlight.txt | 72 +++-
Documentation/power/power_seq.txt | 253 ++++++++++++++
arch/arm/boot/dts/tegra20-ventana.dts | 59 +++-
drivers/power/Kconfig | 1 +
drivers/power/Makefile | 1 +
drivers/power/power_seq/Kconfig | 2 +
drivers/power/power_seq/Makefile | 1 +
drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++
drivers/power/power_seq/power_seq_delay.c | 65 ++++
drivers/power/power_seq/power_seq_gpio.c | 94 ++++++
drivers/power/power_seq/power_seq_pwm.c | 82 +++++
drivers/power/power_seq/power_seq_regulator.c | 83 +++++
drivers/video/backlight/Kconfig | 1 +
drivers/video/backlight/pwm_bl.c | 161 +++++++--
include/linux/power_seq.h | 203 +++++++++++
include/linux/pwm_backlight.h | 18 +-
17 files changed, 1553 insertions(+), 40 deletions(-)
create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt
create mode 100644 Documentation/power/power_seq.txt
create mode 100644 drivers/power/power_seq/Kconfig
create mode 100644 drivers/power/power_seq/Makefile
create mode 100644 drivers/power/power_seq/power_seq.c
create mode 100644 drivers/power/power_seq/power_seq_delay.c
create mode 100644 drivers/power/power_seq/power_seq_gpio.c
create mode 100644 drivers/power/power_seq/power_seq_pwm.c
create mode 100644 drivers/power/power_seq/power_seq_regulator.c
create mode 100644 include/linux/power_seq.h
--
1.7.12.3
^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v7 0/3] Runtime Interpreter Power Sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Quite a big redesign of the feature - both structures and code have been
simplified and should be easier to read and understand, data duplication is
avoided, and much less memory allocations take place at runtime. Usage
interface is also simpler and IMHO more logical.
What happened is that platform_power_seq and power_seq have been merged,
and so power sequences declared as platform data are used "as-is". The
"build" step is not needed anymore - resources are allocated when a
power sequence is added into a set.
There is still one design flaw that I would like to solve: sequences are
still tied to a device, i.e. if you have two devices that use the same
powering scheme, you have to declare two identical power sequences and assign
each of these to one device. It would be much more flexible if sequences could
be shared across devices. The problem is that the resources structure,
references by steps, cannot be shared. Actually we could share it by having
a linked list of devices and resolved resources in the resource structure and
thus share power sequences over devices. That would work for regulator and
PWM resources, which have a get_regulator/pwm(dev, id) function that could
return a different resource depending on the device that is passed.
But there is no similar get_gpio() function for GPIOs which number is directly
specified in the resource, and I don't know if such a function would make
sense otherwise. Opinions on the subject are welcome.
Alexandre Courbot (3):
Runtime Interpreted Power Sequences
pwm_backlight: use power sequences
tegra: ventana: add PWM backlight to device tree
.../devicetree/bindings/power/power_seq.txt | 121 +++++++
.../bindings/video/backlight/pwm-backlight.txt | 72 +++-
Documentation/power/power_seq.txt | 253 ++++++++++++++
arch/arm/boot/dts/tegra20-ventana.dts | 59 +++-
drivers/power/Kconfig | 1 +
drivers/power/Makefile | 1 +
drivers/power/power_seq/Kconfig | 2 +
drivers/power/power_seq/Makefile | 1 +
drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++
drivers/power/power_seq/power_seq_delay.c | 65 ++++
drivers/power/power_seq/power_seq_gpio.c | 94 ++++++
drivers/power/power_seq/power_seq_pwm.c | 82 +++++
drivers/power/power_seq/power_seq_regulator.c | 83 +++++
drivers/video/backlight/Kconfig | 1 +
drivers/video/backlight/pwm_bl.c | 161 +++++++--
include/linux/power_seq.h | 203 +++++++++++
include/linux/pwm_backlight.h | 18 +-
17 files changed, 1553 insertions(+), 40 deletions(-)
create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt
create mode 100644 Documentation/power/power_seq.txt
create mode 100644 drivers/power/power_seq/Kconfig
create mode 100644 drivers/power/power_seq/Makefile
create mode 100644 drivers/power/power_seq/power_seq.c
create mode 100644 drivers/power/power_seq/power_seq_delay.c
create mode 100644 drivers/power/power_seq/power_seq_gpio.c
create mode 100644 drivers/power/power_seq/power_seq_pwm.c
create mode 100644 drivers/power/power_seq/power_seq_regulator.c
create mode 100644 include/linux/power_seq.h
--
1.7.12.3
^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v7 0/3] Runtime Interpreter Power Sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Quite a big redesign of the feature - both structures and code have been
simplified and should be easier to read and understand, data duplication is
avoided, and much less memory allocations take place at runtime. Usage
interface is also simpler and IMHO more logical.
What happened is that platform_power_seq and power_seq have been merged,
and so power sequences declared as platform data are used "as-is". The
"build" step is not needed anymore - resources are allocated when a
power sequence is added into a set.
There is still one design flaw that I would like to solve: sequences are
still tied to a device, i.e. if you have two devices that use the same
powering scheme, you have to declare two identical power sequences and assign
each of these to one device. It would be much more flexible if sequences could
be shared across devices. The problem is that the resources structure,
references by steps, cannot be shared. Actually we could share it by having
a linked list of devices and resolved resources in the resource structure and
thus share power sequences over devices. That would work for regulator and
PWM resources, which have a get_regulator/pwm(dev, id) function that could
return a different resource depending on the device that is passed.
But there is no similar get_gpio() function for GPIOs which number is directly
specified in the resource, and I don't know if such a function would make
sense otherwise. Opinions on the subject are welcome.
Alexandre Courbot (3):
Runtime Interpreted Power Sequences
pwm_backlight: use power sequences
tegra: ventana: add PWM backlight to device tree
.../devicetree/bindings/power/power_seq.txt | 121 +++++++
.../bindings/video/backlight/pwm-backlight.txt | 72 +++-
Documentation/power/power_seq.txt | 253 ++++++++++++++
arch/arm/boot/dts/tegra20-ventana.dts | 59 +++-
drivers/power/Kconfig | 1 +
drivers/power/Makefile | 1 +
drivers/power/power_seq/Kconfig | 2 +
drivers/power/power_seq/Makefile | 1 +
drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++
drivers/power/power_seq/power_seq_delay.c | 65 ++++
drivers/power/power_seq/power_seq_gpio.c | 94 ++++++
drivers/power/power_seq/power_seq_pwm.c | 82 +++++
drivers/power/power_seq/power_seq_regulator.c | 83 +++++
drivers/video/backlight/Kconfig | 1 +
drivers/video/backlight/pwm_bl.c | 161 +++++++--
include/linux/power_seq.h | 203 +++++++++++
include/linux/pwm_backlight.h | 18 +-
17 files changed, 1553 insertions(+), 40 deletions(-)
create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt
create mode 100644 Documentation/power/power_seq.txt
create mode 100644 drivers/power/power_seq/Kconfig
create mode 100644 drivers/power/power_seq/Makefile
create mode 100644 drivers/power/power_seq/power_seq.c
create mode 100644 drivers/power/power_seq/power_seq_delay.c
create mode 100644 drivers/power/power_seq/power_seq_gpio.c
create mode 100644 drivers/power/power_seq/power_seq_pwm.c
create mode 100644 drivers/power/power_seq/power_seq_regulator.c
create mode 100644 include/linux/power_seq.h
--
1.7.12.3
^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v7 1/3] Runtime Interpreted Power Sequences
2012-10-19 9:06 ` Alexandre Courbot
(?)
@ 2012-10-19 9:06 ` Alexandre Courbot
-1 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Some device drivers (e.g. panel backlights ) need to follow precise
sequences for powering on and off, involving GPIOs, regulators, PWMs
with a precise powering order and delays to respect between each steps.
These sequences are device-specific, and do not belong to a particular
driver - therefore they have been performed by board-specific hook
functions to far.
With the advent of the device tree and of ARM kernels that are not
board-tied, we cannot rely on these board-specific hooks anymore but
need a way to implement these sequences in a portable manner. This patch
introduces a simple interpreter that can execute such power sequences
encoded either as platform data or within the device tree.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../devicetree/bindings/power/power_seq.txt | 121 +++++++
Documentation/power/power_seq.txt | 253 ++++++++++++++
drivers/power/Kconfig | 1 +
drivers/power/Makefile | 1 +
drivers/power/power_seq/Kconfig | 2 +
drivers/power/power_seq/Makefile | 1 +
drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++
drivers/power/power_seq/power_seq_delay.c | 65 ++++
drivers/power/power_seq/power_seq_gpio.c | 94 ++++++
drivers/power/power_seq/power_seq_pwm.c | 82 +++++
drivers/power/power_seq/power_seq_regulator.c | 83 +++++
include/linux/power_seq.h | 203 +++++++++++
12 files changed, 1282 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt
create mode 100644 Documentation/power/power_seq.txt
create mode 100644 drivers/power/power_seq/Kconfig
create mode 100644 drivers/power/power_seq/Makefile
create mode 100644 drivers/power/power_seq/power_seq.c
create mode 100644 drivers/power/power_seq/power_seq_delay.c
create mode 100644 drivers/power/power_seq/power_seq_gpio.c
create mode 100644 drivers/power/power_seq/power_seq_pwm.c
create mode 100644 drivers/power/power_seq/power_seq_regulator.c
create mode 100644 include/linux/power_seq.h
diff --git a/Documentation/devicetree/bindings/power/power_seq.txt b/Documentation/devicetree/bindings/power/power_seq.txt
new file mode 100644
index 0000000..7880a6c
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/power_seq.txt
@@ -0,0 +1,121 @@
+Runtime Interpreted Power Sequences
+===================================
+
+Power sequences are sequential descriptions of actions to be performed on
+power-related resources. Having these descriptions in a well-defined data format
+allows us to take much of the board- or device- specific power control code out
+of the kernel and place it into the device tree instead, making kernels less
+board-dependant.
+
+A device typically makes use of multiple power sequences, for different purposes
+such as powering on and off. All the power sequences of a given device are
+grouped into a set. In the device tree, this set is a sub-node of the device
+node named "power-sequences".
+
+Power Sequences Structure
+-------------------------
+Every device that makes use of power sequences must have a "power-sequences"
+node into which individual power sequences are declared as sub-nodes. The name
+of the node becomes the name of the sequence within the power sequences
+framework.
+
+Similarly, each power sequence declares its steps as sub-nodes of itself. Steps
+must be named sequentially, with the first step named step0, the second step1,
+etc. Failure to follow this rule will result in a parsing error.
+
+Power Sequences Steps
+---------------------
+Steps of a sequence describe an action to be performed on a resource. They
+always include a "type" property which indicates what kind of resource this
+step works on. Depending on the resource type, additional properties are defined
+to control the action to be performed.
+
+"delay" type required properties:
+ - delay: delay to wait (in microseconds)
+
+"regulator" type required properties:
+ - id: name of the regulator to use.
+ - enable / disable: one of these two empty properties must be present to
+ enable or disable the resource
+
+"pwm" type required properties:
+ - id: name of the PWM to use.
+ - enable / disable: one of these two empty properties must be present to
+ enable or disable the resource
+
+"gpio" type required properties:
+ - gpio: phandle of the GPIO to use.
+ - value: value this GPIO should take. Must be 0 or 1.
+
+Example
+-------
+Here are example sequences declared within a backlight device that use all the
+supported resources types:
+
+ backlight {
+ compatible = "pwm-backlight";
+ ...
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 2 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&backlight_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
+ };
+
+The first part lists the PWM and regulator resources used by the sequences.
+These resources will be requested on behalf of the backlight device when the
+sequences are built and are declared according to their own bindings (for
+instance, regulators and pwms are resolved by name - note though that name
+declaration is done differently by the two frameworks).
+
+After the resources declaration, two sequences follow for powering the backlight
+on and off. Their names are specified by the pwm-backlight device bindings. Once
+the sequences are built by calling devm_of_parse_power_seq_set() on the
+backlight device, they can be added to a set using
+power_seq_set_add_sequences().
diff --git a/Documentation/power/power_seq.txt b/Documentation/power/power_seq.txt
new file mode 100644
index 0000000..8be0570
--- /dev/null
+++ b/Documentation/power/power_seq.txt
@@ -0,0 +1,253 @@
+Runtime Interpreted Power Sequences
+===================================
+
+Problem
+-------
+Very commonly, boards need the help of out-of-driver code to turn some of their
+devices on and off. For instance, SoC boards might use a GPIO (abstracted to a
+regulator or not) to control the power supply of a backlight. The GPIO that
+should be used, however, as well as the exact power sequence that may also
+involve other resources, is board-dependent and thus unknown to the driver.
+
+This was previously addressed by having hooks in the device's platform data that
+are called whenever the state of the device might need a power status change.
+This approach, however, introduces board-dependant code into the kernel and is
+not compatible with the device tree.
+
+The Runtime Interpreted Power Sequences (or power sequences for short) aim at
+turning this code into platform data or device tree nodes. Power sequences are
+described using a simple format and run by a lightweight interpreter whenever
+needed. This allows device drivers to work without power callbacks and makes the
+kernel less board-dependant.
+
+What are Power Sequences?
+-------------------------
+A power sequence is an array of sequential steps describing an action to be
+performed on a resource. The supported resources and actions operations are:
+- delay (just wait for a given number of microseconds)
+- GPIO (set to 0 or 1)
+- regulator (enable or disable)
+- PWM (enable or disable)
+
+When a power sequence is run, its steps is executed one after the other until
+one step fails or the end of the sequence is reached.
+
+Power sequences are named, and grouped into "sets" which contain all the
+sequences of a device as well as the resources they use.
+
+Power sequences can be declared as platform data or in the device tree.
+
+Platform Data Format
+--------------------
+All relevant data structures for declaring power sequences are located in
+include/linux/power_seq.h.
+
+The platform data for a device may include an instance of platform_power_seq_set
+which references all the power sequences used for a device. The power sequences
+reference resources in their steps, and setup the union member that corresponds
+to the resource's type. Resources, similarly, have a union which relevant member
+depends on their type.
+
+Note that the only "platform data" per se here is platform_power_seq_set. Other
+structures (power_seq and power_seq_resource) will be used at runtime and thus
+*must* survive initialization, so do not declare them with the __initdata
+attribute.
+
+The following example should make it clear how the platform data for power
+sequences is defined. It declares two power sequences named "power-on" and
+"power-off" for a backlight device. The "power-on" sequence enables the "power"
+regulator of the device, waits for 10ms, and then enables PWM "backlight" and
+set GPIO 28 to 1. "power-off" does the opposite.
+
+struct power_seq_resource reg_res = {
+ .type = POWER_SEQ_REGULATOR,
+ .regulator.id = "power",
+};
+
+struct power_seq_resource gpio_res = {
+ .type = POWER_SEQ_GPIO,
+ .gpio.gpio = 28,
+};
+
+struct power_seq_resource pwm_res = {
+ .type = POWER_SEQ_PWM,
+ .pwm.id = "backlight",
+};
+
+struct power_seq_resource delay_res = {
+ .type = POWER_SEQ_DELAY,
+};
+
+struct power_seq power_on_seq = {
+ .id = "power-on",
+ .num_steps = 4,
+ .steps = {
+ {
+ .resource = ®_res,
+ .regulator.enable = true,
+ }, {
+ .resource = &delay_res,
+ .delay.delay = 10000,
+ }, {
+ .resource = &pwm_res,
+ .pwm.enable = true,
+ }, {
+ .resource = &gpio_res,
+ .gpio.value = 1,
+ },
+ },
+};
+
+struct power_seq power_off_seq = {
+ .id = "power-off",
+ .num_steps = 4,
+ .steps = {
+ {
+ .resource = &gpio_res,
+ .gpio.value = 0,
+ }, {
+ .resource = &pwm_res,
+ .pwm.enable = false,
+ }, {
+ .resource = &delay_res,
+ .delay.delay = 10000,
+ }, {
+ .resource = ®_res,
+ .regulator.enable = false,
+ },
+ },
+};
+
+struct platform_power_seq_set backlight_power_seqs __initdata = {
+ .num_seqs = 2,
+ .seqs = {
+ &power_on_seq,
+ &power_off_seq,
+ },
+};
+
+"backlight_power_seqs" can then be passed to power_seq_set_add_sequences() in
+order to add the sequences to a set and allocate all the necessary resources.
+More on this later in this document.
+
+Device Tree
+-----------
+Power sequences can also be encoded as device tree nodes. The following
+properties and nodes are equivalent to the platform data defined previously:
+
+pwms = <&pwm 2 5000000>;
+pwm-names = "backlight";
+power-supply = <&vdd_bl_reg>;
+
+power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+};
+
+See Documentation/devicetree/bindings/power/power_seq.txt for the complete
+syntax of the DT bindings.
+
+Use by Drivers and Resources Management
+---------------------------------------
+Power sequences make use of resources that must be properly allocated and
+managed. The power_seq_set structure manages the sequences and resources for a
+particular device. A driver willing to use power sequences will thus declare one
+instance of power_seq_set per device and initialize it at probe time:
+
+struct my_device_data {
+ struct device *dev;
+ ...
+ struct power_set_set power_seqs;
+ ...
+};
+
+power_seq_set_init(&my_device->power_seqs, my_device->dev);
+
+The power_seq_set_add_sequence() and power_seq_set_add_sequences() functions are
+then used to add one or several sequences to a set. These functions will also
+allocate all the resources used by the sequence(s) and make sure they are ready
+to be run. All resources are allocated through devm and will thus be freed when
+the set's device is removed.
+
+ int power_seq_set_add_sequence(struct power_seq_set *set,
+ struct power_seq *seq);
+ int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs);
+
+Power sequences added to a set can then be resolved by their name using
+power_seq_lookup():
+
+ struct power_seq *power_seq_lookup(struct power_seq_set *seqs,
+ const char *id);
+
+power_seq_lookup() returns a ready-to-run pointer to the power sequence which
+name matches the id parameter.
+
+A retrieved power sequence can then be executed by power_seq_run:
+
+ int power_seq_run(struct power_seq *seq);
+
+It returns 0 if the sequence has successfully been run, or an error code if a
+problem occurred.
+
+Sometimes, you may want to browse the list of resources allocated for the
+sequences of a device, for instance to ensure that a resource of a given type is
+present. The power_seq_for_each_resource() macro does this:
+
+ power_seq_for_each_resource(pos, seqs)
+
+Here "pos" will be a pointer to a struct power_seq_resource. This structure
+contains the type of the resource, the information used for identifying it, and
+the resolved resource itself.
+
+Finally, users of the device tree can obtain a platform_power_seq_set structure
+built from the device's node using devm_of_parse_power_seq_set:
+
+ struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev);
+
+The power sequences must be declared under a "power-sequences" node directly
+declared under the device's node. Detailed syntax contained in Documentation/devicetree/bindings/power/power_seq.txt. As the function name
+states, all memory is allocated through devm. The returned
+platform_power_seq_set can be freed after being added to a set, but the
+sequences themselves must be preserved until they are freed by devm.
\ No newline at end of file
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 49a8939..f20d449 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -338,3 +338,4 @@ config AB8500_BATTERY_THERM_ON_BATCTRL
endif # POWER_SUPPLY
source "drivers/power/avs/Kconfig"
+source "drivers/power/power_seq/Kconfig"
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index b949cf8..883ad4d 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o
obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o
obj-$(CONFIG_POWER_AVS) += avs/
obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o
+obj-$(CONFIG_POWER_SEQ) += power_seq/
diff --git a/drivers/power/power_seq/Kconfig b/drivers/power/power_seq/Kconfig
new file mode 100644
index 0000000..3bff26e
--- /dev/null
+++ b/drivers/power/power_seq/Kconfig
@@ -0,0 +1,2 @@
+config POWER_SEQ
+ bool
diff --git a/drivers/power/power_seq/Makefile b/drivers/power/power_seq/Makefile
new file mode 100644
index 0000000..f77a359
--- /dev/null
+++ b/drivers/power/power_seq/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_POWER_SEQ) += power_seq.o
diff --git a/drivers/power/power_seq/power_seq.c b/drivers/power/power_seq/power_seq.c
new file mode 100644
index 0000000..255b1a0
--- /dev/null
+++ b/drivers/power/power_seq/power_seq.c
@@ -0,0 +1,376 @@
+/*
+ * power_seq.c - power sequence interpreter for platform devices and device tree
+ *
+ * Author: Alexandre Courbot <acourbot@nvidia.com>
+ *
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/power_seq.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/device.h>
+
+#include <linux/of.h>
+
+#define power_seq_err(seq, step_nbr, format, ...) \
+ dev_err(seq->set->dev, "%s[%d]: " format, seq->id, step_nbr, \
+ ##__VA_ARGS__);
+
+/**
+ * struct power_seq_res_ops - operators for power sequences resources
+ * @name: Name of the resource type. Set to null when a resource
+ * type support is not compiled in
+ * @of_parse: Parse a step for this kind of resource from a device
+ * tree node. The result of parsing must be written into
+ * step step_nbr of seq
+ * @step_run: Run a step for this kind of resource
+ * @res_compare: Return true if the resource used by the resource is the
+ * same as the one referenced by the step, false otherwise.
+ * @res_alloc: Resolve and allocate a resource. Return error code if
+ * the resource cannot be allocated, 0 otherwise
+ */
+struct power_seq_res_ops {
+ const char *name;
+ int (*of_parse)(struct device_node *node, struct power_seq *seq,
+ unsigned int step_nbr, struct power_seq_resource *res);
+ int (*step_run)(struct power_seq_step *step);
+ bool (*res_compare)(struct power_seq_resource *res,
+ struct power_seq_resource *res2);
+ int (*res_alloc)(struct device *dev,
+ struct power_seq_resource *res);
+};
+
+static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES];
+
+#ifdef CONFIG_OF
+static int of_power_seq_parse_enable_properties(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ bool *enable)
+{
+ if (of_find_property(node, "enable", NULL)) {
+ *enable = true;
+ } else if (of_find_property(node, "disable", NULL)) {
+ *enable = false;
+ } else {
+ power_seq_err(seq, step_nbr,
+ "missing enable or disable property\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int of_power_seq_parse_step(struct device *dev,
+ struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct list_head *resources)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ struct power_seq_resource res, *res2;
+ const char *type;
+ int i, err;
+
+ err = of_property_read_string(node, "type", &type);
+ if (err < 0) {
+ power_seq_err(seq, step_nbr, "cannot read type property\n");
+ return err;
+ }
+ for (i = 0; i < POWER_SEQ_NUM_TYPES; i++) {
+ if (power_seq_ops[i].name == NULL)
+ continue;
+ if (!strcmp(type, power_seq_ops[i].name))
+ break;
+ }
+ if (i >= POWER_SEQ_NUM_TYPES) {
+ power_seq_err(seq, step_nbr, "unknown type %s\n", type);
+ return -EINVAL;
+ }
+ memset(&res, 0, sizeof(res));
+ res.type = i;
+ err = power_seq_ops[res.type].of_parse(node, seq, step_nbr, &res);
+ if (err < 0)
+ return err;
+
+ /* Use the same instance of the resource if met before */
+ list_for_each_entry(res2, resources, list) {
+ if (res.type == res2->type &&
+ power_seq_ops[res.type].res_compare(&res, res2))
+ break;
+ }
+ /* Resource never met before, create it */
+ if (&res2->list == resources) {
+ res2 = devm_kzalloc(dev, sizeof(*res2), GFP_KERNEL);
+ if (!res2)
+ return -ENOMEM;
+ memcpy(res2, &res, sizeof(res));
+ list_add_tail(&res2->list, resources);
+ }
+ step->resource = res2;
+
+ return 0;
+}
+
+static struct power_seq *of_parse_power_seq(struct device *dev,
+ struct device_node *node,
+ struct list_head *resources)
+{
+ struct device_node *child = NULL;
+ struct power_seq *pseq;
+ int num_steps, sz;
+ int err;
+
+ if (!node)
+ return ERR_PTR(-EINVAL);
+
+ num_steps = of_get_child_count(node);
+ sz = sizeof(*pseq) + sizeof(pseq->steps[0]) * num_steps;
+ pseq = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!pseq)
+ return ERR_PTR(-ENOMEM);
+ pseq->id = node->name;
+ pseq->num_steps = num_steps;
+
+ for_each_child_of_node(node, child) {
+ unsigned int pos;
+
+ /* Check that the name's format is correct and within bounds */
+ if (strncmp("step", child->name, 4)) {
+ err = -EINVAL;
+ goto parse_error;
+ }
+
+ err = kstrtouint(child->name + 4, 10, &pos);
+ if (err < 0)
+ goto parse_error;
+
+ /* Invalid step index or step already parsed? */
+ if (pos >= num_steps || pseq->steps[pos].resource != NULL) {
+ err = -EINVAL;
+ goto parse_error;
+ }
+
+ err = of_power_seq_parse_step(dev, child, pseq, pos, resources);
+ if (err)
+ return ERR_PTR(err);
+ }
+
+ return pseq;
+
+parse_error:
+ dev_err(dev, "%s: invalid power step name %s!\n", pseq->id,
+ child->name);
+ return ERR_PTR(err);
+}
+
+/**
+ * devm_of_parse_power_seq_set - build a power_seq_set from the device tree
+ * @dev: Device to parse the power sequences of
+ *
+ * Sequences must be contained into a subnode named "power-sequences" of the
+ * device root node.
