Re: [PATCH v2 3/3] leds: leds-pwm: Add device tree bindings

From: Grant Likely
Date: Thu Dec 06 2012 - 05:01:30 EST


On Mon, 12 Nov 2012 15:41:10 +0100, Peter Ujfalusi <peter.ujfalusi@xxxxxx> wrote:
> Support for device tree booted kernel.
> When the kernel is booted with DeviceTree blob we support one led per
> leds-pwm device to have cleaner integration with the PWM subsystem.
>
> For usage see:
> Documentation/devicetree/bindings/leds/leds-pwm.txt
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> .../devicetree/bindings/leds/leds-pwm.txt | 34 ++++++
> drivers/leds/leds-pwm.c | 125 +++++++++++++++------
> 2 files changed, 127 insertions(+), 32 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/leds/leds-pwm.txt
>
> diff --git a/Documentation/devicetree/bindings/leds/leds-pwm.txt b/Documentation/devicetree/bindings/leds/leds-pwm.txt
> new file mode 100644
> index 0000000..9fe3040
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-pwm.txt
> @@ -0,0 +1,34 @@
> +LED connected to PWM
> +
> +Required properties:
> +- compatible : should be "pwm-leds".
> +- pwms : PWM property, please refer to:
> + Documentation/devicetree/bindings/pwm/pwm.txt
> +- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
> +- label : (optional) The label for this LED. If omitted, the label is
> + taken from the node name (excluding the unit address).
> +- max-brightness : Maximum brightness possible for the LED
> +- linux,default-trigger : (optional) This parameter, if present, is a
> + string defining the trigger assigned to the LED. Current triggers are:
> + "backlight" - LED will act as a back-light, controlled by the framebuffer
> + system
> + "default-on" - LED will turn on, but see "default-state" below
> + "heartbeat" - LED "double" flashes at a load average based rate
> + "ide-disk" - LED indicates disk activity
> + "timer" - LED flashes at a fixed, configurable rate

The binding mostly looks good. However, it seems to be gratuitously
different from the gpio-leds binding and it duplicates property
definitions. Please match the gpio-leds behaviour with each led defined
as a sub node of the pwm-leds node.

Also, please reference the common properties in bindings/leds/common.txt
(This is a new file in linux-next. See how leds-gpio references it).

Otherwise the binding looks okay to me.

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