+ *
+ * Memory for the sequence is allocated using devm_kzalloc on dev. The returned
+ * platform_power_seq_set can be freed by devm_kfree after the sequences have
+ * been added, but the sequences themselves must be preserved.
+ *
+ * Returns the built set on success, or an error code in case of failure.
+ */
+struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev)
+{
+ struct platform_power_seq_set *set;
+ struct device_node *root = dev->of_node;
+ struct device_node *seq;
+ struct list_head resources;
+ int n, sz;
+
+ if (!root)
+ return NULL;
+
+ root = of_find_node_by_name(root, "power-sequences");
+ if (!root)
+ return NULL;
+
+ n = of_get_child_count(root);
+ sz = sizeof(*set) + sizeof(struct power_seq *) * n;
+ set = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!set)
+ return ERR_PTR(-ENOMEM);
+ set->num_seqs = n;
+
+ n = 0;
+ INIT_LIST_HEAD(&resources);
+ for_each_child_of_node(root, seq) {
+ struct power_seq *pseq;
+
+ pseq = of_parse_power_seq(dev, seq, &resources);
+ if (IS_ERR(pseq))
+ return (void *)pseq;
+
+ set->seqs[n++] = pseq;
+ }
+
+ return set;
+}
+EXPORT_SYMBOL_GPL(devm_of_parse_power_seq_set);
+#endif /* CONFIG_OF */
+
+/**
+ * power_seq_set_init - initialize a power_seq_set
+ * @set: Set to initialize
+ * @dev: Device this set is going to belong to
+ */
+void power_seq_set_init(struct power_seq_set *set, struct device *dev)
+{
+ set->dev = dev;
+ INIT_LIST_HEAD(&set->resources);
+ INIT_LIST_HEAD(&set->seqs);
+}
+EXPORT_SYMBOL_GPL(power_seq_set_init);
+
+/**
+ * power_seq_add_sequence - add a power sequence to a set
+ * @set: Set to add the sequence to
+ * @seq: Sequence to add
+ *
+ * This step will check that all the resources used by the sequence are
+ * allocated. If they are not, an attempt to allocate them is made. This
+ * operation can fail and and return an error code.
+ *
+ * Returns 0 on success, error code if a resource initialization failed.
+ */
+int power_seq_add_sequence(struct power_seq_set *set, struct power_seq *seq)
+{
+ struct power_seq_resource *res;
+ int i, err;
+
+ for (i = 0; i < seq->num_steps; i++) {
+ struct power_seq_step *step = &seq->steps[i];
+ struct power_seq_resource *step_res = step->resource;
+ list_for_each_entry(res, &set->resources, list) {
+ if (res == step_res)
+ break;
+ }
+ /* resource not allocated yet, allocate and add it */
+ if (&res->list == &set->resources) {
+ err = power_seq_ops[step_res->type].res_alloc(set->dev,
+ step_res);
+ if (err)
+ return err;
+ list_add_tail(&step->resource->list, &set->resources);
+ }
+ }
+
+ list_add_tail(&seq->list, &set->seqs);
+ seq->set = set;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_add_sequence);
+
+/**
+ * power_seq_add_sequences - add power sequences defined as platform data
+ * @set: Set to add the sequences to
+ * @seqs: Sequences to add
+ *
+ * See power_seq_add_sequence for more details.
+ *
+ * Returns 0 on success, error code if a resource initialization failed.
+ */
+int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs)
+{
+ int i, ret;
+
+ for (i = 0; i < seqs->num_seqs; i++) {
+ ret = power_seq_add_sequence(set, seqs->seqs[i]);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_set_add_sequences);
+
+/**
+ * power_seq_lookup - Lookup a power sequence by name from a set
+ * @seqs: The set to look in
+ * @id: Name to look after
+ *
+ * Returns a matching power sequence if it exists, NULL if it does not.
+ */
+struct power_seq *power_seq_lookup(struct power_seq_set *set, const char *id)
+{
+ struct power_seq *seq;
+
+ list_for_each_entry(seq, &set->seqs, list) {
+ if (!strcmp(seq->id, id))
+ return seq;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(power_seq_lookup);
+
+/**
+ * power_seq_run() - run a power sequence
+ * @seq: The power sequence to run
+ *
+ * Returns 0 on success, error code in case of failure.
+ */
+int power_seq_run(struct power_seq *seq)
+{
+ unsigned int i;
+ int err;
+
+ if (!seq)
+ return 0;
+
+ if (!seq->set) {
+ pr_err("cannot run a sequence not added to a set");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < seq->num_steps; i++) {
+ unsigned int type = seq->steps[i].resource->type;
+
+ err = power_seq_ops[type].step_run(&seq->steps[i]);
+ if (err) {
+ power_seq_err(seq, i,
+ "error %d while running power sequence step\n",
+ err);
+ return err;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_run);
+
+#include "power_seq_delay.c"
+#include "power_seq_regulator.c"
+#include "power_seq_pwm.c"
+#include "power_seq_gpio.c"
+
+static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES] = {
+ [POWER_SEQ_DELAY] = POWER_SEQ_DELAY_TYPE,
+ [POWER_SEQ_REGULATOR] = POWER_SEQ_REGULATOR_TYPE,
+ [POWER_SEQ_PWM] = POWER_SEQ_PWM_TYPE,
+ [POWER_SEQ_GPIO] = POWER_SEQ_GPIO_TYPE,
+};
+
+MODULE_AUTHOR("Alexandre Courbot <acourbot@nvidia.com>");
+MODULE_DESCRIPTION("Runtime Interpreted Power Sequences");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/power/power_seq/power_seq_delay.c b/drivers/power/power_seq/power_seq_delay.c
new file mode 100644
index 0000000..5bb0a46
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_delay.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/delay.h>
+
+#ifdef CONFIG_OF
+static int of_power_seq_parse_delay(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_u32(node, "delay",
+ &step->delay.delay);
+ if (err < 0)
+ power_seq_err(seq, step_nbr, "error reading delay property\n");
+
+ return err;
+}
+#else
+#define of_power_seq_parse_delay NULL
+#endif
+
+static bool power_seq_res_compare_delay(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ /* Delay resources are just here to hold the type of steps, so they are
+ * all equivalent. */
+ return true;
+}
+
+static int power_seq_res_alloc_delay(struct device *dev,
+ struct power_seq_resource *res)
+{
+ return 0;
+}
+
+static int power_seq_step_run_delay(struct power_seq_step *step)
+{
+ usleep_range(step->delay.delay,
+ step->delay.delay + 1000);
+
+ return 0;
+}
+
+#define POWER_SEQ_DELAY_TYPE { \
+ .name = "delay", \
+ .of_parse = of_power_seq_parse_delay, \
+ .step_run = power_seq_step_run_delay, \
+ .res_compare = power_seq_res_compare_delay, \
+ .res_alloc = power_seq_res_alloc_delay, \
+}
diff --git a/drivers/power/power_seq/power_seq_gpio.c b/drivers/power/power_seq/power_seq_gpio.c
new file mode 100644
index 0000000..44b4a3d
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_gpio.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_gpio(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int gpio;
+ int err;
+
+ gpio = of_get_named_gpio(node, "gpio", 0);
+ if (gpio < 0) {
+ power_seq_err(seq, step_nbr, "error reading gpio property\n");
+ return gpio;
+ }
+ res->gpio.gpio = gpio;
+
+ err = of_property_read_u32(node, "value", &step->gpio.value);
+ if (err < 0) {
+ power_seq_err(seq, step_nbr, "error reading value property\n");
+ } else if (step->gpio.value < 0 || step->gpio.value > 1) {
+ power_seq_err(seq, step_nbr,
+ "value out of range (must be 0 or 1)\n");
+ err = -EINVAL;
+ }
+
+ return err;
+}
+#else
+#define of_power_seq_parse_gpio NULL
+#endif
+
+static bool power_seq_res_compare_gpio(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return res->gpio.gpio == res2->gpio.gpio;
+}
+
+static int power_seq_res_alloc_gpio(struct device *dev,
+ struct power_seq_resource *res)
+{
+ int err;
+
+ err = devm_gpio_request(dev, res->gpio.gpio, dev_name(dev));
+ if (err) {
+ dev_err(dev, "cannot get gpio %d\n", res->gpio.gpio);
+ return err;
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_gpio(struct power_seq_step *step)
+{
+ struct power_seq_resource *res = step->resource;
+
+ /* set the GPIO direction at first use */
+ if (!res->gpio.is_set) {
+ int err = gpio_direction_output(res->gpio.gpio,
+ step->gpio.value);
+ if (err)
+ return err;
+ res->gpio.is_set = true;
+ } else {
+ gpio_set_value_cansleep(res->gpio.gpio, step->gpio.value);
+ }
+
+ return 0;
+}
+
+#define POWER_SEQ_GPIO_TYPE { \
+ .name = "gpio", \
+ .of_parse = power_seq_of_parse_gpio, \
+ .step_run = power_seq_step_run_gpio, \
+ .res_compare = power_seq_res_compare_gpio, \
+ .res_alloc = power_seq_res_alloc_gpio, \
+}
diff --git a/drivers/power/power_seq/power_seq_pwm.c b/drivers/power/power_seq/power_seq_pwm.c
new file mode 100644
index 0000000..c0a1ec3
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_pwm.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifdef CONFIG_PWM
+
+#include <linux/pwm.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_pwm(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_string(node, "id", &res->pwm.id);
+ if (err) {
+ power_seq_err(seq, step_nbr, "error reading id property\n");
+ return err;
+ }
+
+ err = of_power_seq_parse_enable_properties(node, seq, step_nbr,
+ &step->pwm.enable);
+ return err;
+}
+#else
+#define of_power_seq_parse_pwm NULL
+#endif
+
+static bool power_seq_res_compare_pwm(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return !strcmp(res->pwm.id, res2->pwm.id);
+}
+
+static int power_seq_res_alloc_pwm(struct device *dev,
+ struct power_seq_resource *res)
+{
+ res->pwm.pwm = devm_pwm_get(dev, res->pwm.id);
+ if (IS_ERR(res->pwm.pwm)) {
+ dev_err(dev, "cannot get pwm \"%s\"\n", res->pwm.id);
+ return PTR_ERR(res->pwm.pwm);
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_pwm(struct power_seq_step *step)
+{
+ if (step->pwm.enable) {
+ return pwm_enable(step->resource->pwm.pwm);
+ } else {
+ pwm_disable(step->resource->pwm.pwm);
+ return 0;
+ }
+}
+
+#define POWER_SEQ_PWM_TYPE { \
+ .name = "pwm", \
+ .of_parse = power_seq_of_parse_pwm, \
+ .step_run = power_seq_step_run_pwm, \
+ .res_compare = power_seq_res_compare_pwm, \
+ .res_alloc = power_seq_res_alloc_pwm, \
+}
+
+#else
+
+#define POWER_SEQ_PWM_TYPE {}
+
+#endif
diff --git a/drivers/power/power_seq/power_seq_regulator.c b/drivers/power/power_seq/power_seq_regulator.c
new file mode 100644
index 0000000..282cc95
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_regulator.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifdef CONFIG_REGULATOR
+
+#include <linux/regulator/consumer.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_regulator(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_string(node, "id",
+ &res->regulator.id);
+ if (err) {
+ power_seq_err(seq, step_nbr, "error reading id property\n");
+ return err;
+ }
+
+ err = of_power_seq_parse_enable_properties(node, seq, step_nbr,
+ &step->regulator.enable);
+ return err;
+}
+#else
+#define of_power_seq_parse_regulator NULL
+#endif
+
+static bool
+power_seq_res_compare_regulator(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return !strcmp(res->regulator.id, res2->regulator.id);
+}
+
+static int power_seq_res_alloc_regulator(struct device *dev,
+ struct power_seq_resource *res)
+{
+ res->regulator.regulator = devm_regulator_get(dev, res->regulator.id);
+ if (IS_ERR(res->regulator.regulator)) {
+ dev_err(dev, "cannot get regulator \"%s\"\n",
+ res->regulator.id);
+ return PTR_ERR(res->regulator.regulator);
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_regulator(struct power_seq_step *step)
+{
+ if (step->regulator.enable)
+ return regulator_enable(step->resource->regulator.regulator);
+ else
+ return regulator_disable(step->resource->regulator.regulator);
+}
+
+#define POWER_SEQ_REGULATOR_TYPE { \
+ .name = "regulator", \
+ .of_parse = power_seq_of_parse_regulator, \
+ .step_run = power_seq_step_run_regulator, \
+ .res_compare = power_seq_res_compare_regulator, \
+ .res_alloc = power_seq_res_alloc_regulator, \
+}
+
+#else
+
+#define POWER_SEQ_REGULATOR_TYPE {}
+
+#endif
diff --git a/include/linux/power_seq.h b/include/linux/power_seq.h
new file mode 100644
index 0000000..21b95b6
--- /dev/null
+++ b/include/linux/power_seq.h
@@ -0,0 +1,203 @@
+/*
+ * power_seq.h
+ *
+ * Simple interpreter for power sequences defined as platform data or device
+ * tree properties.
+ *
+ * Power sequences are designed to replace the callbacks typically used in
+ * board-specific files that implement board- or device- specific power
+ * sequences (such as those of backlights). A power sequence is an array of
+ * steps referencing resources (regulators, GPIOs, PWMs, ...) with an action to
+ * perform on them. By having the power sequences interpreted, it becomes
+ * possible to describe them in the device tree and thus to remove
+ * board-specific files from the kernel.
+ *
+ * See Documentation/power/power_seqs.txt for detailed information.
+ *
+ * Author: Alexandre Courbot <acourbot@nvidia.com>
+ *
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifndef __LINUX_POWER_SEQ_H
+#define __LINUX_POWER_SEQ_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+
+struct device;
+struct regulator;
+struct pwm_device;
+
+/**
+ * The different kinds of resources that can be controlled by the sequences
+ */
+enum power_seq_res_type {
+ POWER_SEQ_DELAY,
+ POWER_SEQ_REGULATOR,
+ POWER_SEQ_PWM,
+ POWER_SEQ_GPIO,
+ POWER_SEQ_NUM_TYPES,
+};
+
+/**
+ * struct power_seq_regulator_resource
+ * @id: name of the regulator
+ * @regulator: resolved regulator. Written during resource resolution.
+ */
+struct power_seq_regulator_resource {
+ const char *id;
+ struct regulator *regulator;
+};
+
+/**
+ * struct power_seq_pwm_resource
+ * @id: name of the PWM
+ * @regulator: resolved PWM. Written during resource resolution.
+ */
+struct power_seq_pwm_resource {
+ const char *id;
+ struct pwm_device *pwm;
+};
+
+/**
+ * struct power_seq_gpio_resource
+ * @gpio: number of the GPIO
+ * @is_set: track GPIO state to set its direction at first use
+ */
+struct power_seq_gpio_resource {
+ int gpio;
+ bool is_set;
+};
+
+/**
+ * struct power_seq_resource - resource used by power sequences
+ * @type: type of the resource. This decides which member of the union is
+ * used for this resource
+ * @list: link resources together in power_seq_set
+ * @regulator: used if @type == POWER_SEQ_REGULATOR
+ * @pwm: used if @type == POWER_SEQ_PWM
+ * @gpio: used if @type == POWER_SEQ_GPIO
+ */
+struct power_seq_resource {
+ enum power_seq_res_type type;
+ struct list_head list;
+ union {
+ struct power_seq_regulator_resource regulator;
+ struct power_seq_pwm_resource pwm;
+ struct power_seq_gpio_resource gpio;
+ };
+};
+#define power_seq_for_each_resource(pos, set) \
+ list_for_each_entry(pos, &(set)->resources, list)
+
+/**
+ * struct power_seq_delay_step - action data for delay steps
+ * @delay: amount of time to wait, in microseconds
+ */
+struct power_seq_delay_step {
+ unsigned int delay;
+};
+
+/**
+ * struct power_seq_regulator_step - platform data for regulator steps
+ * @enable: whether to enable or disable the regulator during this step
+ */
+struct power_seq_regulator_step {
+ bool enable;
+};
+
+/**
+ * struct power_seq_pwm_step - action data for PWM steps
+ * @enable: whether to enable or disable the PWM during this step
+ */
+struct power_seq_pwm_step {
+ bool enable;
+};
+
+/**
+ * struct power_seq_gpio_step - action data for GPIO steps
+ * @enable: whether to enable or disable the GPIO during this step
+ */
+struct power_seq_gpio_step {
+ int value;
+};
+
+/**
+ * struct power_seq_step - data for power sequences steps
+ * @resource: resource used by this step
+ * @delay: used if resource->type == POWER_SEQ_DELAY
+ * @regulator: used if resource->type == POWER_SEQ_REGULATOR
+ * @pwm: used if resource->type == POWER_SEQ_PWN
+ * @gpio: used if resource->type == POWER_SEQ_GPIO
+ */
+struct power_seq_step {
+ struct power_seq_resource *resource;
+ union {
+ struct power_seq_delay_step delay;
+ struct power_seq_regulator_step regulator;
+ struct power_seq_pwm_step pwm;
+ struct power_seq_gpio_step gpio;
+ };
+};
+
+struct power_seq_set;
+
+/**
+ * struct power_seq - single power sequence
+ * @id: name of this sequence
+ * @list: link sequences together in power_seq_set. Leave as-is
+ * @set: set this sequence belongs to. Written when added to a set
+ * @num_steps: number of steps in the sequence
+ * @steps: array of steps that make the sequence
+ */
+struct power_seq {
+ const char *id;
+ struct list_head list;
+ struct power_seq_set *set;
+ unsigned int num_steps;
+ struct power_seq_step steps[];
+};
+
+/**
+ * struct power_seq_set - power sequences and resources used by a device
+ * @dev: device this set belongs to
+ * @resources: list of resources used by power sequences
+ * @seqs: list of power sequences
+ */
+struct power_seq_set {
+ struct device *dev;
+ struct list_head resources;
+ struct list_head seqs;
+};
+
+/**
+ * struct platform_power_seq_set - define power sequences as platform data
+ * @num_seqs: number of sequences defined
+ * @seqs: array of num_seqs power sequences
+ */
+struct platform_power_seq_set {
+ unsigned int num_seqs;
+ struct power_seq *seqs[];
+};
+
+struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev);
+void power_seq_set_init(struct power_seq_set *set, struct device *dev);
+int power_seq_set_add_sequence(struct power_seq_set *set,
+ struct power_seq *seq);
+int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs);
+struct power_seq *power_seq_lookup(struct power_seq_set *seqs, const char *id);
+int power_seq_run(struct power_seq *seq);
+
+#endif
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 1/3] Runtime Interpreted Power Sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Some device drivers (e.g. panel backlights ) need to follow precise
sequences for powering on and off, involving GPIOs, regulators, PWMs
with a precise powering order and delays to respect between each steps.
These sequences are device-specific, and do not belong to a particular
driver - therefore they have been performed by board-specific hook
functions to far.
With the advent of the device tree and of ARM kernels that are not
board-tied, we cannot rely on these board-specific hooks anymore but
need a way to implement these sequences in a portable manner. This patch
introduces a simple interpreter that can execute such power sequences
encoded either as platform data or within the device tree.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../devicetree/bindings/power/power_seq.txt | 121 +++++++
Documentation/power/power_seq.txt | 253 ++++++++++++++
drivers/power/Kconfig | 1 +
drivers/power/Makefile | 1 +
drivers/power/power_seq/Kconfig | 2 +
drivers/power/power_seq/Makefile | 1 +
drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++
drivers/power/power_seq/power_seq_delay.c | 65 ++++
drivers/power/power_seq/power_seq_gpio.c | 94 ++++++
drivers/power/power_seq/power_seq_pwm.c | 82 +++++
drivers/power/power_seq/power_seq_regulator.c | 83 +++++
include/linux/power_seq.h | 203 +++++++++++
12 files changed, 1282 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt
create mode 100644 Documentation/power/power_seq.txt
create mode 100644 drivers/power/power_seq/Kconfig
create mode 100644 drivers/power/power_seq/Makefile
create mode 100644 drivers/power/power_seq/power_seq.c
create mode 100644 drivers/power/power_seq/power_seq_delay.c
create mode 100644 drivers/power/power_seq/power_seq_gpio.c
create mode 100644 drivers/power/power_seq/power_seq_pwm.c
create mode 100644 drivers/power/power_seq/power_seq_regulator.c
create mode 100644 include/linux/power_seq.h
diff --git a/Documentation/devicetree/bindings/power/power_seq.txt b/Documentation/devicetree/bindings/power/power_seq.txt
new file mode 100644
index 0000000..7880a6c
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/power_seq.txt
@@ -0,0 +1,121 @@
+Runtime Interpreted Power Sequences
+===================================
+
+Power sequences are sequential descriptions of actions to be performed on
+power-related resources. Having these descriptions in a well-defined data format
+allows us to take much of the board- or device- specific power control code out
+of the kernel and place it into the device tree instead, making kernels less
+board-dependant.
+
+A device typically makes use of multiple power sequences, for different purposes
+such as powering on and off. All the power sequences of a given device are
+grouped into a set. In the device tree, this set is a sub-node of the device
+node named "power-sequences".
+
+Power Sequences Structure
+-------------------------
+Every device that makes use of power sequences must have a "power-sequences"
+node into which individual power sequences are declared as sub-nodes. The name
+of the node becomes the name of the sequence within the power sequences
+framework.
+
+Similarly, each power sequence declares its steps as sub-nodes of itself. Steps
+must be named sequentially, with the first step named step0, the second step1,
+etc. Failure to follow this rule will result in a parsing error.
+
+Power Sequences Steps
+---------------------
+Steps of a sequence describe an action to be performed on a resource. They
+always include a "type" property which indicates what kind of resource this
+step works on. Depending on the resource type, additional properties are defined
+to control the action to be performed.
+
+"delay" type required properties:
+ - delay: delay to wait (in microseconds)
+
+"regulator" type required properties:
+ - id: name of the regulator to use.
+ - enable / disable: one of these two empty properties must be present to
+ enable or disable the resource
+
+"pwm" type required properties:
+ - id: name of the PWM to use.
+ - enable / disable: one of these two empty properties must be present to
+ enable or disable the resource
+
+"gpio" type required properties:
+ - gpio: phandle of the GPIO to use.
+ - value: value this GPIO should take. Must be 0 or 1.
+
+Example
+-------
+Here are example sequences declared within a backlight device that use all the
+supported resources types:
+
+ backlight {
+ compatible = "pwm-backlight";
+ ...
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 2 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&backlight_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
+ };
+
+The first part lists the PWM and regulator resources used by the sequences.
+These resources will be requested on behalf of the backlight device when the
+sequences are built and are declared according to their own bindings (for
+instance, regulators and pwms are resolved by name - note though that name
+declaration is done differently by the two frameworks).
+
+After the resources declaration, two sequences follow for powering the backlight
+on and off. Their names are specified by the pwm-backlight device bindings. Once
+the sequences are built by calling devm_of_parse_power_seq_set() on the
+backlight device, they can be added to a set using
+power_seq_set_add_sequences().
diff --git a/Documentation/power/power_seq.txt b/Documentation/power/power_seq.txt
new file mode 100644
index 0000000..8be0570
--- /dev/null
+++ b/Documentation/power/power_seq.txt
@@ -0,0 +1,253 @@
+Runtime Interpreted Power Sequences
+===================================
+
+Problem
+-------
+Very commonly, boards need the help of out-of-driver code to turn some of their
+devices on and off. For instance, SoC boards might use a GPIO (abstracted to a
+regulator or not) to control the power supply of a backlight. The GPIO that
+should be used, however, as well as the exact power sequence that may also
+involve other resources, is board-dependent and thus unknown to the driver.
+
+This was previously addressed by having hooks in the device's platform data that
+are called whenever the state of the device might need a power status change.
+This approach, however, introduces board-dependant code into the kernel and is
+not compatible with the device tree.
+
+The Runtime Interpreted Power Sequences (or power sequences for short) aim at
+turning this code into platform data or device tree nodes. Power sequences are
+described using a simple format and run by a lightweight interpreter whenever
+needed. This allows device drivers to work without power callbacks and makes the
+kernel less board-dependant.
+
+What are Power Sequences?
+-------------------------
+A power sequence is an array of sequential steps describing an action to be
+performed on a resource. The supported resources and actions operations are:
+- delay (just wait for a given number of microseconds)
+- GPIO (set to 0 or 1)
+- regulator (enable or disable)
+- PWM (enable or disable)
+
+When a power sequence is run, its steps is executed one after the other until
+one step fails or the end of the sequence is reached.
+
+Power sequences are named, and grouped into "sets" which contain all the
+sequences of a device as well as the resources they use.
+
+Power sequences can be declared as platform data or in the device tree.
+
+Platform Data Format
+--------------------
+All relevant data structures for declaring power sequences are located in
+include/linux/power_seq.h.
+
+The platform data for a device may include an instance of platform_power_seq_set
+which references all the power sequences used for a device. The power sequences
+reference resources in their steps, and setup the union member that corresponds
+to the resource's type. Resources, similarly, have a union which relevant member
+depends on their type.
+
+Note that the only "platform data" per se here is platform_power_seq_set. Other
+structures (power_seq and power_seq_resource) will be used at runtime and thus
+*must* survive initialization, so do not declare them with the __initdata
+attribute.
+
+The following example should make it clear how the platform data for power
+sequences is defined. It declares two power sequences named "power-on" and
+"power-off" for a backlight device. The "power-on" sequence enables the "power"
+regulator of the device, waits for 10ms, and then enables PWM "backlight" and
+set GPIO 28 to 1. "power-off" does the opposite.
+
+struct power_seq_resource reg_res = {
+ .type = POWER_SEQ_REGULATOR,
+ .regulator.id = "power",
+};
+
+struct power_seq_resource gpio_res = {
+ .type = POWER_SEQ_GPIO,
+ .gpio.gpio = 28,
+};
+
+struct power_seq_resource pwm_res = {
+ .type = POWER_SEQ_PWM,
+ .pwm.id = "backlight",
+};
+
+struct power_seq_resource delay_res = {
+ .type = POWER_SEQ_DELAY,
+};
+
+struct power_seq power_on_seq = {
+ .id = "power-on",
+ .num_steps = 4,
+ .steps = {
+ {
+ .resource = ®_res,
+ .regulator.enable = true,
+ }, {
+ .resource = &delay_res,
+ .delay.delay = 10000,
+ }, {
+ .resource = &pwm_res,
+ .pwm.enable = true,
+ }, {
+ .resource = &gpio_res,
+ .gpio.value = 1,
+ },
+ },
+};
+
+struct power_seq power_off_seq = {
+ .id = "power-off",
+ .num_steps = 4,
+ .steps = {
+ {
+ .resource = &gpio_res,
+ .gpio.value = 0,
+ }, {
+ .resource = &pwm_res,
+ .pwm.enable = false,
+ }, {
+ .resource = &delay_res,
+ .delay.delay = 10000,
+ }, {
+ .resource = ®_res,
+ .regulator.enable = false,
+ },
+ },
+};
+
+struct platform_power_seq_set backlight_power_seqs __initdata = {
+ .num_seqs = 2,
+ .seqs = {
+ &power_on_seq,
+ &power_off_seq,
+ },
+};
+
+"backlight_power_seqs" can then be passed to power_seq_set_add_sequences() in
+order to add the sequences to a set and allocate all the necessary resources.
+More on this later in this document.
+
+Device Tree
+-----------
+Power sequences can also be encoded as device tree nodes. The following
+properties and nodes are equivalent to the platform data defined previously:
+
+pwms = <&pwm 2 5000000>;
+pwm-names = "backlight";
+power-supply = <&vdd_bl_reg>;
+
+power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+};
+
+See Documentation/devicetree/bindings/power/power_seq.txt for the complete
+syntax of the DT bindings.
+
+Use by Drivers and Resources Management
+---------------------------------------
+Power sequences make use of resources that must be properly allocated and
+managed. The power_seq_set structure manages the sequences and resources for a
+particular device. A driver willing to use power sequences will thus declare one
+instance of power_seq_set per device and initialize it at probe time:
+
+struct my_device_data {
+ struct device *dev;
+ ...
+ struct power_set_set power_seqs;
+ ...
+};
+
+power_seq_set_init(&my_device->power_seqs, my_device->dev);
+
+The power_seq_set_add_sequence() and power_seq_set_add_sequences() functions are
+then used to add one or several sequences to a set. These functions will also
+allocate all the resources used by the sequence(s) and make sure they are ready
+to be run. All resources are allocated through devm and will thus be freed when
+the set's device is removed.
+
+ int power_seq_set_add_sequence(struct power_seq_set *set,
+ struct power_seq *seq);
+ int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs);
+
+Power sequences added to a set can then be resolved by their name using
+power_seq_lookup():
+
+ struct power_seq *power_seq_lookup(struct power_seq_set *seqs,
+ const char *id);
+
+power_seq_lookup() returns a ready-to-run pointer to the power sequence which
+name matches the id parameter.
+
+A retrieved power sequence can then be executed by power_seq_run:
+
+ int power_seq_run(struct power_seq *seq);
+
+It returns 0 if the sequence has successfully been run, or an error code if a
+problem occurred.
+
+Sometimes, you may want to browse the list of resources allocated for the
+sequences of a device, for instance to ensure that a resource of a given type is
+present. The power_seq_for_each_resource() macro does this:
+
+ power_seq_for_each_resource(pos, seqs)
+
+Here "pos" will be a pointer to a struct power_seq_resource. This structure
+contains the type of the resource, the information used for identifying it, and
+the resolved resource itself.
+
+Finally, users of the device tree can obtain a platform_power_seq_set structure
+built from the device's node using devm_of_parse_power_seq_set:
+
+ struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev);
+
+The power sequences must be declared under a "power-sequences" node directly
+declared under the device's node. Detailed syntax contained in Documentation/devicetree/bindings/power/power_seq.txt. As the function name
+states, all memory is allocated through devm. The returned
+platform_power_seq_set can be freed after being added to a set, but the
+sequences themselves must be preserved until they are freed by devm.
\ No newline at end of file
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 49a8939..f20d449 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -338,3 +338,4 @@ config AB8500_BATTERY_THERM_ON_BATCTRL
endif # POWER_SUPPLY
source "drivers/power/avs/Kconfig"
+source "drivers/power/power_seq/Kconfig"
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index b949cf8..883ad4d 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o
obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o
obj-$(CONFIG_POWER_AVS) += avs/
obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o
+obj-$(CONFIG_POWER_SEQ) += power_seq/
diff --git a/drivers/power/power_seq/Kconfig b/drivers/power/power_seq/Kconfig
new file mode 100644
index 0000000..3bff26e
--- /dev/null
+++ b/drivers/power/power_seq/Kconfig
@@ -0,0 +1,2 @@
+config POWER_SEQ
+ bool
diff --git a/drivers/power/power_seq/Makefile b/drivers/power/power_seq/Makefile
new file mode 100644
index 0000000..f77a359
--- /dev/null
+++ b/drivers/power/power_seq/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_POWER_SEQ) += power_seq.o
diff --git a/drivers/power/power_seq/power_seq.c b/drivers/power/power_seq/power_seq.c
new file mode 100644
index 0000000..255b1a0
--- /dev/null
+++ b/drivers/power/power_seq/power_seq.c
@@ -0,0 +1,376 @@
+/*
+ * power_seq.c - power sequence interpreter for platform devices and device tree
+ *
+ * Author: Alexandre Courbot <acourbot@nvidia.com>
+ *
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/power_seq.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/device.h>
+
+#include <linux/of.h>
+
+#define power_seq_err(seq, step_nbr, format, ...) \
+ dev_err(seq->set->dev, "%s[%d]: " format, seq->id, step_nbr, \
+ ##__VA_ARGS__);
+
+/**
+ * struct power_seq_res_ops - operators for power sequences resources
+ * @name: Name of the resource type. Set to null when a resource
+ * type support is not compiled in
+ * @of_parse: Parse a step for this kind of resource from a device
+ * tree node. The result of parsing must be written into
+ * step step_nbr of seq
+ * @step_run: Run a step for this kind of resource
+ * @res_compare: Return true if the resource used by the resource is the
+ * same as the one referenced by the step, false otherwise.
+ * @res_alloc: Resolve and allocate a resource. Return error code if
+ * the resource cannot be allocated, 0 otherwise
+ */
+struct power_seq_res_ops {
+ const char *name;
+ int (*of_parse)(struct device_node *node, struct power_seq *seq,
+ unsigned int step_nbr, struct power_seq_resource *res);
+ int (*step_run)(struct power_seq_step *step);
+ bool (*res_compare)(struct power_seq_resource *res,
+ struct power_seq_resource *res2);
+ int (*res_alloc)(struct device *dev,
+ struct power_seq_resource *res);
+};
+
+static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES];
+
+#ifdef CONFIG_OF
+static int of_power_seq_parse_enable_properties(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ bool *enable)
+{
+ if (of_find_property(node, "enable", NULL)) {
+ *enable = true;
+ } else if (of_find_property(node, "disable", NULL)) {
+ *enable = false;
+ } else {
+ power_seq_err(seq, step_nbr,
+ "missing enable or disable property\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int of_power_seq_parse_step(struct device *dev,
+ struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct list_head *resources)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ struct power_seq_resource res, *res2;
+ const char *type;
+ int i, err;
+
+ err = of_property_read_string(node, "type", &type);
+ if (err < 0) {
+ power_seq_err(seq, step_nbr, "cannot read type property\n");
+ return err;
+ }
+ for (i = 0; i < POWER_SEQ_NUM_TYPES; i++) {
+ if (power_seq_ops[i].name == NULL)
+ continue;
+ if (!strcmp(type, power_seq_ops[i].name))
+ break;
+ }
+ if (i >= POWER_SEQ_NUM_TYPES) {
+ power_seq_err(seq, step_nbr, "unknown type %s\n", type);
+ return -EINVAL;
+ }
+ memset(&res, 0, sizeof(res));
+ res.type = i;
+ err = power_seq_ops[res.type].of_parse(node, seq, step_nbr, &res);
+ if (err < 0)
+ return err;
+
+ /* Use the same instance of the resource if met before */
+ list_for_each_entry(res2, resources, list) {
+ if (res.type == res2->type &&
+ power_seq_ops[res.type].res_compare(&res, res2))
+ break;
+ }
+ /* Resource never met before, create it */
+ if (&res2->list == resources) {
+ res2 = devm_kzalloc(dev, sizeof(*res2), GFP_KERNEL);
+ if (!res2)
+ return -ENOMEM;
+ memcpy(res2, &res, sizeof(res));
+ list_add_tail(&res2->list, resources);
+ }
+ step->resource = res2;
+
+ return 0;
+}
+
+static struct power_seq *of_parse_power_seq(struct device *dev,
+ struct device_node *node,
+ struct list_head *resources)
+{
+ struct device_node *child = NULL;
+ struct power_seq *pseq;
+ int num_steps, sz;
+ int err;
+
+ if (!node)
+ return ERR_PTR(-EINVAL);
+
+ num_steps = of_get_child_count(node);
+ sz = sizeof(*pseq) + sizeof(pseq->steps[0]) * num_steps;
+ pseq = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!pseq)
+ return ERR_PTR(-ENOMEM);
+ pseq->id = node->name;
+ pseq->num_steps = num_steps;
+
+ for_each_child_of_node(node, child) {
+ unsigned int pos;
+
+ /* Check that the name's format is correct and within bounds */
+ if (strncmp("step", child->name, 4)) {
+ err = -EINVAL;
+ goto parse_error;
+ }
+
+ err = kstrtouint(child->name + 4, 10, &pos);
+ if (err < 0)
+ goto parse_error;
+
+ /* Invalid step index or step already parsed? */
+ if (pos >= num_steps || pseq->steps[pos].resource != NULL) {
+ err = -EINVAL;
+ goto parse_error;
+ }
+
+ err = of_power_seq_parse_step(dev, child, pseq, pos, resources);
+ if (err)
+ return ERR_PTR(err);
+ }
+
+ return pseq;
+
+parse_error:
+ dev_err(dev, "%s: invalid power step name %s!\n", pseq->id,
+ child->name);
+ return ERR_PTR(err);
+}
+
+/**
+ * devm_of_parse_power_seq_set - build a power_seq_set from the device tree
+ * @dev: Device to parse the power sequences of
+ *
+ * Sequences must be contained into a subnode named "power-sequences" of the
+ * device root node.
+ *
+ * Memory for the sequence is allocated using devm_kzalloc on dev. The returned
+ * platform_power_seq_set can be freed by devm_kfree after the sequences have
+ * been added, but the sequences themselves must be preserved.
+ *
+ * Returns the built set on success, or an error code in case of failure.
+ */
+struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev)
+{
+ struct platform_power_seq_set *set;
+ struct device_node *root = dev->of_node;
+ struct device_node *seq;
+ struct list_head resources;
+ int n, sz;
+
+ if (!root)
+ return NULL;
+
+ root = of_find_node_by_name(root, "power-sequences");
+ if (!root)
+ return NULL;
+
+ n = of_get_child_count(root);
+ sz = sizeof(*set) + sizeof(struct power_seq *) * n;
+ set = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!set)
+ return ERR_PTR(-ENOMEM);
+ set->num_seqs = n;
+
+ n = 0;
+ INIT_LIST_HEAD(&resources);
+ for_each_child_of_node(root, seq) {
+ struct power_seq *pseq;
+
+ pseq = of_parse_power_seq(dev, seq, &resources);
+ if (IS_ERR(pseq))
+ return (void *)pseq;
+
+ set->seqs[n++] = pseq;
+ }
+
+ return set;
+}
+EXPORT_SYMBOL_GPL(devm_of_parse_power_seq_set);
+#endif /* CONFIG_OF */
+
+/**
+ * power_seq_set_init - initialize a power_seq_set
+ * @set: Set to initialize
+ * @dev: Device this set is going to belong to
+ */
+void power_seq_set_init(struct power_seq_set *set, struct device *dev)
+{
+ set->dev = dev;
+ INIT_LIST_HEAD(&set->resources);
+ INIT_LIST_HEAD(&set->seqs);
+}
+EXPORT_SYMBOL_GPL(power_seq_set_init);
+
+/**
+ * power_seq_add_sequence - add a power sequence to a set
+ * @set: Set to add the sequence to
+ * @seq: Sequence to add
+ *
+ * This step will check that all the resources used by the sequence are
+ * allocated. If they are not, an attempt to allocate them is made. This
+ * operation can fail and and return an error code.
+ *
+ * Returns 0 on success, error code if a resource initialization failed.
+ */
+int power_seq_add_sequence(struct power_seq_set *set, struct power_seq *seq)
+{
+ struct power_seq_resource *res;
+ int i, err;
+
+ for (i = 0; i < seq->num_steps; i++) {
+ struct power_seq_step *step = &seq->steps[i];
+ struct power_seq_resource *step_res = step->resource;
+ list_for_each_entry(res, &set->resources, list) {
+ if (res == step_res)
+ break;
+ }
+ /* resource not allocated yet, allocate and add it */
+ if (&res->list == &set->resources) {
+ err = power_seq_ops[step_res->type].res_alloc(set->dev,
+ step_res);
+ if (err)
+ return err;
+ list_add_tail(&step->resource->list, &set->resources);
+ }
+ }
+
+ list_add_tail(&seq->list, &set->seqs);
+ seq->set = set;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_add_sequence);
+
+/**
+ * power_seq_add_sequences - add power sequences defined as platform data
+ * @set: Set to add the sequences to
+ * @seqs: Sequences to add
+ *
+ * See power_seq_add_sequence for more details.
+ *
+ * Returns 0 on success, error code if a resource initialization failed.
+ */
+int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs)
+{
+ int i, ret;
+
+ for (i = 0; i < seqs->num_seqs; i++) {
+ ret = power_seq_add_sequence(set, seqs->seqs[i]);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_set_add_sequences);
+
+/**
+ * power_seq_lookup - Lookup a power sequence by name from a set
+ * @seqs: The set to look in
+ * @id: Name to look after
+ *
+ * Returns a matching power sequence if it exists, NULL if it does not.
+ */
+struct power_seq *power_seq_lookup(struct power_seq_set *set, const char *id)
+{
+ struct power_seq *seq;
+
+ list_for_each_entry(seq, &set->seqs, list) {
+ if (!strcmp(seq->id, id))
+ return seq;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(power_seq_lookup);
+
+/**
+ * power_seq_run() - run a power sequence
+ * @seq: The power sequence to run
+ *
+ * Returns 0 on success, error code in case of failure.
+ */
+int power_seq_run(struct power_seq *seq)
+{
+ unsigned int i;
+ int err;
+
+ if (!seq)
+ return 0;
+
+ if (!seq->set) {
+ pr_err("cannot run a sequence not added to a set");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < seq->num_steps; i++) {
+ unsigned int type = seq->steps[i].resource->type;
+
+ err = power_seq_ops[type].step_run(&seq->steps[i]);
+ if (err) {
+ power_seq_err(seq, i,
+ "error %d while running power sequence step\n",
+ err);
+ return err;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_run);
+
+#include "power_seq_delay.c"
+#include "power_seq_regulator.c"
+#include "power_seq_pwm.c"
+#include "power_seq_gpio.c"
+
+static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES] = {
+ [POWER_SEQ_DELAY] = POWER_SEQ_DELAY_TYPE,
+ [POWER_SEQ_REGULATOR] = POWER_SEQ_REGULATOR_TYPE,
+ [POWER_SEQ_PWM] = POWER_SEQ_PWM_TYPE,
+ [POWER_SEQ_GPIO] = POWER_SEQ_GPIO_TYPE,
+};
+
+MODULE_AUTHOR("Alexandre Courbot <acourbot@nvidia.com>");
+MODULE_DESCRIPTION("Runtime Interpreted Power Sequences");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/power/power_seq/power_seq_delay.c b/drivers/power/power_seq/power_seq_delay.c
new file mode 100644
index 0000000..5bb0a46
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_delay.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/delay.h>
+
+#ifdef CONFIG_OF
+static int of_power_seq_parse_delay(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_u32(node, "delay",
+ &step->delay.delay);
+ if (err < 0)
+ power_seq_err(seq, step_nbr, "error reading delay property\n");
+
+ return err;
+}
+#else
+#define of_power_seq_parse_delay NULL
+#endif
+
+static bool power_seq_res_compare_delay(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ /* Delay resources are just here to hold the type of steps, so they are
+ * all equivalent. */
+ return true;
+}
+
+static int power_seq_res_alloc_delay(struct device *dev,
+ struct power_seq_resource *res)
+{
+ return 0;
+}
+
+static int power_seq_step_run_delay(struct power_seq_step *step)
+{
+ usleep_range(step->delay.delay,
+ step->delay.delay + 1000);
+
+ return 0;
+}
+
+#define POWER_SEQ_DELAY_TYPE { \
+ .name = "delay", \
+ .of_parse = of_power_seq_parse_delay, \
+ .step_run = power_seq_step_run_delay, \
+ .res_compare = power_seq_res_compare_delay, \
+ .res_alloc = power_seq_res_alloc_delay, \
+}
diff --git a/drivers/power/power_seq/power_seq_gpio.c b/drivers/power/power_seq/power_seq_gpio.c
new file mode 100644
index 0000000..44b4a3d
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_gpio.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_gpio(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int gpio;
+ int err;
+
+ gpio = of_get_named_gpio(node, "gpio", 0);
+ if (gpio < 0) {
+ power_seq_err(seq, step_nbr, "error reading gpio property\n");
+ return gpio;
+ }
+ res->gpio.gpio = gpio;
+
+ err = of_property_read_u32(node, "value", &step->gpio.value);
+ if (err < 0) {
+ power_seq_err(seq, step_nbr, "error reading value property\n");
+ } else if (step->gpio.value < 0 || step->gpio.value > 1) {
+ power_seq_err(seq, step_nbr,
+ "value out of range (must be 0 or 1)\n");
+ err = -EINVAL;
+ }
+
+ return err;
+}
+#else
+#define of_power_seq_parse_gpio NULL
+#endif
+
+static bool power_seq_res_compare_gpio(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return res->gpio.gpio == res2->gpio.gpio;
+}
+
+static int power_seq_res_alloc_gpio(struct device *dev,
+ struct power_seq_resource *res)
+{
+ int err;
+
+ err = devm_gpio_request(dev, res->gpio.gpio, dev_name(dev));
+ if (err) {
+ dev_err(dev, "cannot get gpio %d\n", res->gpio.gpio);
+ return err;
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_gpio(struct power_seq_step *step)
+{
+ struct power_seq_resource *res = step->resource;
+
+ /* set the GPIO direction at first use */
+ if (!res->gpio.is_set) {
+ int err = gpio_direction_output(res->gpio.gpio,
+ step->gpio.value);
+ if (err)
+ return err;
+ res->gpio.is_set = true;
+ } else {
+ gpio_set_value_cansleep(res->gpio.gpio, step->gpio.value);
+ }
+
+ return 0;
+}
+
+#define POWER_SEQ_GPIO_TYPE { \
+ .name = "gpio", \
+ .of_parse = power_seq_of_parse_gpio, \
+ .step_run = power_seq_step_run_gpio, \
+ .res_compare = power_seq_res_compare_gpio, \
+ .res_alloc = power_seq_res_alloc_gpio, \
+}
diff --git a/drivers/power/power_seq/power_seq_pwm.c b/drivers/power/power_seq/power_seq_pwm.c
new file mode 100644
index 0000000..c0a1ec3
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_pwm.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifdef CONFIG_PWM
+
+#include <linux/pwm.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_pwm(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_string(node, "id", &res->pwm.id);
+ if (err) {
+ power_seq_err(seq, step_nbr, "error reading id property\n");
+ return err;
+ }
+
+ err = of_power_seq_parse_enable_properties(node, seq, step_nbr,
+ &step->pwm.enable);
+ return err;
+}
+#else
+#define of_power_seq_parse_pwm NULL
+#endif
+
+static bool power_seq_res_compare_pwm(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return !strcmp(res->pwm.id, res2->pwm.id);
+}
+
+static int power_seq_res_alloc_pwm(struct device *dev,
+ struct power_seq_resource *res)
+{
+ res->pwm.pwm = devm_pwm_get(dev, res->pwm.id);
+ if (IS_ERR(res->pwm.pwm)) {
+ dev_err(dev, "cannot get pwm \"%s\"\n", res->pwm.id);
+ return PTR_ERR(res->pwm.pwm);
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_pwm(struct power_seq_step *step)
+{
+ if (step->pwm.enable) {
+ return pwm_enable(step->resource->pwm.pwm);
+ } else {
+ pwm_disable(step->resource->pwm.pwm);
+ return 0;
+ }
+}
+
+#define POWER_SEQ_PWM_TYPE { \
+ .name = "pwm", \
+ .of_parse = power_seq_of_parse_pwm, \
+ .step_run = power_seq_step_run_pwm, \
+ .res_compare = power_seq_res_compare_pwm, \
+ .res_alloc = power_seq_res_alloc_pwm, \
+}
+
+#else
+
+#define POWER_SEQ_PWM_TYPE {}
+
+#endif
diff --git a/drivers/power/power_seq/power_seq_regulator.c b/drivers/power/power_seq/power_seq_regulator.c
new file mode 100644
index 0000000..282cc95
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_regulator.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifdef CONFIG_REGULATOR
+
+#include <linux/regulator/consumer.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_regulator(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_string(node, "id",
+ &res->regulator.id);
+ if (err) {
+ power_seq_err(seq, step_nbr, "error reading id property\n");
+ return err;
+ }
+
+ err = of_power_seq_parse_enable_properties(node, seq, step_nbr,
+ &step->regulator.enable);
+ return err;
+}
+#else
+#define of_power_seq_parse_regulator NULL
+#endif
+
+static bool
+power_seq_res_compare_regulator(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return !strcmp(res->regulator.id, res2->regulator.id);
+}
+
+static int power_seq_res_alloc_regulator(struct device *dev,
+ struct power_seq_resource *res)
+{
+ res->regulator.regulator = devm_regulator_get(dev, res->regulator.id);
+ if (IS_ERR(res->regulator.regulator)) {
+ dev_err(dev, "cannot get regulator \"%s\"\n",
+ res->regulator.id);
+ return PTR_ERR(res->regulator.regulator);
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_regulator(struct power_seq_step *step)
+{
+ if (step->regulator.enable)
+ return regulator_enable(step->resource->regulator.regulator);
+ else
+ return regulator_disable(step->resource->regulator.regulator);
+}
+
+#define POWER_SEQ_REGULATOR_TYPE { \
+ .name = "regulator", \
+ .of_parse = power_seq_of_parse_regulator, \
+ .step_run = power_seq_step_run_regulator, \
+ .res_compare = power_seq_res_compare_regulator, \
+ .res_alloc = power_seq_res_alloc_regulator, \
+}
+
+#else
+
+#define POWER_SEQ_REGULATOR_TYPE {}
+
+#endif
diff --git a/include/linux/power_seq.h b/include/linux/power_seq.h
new file mode 100644
index 0000000..21b95b6
--- /dev/null
+++ b/include/linux/power_seq.h
@@ -0,0 +1,203 @@
+/*
+ * power_seq.h
+ *
+ * Simple interpreter for power sequences defined as platform data or device
+ * tree properties.
+ *
+ * Power sequences are designed to replace the callbacks typically used in
+ * board-specific files that implement board- or device- specific power
+ * sequences (such as those of backlights). A power sequence is an array of
+ * steps referencing resources (regulators, GPIOs, PWMs, ...) with an action to
+ * perform on them. By having the power sequences interpreted, it becomes
+ * possible to describe them in the device tree and thus to remove
+ * board-specific files from the kernel.
+ *
+ * See Documentation/power/power_seqs.txt for detailed information.
+ *
+ * Author: Alexandre Courbot <acourbot@nvidia.com>
+ *
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifndef __LINUX_POWER_SEQ_H
+#define __LINUX_POWER_SEQ_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+
+struct device;
+struct regulator;
+struct pwm_device;
+
+/**
+ * The different kinds of resources that can be controlled by the sequences
+ */
+enum power_seq_res_type {
+ POWER_SEQ_DELAY,
+ POWER_SEQ_REGULATOR,
+ POWER_SEQ_PWM,
+ POWER_SEQ_GPIO,
+ POWER_SEQ_NUM_TYPES,
+};
+
+/**
+ * struct power_seq_regulator_resource
+ * @id: name of the regulator
+ * @regulator: resolved regulator. Written during resource resolution.
+ */
+struct power_seq_regulator_resource {
+ const char *id;
+ struct regulator *regulator;
+};
+
+/**
+ * struct power_seq_pwm_resource
+ * @id: name of the PWM
+ * @regulator: resolved PWM. Written during resource resolution.
+ */
+struct power_seq_pwm_resource {
+ const char *id;
+ struct pwm_device *pwm;
+};
+
+/**
+ * struct power_seq_gpio_resource
+ * @gpio: number of the GPIO
+ * @is_set: track GPIO state to set its direction at first use
+ */
+struct power_seq_gpio_resource {
+ int gpio;
+ bool is_set;
+};
+
+/**
+ * struct power_seq_resource - resource used by power sequences
+ * @type: type of the resource. This decides which member of the union is
+ * used for this resource
+ * @list: link resources together in power_seq_set
+ * @regulator: used if @type == POWER_SEQ_REGULATOR
+ * @pwm: used if @type == POWER_SEQ_PWM
+ * @gpio: used if @type == POWER_SEQ_GPIO
+ */
+struct power_seq_resource {
+ enum power_seq_res_type type;
+ struct list_head list;
+ union {
+ struct power_seq_regulator_resource regulator;
+ struct power_seq_pwm_resource pwm;
+ struct power_seq_gpio_resource gpio;
+ };
+};
+#define power_seq_for_each_resource(pos, set) \
+ list_for_each_entry(pos, &(set)->resources, list)
+
+/**
+ * struct power_seq_delay_step - action data for delay steps
+ * @delay: amount of time to wait, in microseconds
+ */
+struct power_seq_delay_step {
+ unsigned int delay;
+};
+
+/**
+ * struct power_seq_regulator_step - platform data for regulator steps
+ * @enable: whether to enable or disable the regulator during this step
+ */
+struct power_seq_regulator_step {
+ bool enable;
+};
+
+/**
+ * struct power_seq_pwm_step - action data for PWM steps
+ * @enable: whether to enable or disable the PWM during this step
+ */
+struct power_seq_pwm_step {
+ bool enable;
+};
+
+/**
+ * struct power_seq_gpio_step - action data for GPIO steps
+ * @enable: whether to enable or disable the GPIO during this step
+ */
+struct power_seq_gpio_step {
+ int value;
+};
+
+/**
+ * struct power_seq_step - data for power sequences steps
+ * @resource: resource used by this step
+ * @delay: used if resource->type == POWER_SEQ_DELAY
+ * @regulator: used if resource->type == POWER_SEQ_REGULATOR
+ * @pwm: used if resource->type == POWER_SEQ_PWN
+ * @gpio: used if resource->type == POWER_SEQ_GPIO
+ */
+struct power_seq_step {
+ struct power_seq_resource *resource;
+ union {
+ struct power_seq_delay_step delay;
+ struct power_seq_regulator_step regulator;
+ struct power_seq_pwm_step pwm;
+ struct power_seq_gpio_step gpio;
+ };
+};
+
+struct power_seq_set;
+
+/**
+ * struct power_seq - single power sequence
+ * @id: name of this sequence
+ * @list: link sequences together in power_seq_set. Leave as-is
+ * @set: set this sequence belongs to. Written when added to a set
+ * @num_steps: number of steps in the sequence
+ * @steps: array of steps that make the sequence
+ */
+struct power_seq {
+ const char *id;
+ struct list_head list;
+ struct power_seq_set *set;
+ unsigned int num_steps;
+ struct power_seq_step steps[];
+};
+
+/**
+ * struct power_seq_set - power sequences and resources used by a device
+ * @dev: device this set belongs to
+ * @resources: list of resources used by power sequences
+ * @seqs: list of power sequences
+ */
+struct power_seq_set {
+ struct device *dev;
+ struct list_head resources;
+ struct list_head seqs;
+};
+
+/**
+ * struct platform_power_seq_set - define power sequences as platform data
+ * @num_seqs: number of sequences defined
+ * @seqs: array of num_seqs power sequences
+ */
+struct platform_power_seq_set {
+ unsigned int num_seqs;
+ struct power_seq *seqs[];
+};
+
+struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev);
+void power_seq_set_init(struct power_seq_set *set, struct device *dev);
+int power_seq_set_add_sequence(struct power_seq_set *set,
+ struct power_seq *seq);
+int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs);
+struct power_seq *power_seq_lookup(struct power_seq_set *seqs, const char *id);
+int power_seq_run(struct power_seq *seq);
+
+#endif
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 1/3] Runtime Interpreted Power Sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Some device drivers (e.g. panel backlights ) need to follow precise
sequences for powering on and off, involving GPIOs, regulators, PWMs
with a precise powering order and delays to respect between each steps.
These sequences are device-specific, and do not belong to a particular
driver - therefore they have been performed by board-specific hook
functions to far.
With the advent of the device tree and of ARM kernels that are not
board-tied, we cannot rely on these board-specific hooks anymore but
need a way to implement these sequences in a portable manner. This patch
introduces a simple interpreter that can execute such power sequences
encoded either as platform data or within the device tree.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../devicetree/bindings/power/power_seq.txt | 121 +++++++
Documentation/power/power_seq.txt | 253 ++++++++++++++
drivers/power/Kconfig | 1 +
drivers/power/Makefile | 1 +
drivers/power/power_seq/Kconfig | 2 +
drivers/power/power_seq/Makefile | 1 +
drivers/power/power_seq/power_seq.c | 376 +++++++++++++++++++++
drivers/power/power_seq/power_seq_delay.c | 65 ++++
drivers/power/power_seq/power_seq_gpio.c | 94 ++++++
drivers/power/power_seq/power_seq_pwm.c | 82 +++++
drivers/power/power_seq/power_seq_regulator.c | 83 +++++
include/linux/power_seq.h | 203 +++++++++++
12 files changed, 1282 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/power_seq.txt
create mode 100644 Documentation/power/power_seq.txt
create mode 100644 drivers/power/power_seq/Kconfig
create mode 100644 drivers/power/power_seq/Makefile
create mode 100644 drivers/power/power_seq/power_seq.c
create mode 100644 drivers/power/power_seq/power_seq_delay.c
create mode 100644 drivers/power/power_seq/power_seq_gpio.c
create mode 100644 drivers/power/power_seq/power_seq_pwm.c
create mode 100644 drivers/power/power_seq/power_seq_regulator.c
create mode 100644 include/linux/power_seq.h
diff --git a/Documentation/devicetree/bindings/power/power_seq.txt b/Documentation/devicetree/bindings/power/power_seq.txt
new file mode 100644
index 0000000..7880a6c
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/power_seq.txt
@@ -0,0 +1,121 @@
+Runtime Interpreted Power Sequences
+=================+
+Power sequences are sequential descriptions of actions to be performed on
+power-related resources. Having these descriptions in a well-defined data format
+allows us to take much of the board- or device- specific power control code out
+of the kernel and place it into the device tree instead, making kernels less
+board-dependant.
+
+A device typically makes use of multiple power sequences, for different purposes
+such as powering on and off. All the power sequences of a given device are
+grouped into a set. In the device tree, this set is a sub-node of the device
+node named "power-sequences".
+
+Power Sequences Structure
+-------------------------
+Every device that makes use of power sequences must have a "power-sequences"
+node into which individual power sequences are declared as sub-nodes. The name
+of the node becomes the name of the sequence within the power sequences
+framework.
+
+Similarly, each power sequence declares its steps as sub-nodes of itself. Steps
+must be named sequentially, with the first step named step0, the second step1,
+etc. Failure to follow this rule will result in a parsing error.
+
+Power Sequences Steps
+---------------------
+Steps of a sequence describe an action to be performed on a resource. They
+always include a "type" property which indicates what kind of resource this
+step works on. Depending on the resource type, additional properties are defined
+to control the action to be performed.
+
+"delay" type required properties:
+ - delay: delay to wait (in microseconds)
+
+"regulator" type required properties:
+ - id: name of the regulator to use.
+ - enable / disable: one of these two empty properties must be present to
+ enable or disable the resource
+
+"pwm" type required properties:
+ - id: name of the PWM to use.
+ - enable / disable: one of these two empty properties must be present to
+ enable or disable the resource
+
+"gpio" type required properties:
+ - gpio: phandle of the GPIO to use.
+ - value: value this GPIO should take. Must be 0 or 1.
+
+Example
+-------
+Here are example sequences declared within a backlight device that use all the
+supported resources types:
+
+ backlight {
+ compatible = "pwm-backlight";
+ ...
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 2 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&backlight_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
+ };
+
+The first part lists the PWM and regulator resources used by the sequences.
+These resources will be requested on behalf of the backlight device when the
+sequences are built and are declared according to their own bindings (for
+instance, regulators and pwms are resolved by name - note though that name
+declaration is done differently by the two frameworks).
+
+After the resources declaration, two sequences follow for powering the backlight
+on and off. Their names are specified by the pwm-backlight device bindings. Once
+the sequences are built by calling devm_of_parse_power_seq_set() on the
+backlight device, they can be added to a set using
+power_seq_set_add_sequences().
diff --git a/Documentation/power/power_seq.txt b/Documentation/power/power_seq.txt
new file mode 100644
index 0000000..8be0570
--- /dev/null
+++ b/Documentation/power/power_seq.txt
@@ -0,0 +1,253 @@
+Runtime Interpreted Power Sequences
+=================+
+Problem
+-------
+Very commonly, boards need the help of out-of-driver code to turn some of their
+devices on and off. For instance, SoC boards might use a GPIO (abstracted to a
+regulator or not) to control the power supply of a backlight. The GPIO that
+should be used, however, as well as the exact power sequence that may also
+involve other resources, is board-dependent and thus unknown to the driver.
+
+This was previously addressed by having hooks in the device's platform data that
+are called whenever the state of the device might need a power status change.
+This approach, however, introduces board-dependant code into the kernel and is
+not compatible with the device tree.
+
+The Runtime Interpreted Power Sequences (or power sequences for short) aim at
+turning this code into platform data or device tree nodes. Power sequences are
+described using a simple format and run by a lightweight interpreter whenever
+needed. This allows device drivers to work without power callbacks and makes the
+kernel less board-dependant.
+
+What are Power Sequences?
+-------------------------
+A power sequence is an array of sequential steps describing an action to be
+performed on a resource. The supported resources and actions operations are:
+- delay (just wait for a given number of microseconds)
+- GPIO (set to 0 or 1)
+- regulator (enable or disable)
+- PWM (enable or disable)
+
+When a power sequence is run, its steps is executed one after the other until
+one step fails or the end of the sequence is reached.
+
+Power sequences are named, and grouped into "sets" which contain all the
+sequences of a device as well as the resources they use.
+
+Power sequences can be declared as platform data or in the device tree.
+
+Platform Data Format
+--------------------
+All relevant data structures for declaring power sequences are located in
+include/linux/power_seq.h.
+
+The platform data for a device may include an instance of platform_power_seq_set
+which references all the power sequences used for a device. The power sequences
+reference resources in their steps, and setup the union member that corresponds
+to the resource's type. Resources, similarly, have a union which relevant member
+depends on their type.
+
+Note that the only "platform data" per se here is platform_power_seq_set. Other
+structures (power_seq and power_seq_resource) will be used at runtime and thus
+*must* survive initialization, so do not declare them with the __initdata
+attribute.
+
+The following example should make it clear how the platform data for power
+sequences is defined. It declares two power sequences named "power-on" and
+"power-off" for a backlight device. The "power-on" sequence enables the "power"
+regulator of the device, waits for 10ms, and then enables PWM "backlight" and
+set GPIO 28 to 1. "power-off" does the opposite.
+
+struct power_seq_resource reg_res = {
+ .type = POWER_SEQ_REGULATOR,
+ .regulator.id = "power",
+};
+
+struct power_seq_resource gpio_res = {
+ .type = POWER_SEQ_GPIO,
+ .gpio.gpio = 28,
+};
+
+struct power_seq_resource pwm_res = {
+ .type = POWER_SEQ_PWM,
+ .pwm.id = "backlight",
+};
+
+struct power_seq_resource delay_res = {
+ .type = POWER_SEQ_DELAY,
+};
+
+struct power_seq power_on_seq = {
+ .id = "power-on",
+ .num_steps = 4,
+ .steps = {
+ {
+ .resource = ®_res,
+ .regulator.enable = true,
+ }, {
+ .resource = &delay_res,
+ .delay.delay = 10000,
+ }, {
+ .resource = &pwm_res,
+ .pwm.enable = true,
+ }, {
+ .resource = &gpio_res,
+ .gpio.value = 1,
+ },
+ },
+};
+
+struct power_seq power_off_seq = {
+ .id = "power-off",
+ .num_steps = 4,
+ .steps = {
+ {
+ .resource = &gpio_res,
+ .gpio.value = 0,
+ }, {
+ .resource = &pwm_res,
+ .pwm.enable = false,
+ }, {
+ .resource = &delay_res,
+ .delay.delay = 10000,
+ }, {
+ .resource = ®_res,
+ .regulator.enable = false,
+ },
+ },
+};
+
+struct platform_power_seq_set backlight_power_seqs __initdata = {
+ .num_seqs = 2,
+ .seqs = {
+ &power_on_seq,
+ &power_off_seq,
+ },
+};
+
+"backlight_power_seqs" can then be passed to power_seq_set_add_sequences() in
+order to add the sequences to a set and allocate all the necessary resources.
+More on this later in this document.
+
+Device Tree
+-----------
+Power sequences can also be encoded as device tree nodes. The following
+properties and nodes are equivalent to the platform data defined previously:
+
+pwms = <&pwm 2 5000000>;
+pwm-names = "backlight";
+power-supply = <&vdd_bl_reg>;
+
+power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+};
+
+See Documentation/devicetree/bindings/power/power_seq.txt for the complete
+syntax of the DT bindings.
+
+Use by Drivers and Resources Management
+---------------------------------------
+Power sequences make use of resources that must be properly allocated and
+managed. The power_seq_set structure manages the sequences and resources for a
+particular device. A driver willing to use power sequences will thus declare one
+instance of power_seq_set per device and initialize it at probe time:
+
+struct my_device_data {
+ struct device *dev;
+ ...
+ struct power_set_set power_seqs;
+ ...
+};
+
+power_seq_set_init(&my_device->power_seqs, my_device->dev);
+
+The power_seq_set_add_sequence() and power_seq_set_add_sequences() functions are
+then used to add one or several sequences to a set. These functions will also
+allocate all the resources used by the sequence(s) and make sure they are ready
+to be run. All resources are allocated through devm and will thus be freed when
+the set's device is removed.
+
+ int power_seq_set_add_sequence(struct power_seq_set *set,
+ struct power_seq *seq);
+ int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs);
+
+Power sequences added to a set can then be resolved by their name using
+power_seq_lookup():
+
+ struct power_seq *power_seq_lookup(struct power_seq_set *seqs,
+ const char *id);
+
+power_seq_lookup() returns a ready-to-run pointer to the power sequence which
+name matches the id parameter.
+
+A retrieved power sequence can then be executed by power_seq_run:
+
+ int power_seq_run(struct power_seq *seq);
+
+It returns 0 if the sequence has successfully been run, or an error code if a
+problem occurred.
+
+Sometimes, you may want to browse the list of resources allocated for the
+sequences of a device, for instance to ensure that a resource of a given type is
+present. The power_seq_for_each_resource() macro does this:
+
+ power_seq_for_each_resource(pos, seqs)
+
+Here "pos" will be a pointer to a struct power_seq_resource. This structure
+contains the type of the resource, the information used for identifying it, and
+the resolved resource itself.
+
+Finally, users of the device tree can obtain a platform_power_seq_set structure
+built from the device's node using devm_of_parse_power_seq_set:
+
+ struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev);
+
+The power sequences must be declared under a "power-sequences" node directly
+declared under the device's node. Detailed syntax contained in Documentation/devicetree/bindings/power/power_seq.txt. As the function name
+states, all memory is allocated through devm. The returned
+platform_power_seq_set can be freed after being added to a set, but the
+sequences themselves must be preserved until they are freed by devm.
\ No newline at end of file
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 49a8939..f20d449 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -338,3 +338,4 @@ config AB8500_BATTERY_THERM_ON_BATCTRL
endif # POWER_SUPPLY
source "drivers/power/avs/Kconfig"
+source "drivers/power/power_seq/Kconfig"
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index b949cf8..883ad4d 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o
obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o
obj-$(CONFIG_POWER_AVS) += avs/
obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o
+obj-$(CONFIG_POWER_SEQ) += power_seq/
diff --git a/drivers/power/power_seq/Kconfig b/drivers/power/power_seq/Kconfig
new file mode 100644
index 0000000..3bff26e
--- /dev/null
+++ b/drivers/power/power_seq/Kconfig
@@ -0,0 +1,2 @@
+config POWER_SEQ
+ bool
diff --git a/drivers/power/power_seq/Makefile b/drivers/power/power_seq/Makefile
new file mode 100644
index 0000000..f77a359
--- /dev/null
+++ b/drivers/power/power_seq/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_POWER_SEQ) += power_seq.o
diff --git a/drivers/power/power_seq/power_seq.c b/drivers/power/power_seq/power_seq.c
new file mode 100644
index 0000000..255b1a0
--- /dev/null
+++ b/drivers/power/power_seq/power_seq.c
@@ -0,0 +1,376 @@
+/*
+ * power_seq.c - power sequence interpreter for platform devices and device tree
+ *
+ * Author: Alexandre Courbot <acourbot@nvidia.com>
+ *
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/power_seq.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/device.h>
+
+#include <linux/of.h>
+
+#define power_seq_err(seq, step_nbr, format, ...) \
+ dev_err(seq->set->dev, "%s[%d]: " format, seq->id, step_nbr, \
+ ##__VA_ARGS__);
+
+/**
+ * struct power_seq_res_ops - operators for power sequences resources
+ * @name: Name of the resource type. Set to null when a resource
+ * type support is not compiled in
+ * @of_parse: Parse a step for this kind of resource from a device
+ * tree node. The result of parsing must be written into
+ * step step_nbr of seq
+ * @step_run: Run a step for this kind of resource
+ * @res_compare: Return true if the resource used by the resource is the
+ * same as the one referenced by the step, false otherwise.
+ * @res_alloc: Resolve and allocate a resource. Return error code if
+ * the resource cannot be allocated, 0 otherwise
+ */
+struct power_seq_res_ops {
+ const char *name;
+ int (*of_parse)(struct device_node *node, struct power_seq *seq,
+ unsigned int step_nbr, struct power_seq_resource *res);
+ int (*step_run)(struct power_seq_step *step);
+ bool (*res_compare)(struct power_seq_resource *res,
+ struct power_seq_resource *res2);
+ int (*res_alloc)(struct device *dev,
+ struct power_seq_resource *res);
+};
+
+static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES];
+
+#ifdef CONFIG_OF
+static int of_power_seq_parse_enable_properties(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ bool *enable)
+{
+ if (of_find_property(node, "enable", NULL)) {
+ *enable = true;
+ } else if (of_find_property(node, "disable", NULL)) {
+ *enable = false;
+ } else {
+ power_seq_err(seq, step_nbr,
+ "missing enable or disable property\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int of_power_seq_parse_step(struct device *dev,
+ struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct list_head *resources)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ struct power_seq_resource res, *res2;
+ const char *type;
+ int i, err;
+
+ err = of_property_read_string(node, "type", &type);
+ if (err < 0) {
+ power_seq_err(seq, step_nbr, "cannot read type property\n");
+ return err;
+ }
+ for (i = 0; i < POWER_SEQ_NUM_TYPES; i++) {
+ if (power_seq_ops[i].name = NULL)
+ continue;
+ if (!strcmp(type, power_seq_ops[i].name))
+ break;
+ }
+ if (i >= POWER_SEQ_NUM_TYPES) {
+ power_seq_err(seq, step_nbr, "unknown type %s\n", type);
+ return -EINVAL;
+ }
+ memset(&res, 0, sizeof(res));
+ res.type = i;
+ err = power_seq_ops[res.type].of_parse(node, seq, step_nbr, &res);
+ if (err < 0)
+ return err;
+
+ /* Use the same instance of the resource if met before */
+ list_for_each_entry(res2, resources, list) {
+ if (res.type = res2->type &&
+ power_seq_ops[res.type].res_compare(&res, res2))
+ break;
+ }
+ /* Resource never met before, create it */
+ if (&res2->list = resources) {
+ res2 = devm_kzalloc(dev, sizeof(*res2), GFP_KERNEL);
+ if (!res2)
+ return -ENOMEM;
+ memcpy(res2, &res, sizeof(res));
+ list_add_tail(&res2->list, resources);
+ }
+ step->resource = res2;
+
+ return 0;
+}
+
+static struct power_seq *of_parse_power_seq(struct device *dev,
+ struct device_node *node,
+ struct list_head *resources)
+{
+ struct device_node *child = NULL;
+ struct power_seq *pseq;
+ int num_steps, sz;
+ int err;
+
+ if (!node)
+ return ERR_PTR(-EINVAL);
+
+ num_steps = of_get_child_count(node);
+ sz = sizeof(*pseq) + sizeof(pseq->steps[0]) * num_steps;
+ pseq = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!pseq)
+ return ERR_PTR(-ENOMEM);
+ pseq->id = node->name;
+ pseq->num_steps = num_steps;
+
+ for_each_child_of_node(node, child) {
+ unsigned int pos;
+
+ /* Check that the name's format is correct and within bounds */
+ if (strncmp("step", child->name, 4)) {
+ err = -EINVAL;
+ goto parse_error;
+ }
+
+ err = kstrtouint(child->name + 4, 10, &pos);
+ if (err < 0)
+ goto parse_error;
+
+ /* Invalid step index or step already parsed? */
+ if (pos >= num_steps || pseq->steps[pos].resource != NULL) {
+ err = -EINVAL;
+ goto parse_error;
+ }
+
+ err = of_power_seq_parse_step(dev, child, pseq, pos, resources);
+ if (err)
+ return ERR_PTR(err);
+ }
+
+ return pseq;
+
+parse_error:
+ dev_err(dev, "%s: invalid power step name %s!\n", pseq->id,
+ child->name);
+ return ERR_PTR(err);
+}
+
+/**
+ * devm_of_parse_power_seq_set - build a power_seq_set from the device tree
+ * @dev: Device to parse the power sequences of
+ *
+ * Sequences must be contained into a subnode named "power-sequences" of the
+ * device root node.
+ *
+ * Memory for the sequence is allocated using devm_kzalloc on dev. The returned
+ * platform_power_seq_set can be freed by devm_kfree after the sequences have
+ * been added, but the sequences themselves must be preserved.
+ *
+ * Returns the built set on success, or an error code in case of failure.
+ */
+struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev)
+{
+ struct platform_power_seq_set *set;
+ struct device_node *root = dev->of_node;
+ struct device_node *seq;
+ struct list_head resources;
+ int n, sz;
+
+ if (!root)
+ return NULL;
+
+ root = of_find_node_by_name(root, "power-sequences");
+ if (!root)
+ return NULL;
+
+ n = of_get_child_count(root);
+ sz = sizeof(*set) + sizeof(struct power_seq *) * n;
+ set = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!set)
+ return ERR_PTR(-ENOMEM);
+ set->num_seqs = n;
+
+ n = 0;
+ INIT_LIST_HEAD(&resources);
+ for_each_child_of_node(root, seq) {
+ struct power_seq *pseq;
+
+ pseq = of_parse_power_seq(dev, seq, &resources);
+ if (IS_ERR(pseq))
+ return (void *)pseq;
+
+ set->seqs[n++] = pseq;
+ }
+
+ return set;
+}
+EXPORT_SYMBOL_GPL(devm_of_parse_power_seq_set);
+#endif /* CONFIG_OF */
+
+/**
+ * power_seq_set_init - initialize a power_seq_set
+ * @set: Set to initialize
+ * @dev: Device this set is going to belong to
+ */
+void power_seq_set_init(struct power_seq_set *set, struct device *dev)
+{
+ set->dev = dev;
+ INIT_LIST_HEAD(&set->resources);
+ INIT_LIST_HEAD(&set->seqs);
+}
+EXPORT_SYMBOL_GPL(power_seq_set_init);
+
+/**
+ * power_seq_add_sequence - add a power sequence to a set
+ * @set: Set to add the sequence to
+ * @seq: Sequence to add
+ *
+ * This step will check that all the resources used by the sequence are
+ * allocated. If they are not, an attempt to allocate them is made. This
+ * operation can fail and and return an error code.
+ *
+ * Returns 0 on success, error code if a resource initialization failed.
+ */
+int power_seq_add_sequence(struct power_seq_set *set, struct power_seq *seq)
+{
+ struct power_seq_resource *res;
+ int i, err;
+
+ for (i = 0; i < seq->num_steps; i++) {
+ struct power_seq_step *step = &seq->steps[i];
+ struct power_seq_resource *step_res = step->resource;
+ list_for_each_entry(res, &set->resources, list) {
+ if (res = step_res)
+ break;
+ }
+ /* resource not allocated yet, allocate and add it */
+ if (&res->list = &set->resources) {
+ err = power_seq_ops[step_res->type].res_alloc(set->dev,
+ step_res);
+ if (err)
+ return err;
+ list_add_tail(&step->resource->list, &set->resources);
+ }
+ }
+
+ list_add_tail(&seq->list, &set->seqs);
+ seq->set = set;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_add_sequence);
+
+/**
+ * power_seq_add_sequences - add power sequences defined as platform data
+ * @set: Set to add the sequences to
+ * @seqs: Sequences to add
+ *
+ * See power_seq_add_sequence for more details.
+ *
+ * Returns 0 on success, error code if a resource initialization failed.
+ */
+int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs)
+{
+ int i, ret;
+
+ for (i = 0; i < seqs->num_seqs; i++) {
+ ret = power_seq_add_sequence(set, seqs->seqs[i]);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_set_add_sequences);
+
+/**
+ * power_seq_lookup - Lookup a power sequence by name from a set
+ * @seqs: The set to look in
+ * @id: Name to look after
+ *
+ * Returns a matching power sequence if it exists, NULL if it does not.
+ */
+struct power_seq *power_seq_lookup(struct power_seq_set *set, const char *id)
+{
+ struct power_seq *seq;
+
+ list_for_each_entry(seq, &set->seqs, list) {
+ if (!strcmp(seq->id, id))
+ return seq;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(power_seq_lookup);
+
+/**
+ * power_seq_run() - run a power sequence
+ * @seq: The power sequence to run
+ *
+ * Returns 0 on success, error code in case of failure.
+ */
+int power_seq_run(struct power_seq *seq)
+{
+ unsigned int i;
+ int err;
+
+ if (!seq)
+ return 0;
+
+ if (!seq->set) {
+ pr_err("cannot run a sequence not added to a set");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < seq->num_steps; i++) {
+ unsigned int type = seq->steps[i].resource->type;
+
+ err = power_seq_ops[type].step_run(&seq->steps[i]);
+ if (err) {
+ power_seq_err(seq, i,
+ "error %d while running power sequence step\n",
+ err);
+ return err;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(power_seq_run);
+
+#include "power_seq_delay.c"
+#include "power_seq_regulator.c"
+#include "power_seq_pwm.c"
+#include "power_seq_gpio.c"
+
+static const struct power_seq_res_ops power_seq_ops[POWER_SEQ_NUM_TYPES] = {
+ [POWER_SEQ_DELAY] = POWER_SEQ_DELAY_TYPE,
+ [POWER_SEQ_REGULATOR] = POWER_SEQ_REGULATOR_TYPE,
+ [POWER_SEQ_PWM] = POWER_SEQ_PWM_TYPE,
+ [POWER_SEQ_GPIO] = POWER_SEQ_GPIO_TYPE,
+};
+
+MODULE_AUTHOR("Alexandre Courbot <acourbot@nvidia.com>");
+MODULE_DESCRIPTION("Runtime Interpreted Power Sequences");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/power/power_seq/power_seq_delay.c b/drivers/power/power_seq/power_seq_delay.c
new file mode 100644
index 0000000..5bb0a46
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_delay.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/delay.h>
+
+#ifdef CONFIG_OF
+static int of_power_seq_parse_delay(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_u32(node, "delay",
+ &step->delay.delay);
+ if (err < 0)
+ power_seq_err(seq, step_nbr, "error reading delay property\n");
+
+ return err;
+}
+#else
+#define of_power_seq_parse_delay NULL
+#endif
+
+static bool power_seq_res_compare_delay(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ /* Delay resources are just here to hold the type of steps, so they are
+ * all equivalent. */
+ return true;
+}
+
+static int power_seq_res_alloc_delay(struct device *dev,
+ struct power_seq_resource *res)
+{
+ return 0;
+}
+
+static int power_seq_step_run_delay(struct power_seq_step *step)
+{
+ usleep_range(step->delay.delay,
+ step->delay.delay + 1000);
+
+ return 0;
+}
+
+#define POWER_SEQ_DELAY_TYPE { \
+ .name = "delay", \
+ .of_parse = of_power_seq_parse_delay, \
+ .step_run = power_seq_step_run_delay, \
+ .res_compare = power_seq_res_compare_delay, \
+ .res_alloc = power_seq_res_alloc_delay, \
+}
diff --git a/drivers/power/power_seq/power_seq_gpio.c b/drivers/power/power_seq/power_seq_gpio.c
new file mode 100644
index 0000000..44b4a3d
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_gpio.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_gpio(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int gpio;
+ int err;
+
+ gpio = of_get_named_gpio(node, "gpio", 0);
+ if (gpio < 0) {
+ power_seq_err(seq, step_nbr, "error reading gpio property\n");
+ return gpio;
+ }
+ res->gpio.gpio = gpio;
+
+ err = of_property_read_u32(node, "value", &step->gpio.value);
+ if (err < 0) {
+ power_seq_err(seq, step_nbr, "error reading value property\n");
+ } else if (step->gpio.value < 0 || step->gpio.value > 1) {
+ power_seq_err(seq, step_nbr,
+ "value out of range (must be 0 or 1)\n");
+ err = -EINVAL;
+ }
+
+ return err;
+}
+#else
+#define of_power_seq_parse_gpio NULL
+#endif
+
+static bool power_seq_res_compare_gpio(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return res->gpio.gpio = res2->gpio.gpio;
+}
+
+static int power_seq_res_alloc_gpio(struct device *dev,
+ struct power_seq_resource *res)
+{
+ int err;
+
+ err = devm_gpio_request(dev, res->gpio.gpio, dev_name(dev));
+ if (err) {
+ dev_err(dev, "cannot get gpio %d\n", res->gpio.gpio);
+ return err;
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_gpio(struct power_seq_step *step)
+{
+ struct power_seq_resource *res = step->resource;
+
+ /* set the GPIO direction at first use */
+ if (!res->gpio.is_set) {
+ int err = gpio_direction_output(res->gpio.gpio,
+ step->gpio.value);
+ if (err)
+ return err;
+ res->gpio.is_set = true;
+ } else {
+ gpio_set_value_cansleep(res->gpio.gpio, step->gpio.value);
+ }
+
+ return 0;
+}
+
+#define POWER_SEQ_GPIO_TYPE { \
+ .name = "gpio", \
+ .of_parse = power_seq_of_parse_gpio, \
+ .step_run = power_seq_step_run_gpio, \
+ .res_compare = power_seq_res_compare_gpio, \
+ .res_alloc = power_seq_res_alloc_gpio, \
+}
diff --git a/drivers/power/power_seq/power_seq_pwm.c b/drivers/power/power_seq/power_seq_pwm.c
new file mode 100644
index 0000000..c0a1ec3
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_pwm.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifdef CONFIG_PWM
+
+#include <linux/pwm.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_pwm(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_string(node, "id", &res->pwm.id);
+ if (err) {
+ power_seq_err(seq, step_nbr, "error reading id property\n");
+ return err;
+ }
+
+ err = of_power_seq_parse_enable_properties(node, seq, step_nbr,
+ &step->pwm.enable);
+ return err;
+}
+#else
+#define of_power_seq_parse_pwm NULL
+#endif
+
+static bool power_seq_res_compare_pwm(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return !strcmp(res->pwm.id, res2->pwm.id);
+}
+
+static int power_seq_res_alloc_pwm(struct device *dev,
+ struct power_seq_resource *res)
+{
+ res->pwm.pwm = devm_pwm_get(dev, res->pwm.id);
+ if (IS_ERR(res->pwm.pwm)) {
+ dev_err(dev, "cannot get pwm \"%s\"\n", res->pwm.id);
+ return PTR_ERR(res->pwm.pwm);
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_pwm(struct power_seq_step *step)
+{
+ if (step->pwm.enable) {
+ return pwm_enable(step->resource->pwm.pwm);
+ } else {
+ pwm_disable(step->resource->pwm.pwm);
+ return 0;
+ }
+}
+
+#define POWER_SEQ_PWM_TYPE { \
+ .name = "pwm", \
+ .of_parse = power_seq_of_parse_pwm, \
+ .step_run = power_seq_step_run_pwm, \
+ .res_compare = power_seq_res_compare_pwm, \
+ .res_alloc = power_seq_res_alloc_pwm, \
+}
+
+#else
+
+#define POWER_SEQ_PWM_TYPE {}
+
+#endif
diff --git a/drivers/power/power_seq/power_seq_regulator.c b/drivers/power/power_seq/power_seq_regulator.c
new file mode 100644
index 0000000..282cc95
--- /dev/null
+++ b/drivers/power/power_seq/power_seq_regulator.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifdef CONFIG_REGULATOR
+
+#include <linux/regulator/consumer.h>
+
+#ifdef CONFIG_OF
+static int power_seq_of_parse_regulator(struct device_node *node,
+ struct power_seq *seq,
+ unsigned int step_nbr,
+ struct power_seq_resource *res)
+{
+ struct power_seq_step *step = &seq->steps[step_nbr];
+ int err;
+
+ err = of_property_read_string(node, "id",
+ &res->regulator.id);
+ if (err) {
+ power_seq_err(seq, step_nbr, "error reading id property\n");
+ return err;
+ }
+
+ err = of_power_seq_parse_enable_properties(node, seq, step_nbr,
+ &step->regulator.enable);
+ return err;
+}
+#else
+#define of_power_seq_parse_regulator NULL
+#endif
+
+static bool
+power_seq_res_compare_regulator(struct power_seq_resource *res,
+ struct power_seq_resource *res2)
+{
+ return !strcmp(res->regulator.id, res2->regulator.id);
+}
+
+static int power_seq_res_alloc_regulator(struct device *dev,
+ struct power_seq_resource *res)
+{
+ res->regulator.regulator = devm_regulator_get(dev, res->regulator.id);
+ if (IS_ERR(res->regulator.regulator)) {
+ dev_err(dev, "cannot get regulator \"%s\"\n",
+ res->regulator.id);
+ return PTR_ERR(res->regulator.regulator);
+ }
+
+ return 0;
+}
+
+static int power_seq_step_run_regulator(struct power_seq_step *step)
+{
+ if (step->regulator.enable)
+ return regulator_enable(step->resource->regulator.regulator);
+ else
+ return regulator_disable(step->resource->regulator.regulator);
+}
+
+#define POWER_SEQ_REGULATOR_TYPE { \
+ .name = "regulator", \
+ .of_parse = power_seq_of_parse_regulator, \
+ .step_run = power_seq_step_run_regulator, \
+ .res_compare = power_seq_res_compare_regulator, \
+ .res_alloc = power_seq_res_alloc_regulator, \
+}
+
+#else
+
+#define POWER_SEQ_REGULATOR_TYPE {}
+
+#endif
diff --git a/include/linux/power_seq.h b/include/linux/power_seq.h
new file mode 100644
index 0000000..21b95b6
--- /dev/null
+++ b/include/linux/power_seq.h
@@ -0,0 +1,203 @@
+/*
+ * power_seq.h
+ *
+ * Simple interpreter for power sequences defined as platform data or device
+ * tree properties.
+ *
+ * Power sequences are designed to replace the callbacks typically used in
+ * board-specific files that implement board- or device- specific power
+ * sequences (such as those of backlights). A power sequence is an array of
+ * steps referencing resources (regulators, GPIOs, PWMs, ...) with an action to
+ * perform on them. By having the power sequences interpreted, it becomes
+ * possible to describe them in the device tree and thus to remove
+ * board-specific files from the kernel.
+ *
+ * See Documentation/power/power_seqs.txt for detailed information.
+ *
+ * Author: Alexandre Courbot <acourbot@nvidia.com>
+ *
+ * Copyright (c) 2012 NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifndef __LINUX_POWER_SEQ_H
+#define __LINUX_POWER_SEQ_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+
+struct device;
+struct regulator;
+struct pwm_device;
+
+/**
+ * The different kinds of resources that can be controlled by the sequences
+ */
+enum power_seq_res_type {
+ POWER_SEQ_DELAY,
+ POWER_SEQ_REGULATOR,
+ POWER_SEQ_PWM,
+ POWER_SEQ_GPIO,
+ POWER_SEQ_NUM_TYPES,
+};
+
+/**
+ * struct power_seq_regulator_resource
+ * @id: name of the regulator
+ * @regulator: resolved regulator. Written during resource resolution.
+ */
+struct power_seq_regulator_resource {
+ const char *id;
+ struct regulator *regulator;
+};
+
+/**
+ * struct power_seq_pwm_resource
+ * @id: name of the PWM
+ * @regulator: resolved PWM. Written during resource resolution.
+ */
+struct power_seq_pwm_resource {
+ const char *id;
+ struct pwm_device *pwm;
+};
+
+/**
+ * struct power_seq_gpio_resource
+ * @gpio: number of the GPIO
+ * @is_set: track GPIO state to set its direction at first use
+ */
+struct power_seq_gpio_resource {
+ int gpio;
+ bool is_set;
+};
+
+/**
+ * struct power_seq_resource - resource used by power sequences
+ * @type: type of the resource. This decides which member of the union is
+ * used for this resource
+ * @list: link resources together in power_seq_set
+ * @regulator: used if @type = POWER_SEQ_REGULATOR
+ * @pwm: used if @type = POWER_SEQ_PWM
+ * @gpio: used if @type = POWER_SEQ_GPIO
+ */
+struct power_seq_resource {
+ enum power_seq_res_type type;
+ struct list_head list;
+ union {
+ struct power_seq_regulator_resource regulator;
+ struct power_seq_pwm_resource pwm;
+ struct power_seq_gpio_resource gpio;
+ };
+};
+#define power_seq_for_each_resource(pos, set) \
+ list_for_each_entry(pos, &(set)->resources, list)
+
+/**
+ * struct power_seq_delay_step - action data for delay steps
+ * @delay: amount of time to wait, in microseconds
+ */
+struct power_seq_delay_step {
+ unsigned int delay;
+};
+
+/**
+ * struct power_seq_regulator_step - platform data for regulator steps
+ * @enable: whether to enable or disable the regulator during this step
+ */
+struct power_seq_regulator_step {
+ bool enable;
+};
+
+/**
+ * struct power_seq_pwm_step - action data for PWM steps
+ * @enable: whether to enable or disable the PWM during this step
+ */
+struct power_seq_pwm_step {
+ bool enable;
+};
+
+/**
+ * struct power_seq_gpio_step - action data for GPIO steps
+ * @enable: whether to enable or disable the GPIO during this step
+ */
+struct power_seq_gpio_step {
+ int value;
+};
+
+/**
+ * struct power_seq_step - data for power sequences steps
+ * @resource: resource used by this step
+ * @delay: used if resource->type = POWER_SEQ_DELAY
+ * @regulator: used if resource->type = POWER_SEQ_REGULATOR
+ * @pwm: used if resource->type = POWER_SEQ_PWN
+ * @gpio: used if resource->type = POWER_SEQ_GPIO
+ */
+struct power_seq_step {
+ struct power_seq_resource *resource;
+ union {
+ struct power_seq_delay_step delay;
+ struct power_seq_regulator_step regulator;
+ struct power_seq_pwm_step pwm;
+ struct power_seq_gpio_step gpio;
+ };
+};
+
+struct power_seq_set;
+
+/**
+ * struct power_seq - single power sequence
+ * @id: name of this sequence
+ * @list: link sequences together in power_seq_set. Leave as-is
+ * @set: set this sequence belongs to. Written when added to a set
+ * @num_steps: number of steps in the sequence
+ * @steps: array of steps that make the sequence
+ */
+struct power_seq {
+ const char *id;
+ struct list_head list;
+ struct power_seq_set *set;
+ unsigned int num_steps;
+ struct power_seq_step steps[];
+};
+
+/**
+ * struct power_seq_set - power sequences and resources used by a device
+ * @dev: device this set belongs to
+ * @resources: list of resources used by power sequences
+ * @seqs: list of power sequences
+ */
+struct power_seq_set {
+ struct device *dev;
+ struct list_head resources;
+ struct list_head seqs;
+};
+
+/**
+ * struct platform_power_seq_set - define power sequences as platform data
+ * @num_seqs: number of sequences defined
+ * @seqs: array of num_seqs power sequences
+ */
+struct platform_power_seq_set {
+ unsigned int num_seqs;
+ struct power_seq *seqs[];
+};
+
+struct platform_power_seq_set *devm_of_parse_power_seq_set(struct device *dev);
+void power_seq_set_init(struct power_seq_set *set, struct device *dev);
+int power_seq_set_add_sequence(struct power_seq_set *set,
+ struct power_seq *seq);
+int power_seq_set_add_sequences(struct power_seq_set *set,
+ struct platform_power_seq_set *seqs);
+struct power_seq *power_seq_lookup(struct power_seq_set *seqs, const char *id);
+int power_seq_run(struct power_seq *seq);
+
+#endif
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 2/3] pwm_backlight: use power sequences
2012-10-19 9:06 ` Alexandre Courbot
(?)
@ 2012-10-19 9:06 ` Alexandre Courbot
-1 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-pm-u79uwXL29TY76Z2rM5mHXA, Leela Krishna Amudala,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA
Make use of the power sequences specified in the device tree or platform
data to control how the backlight is powered on and off.
Signed-off-by: Alexandre Courbot <acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
.../bindings/video/backlight/pwm-backlight.txt | 72 ++++++++-
drivers/video/backlight/Kconfig | 1 +
drivers/video/backlight/pwm_bl.c | 161 ++++++++++++++++-----
include/linux/pwm_backlight.h | 18 ++-
4 files changed, 213 insertions(+), 39 deletions(-)
diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
index 1e4fc72..3ba25ea 100644
--- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
+++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
@@ -14,15 +14,83 @@ Required properties:
Optional properties:
- pwm-names: a list of names for the PWM devices specified in the
"pwms" property (see PWM binding[0])
+ - low-threshold-brightness: brightness threshold low level. Sets the lowest
+ brightness value.
+ On some panels the backlight misbehaves if the duty cycle percentage of the
+ PWM wave is less than a certain level (say 20%). In this example the user
+ can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus
+ preventing the PWM duty cycle from going too low.
+ On setting low-threshold-brightness the range of brightness levels is
+ calculated in the range low-threshold-brightness to the maximum value in
+ brightness-levels, described above.
+ - pwm-names: name for the PWM device specified in the "pwms" property (see PWM
+ binding[0]). Necessary if power sequences are used
+ - power-sequences: Power sequences (see Power sequences[1]) used to bring the
+ backlight on and off. If this property is present, then two power
+ sequences named "power-on" and "power-off" must be defined to control how
+ the backlight is to be powered on and off. These sequences must reference
+ the PWM specified in the pwms property by its name, and can also reference
+ other resources supported by the power sequences mechanism
[0]: Documentation/devicetree/bindings/pwm/pwm.txt
+[1]: Documentation/devicetree/bindings/power/power_seq.txt
Example:
backlight {
compatible = "pwm-backlight";
- pwms = <&pwm 0 5000000>;
-
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
+ low-threshold-brightness = <50>;
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 0 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&backlight_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
};
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index c101697..c2e5f79 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -239,6 +239,7 @@ config BACKLIGHT_CARILLO_RANCH
config BACKLIGHT_PWM
tristate "Generic PWM based Backlight Driver"
depends on PWM
+ select POWER_SEQ
help
If you have a LCD backlight adjustable by PWM, say Y to enable
this driver.
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 069983c..e607c6e 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -27,6 +27,12 @@ struct pwm_bl_data {
unsigned int period;
unsigned int lth_brightness;
unsigned int *levels;
+ bool enabled;
+ struct power_seq_set power_seqs;
+ struct power_seq *power_on_seq;
+ struct power_seq *power_off_seq;
+
+ /* Legacy callbacks */
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
@@ -35,6 +41,52 @@ struct pwm_bl_data {
void (*exit)(struct device *);
};
+static void pwm_backlight_on(struct backlight_device *bl)
+{
+ struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+ int ret;
+
+ if (pb->enabled)
+ return;
+
+ if (pb->power_on_seq) {
+ ret = power_seq_run(pb->power_on_seq);
+ if (ret < 0) {
+ dev_err(&bl->dev, "cannot run power on sequence\n");
+ return;
+ }
+ } else {
+ /* legacy framework */
+ pwm_config(pb->pwm, 0, pb->period);
+ pwm_disable(pb->pwm);
+ }
+
+ pb->enabled = true;
+}
+
+static void pwm_backlight_off(struct backlight_device *bl)
+{
+ struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+ int ret;
+
+ if (!pb->enabled)
+ return;
+
+ if (pb->power_off_seq) {
+ ret = power_seq_run(pb->power_off_seq);
+ if (ret < 0) {
+ dev_err(&bl->dev, "cannot run power off sequence\n");
+ return;
+ }
+ } else {
+ /* legacy framework */
+ pwm_enable(pb->pwm);
+ return;
+ }
+
+ pb->enabled = false;
+}
+
static int pwm_backlight_update_status(struct backlight_device *bl)
{
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
@@ -51,8 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
brightness = pb->notify(pb->dev, brightness);
if (brightness == 0) {
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
} else {
int duty_cycle;
@@ -66,7 +117,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
duty_cycle = pb->lth_brightness +
(duty_cycle * (pb->period - pb->lth_brightness) / max);
pwm_config(pb->pwm, duty_cycle, pb->period);
- pwm_enable(pb->pwm);
+ pwm_backlight_on(bl);
}
if (pb->notify_after)
@@ -145,11 +196,10 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}
- /*
- * TODO: Most users of this driver use a number of GPIOs to control
- * backlight power. Support for specifying these needs to be
- * added.
- */
+ /* read power sequences */
+ data->power_seqs = devm_of_parse_power_seq_set(dev);
+ if (IS_ERR(data->power_seqs))
+ return PTR_ERR(data->power_seqs);
return 0;
}
@@ -172,6 +222,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
{
struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
struct platform_pwm_backlight_data defdata;
+ struct power_seq_resource *res;
struct backlight_properties props;
struct backlight_device *bl;
struct pwm_bl_data *pb;
@@ -180,7 +231,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (!data) {
ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
- if (ret < 0) {
+ if (ret == -EPROBE_DEFER) {
+ return ret;
+ } else if (ret < 0) {
dev_err(&pdev->dev, "failed to find platform data\n");
return ret;
}
@@ -201,6 +254,68 @@ static int pwm_backlight_probe(struct platform_device *pdev)
goto err_alloc;
}
+ if (data->power_seqs) {
+ /* use power sequences */
+ struct power_seq_set *seqs = &pb->power_seqs;
+
+ power_seq_set_init(seqs, &pdev->dev);
+ power_seq_set_add_sequences(seqs, data->power_seqs);
+
+ /* Check that the required sequences are here */
+ pb->power_on_seq = power_seq_lookup(seqs, "power-on");
+ if (!pb->power_on_seq) {
+ dev_err(&pdev->dev, "missing power-on sequence\n");
+ return -EINVAL;
+ }
+ pb->power_off_seq = power_seq_lookup(seqs, "power-off");
+ if (!pb->power_off_seq) {
+ dev_err(&pdev->dev, "missing power-off sequence\n");
+ return -EINVAL;
+ }
+
+ /* we must have exactly one PWM resource for this driver */
+ power_seq_for_each_resource(res, seqs) {
+ if (res->type != POWER_SEQ_PWM)
+ continue;
+ if (pb->pwm) {
+ dev_err(&pdev->dev, "more than one PWM used\n");
+ return -EINVAL;
+ }
+ /* keep the pwm at hand */
+ pb->pwm = res->pwm.pwm;
+ }
+ /* from here we should have a PWM */
+ if (!pb->pwm) {
+ dev_err(&pdev->dev, "no PWM defined!\n");
+ return -EINVAL;
+ }
+ } else {
+ /* use legacy interface */
+ pb->pwm = devm_pwm_get(&pdev->dev, NULL);
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev,
+ "unable to request PWM, trying legacy API\n");
+
+ pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev,
+ "unable to request legacy PWM\n");
+ ret = PTR_ERR(pb->pwm);
+ goto err_alloc;
+ }
+ }
+
+ dev_dbg(&pdev->dev, "got pwm for backlight\n");
+
+ /*
+ * The DT case will set the pwm_period_ns field to 0 and store
+ * the period, parsed from the DT, in the PWM device. For the
+ * non-DT case, set the period from platform data.
+ */
+ if (data->pwm_period_ns > 0)
+ pwm_set_period(pb->pwm, data->pwm_period_ns);
+ }
+
if (data->levels) {
max = data->levels[data->max_brightness];
pb->levels = data->levels;
@@ -213,28 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->exit = data->exit;
pb->dev = &pdev->dev;
- pb->pwm = devm_pwm_get(&pdev->dev, NULL);
- if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
-
- pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
- if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request legacy PWM\n");
- ret = PTR_ERR(pb->pwm);
- goto err_alloc;
- }
- }
-
- dev_dbg(&pdev->dev, "got pwm for backlight\n");
-
- /*
- * The DT case will set the pwm_period_ns field to 0 and store the
- * period, parsed from the DT, in the PWM device. For the non-DT case,
- * set the period from platform data.
- */
- if (data->pwm_period_ns > 0)
- pwm_set_period(pb->pwm, data->pwm_period_ns);
-
pb->period = pwm_get_period(pb->pwm);
pb->lth_brightness = data->lth_brightness * (pb->period / max);
@@ -267,8 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev)
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
backlight_device_unregister(bl);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
if (pb->exit)
pb->exit(&pdev->dev);
return 0;
@@ -282,8 +374,7 @@ static int pwm_backlight_suspend(struct device *dev)
if (pb->notify)
pb->notify(pb->dev, 0);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
if (pb->notify_after)
pb->notify_after(pb->dev, 0);
return 0;
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 56f4a86..0dcec1d 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -5,14 +5,28 @@
#define __LINUX_PWM_BACKLIGHT_H
#include <linux/backlight.h>
+#include <linux/power_seq.h>
struct platform_pwm_backlight_data {
- int pwm_id;
unsigned int max_brightness;
unsigned int dft_brightness;
unsigned int lth_brightness;
- unsigned int pwm_period_ns;
unsigned int *levels;
+ /*
+ * New interface using power sequences. Must include exactly
+ * two power sequences named 'power-on' and 'power-off'. If NULL,
+ * the legacy interface is used.
+ */
+ struct platform_power_seq_set *power_seqs;
+
+ /*
+ * Legacy interface - use power sequences instead!
+ *
+ * pwm_id and pwm_period_ns need only be specified
+ * if get_pwm(dev, NULL) would return NULL.
+ */
+ int pwm_id;
+ unsigned int pwm_period_ns;
int (*init)(struct device *dev);
int (*notify)(struct device *dev, int brightness);
void (*notify_after)(struct device *dev, int brightness);
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Make use of the power sequences specified in the device tree or platform
data to control how the backlight is powered on and off.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../bindings/video/backlight/pwm-backlight.txt | 72 ++++++++-
drivers/video/backlight/Kconfig | 1 +
drivers/video/backlight/pwm_bl.c | 161 ++++++++++++++++-----
include/linux/pwm_backlight.h | 18 ++-
4 files changed, 213 insertions(+), 39 deletions(-)
diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
index 1e4fc72..3ba25ea 100644
--- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
+++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
@@ -14,15 +14,83 @@ Required properties:
Optional properties:
- pwm-names: a list of names for the PWM devices specified in the
"pwms" property (see PWM binding[0])
+ - low-threshold-brightness: brightness threshold low level. Sets the lowest
+ brightness value.
+ On some panels the backlight misbehaves if the duty cycle percentage of the
+ PWM wave is less than a certain level (say 20%). In this example the user
+ can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus
+ preventing the PWM duty cycle from going too low.
+ On setting low-threshold-brightness the range of brightness levels is
+ calculated in the range low-threshold-brightness to the maximum value in
+ brightness-levels, described above.
+ - pwm-names: name for the PWM device specified in the "pwms" property (see PWM
+ binding[0]). Necessary if power sequences are used
+ - power-sequences: Power sequences (see Power sequences[1]) used to bring the
+ backlight on and off. If this property is present, then two power
+ sequences named "power-on" and "power-off" must be defined to control how
+ the backlight is to be powered on and off. These sequences must reference
+ the PWM specified in the pwms property by its name, and can also reference
+ other resources supported by the power sequences mechanism
[0]: Documentation/devicetree/bindings/pwm/pwm.txt
+[1]: Documentation/devicetree/bindings/power/power_seq.txt
Example:
backlight {
compatible = "pwm-backlight";
- pwms = <&pwm 0 5000000>;
-
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
+ low-threshold-brightness = <50>;
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 0 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&backlight_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
};
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index c101697..c2e5f79 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -239,6 +239,7 @@ config BACKLIGHT_CARILLO_RANCH
config BACKLIGHT_PWM
tristate "Generic PWM based Backlight Driver"
depends on PWM
+ select POWER_SEQ
help
If you have a LCD backlight adjustable by PWM, say Y to enable
this driver.
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 069983c..e607c6e 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -27,6 +27,12 @@ struct pwm_bl_data {
unsigned int period;
unsigned int lth_brightness;
unsigned int *levels;
+ bool enabled;
+ struct power_seq_set power_seqs;
+ struct power_seq *power_on_seq;
+ struct power_seq *power_off_seq;
+
+ /* Legacy callbacks */
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
@@ -35,6 +41,52 @@ struct pwm_bl_data {
void (*exit)(struct device *);
};
+static void pwm_backlight_on(struct backlight_device *bl)
+{
+ struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+ int ret;
+
+ if (pb->enabled)
+ return;
+
+ if (pb->power_on_seq) {
+ ret = power_seq_run(pb->power_on_seq);
+ if (ret < 0) {
+ dev_err(&bl->dev, "cannot run power on sequence\n");
+ return;
+ }
+ } else {
+ /* legacy framework */
+ pwm_config(pb->pwm, 0, pb->period);
+ pwm_disable(pb->pwm);
+ }
+
+ pb->enabled = true;
+}
+
+static void pwm_backlight_off(struct backlight_device *bl)
+{
+ struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+ int ret;
+
+ if (!pb->enabled)
+ return;
+
+ if (pb->power_off_seq) {
+ ret = power_seq_run(pb->power_off_seq);
+ if (ret < 0) {
+ dev_err(&bl->dev, "cannot run power off sequence\n");
+ return;
+ }
+ } else {
+ /* legacy framework */
+ pwm_enable(pb->pwm);
+ return;
+ }
+
+ pb->enabled = false;
+}
+
static int pwm_backlight_update_status(struct backlight_device *bl)
{
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
@@ -51,8 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
brightness = pb->notify(pb->dev, brightness);
if (brightness == 0) {
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
} else {
int duty_cycle;
@@ -66,7 +117,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
duty_cycle = pb->lth_brightness +
(duty_cycle * (pb->period - pb->lth_brightness) / max);
pwm_config(pb->pwm, duty_cycle, pb->period);
- pwm_enable(pb->pwm);
+ pwm_backlight_on(bl);
}
if (pb->notify_after)
@@ -145,11 +196,10 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}
- /*
- * TODO: Most users of this driver use a number of GPIOs to control
- * backlight power. Support for specifying these needs to be
- * added.
- */
+ /* read power sequences */
+ data->power_seqs = devm_of_parse_power_seq_set(dev);
+ if (IS_ERR(data->power_seqs))
+ return PTR_ERR(data->power_seqs);
return 0;
}
@@ -172,6 +222,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
{
struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
struct platform_pwm_backlight_data defdata;
+ struct power_seq_resource *res;
struct backlight_properties props;
struct backlight_device *bl;
struct pwm_bl_data *pb;
@@ -180,7 +231,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (!data) {
ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
- if (ret < 0) {
+ if (ret == -EPROBE_DEFER) {
+ return ret;
+ } else if (ret < 0) {
dev_err(&pdev->dev, "failed to find platform data\n");
return ret;
}
@@ -201,6 +254,68 @@ static int pwm_backlight_probe(struct platform_device *pdev)
goto err_alloc;
}
+ if (data->power_seqs) {
+ /* use power sequences */
+ struct power_seq_set *seqs = &pb->power_seqs;
+
+ power_seq_set_init(seqs, &pdev->dev);
+ power_seq_set_add_sequences(seqs, data->power_seqs);
+
+ /* Check that the required sequences are here */
+ pb->power_on_seq = power_seq_lookup(seqs, "power-on");
+ if (!pb->power_on_seq) {
+ dev_err(&pdev->dev, "missing power-on sequence\n");
+ return -EINVAL;
+ }
+ pb->power_off_seq = power_seq_lookup(seqs, "power-off");
+ if (!pb->power_off_seq) {
+ dev_err(&pdev->dev, "missing power-off sequence\n");
+ return -EINVAL;
+ }
+
+ /* we must have exactly one PWM resource for this driver */
+ power_seq_for_each_resource(res, seqs) {
+ if (res->type != POWER_SEQ_PWM)
+ continue;
+ if (pb->pwm) {
+ dev_err(&pdev->dev, "more than one PWM used\n");
+ return -EINVAL;
+ }
+ /* keep the pwm at hand */
+ pb->pwm = res->pwm.pwm;
+ }
+ /* from here we should have a PWM */
+ if (!pb->pwm) {
+ dev_err(&pdev->dev, "no PWM defined!\n");
+ return -EINVAL;
+ }
+ } else {
+ /* use legacy interface */
+ pb->pwm = devm_pwm_get(&pdev->dev, NULL);
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev,
+ "unable to request PWM, trying legacy API\n");
+
+ pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev,
+ "unable to request legacy PWM\n");
+ ret = PTR_ERR(pb->pwm);
+ goto err_alloc;
+ }
+ }
+
+ dev_dbg(&pdev->dev, "got pwm for backlight\n");
+
+ /*
+ * The DT case will set the pwm_period_ns field to 0 and store
+ * the period, parsed from the DT, in the PWM device. For the
+ * non-DT case, set the period from platform data.
+ */
+ if (data->pwm_period_ns > 0)
+ pwm_set_period(pb->pwm, data->pwm_period_ns);
+ }
+
if (data->levels) {
max = data->levels[data->max_brightness];
pb->levels = data->levels;
@@ -213,28 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->exit = data->exit;
pb->dev = &pdev->dev;
- pb->pwm = devm_pwm_get(&pdev->dev, NULL);
- if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
-
- pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
- if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request legacy PWM\n");
- ret = PTR_ERR(pb->pwm);
- goto err_alloc;
- }
- }
-
- dev_dbg(&pdev->dev, "got pwm for backlight\n");
-
- /*
- * The DT case will set the pwm_period_ns field to 0 and store the
- * period, parsed from the DT, in the PWM device. For the non-DT case,
- * set the period from platform data.
- */
- if (data->pwm_period_ns > 0)
- pwm_set_period(pb->pwm, data->pwm_period_ns);
-
pb->period = pwm_get_period(pb->pwm);
pb->lth_brightness = data->lth_brightness * (pb->period / max);
@@ -267,8 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev)
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
backlight_device_unregister(bl);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
if (pb->exit)
pb->exit(&pdev->dev);
return 0;
@@ -282,8 +374,7 @@ static int pwm_backlight_suspend(struct device *dev)
if (pb->notify)
pb->notify(pb->dev, 0);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
if (pb->notify_after)
pb->notify_after(pb->dev, 0);
return 0;
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 56f4a86..0dcec1d 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -5,14 +5,28 @@
#define __LINUX_PWM_BACKLIGHT_H
#include <linux/backlight.h>
+#include <linux/power_seq.h>
struct platform_pwm_backlight_data {
- int pwm_id;
unsigned int max_brightness;
unsigned int dft_brightness;
unsigned int lth_brightness;
- unsigned int pwm_period_ns;
unsigned int *levels;
+ /*
+ * New interface using power sequences. Must include exactly
+ * two power sequences named 'power-on' and 'power-off'. If NULL,
+ * the legacy interface is used.
+ */
+ struct platform_power_seq_set *power_seqs;
+
+ /*
+ * Legacy interface - use power sequences instead!
+ *
+ * pwm_id and pwm_period_ns need only be specified
+ * if get_pwm(dev, NULL) would return NULL.
+ */
+ int pwm_id;
+ unsigned int pwm_period_ns;
int (*init)(struct device *dev);
int (*notify)(struct device *dev, int brightness);
void (*notify_after)(struct device *dev, int brightness);
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-pm-u79uwXL29TY76Z2rM5mHXA, Leela Krishna Amudala,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA
Make use of the power sequences specified in the device tree or platform
data to control how the backlight is powered on and off.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../bindings/video/backlight/pwm-backlight.txt | 72 ++++++++-
drivers/video/backlight/Kconfig | 1 +
drivers/video/backlight/pwm_bl.c | 161 ++++++++++++++++-----
include/linux/pwm_backlight.h | 18 ++-
4 files changed, 213 insertions(+), 39 deletions(-)
diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
index 1e4fc72..3ba25ea 100644
--- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
+++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
@@ -14,15 +14,83 @@ Required properties:
Optional properties:
- pwm-names: a list of names for the PWM devices specified in the
"pwms" property (see PWM binding[0])
+ - low-threshold-brightness: brightness threshold low level. Sets the lowest
+ brightness value.
+ On some panels the backlight misbehaves if the duty cycle percentage of the
+ PWM wave is less than a certain level (say 20%). In this example the user
+ can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus
+ preventing the PWM duty cycle from going too low.
+ On setting low-threshold-brightness the range of brightness levels is
+ calculated in the range low-threshold-brightness to the maximum value in
+ brightness-levels, described above.
+ - pwm-names: name for the PWM device specified in the "pwms" property (see PWM
+ binding[0]). Necessary if power sequences are used
+ - power-sequences: Power sequences (see Power sequences[1]) used to bring the
+ backlight on and off. If this property is present, then two power
+ sequences named "power-on" and "power-off" must be defined to control how
+ the backlight is to be powered on and off. These sequences must reference
+ the PWM specified in the pwms property by its name, and can also reference
+ other resources supported by the power sequences mechanism
[0]: Documentation/devicetree/bindings/pwm/pwm.txt
+[1]: Documentation/devicetree/bindings/power/power_seq.txt
Example:
backlight {
compatible = "pwm-backlight";
- pwms = <&pwm 0 5000000>;
-
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
+ low-threshold-brightness = <50>;
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 0 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&backlight_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
};
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index c101697..c2e5f79 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -239,6 +239,7 @@ config BACKLIGHT_CARILLO_RANCH
config BACKLIGHT_PWM
tristate "Generic PWM based Backlight Driver"
depends on PWM
+ select POWER_SEQ
help
If you have a LCD backlight adjustable by PWM, say Y to enable
this driver.
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 069983c..e607c6e 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -27,6 +27,12 @@ struct pwm_bl_data {
unsigned int period;
unsigned int lth_brightness;
unsigned int *levels;
+ bool enabled;
+ struct power_seq_set power_seqs;
+ struct power_seq *power_on_seq;
+ struct power_seq *power_off_seq;
+
+ /* Legacy callbacks */
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
@@ -35,6 +41,52 @@ struct pwm_bl_data {
void (*exit)(struct device *);
};
+static void pwm_backlight_on(struct backlight_device *bl)
+{
+ struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+ int ret;
+
+ if (pb->enabled)
+ return;
+
+ if (pb->power_on_seq) {
+ ret = power_seq_run(pb->power_on_seq);
+ if (ret < 0) {
+ dev_err(&bl->dev, "cannot run power on sequence\n");
+ return;
+ }
+ } else {
+ /* legacy framework */
+ pwm_config(pb->pwm, 0, pb->period);
+ pwm_disable(pb->pwm);
+ }
+
+ pb->enabled = true;
+}
+
+static void pwm_backlight_off(struct backlight_device *bl)
+{
+ struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+ int ret;
+
+ if (!pb->enabled)
+ return;
+
+ if (pb->power_off_seq) {
+ ret = power_seq_run(pb->power_off_seq);
+ if (ret < 0) {
+ dev_err(&bl->dev, "cannot run power off sequence\n");
+ return;
+ }
+ } else {
+ /* legacy framework */
+ pwm_enable(pb->pwm);
+ return;
+ }
+
+ pb->enabled = false;
+}
+
static int pwm_backlight_update_status(struct backlight_device *bl)
{
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
@@ -51,8 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
brightness = pb->notify(pb->dev, brightness);
if (brightness = 0) {
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
} else {
int duty_cycle;
@@ -66,7 +117,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
duty_cycle = pb->lth_brightness +
(duty_cycle * (pb->period - pb->lth_brightness) / max);
pwm_config(pb->pwm, duty_cycle, pb->period);
- pwm_enable(pb->pwm);
+ pwm_backlight_on(bl);
}
if (pb->notify_after)
@@ -145,11 +196,10 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}
- /*
- * TODO: Most users of this driver use a number of GPIOs to control
- * backlight power. Support for specifying these needs to be
- * added.
- */
+ /* read power sequences */
+ data->power_seqs = devm_of_parse_power_seq_set(dev);
+ if (IS_ERR(data->power_seqs))
+ return PTR_ERR(data->power_seqs);
return 0;
}
@@ -172,6 +222,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
{
struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
struct platform_pwm_backlight_data defdata;
+ struct power_seq_resource *res;
struct backlight_properties props;
struct backlight_device *bl;
struct pwm_bl_data *pb;
@@ -180,7 +231,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
if (!data) {
ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
- if (ret < 0) {
+ if (ret = -EPROBE_DEFER) {
+ return ret;
+ } else if (ret < 0) {
dev_err(&pdev->dev, "failed to find platform data\n");
return ret;
}
@@ -201,6 +254,68 @@ static int pwm_backlight_probe(struct platform_device *pdev)
goto err_alloc;
}
+ if (data->power_seqs) {
+ /* use power sequences */
+ struct power_seq_set *seqs = &pb->power_seqs;
+
+ power_seq_set_init(seqs, &pdev->dev);
+ power_seq_set_add_sequences(seqs, data->power_seqs);
+
+ /* Check that the required sequences are here */
+ pb->power_on_seq = power_seq_lookup(seqs, "power-on");
+ if (!pb->power_on_seq) {
+ dev_err(&pdev->dev, "missing power-on sequence\n");
+ return -EINVAL;
+ }
+ pb->power_off_seq = power_seq_lookup(seqs, "power-off");
+ if (!pb->power_off_seq) {
+ dev_err(&pdev->dev, "missing power-off sequence\n");
+ return -EINVAL;
+ }
+
+ /* we must have exactly one PWM resource for this driver */
+ power_seq_for_each_resource(res, seqs) {
+ if (res->type != POWER_SEQ_PWM)
+ continue;
+ if (pb->pwm) {
+ dev_err(&pdev->dev, "more than one PWM used\n");
+ return -EINVAL;
+ }
+ /* keep the pwm at hand */
+ pb->pwm = res->pwm.pwm;
+ }
+ /* from here we should have a PWM */
+ if (!pb->pwm) {
+ dev_err(&pdev->dev, "no PWM defined!\n");
+ return -EINVAL;
+ }
+ } else {
+ /* use legacy interface */
+ pb->pwm = devm_pwm_get(&pdev->dev, NULL);
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev,
+ "unable to request PWM, trying legacy API\n");
+
+ pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
+ if (IS_ERR(pb->pwm)) {
+ dev_err(&pdev->dev,
+ "unable to request legacy PWM\n");
+ ret = PTR_ERR(pb->pwm);
+ goto err_alloc;
+ }
+ }
+
+ dev_dbg(&pdev->dev, "got pwm for backlight\n");
+
+ /*
+ * The DT case will set the pwm_period_ns field to 0 and store
+ * the period, parsed from the DT, in the PWM device. For the
+ * non-DT case, set the period from platform data.
+ */
+ if (data->pwm_period_ns > 0)
+ pwm_set_period(pb->pwm, data->pwm_period_ns);
+ }
+
if (data->levels) {
max = data->levels[data->max_brightness];
pb->levels = data->levels;
@@ -213,28 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->exit = data->exit;
pb->dev = &pdev->dev;
- pb->pwm = devm_pwm_get(&pdev->dev, NULL);
- if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
-
- pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
- if (IS_ERR(pb->pwm)) {
- dev_err(&pdev->dev, "unable to request legacy PWM\n");
- ret = PTR_ERR(pb->pwm);
- goto err_alloc;
- }
- }
-
- dev_dbg(&pdev->dev, "got pwm for backlight\n");
-
- /*
- * The DT case will set the pwm_period_ns field to 0 and store the
- * period, parsed from the DT, in the PWM device. For the non-DT case,
- * set the period from platform data.
- */
- if (data->pwm_period_ns > 0)
- pwm_set_period(pb->pwm, data->pwm_period_ns);
-
pb->period = pwm_get_period(pb->pwm);
pb->lth_brightness = data->lth_brightness * (pb->period / max);
@@ -267,8 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev)
struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
backlight_device_unregister(bl);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
if (pb->exit)
pb->exit(&pdev->dev);
return 0;
@@ -282,8 +374,7 @@ static int pwm_backlight_suspend(struct device *dev)
if (pb->notify)
pb->notify(pb->dev, 0);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_off(bl);
if (pb->notify_after)
pb->notify_after(pb->dev, 0);
return 0;
diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
index 56f4a86..0dcec1d 100644
--- a/include/linux/pwm_backlight.h
+++ b/include/linux/pwm_backlight.h
@@ -5,14 +5,28 @@
#define __LINUX_PWM_BACKLIGHT_H
#include <linux/backlight.h>
+#include <linux/power_seq.h>
struct platform_pwm_backlight_data {
- int pwm_id;
unsigned int max_brightness;
unsigned int dft_brightness;
unsigned int lth_brightness;
- unsigned int pwm_period_ns;
unsigned int *levels;
+ /*
+ * New interface using power sequences. Must include exactly
+ * two power sequences named 'power-on' and 'power-off'. If NULL,
+ * the legacy interface is used.
+ */
+ struct platform_power_seq_set *power_seqs;
+
+ /*
+ * Legacy interface - use power sequences instead!
+ *
+ * pwm_id and pwm_period_ns need only be specified
+ * if get_pwm(dev, NULL) would return NULL.
+ */
+ int pwm_id;
+ unsigned int pwm_period_ns;
int (*init)(struct device *dev);
int (*notify)(struct device *dev, int brightness);
void (*notify_after)(struct device *dev, int brightness);
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 3/3] tegra: ventana: add PWM backlight to device tree
2012-10-19 9:06 ` Alexandre Courbot
(?)
@ 2012-10-19 9:06 ` Alexandre Courbot
-1 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-pm-u79uwXL29TY76Z2rM5mHXA, Leela Krishna Amudala,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA
Signed-off-by: Alexandre Courbot <acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
arch/arm/boot/dts/tegra20-ventana.dts | 59 ++++++++++++++++++++++++++++++++++-
1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index bec8bb2..877a1bb 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts
@@ -454,6 +454,63 @@
bus-width = <8>;
};
+ backlight {
+ compatible = "pwm-backlight";
+ brightness-levels = <0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 255>;
+ default-brightness-level = <12>;
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 2 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&vdd_bl_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
+ };
+
regulators {
compatible = "simple-bus";
#address-cells = <1>;
@@ -497,7 +554,7 @@
enable-active-high;
};
- regulator@4 {
+ vdd_bl_reg: regulator@4 {
compatible = "regulator-fixed";
reg = <4>;
regulator-name = "vdd_bl";
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 3/3] tegra: ventana: add PWM backlight to device tree
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: Leela Krishna Amudala, linux-tegra, linux-kernel, linux-fbdev,
devicetree-discuss, linux-pm, linux-doc, Alexandre Courbot
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
arch/arm/boot/dts/tegra20-ventana.dts | 59 ++++++++++++++++++++++++++++++++++-
1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index bec8bb2..877a1bb 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts
@@ -454,6 +454,63 @@
bus-width = <8>;
};
+ backlight {
+ compatible = "pwm-backlight";
+ brightness-levels = <0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 255>;
+ default-brightness-level = <12>;
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 2 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&vdd_bl_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
+ };
+
regulators {
compatible = "simple-bus";
#address-cells = <1>;
@@ -497,7 +554,7 @@
enable-active-high;
};
- regulator@4 {
+ vdd_bl_reg: regulator@4 {
compatible = "regulator-fixed";
reg = <4>;
regulator-name = "vdd_bl";
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v7 3/3] tegra: ventana: add PWM backlight to device tree
@ 2012-10-19 9:06 ` Alexandre Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alexandre Courbot @ 2012-10-19 9:06 UTC (permalink / raw)
To: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-pm-u79uwXL29TY76Z2rM5mHXA, Leela Krishna Amudala,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
arch/arm/boot/dts/tegra20-ventana.dts | 59 ++++++++++++++++++++++++++++++++++-
1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index bec8bb2..877a1bb 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts
@@ -454,6 +454,63 @@
bus-width = <8>;
};
+ backlight {
+ compatible = "pwm-backlight";
+ brightness-levels = <0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 255>;
+ default-brightness-level = <12>;
+
+ /* resources used by the power sequences */
+ pwms = <&pwm 2 5000000>;
+ pwm-names = "backlight";
+ power-supply = <&vdd_bl_reg>;
+
+ power-sequences {
+ power-on {
+ step0 {
+ type = "regulator";
+ id = "power";
+ enable;
+ };
+ step1 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step2 {
+ type = "pwm";
+ id = "backlight";
+ enable;
+ };
+ step3 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <1>;
+ };
+ };
+
+ power-off {
+ step0 {
+ type = "gpio";
+ gpio = <&gpio 28 0>;
+ value = <0>;
+ };
+ step1 {
+ type = "pwm";
+ id = "backlight";
+ disable;
+ };
+ step2 {
+ type = "delay";
+ delay = <10000>;
+ };
+ step3 {
+ type = "regulator";
+ id = "power";
+ disable;
+ };
+ };
+ };
+ };
+
regulators {
compatible = "simple-bus";
#address-cells = <1>;
@@ -497,7 +554,7 @@
enable-active-high;
};
- regulator@4 {
+ vdd_bl_reg: regulator@4 {
compatible = "regulator-fixed";
reg = <4>;
regulator-name = "vdd_bl";
--
1.7.12.3
^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
2012-10-19 9:06 ` Alexandre Courbot
(?)
@ 2012-10-19 9:20 ` Tony Prisk
-1 siblings, 0 replies; 20+ messages in thread
From: Tony Prisk @ 2012-10-19 9:20 UTC (permalink / raw)
To: Alexandre Courbot
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA, Mark Brown, Stephen Warren,
linux-pm-u79uwXL29TY76Z2rM5mHXA, Leela Krishna Amudala,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, Rob Herring,
Anton Vorontsov, linux-tegra-u79uwXL29TY76Z2rM5mHXA,
David Woodhouse, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ
On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
> Make use of the power sequences specified in the device tree or platform
> data to control how the backlight is powered on and off.
>
> Signed-off-by: Alexandre Courbot <acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
> .../bindings/video/backlight/pwm-backlight.txt | 72 ++++++++-
> drivers/video/backlight/Kconfig | 1 +
> drivers/video/backlight/pwm_bl.c | 161 ++++++++++++++++-----
> include/linux/pwm_backlight.h | 18 ++-
> 4 files changed, 213 insertions(+), 39 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> index 1e4fc72..3ba25ea 100644
> --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> @@ -14,15 +14,83 @@ Required properties:
> Optional properties:
> - pwm-names: a list of names for the PWM devices specified in the
> "pwms" property (see PWM binding[0])
> + - low-threshold-brightness: brightness threshold low level. Sets the lowest
> + brightness value.
> + On some panels the backlight misbehaves if the duty cycle percentage of the
> + PWM wave is less than a certain level (say 20%). In this example the user
> + can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus
> + preventing the PWM duty cycle from going too low.
> + On setting low-threshold-brightness the range of brightness levels is
> + calculated in the range low-threshold-brightness to the maximum value in
> + brightness-levels, described above.
> + - pwm-names: name for the PWM device specified in the "pwms" property (see PWM
> + binding[0]). Necessary if power sequences are used
> + - power-sequences: Power sequences (see Power sequences[1]) used to bring the
> + backlight on and off. If this property is present, then two power
> + sequences named "power-on" and "power-off" must be defined to control how
> + the backlight is to be powered on and off. These sequences must reference
> + the PWM specified in the pwms property by its name, and can also reference
> + other resources supported by the power sequences mechanism
>
> [0]: Documentation/devicetree/bindings/pwm/pwm.txt
> +[1]: Documentation/devicetree/bindings/power/power_seq.txt
>
> Example:
>
> backlight {
> compatible = "pwm-backlight";
> - pwms = <&pwm 0 5000000>;
> -
> brightness-levels = <0 4 8 16 32 64 128 255>;
> default-brightness-level = <6>;
> + low-threshold-brightness = <50>;
> +
> + /* resources used by the power sequences */
> + pwms = <&pwm 0 5000000>;
> + pwm-names = "backlight";
> + power-supply = <&backlight_reg>;
> +
> + power-sequences {
> + power-on {
> + step0 {
> + type = "regulator";
> + id = "power";
> + enable;
> + };
> + step1 {
> + type = "delay";
> + delay = <10000>;
> + };
> + step2 {
> + type = "pwm";
> + id = "backlight";
> + enable;
> + };
> + step3 {
> + type = "gpio";
> + gpio = <&gpio 28 0>;
> + value = <1>;
> + };
> + };
> +
> + power-off {
> + step0 {
> + type = "gpio";
> + gpio = <&gpio 28 0>;
> + value = <0>;
> + };
> + step1 {
> + type = "pwm";
> + id = "backlight";
> + disable;
> + };
> + step2 {
> + type = "delay";
> + delay = <10000>;
> + };
> + step3 {
> + type = "regulator";
> + id = "power";
> + disable;
> + };
> + };
> + };
> };
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index c101697..c2e5f79 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -239,6 +239,7 @@ config BACKLIGHT_CARILLO_RANCH
> config BACKLIGHT_PWM
> tristate "Generic PWM based Backlight Driver"
> depends on PWM
> + select POWER_SEQ
> help
> If you have a LCD backlight adjustable by PWM, say Y to enable
> this driver.
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 069983c..e607c6e 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -27,6 +27,12 @@ struct pwm_bl_data {
> unsigned int period;
> unsigned int lth_brightness;
> unsigned int *levels;
> + bool enabled;
> + struct power_seq_set power_seqs;
> + struct power_seq *power_on_seq;
> + struct power_seq *power_off_seq;
> +
> + /* Legacy callbacks */
> int (*notify)(struct device *,
> int brightness);
> void (*notify_after)(struct device *,
> @@ -35,6 +41,52 @@ struct pwm_bl_data {
> void (*exit)(struct device *);
> };
>
> +static void pwm_backlight_on(struct backlight_device *bl)
> +{
> + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> + int ret;
> +
> + if (pb->enabled)
> + return;
> +
> + if (pb->power_on_seq) {
> + ret = power_seq_run(pb->power_on_seq);
> + if (ret < 0) {
> + dev_err(&bl->dev, "cannot run power on sequence\n");
> + return;
> + }
> + } else {
> + /* legacy framework */
> + pwm_config(pb->pwm, 0, pb->period);
> + pwm_disable(pb->pwm);
Is this right? pwm_disable() in the backlight_on function?
> + }
> +
> + pb->enabled = true;
> +}
> +
> +static void pwm_backlight_off(struct backlight_device *bl)
> +{
> + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> + int ret;
> +
> + if (!pb->enabled)
> + return;
> +
> + if (pb->power_off_seq) {
> + ret = power_seq_run(pb->power_off_seq);
> + if (ret < 0) {
> + dev_err(&bl->dev, "cannot run power off sequence\n");
> + return;
> + }
> + } else {
> + /* legacy framework */
> + pwm_enable(pb->pwm);
Same here.. owm_enable() in backlight_off()
> + return;
> + }
> +
> + pb->enabled = false;
> +}
> +
> static int pwm_backlight_update_status(struct backlight_device *bl)
> {
> struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> @@ -51,8 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
> brightness = pb->notify(pb->dev, brightness);
>
> if (brightness == 0) {
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> } else {
> int duty_cycle;
>
> @@ -66,7 +117,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
> duty_cycle = pb->lth_brightness +
> (duty_cycle * (pb->period - pb->lth_brightness) / max);
> pwm_config(pb->pwm, duty_cycle, pb->period);
> - pwm_enable(pb->pwm);
> + pwm_backlight_on(bl);
> }
>
> if (pb->notify_after)
> @@ -145,11 +196,10 @@ static int pwm_backlight_parse_dt(struct device *dev,
> data->max_brightness--;
> }
>
> - /*
> - * TODO: Most users of this driver use a number of GPIOs to control
> - * backlight power. Support for specifying these needs to be
> - * added.
> - */
> + /* read power sequences */
> + data->power_seqs = devm_of_parse_power_seq_set(dev);
> + if (IS_ERR(data->power_seqs))
> + return PTR_ERR(data->power_seqs);
>
> return 0;
> }
> @@ -172,6 +222,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> {
> struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
> struct platform_pwm_backlight_data defdata;
> + struct power_seq_resource *res;
> struct backlight_properties props;
> struct backlight_device *bl;
> struct pwm_bl_data *pb;
> @@ -180,7 +231,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>
> if (!data) {
> ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
> - if (ret < 0) {
> + if (ret == -EPROBE_DEFER) {
> + return ret;
> + } else if (ret < 0) {
> dev_err(&pdev->dev, "failed to find platform data\n");
> return ret;
> }
> @@ -201,6 +254,68 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> goto err_alloc;
> }
>
> + if (data->power_seqs) {
> + /* use power sequences */
> + struct power_seq_set *seqs = &pb->power_seqs;
> +
> + power_seq_set_init(seqs, &pdev->dev);
> + power_seq_set_add_sequences(seqs, data->power_seqs);
> +
> + /* Check that the required sequences are here */
> + pb->power_on_seq = power_seq_lookup(seqs, "power-on");
> + if (!pb->power_on_seq) {
> + dev_err(&pdev->dev, "missing power-on sequence\n");
> + return -EINVAL;
> + }
> + pb->power_off_seq = power_seq_lookup(seqs, "power-off");
> + if (!pb->power_off_seq) {
> + dev_err(&pdev->dev, "missing power-off sequence\n");
> + return -EINVAL;
> + }
> +
> + /* we must have exactly one PWM resource for this driver */
> + power_seq_for_each_resource(res, seqs) {
> + if (res->type != POWER_SEQ_PWM)
> + continue;
> + if (pb->pwm) {
> + dev_err(&pdev->dev, "more than one PWM used\n");
> + return -EINVAL;
> + }
> + /* keep the pwm at hand */
> + pb->pwm = res->pwm.pwm;
> + }
> + /* from here we should have a PWM */
> + if (!pb->pwm) {
> + dev_err(&pdev->dev, "no PWM defined!\n");
> + return -EINVAL;
> + }
> + } else {
> + /* use legacy interface */
> + pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> + if (IS_ERR(pb->pwm)) {
> + dev_err(&pdev->dev,
> + "unable to request PWM, trying legacy API\n");
> +
> + pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> + if (IS_ERR(pb->pwm)) {
> + dev_err(&pdev->dev,
> + "unable to request legacy PWM\n");
> + ret = PTR_ERR(pb->pwm);
> + goto err_alloc;
> + }
> + }
> +
> + dev_dbg(&pdev->dev, "got pwm for backlight\n");
> +
> + /*
> + * The DT case will set the pwm_period_ns field to 0 and store
> + * the period, parsed from the DT, in the PWM device. For the
> + * non-DT case, set the period from platform data.
> + */
> + if (data->pwm_period_ns > 0)
> + pwm_set_period(pb->pwm, data->pwm_period_ns);
> + }
> +
> if (data->levels) {
> max = data->levels[data->max_brightness];
> pb->levels = data->levels;
> @@ -213,28 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> pb->exit = data->exit;
> pb->dev = &pdev->dev;
>
> - pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> - if (IS_ERR(pb->pwm)) {
> - dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
> -
> - pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> - if (IS_ERR(pb->pwm)) {
> - dev_err(&pdev->dev, "unable to request legacy PWM\n");
> - ret = PTR_ERR(pb->pwm);
> - goto err_alloc;
> - }
> - }
> -
> - dev_dbg(&pdev->dev, "got pwm for backlight\n");
> -
> - /*
> - * The DT case will set the pwm_period_ns field to 0 and store the
> - * period, parsed from the DT, in the PWM device. For the non-DT case,
> - * set the period from platform data.
> - */
> - if (data->pwm_period_ns > 0)
> - pwm_set_period(pb->pwm, data->pwm_period_ns);
> -
> pb->period = pwm_get_period(pb->pwm);
> pb->lth_brightness = data->lth_brightness * (pb->period / max);
>
> @@ -267,8 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev)
> struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
>
> backlight_device_unregister(bl);
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> if (pb->exit)
> pb->exit(&pdev->dev);
> return 0;
> @@ -282,8 +374,7 @@ static int pwm_backlight_suspend(struct device *dev)
>
> if (pb->notify)
> pb->notify(pb->dev, 0);
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> if (pb->notify_after)
> pb->notify_after(pb->dev, 0);
> return 0;
> diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
> index 56f4a86..0dcec1d 100644
> --- a/include/linux/pwm_backlight.h
> +++ b/include/linux/pwm_backlight.h
> @@ -5,14 +5,28 @@
> #define __LINUX_PWM_BACKLIGHT_H
>
> #include <linux/backlight.h>
> +#include <linux/power_seq.h>
>
> struct platform_pwm_backlight_data {
> - int pwm_id;
> unsigned int max_brightness;
> unsigned int dft_brightness;
> unsigned int lth_brightness;
> - unsigned int pwm_period_ns;
> unsigned int *levels;
> + /*
> + * New interface using power sequences. Must include exactly
> + * two power sequences named 'power-on' and 'power-off'. If NULL,
> + * the legacy interface is used.
> + */
> + struct platform_power_seq_set *power_seqs;
> +
> + /*
> + * Legacy interface - use power sequences instead!
> + *
> + * pwm_id and pwm_period_ns need only be specified
> + * if get_pwm(dev, NULL) would return NULL.
> + */
> + int pwm_id;
> + unsigned int pwm_period_ns;
> int (*init)(struct device *dev);
> int (*notify)(struct device *dev, int brightness);
> void (*notify_after)(struct device *dev, int brightness);
Regards
Tony P
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 9:20 ` Tony Prisk
0 siblings, 0 replies; 20+ messages in thread
From: Tony Prisk @ 2012-10-19 9:20 UTC (permalink / raw)
To: Alexandre Courbot
Cc: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann, linux-fbdev, linux-pm, Leela Krishna Amudala,
devicetree-discuss, linux-doc, linux-kernel, linux-tegra
On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
> Make use of the power sequences specified in the device tree or platform
> data to control how the backlight is powered on and off.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
> .../bindings/video/backlight/pwm-backlight.txt | 72 ++++++++-
> drivers/video/backlight/Kconfig | 1 +
> drivers/video/backlight/pwm_bl.c | 161 ++++++++++++++++-----
> include/linux/pwm_backlight.h | 18 ++-
> 4 files changed, 213 insertions(+), 39 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> index 1e4fc72..3ba25ea 100644
> --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> @@ -14,15 +14,83 @@ Required properties:
> Optional properties:
> - pwm-names: a list of names for the PWM devices specified in the
> "pwms" property (see PWM binding[0])
> + - low-threshold-brightness: brightness threshold low level. Sets the lowest
> + brightness value.
> + On some panels the backlight misbehaves if the duty cycle percentage of the
> + PWM wave is less than a certain level (say 20%). In this example the user
> + can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus
> + preventing the PWM duty cycle from going too low.
> + On setting low-threshold-brightness the range of brightness levels is
> + calculated in the range low-threshold-brightness to the maximum value in
> + brightness-levels, described above.
> + - pwm-names: name for the PWM device specified in the "pwms" property (see PWM
> + binding[0]). Necessary if power sequences are used
> + - power-sequences: Power sequences (see Power sequences[1]) used to bring the
> + backlight on and off. If this property is present, then two power
> + sequences named "power-on" and "power-off" must be defined to control how
> + the backlight is to be powered on and off. These sequences must reference
> + the PWM specified in the pwms property by its name, and can also reference
> + other resources supported by the power sequences mechanism
>
> [0]: Documentation/devicetree/bindings/pwm/pwm.txt
> +[1]: Documentation/devicetree/bindings/power/power_seq.txt
>
> Example:
>
> backlight {
> compatible = "pwm-backlight";
> - pwms = <&pwm 0 5000000>;
> -
> brightness-levels = <0 4 8 16 32 64 128 255>;
> default-brightness-level = <6>;
> + low-threshold-brightness = <50>;
> +
> + /* resources used by the power sequences */
> + pwms = <&pwm 0 5000000>;
> + pwm-names = "backlight";
> + power-supply = <&backlight_reg>;
> +
> + power-sequences {
> + power-on {
> + step0 {
> + type = "regulator";
> + id = "power";
> + enable;
> + };
> + step1 {
> + type = "delay";
> + delay = <10000>;
> + };
> + step2 {
> + type = "pwm";
> + id = "backlight";
> + enable;
> + };
> + step3 {
> + type = "gpio";
> + gpio = <&gpio 28 0>;
> + value = <1>;
> + };
> + };
> +
> + power-off {
> + step0 {
> + type = "gpio";
> + gpio = <&gpio 28 0>;
> + value = <0>;
> + };
> + step1 {
> + type = "pwm";
> + id = "backlight";
> + disable;
> + };
> + step2 {
> + type = "delay";
> + delay = <10000>;
> + };
> + step3 {
> + type = "regulator";
> + id = "power";
> + disable;
> + };
> + };
> + };
> };
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index c101697..c2e5f79 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -239,6 +239,7 @@ config BACKLIGHT_CARILLO_RANCH
> config BACKLIGHT_PWM
> tristate "Generic PWM based Backlight Driver"
> depends on PWM
> + select POWER_SEQ
> help
> If you have a LCD backlight adjustable by PWM, say Y to enable
> this driver.
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 069983c..e607c6e 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -27,6 +27,12 @@ struct pwm_bl_data {
> unsigned int period;
> unsigned int lth_brightness;
> unsigned int *levels;
> + bool enabled;
> + struct power_seq_set power_seqs;
> + struct power_seq *power_on_seq;
> + struct power_seq *power_off_seq;
> +
> + /* Legacy callbacks */
> int (*notify)(struct device *,
> int brightness);
> void (*notify_after)(struct device *,
> @@ -35,6 +41,52 @@ struct pwm_bl_data {
> void (*exit)(struct device *);
> };
>
> +static void pwm_backlight_on(struct backlight_device *bl)
> +{
> + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> + int ret;
> +
> + if (pb->enabled)
> + return;
> +
> + if (pb->power_on_seq) {
> + ret = power_seq_run(pb->power_on_seq);
> + if (ret < 0) {
> + dev_err(&bl->dev, "cannot run power on sequence\n");
> + return;
> + }
> + } else {
> + /* legacy framework */
> + pwm_config(pb->pwm, 0, pb->period);
> + pwm_disable(pb->pwm);
Is this right? pwm_disable() in the backlight_on function?
> + }
> +
> + pb->enabled = true;
> +}
> +
> +static void pwm_backlight_off(struct backlight_device *bl)
> +{
> + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> + int ret;
> +
> + if (!pb->enabled)
> + return;
> +
> + if (pb->power_off_seq) {
> + ret = power_seq_run(pb->power_off_seq);
> + if (ret < 0) {
> + dev_err(&bl->dev, "cannot run power off sequence\n");
> + return;
> + }
> + } else {
> + /* legacy framework */
> + pwm_enable(pb->pwm);
Same here.. owm_enable() in backlight_off()
> + return;
> + }
> +
> + pb->enabled = false;
> +}
> +
> static int pwm_backlight_update_status(struct backlight_device *bl)
> {
> struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> @@ -51,8 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
> brightness = pb->notify(pb->dev, brightness);
>
> if (brightness == 0) {
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> } else {
> int duty_cycle;
>
> @@ -66,7 +117,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
> duty_cycle = pb->lth_brightness +
> (duty_cycle * (pb->period - pb->lth_brightness) / max);
> pwm_config(pb->pwm, duty_cycle, pb->period);
> - pwm_enable(pb->pwm);
> + pwm_backlight_on(bl);
> }
>
> if (pb->notify_after)
> @@ -145,11 +196,10 @@ static int pwm_backlight_parse_dt(struct device *dev,
> data->max_brightness--;
> }
>
> - /*
> - * TODO: Most users of this driver use a number of GPIOs to control
> - * backlight power. Support for specifying these needs to be
> - * added.
> - */
> + /* read power sequences */
> + data->power_seqs = devm_of_parse_power_seq_set(dev);
> + if (IS_ERR(data->power_seqs))
> + return PTR_ERR(data->power_seqs);
>
> return 0;
> }
> @@ -172,6 +222,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> {
> struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
> struct platform_pwm_backlight_data defdata;
> + struct power_seq_resource *res;
> struct backlight_properties props;
> struct backlight_device *bl;
> struct pwm_bl_data *pb;
> @@ -180,7 +231,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>
> if (!data) {
> ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
> - if (ret < 0) {
> + if (ret == -EPROBE_DEFER) {
> + return ret;
> + } else if (ret < 0) {
> dev_err(&pdev->dev, "failed to find platform data\n");
> return ret;
> }
> @@ -201,6 +254,68 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> goto err_alloc;
> }
>
> + if (data->power_seqs) {
> + /* use power sequences */
> + struct power_seq_set *seqs = &pb->power_seqs;
> +
> + power_seq_set_init(seqs, &pdev->dev);
> + power_seq_set_add_sequences(seqs, data->power_seqs);
> +
> + /* Check that the required sequences are here */
> + pb->power_on_seq = power_seq_lookup(seqs, "power-on");
> + if (!pb->power_on_seq) {
> + dev_err(&pdev->dev, "missing power-on sequence\n");
> + return -EINVAL;
> + }
> + pb->power_off_seq = power_seq_lookup(seqs, "power-off");
> + if (!pb->power_off_seq) {
> + dev_err(&pdev->dev, "missing power-off sequence\n");
> + return -EINVAL;
> + }
> +
> + /* we must have exactly one PWM resource for this driver */
> + power_seq_for_each_resource(res, seqs) {
> + if (res->type != POWER_SEQ_PWM)
> + continue;
> + if (pb->pwm) {
> + dev_err(&pdev->dev, "more than one PWM used\n");
> + return -EINVAL;
> + }
> + /* keep the pwm at hand */
> + pb->pwm = res->pwm.pwm;
> + }
> + /* from here we should have a PWM */
> + if (!pb->pwm) {
> + dev_err(&pdev->dev, "no PWM defined!\n");
> + return -EINVAL;
> + }
> + } else {
> + /* use legacy interface */
> + pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> + if (IS_ERR(pb->pwm)) {
> + dev_err(&pdev->dev,
> + "unable to request PWM, trying legacy API\n");
> +
> + pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> + if (IS_ERR(pb->pwm)) {
> + dev_err(&pdev->dev,
> + "unable to request legacy PWM\n");
> + ret = PTR_ERR(pb->pwm);
> + goto err_alloc;
> + }
> + }
> +
> + dev_dbg(&pdev->dev, "got pwm for backlight\n");
> +
> + /*
> + * The DT case will set the pwm_period_ns field to 0 and store
> + * the period, parsed from the DT, in the PWM device. For the
> + * non-DT case, set the period from platform data.
> + */
> + if (data->pwm_period_ns > 0)
> + pwm_set_period(pb->pwm, data->pwm_period_ns);
> + }
> +
> if (data->levels) {
> max = data->levels[data->max_brightness];
> pb->levels = data->levels;
> @@ -213,28 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> pb->exit = data->exit;
> pb->dev = &pdev->dev;
>
> - pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> - if (IS_ERR(pb->pwm)) {
> - dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
> -
> - pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> - if (IS_ERR(pb->pwm)) {
> - dev_err(&pdev->dev, "unable to request legacy PWM\n");
> - ret = PTR_ERR(pb->pwm);
> - goto err_alloc;
> - }
> - }
> -
> - dev_dbg(&pdev->dev, "got pwm for backlight\n");
> -
> - /*
> - * The DT case will set the pwm_period_ns field to 0 and store the
> - * period, parsed from the DT, in the PWM device. For the non-DT case,
> - * set the period from platform data.
> - */
> - if (data->pwm_period_ns > 0)
> - pwm_set_period(pb->pwm, data->pwm_period_ns);
> -
> pb->period = pwm_get_period(pb->pwm);
> pb->lth_brightness = data->lth_brightness * (pb->period / max);
>
> @@ -267,8 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev)
> struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
>
> backlight_device_unregister(bl);
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> if (pb->exit)
> pb->exit(&pdev->dev);
> return 0;
> @@ -282,8 +374,7 @@ static int pwm_backlight_suspend(struct device *dev)
>
> if (pb->notify)
> pb->notify(pb->dev, 0);
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> if (pb->notify_after)
> pb->notify_after(pb->dev, 0);
> return 0;
> diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
> index 56f4a86..0dcec1d 100644
> --- a/include/linux/pwm_backlight.h
> +++ b/include/linux/pwm_backlight.h
> @@ -5,14 +5,28 @@
> #define __LINUX_PWM_BACKLIGHT_H
>
> #include <linux/backlight.h>
> +#include <linux/power_seq.h>
>
> struct platform_pwm_backlight_data {
> - int pwm_id;
> unsigned int max_brightness;
> unsigned int dft_brightness;
> unsigned int lth_brightness;
> - unsigned int pwm_period_ns;
> unsigned int *levels;
> + /*
> + * New interface using power sequences. Must include exactly
> + * two power sequences named 'power-on' and 'power-off'. If NULL,
> + * the legacy interface is used.
> + */
> + struct platform_power_seq_set *power_seqs;
> +
> + /*
> + * Legacy interface - use power sequences instead!
> + *
> + * pwm_id and pwm_period_ns need only be specified
> + * if get_pwm(dev, NULL) would return NULL.
> + */
> + int pwm_id;
> + unsigned int pwm_period_ns;
> int (*init)(struct device *dev);
> int (*notify)(struct device *dev, int brightness);
> void (*notify_after)(struct device *dev, int brightness);
Regards
Tony P
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 9:20 ` Tony Prisk
0 siblings, 0 replies; 20+ messages in thread
From: Tony Prisk @ 2012-10-19 9:20 UTC (permalink / raw)
To: Alexandre Courbot
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA, Mark Brown, Stephen Warren,
linux-pm-u79uwXL29TY76Z2rM5mHXA, Leela Krishna Amudala,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, Rob Herring,
Anton Vorontsov, linux-tegra-u79uwXL29TY76Z2rM5mHXA,
David Woodhouse, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ
On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
> Make use of the power sequences specified in the device tree or platform
> data to control how the backlight is powered on and off.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
> .../bindings/video/backlight/pwm-backlight.txt | 72 ++++++++-
> drivers/video/backlight/Kconfig | 1 +
> drivers/video/backlight/pwm_bl.c | 161 ++++++++++++++++-----
> include/linux/pwm_backlight.h | 18 ++-
> 4 files changed, 213 insertions(+), 39 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> index 1e4fc72..3ba25ea 100644
> --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> @@ -14,15 +14,83 @@ Required properties:
> Optional properties:
> - pwm-names: a list of names for the PWM devices specified in the
> "pwms" property (see PWM binding[0])
> + - low-threshold-brightness: brightness threshold low level. Sets the lowest
> + brightness value.
> + On some panels the backlight misbehaves if the duty cycle percentage of the
> + PWM wave is less than a certain level (say 20%). In this example the user
> + can set low-threshold-brightness to a value above 50 (ie, 20% of 255), thus
> + preventing the PWM duty cycle from going too low.
> + On setting low-threshold-brightness the range of brightness levels is
> + calculated in the range low-threshold-brightness to the maximum value in
> + brightness-levels, described above.
> + - pwm-names: name for the PWM device specified in the "pwms" property (see PWM
> + binding[0]). Necessary if power sequences are used
> + - power-sequences: Power sequences (see Power sequences[1]) used to bring the
> + backlight on and off. If this property is present, then two power
> + sequences named "power-on" and "power-off" must be defined to control how
> + the backlight is to be powered on and off. These sequences must reference
> + the PWM specified in the pwms property by its name, and can also reference
> + other resources supported by the power sequences mechanism
>
> [0]: Documentation/devicetree/bindings/pwm/pwm.txt
> +[1]: Documentation/devicetree/bindings/power/power_seq.txt
>
> Example:
>
> backlight {
> compatible = "pwm-backlight";
> - pwms = <&pwm 0 5000000>;
> -
> brightness-levels = <0 4 8 16 32 64 128 255>;
> default-brightness-level = <6>;
> + low-threshold-brightness = <50>;
> +
> + /* resources used by the power sequences */
> + pwms = <&pwm 0 5000000>;
> + pwm-names = "backlight";
> + power-supply = <&backlight_reg>;
> +
> + power-sequences {
> + power-on {
> + step0 {
> + type = "regulator";
> + id = "power";
> + enable;
> + };
> + step1 {
> + type = "delay";
> + delay = <10000>;
> + };
> + step2 {
> + type = "pwm";
> + id = "backlight";
> + enable;
> + };
> + step3 {
> + type = "gpio";
> + gpio = <&gpio 28 0>;
> + value = <1>;
> + };
> + };
> +
> + power-off {
> + step0 {
> + type = "gpio";
> + gpio = <&gpio 28 0>;
> + value = <0>;
> + };
> + step1 {
> + type = "pwm";
> + id = "backlight";
> + disable;
> + };
> + step2 {
> + type = "delay";
> + delay = <10000>;
> + };
> + step3 {
> + type = "regulator";
> + id = "power";
> + disable;
> + };
> + };
> + };
> };
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index c101697..c2e5f79 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -239,6 +239,7 @@ config BACKLIGHT_CARILLO_RANCH
> config BACKLIGHT_PWM
> tristate "Generic PWM based Backlight Driver"
> depends on PWM
> + select POWER_SEQ
> help
> If you have a LCD backlight adjustable by PWM, say Y to enable
> this driver.
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 069983c..e607c6e 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -27,6 +27,12 @@ struct pwm_bl_data {
> unsigned int period;
> unsigned int lth_brightness;
> unsigned int *levels;
> + bool enabled;
> + struct power_seq_set power_seqs;
> + struct power_seq *power_on_seq;
> + struct power_seq *power_off_seq;
> +
> + /* Legacy callbacks */
> int (*notify)(struct device *,
> int brightness);
> void (*notify_after)(struct device *,
> @@ -35,6 +41,52 @@ struct pwm_bl_data {
> void (*exit)(struct device *);
> };
>
> +static void pwm_backlight_on(struct backlight_device *bl)
> +{
> + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> + int ret;
> +
> + if (pb->enabled)
> + return;
> +
> + if (pb->power_on_seq) {
> + ret = power_seq_run(pb->power_on_seq);
> + if (ret < 0) {
> + dev_err(&bl->dev, "cannot run power on sequence\n");
> + return;
> + }
> + } else {
> + /* legacy framework */
> + pwm_config(pb->pwm, 0, pb->period);
> + pwm_disable(pb->pwm);
Is this right? pwm_disable() in the backlight_on function?
> + }
> +
> + pb->enabled = true;
> +}
> +
> +static void pwm_backlight_off(struct backlight_device *bl)
> +{
> + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> + int ret;
> +
> + if (!pb->enabled)
> + return;
> +
> + if (pb->power_off_seq) {
> + ret = power_seq_run(pb->power_off_seq);
> + if (ret < 0) {
> + dev_err(&bl->dev, "cannot run power off sequence\n");
> + return;
> + }
> + } else {
> + /* legacy framework */
> + pwm_enable(pb->pwm);
Same here.. owm_enable() in backlight_off()
> + return;
> + }
> +
> + pb->enabled = false;
> +}
> +
> static int pwm_backlight_update_status(struct backlight_device *bl)
> {
> struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> @@ -51,8 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
> brightness = pb->notify(pb->dev, brightness);
>
> if (brightness = 0) {
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> } else {
> int duty_cycle;
>
> @@ -66,7 +117,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
> duty_cycle = pb->lth_brightness +
> (duty_cycle * (pb->period - pb->lth_brightness) / max);
> pwm_config(pb->pwm, duty_cycle, pb->period);
> - pwm_enable(pb->pwm);
> + pwm_backlight_on(bl);
> }
>
> if (pb->notify_after)
> @@ -145,11 +196,10 @@ static int pwm_backlight_parse_dt(struct device *dev,
> data->max_brightness--;
> }
>
> - /*
> - * TODO: Most users of this driver use a number of GPIOs to control
> - * backlight power. Support for specifying these needs to be
> - * added.
> - */
> + /* read power sequences */
> + data->power_seqs = devm_of_parse_power_seq_set(dev);
> + if (IS_ERR(data->power_seqs))
> + return PTR_ERR(data->power_seqs);
>
> return 0;
> }
> @@ -172,6 +222,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> {
> struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
> struct platform_pwm_backlight_data defdata;
> + struct power_seq_resource *res;
> struct backlight_properties props;
> struct backlight_device *bl;
> struct pwm_bl_data *pb;
> @@ -180,7 +231,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>
> if (!data) {
> ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
> - if (ret < 0) {
> + if (ret = -EPROBE_DEFER) {
> + return ret;
> + } else if (ret < 0) {
> dev_err(&pdev->dev, "failed to find platform data\n");
> return ret;
> }
> @@ -201,6 +254,68 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> goto err_alloc;
> }
>
> + if (data->power_seqs) {
> + /* use power sequences */
> + struct power_seq_set *seqs = &pb->power_seqs;
> +
> + power_seq_set_init(seqs, &pdev->dev);
> + power_seq_set_add_sequences(seqs, data->power_seqs);
> +
> + /* Check that the required sequences are here */
> + pb->power_on_seq = power_seq_lookup(seqs, "power-on");
> + if (!pb->power_on_seq) {
> + dev_err(&pdev->dev, "missing power-on sequence\n");
> + return -EINVAL;
> + }
> + pb->power_off_seq = power_seq_lookup(seqs, "power-off");
> + if (!pb->power_off_seq) {
> + dev_err(&pdev->dev, "missing power-off sequence\n");
> + return -EINVAL;
> + }
> +
> + /* we must have exactly one PWM resource for this driver */
> + power_seq_for_each_resource(res, seqs) {
> + if (res->type != POWER_SEQ_PWM)
> + continue;
> + if (pb->pwm) {
> + dev_err(&pdev->dev, "more than one PWM used\n");
> + return -EINVAL;
> + }
> + /* keep the pwm at hand */
> + pb->pwm = res->pwm.pwm;
> + }
> + /* from here we should have a PWM */
> + if (!pb->pwm) {
> + dev_err(&pdev->dev, "no PWM defined!\n");
> + return -EINVAL;
> + }
> + } else {
> + /* use legacy interface */
> + pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> + if (IS_ERR(pb->pwm)) {
> + dev_err(&pdev->dev,
> + "unable to request PWM, trying legacy API\n");
> +
> + pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> + if (IS_ERR(pb->pwm)) {
> + dev_err(&pdev->dev,
> + "unable to request legacy PWM\n");
> + ret = PTR_ERR(pb->pwm);
> + goto err_alloc;
> + }
> + }
> +
> + dev_dbg(&pdev->dev, "got pwm for backlight\n");
> +
> + /*
> + * The DT case will set the pwm_period_ns field to 0 and store
> + * the period, parsed from the DT, in the PWM device. For the
> + * non-DT case, set the period from platform data.
> + */
> + if (data->pwm_period_ns > 0)
> + pwm_set_period(pb->pwm, data->pwm_period_ns);
> + }
> +
> if (data->levels) {
> max = data->levels[data->max_brightness];
> pb->levels = data->levels;
> @@ -213,28 +328,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> pb->exit = data->exit;
> pb->dev = &pdev->dev;
>
> - pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> - if (IS_ERR(pb->pwm)) {
> - dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
> -
> - pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> - if (IS_ERR(pb->pwm)) {
> - dev_err(&pdev->dev, "unable to request legacy PWM\n");
> - ret = PTR_ERR(pb->pwm);
> - goto err_alloc;
> - }
> - }
> -
> - dev_dbg(&pdev->dev, "got pwm for backlight\n");
> -
> - /*
> - * The DT case will set the pwm_period_ns field to 0 and store the
> - * period, parsed from the DT, in the PWM device. For the non-DT case,
> - * set the period from platform data.
> - */
> - if (data->pwm_period_ns > 0)
> - pwm_set_period(pb->pwm, data->pwm_period_ns);
> -
> pb->period = pwm_get_period(pb->pwm);
> pb->lth_brightness = data->lth_brightness * (pb->period / max);
>
> @@ -267,8 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev)
> struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
>
> backlight_device_unregister(bl);
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> if (pb->exit)
> pb->exit(&pdev->dev);
> return 0;
> @@ -282,8 +374,7 @@ static int pwm_backlight_suspend(struct device *dev)
>
> if (pb->notify)
> pb->notify(pb->dev, 0);
> - pwm_config(pb->pwm, 0, pb->period);
> - pwm_disable(pb->pwm);
> + pwm_backlight_off(bl);
> if (pb->notify_after)
> pb->notify_after(pb->dev, 0);
> return 0;
> diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h
> index 56f4a86..0dcec1d 100644
> --- a/include/linux/pwm_backlight.h
> +++ b/include/linux/pwm_backlight.h
> @@ -5,14 +5,28 @@
> #define __LINUX_PWM_BACKLIGHT_H
>
> #include <linux/backlight.h>
> +#include <linux/power_seq.h>
>
> struct platform_pwm_backlight_data {
> - int pwm_id;
> unsigned int max_brightness;
> unsigned int dft_brightness;
> unsigned int lth_brightness;
> - unsigned int pwm_period_ns;
> unsigned int *levels;
> + /*
> + * New interface using power sequences. Must include exactly
> + * two power sequences named 'power-on' and 'power-off'. If NULL,
> + * the legacy interface is used.
> + */
> + struct platform_power_seq_set *power_seqs;
> +
> + /*
> + * Legacy interface - use power sequences instead!
> + *
> + * pwm_id and pwm_period_ns need only be specified
> + * if get_pwm(dev, NULL) would return NULL.
> + */
> + int pwm_id;
> + unsigned int pwm_period_ns;
> int (*init)(struct device *dev);
> int (*notify)(struct device *dev, int brightness);
> void (*notify_after)(struct device *dev, int brightness);
Regards
Tony P
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
2012-10-19 9:20 ` Tony Prisk
(?)
@ 2012-10-19 9:31 ` Alex Courbot
-1 siblings, 0 replies; 20+ messages in thread
From: Alex Courbot @ 2012-10-19 9:31 UTC (permalink / raw)
To: Tony Prisk
Cc: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann, linux-fbdev, linux-pm, Leela Krishna Amudala,
devicetree-discuss, linux-doc, linux-kernel, linux-tegra
On Friday 19 October 2012 17:20:36 Tony Prisk wrote:
> On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
> > +static void pwm_backlight_on(struct backlight_device *bl)
> > +{
> > + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> > + int ret;
> > +
> > + if (pb->enabled)
> > + return;
> > +
> > + if (pb->power_on_seq) {
> > + ret = power_seq_run(pb->power_on_seq);
> > + if (ret < 0) {
> > + dev_err(&bl->dev, "cannot run power on
> > sequence\n");
> > + return;
> > + }
> > + } else {
> > + /* legacy framework */
> > + pwm_config(pb->pwm, 0, pb->period);
> > + pwm_disable(pb->pwm);
>
> Is this right? pwm_disable() in the backlight_on function?
Now everybody will notice that I never really tested the legacy interface. >_<
Thanks, this was totally wrong indeed.
Alex.
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 9:31 ` Alex Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alex Courbot @ 2012-10-19 9:31 UTC (permalink / raw)
To: Tony Prisk
Cc: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann, linux-fbdev, linux-pm, Leela Krishna Amudala,
devicetree-discuss, linux-doc, linux-kernel, linux-tegra
On Friday 19 October 2012 17:20:36 Tony Prisk wrote:
> On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
> > +static void pwm_backlight_on(struct backlight_device *bl)
> > +{
> > + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> > + int ret;
> > +
> > + if (pb->enabled)
> > + return;
> > +
> > + if (pb->power_on_seq) {
> > + ret = power_seq_run(pb->power_on_seq);
> > + if (ret < 0) {
> > + dev_err(&bl->dev, "cannot run power on
> > sequence\n");
> > + return;
> > + }
> > + } else {
> > + /* legacy framework */
> > + pwm_config(pb->pwm, 0, pb->period);
> > + pwm_disable(pb->pwm);
>
> Is this right? pwm_disable() in the backlight_on function?
Now everybody will notice that I never really tested the legacy interface. >_<
Thanks, this was totally wrong indeed.
Alex.
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 9:31 ` Alex Courbot
0 siblings, 0 replies; 20+ messages in thread
From: Alex Courbot @ 2012-10-19 9:31 UTC (permalink / raw)
To: Tony Prisk
Cc: Stephen Warren, Thierry Reding, Simon Glass, Grant Likely,
Rob Herring, Mark Brown, Anton Vorontsov, David Woodhouse,
Arnd Bergmann, linux-fbdev, linux-pm, Leela Krishna Amudala,
devicetree-discuss, linux-doc, linux-kernel, linux-tegra
On Friday 19 October 2012 17:20:36 Tony Prisk wrote:
> On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
> > +static void pwm_backlight_on(struct backlight_device *bl)
> > +{
> > + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
> > + int ret;
> > +
> > + if (pb->enabled)
> > + return;
> > +
> > + if (pb->power_on_seq) {
> > + ret = power_seq_run(pb->power_on_seq);
> > + if (ret < 0) {
> > + dev_err(&bl->dev, "cannot run power on
> > sequence\n");
> > + return;
> > + }
> > + } else {
> > + /* legacy framework */
> > + pwm_config(pb->pwm, 0, pb->period);
> > + pwm_disable(pb->pwm);
>
> Is this right? pwm_disable() in the backlight_on function?
Now everybody will notice that I never really tested the legacy interface. >_<
Thanks, this was totally wrong indeed.
Alex.
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
2012-10-19 9:20 ` Tony Prisk
@ 2012-10-19 16:00 ` Stephen Warren
-1 siblings, 0 replies; 20+ messages in thread
From: Stephen Warren @ 2012-10-19 16:00 UTC (permalink / raw)
To: Tony Prisk
Cc: Alexandre Courbot, linux-fbdev, Mark Brown, Stephen Warren,
linux-pm, Leela Krishna Amudala, linux-doc, linux-kernel,
Rob Herring, Anton Vorontsov, linux-tegra, David Woodhouse,
devicetree-discuss
On 10/19/2012 03:20 AM, Tony Prisk wrote:
> On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
>> Make use of the power sequences specified in the device tree or platform
>> data to control how the backlight is powered on and off.
Tony, please do cut down the amount of the patch that you quote. If you
don't, it's impossible to find your comments. Thanks.
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v7 2/3] pwm_backlight: use power sequences
@ 2012-10-19 16:00 ` Stephen Warren
0 siblings, 0 replies; 20+ messages in thread
From: Stephen Warren @ 2012-10-19 16:00 UTC (permalink / raw)
To: Tony Prisk
Cc: Alexandre Courbot, linux-fbdev, Mark Brown, Stephen Warren,
linux-pm, Leela Krishna Amudala, linux-doc, linux-kernel,
Rob Herring, Anton Vorontsov, linux-tegra, David Woodhouse,
devicetree-discuss
On 10/19/2012 03:20 AM, Tony Prisk wrote:
> On Fri, 2012-10-19 at 18:06 +0900, Alexandre Courbot wrote:
>> Make use of the power sequences specified in the device tree or platform
>> data to control how the backlight is powered on and off.
Tony, please do cut down the amount of the patch that you quote. If you
don't, it's impossible to find your comments. Thanks.
^ permalink raw reply [flat|nested] 20+ messages in thread
end of thread, other threads:[~2012-10-19 16:00 UTC | newest]
Thread overview: 20+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-10-19 9:06 [PATCH v7 0/3] Runtime Interpreter Power Sequences Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
2012-10-19 9:06 ` [PATCH v7 1/3] Runtime Interpreted " Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
[not found] ` <1350637589-7405-1-git-send-email-acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-10-19 9:06 ` [PATCH v7 2/3] pwm_backlight: use power sequences Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
[not found] ` <1350637589-7405-3-git-send-email-acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-10-19 9:20 ` Tony Prisk
2012-10-19 9:20 ` Tony Prisk
2012-10-19 9:20 ` Tony Prisk
2012-10-19 9:31 ` Alex Courbot
2012-10-19 9:31 ` Alex Courbot
2012-10-19 9:31 ` Alex Courbot
2012-10-19 16:00 ` Stephen Warren
2012-10-19 16:00 ` Stephen Warren
2012-10-19 9:06 ` [PATCH v7 3/3] tegra: ventana: add PWM backlight to device tree Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
2012-10-19 9:06 ` Alexandre Courbot
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