Re: [PATCH/RFC v8 03/14] Documentation: leds: Add description of v4l2-flash sub-device

From: Bryan Wu
Date: Fri Dec 05 2014 - 14:50:30 EST

On Fri, Nov 28, 2014 at 1:17 AM, Jacek Anaszewski
<j.anaszewski@xxxxxxxxxxx> wrote:
> This patch extends LED Flash class documention by
> the description of interactions with v4l2-flash sub-device.
> Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
> Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Cc: Bryan Wu <cooloney@xxxxxxxxx>
> Cc: Richard Purdie <rpurdie@xxxxxxxxx>
> ---

This patch looks good to me. I will take it with other patches!


> Documentation/leds/leds-class-flash.txt | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
> diff --git a/Documentation/leds/leds-class-flash.txt b/Documentation/leds/leds-class-flash.txt
> index d68565c..1a611ec 100644
> --- a/Documentation/leds/leds-class-flash.txt
> +++ b/Documentation/leds/leds-class-flash.txt
> @@ -46,3 +46,16 @@ Following sysfs attributes are exposed for controlling flash led devices:
> until this flag is no longer set
> * 0x100 - the temperature of the LED has exceeded its allowed
> upper limit
> +
> +A LED subsystem driver can be controlled also from the level of VideoForLinux2
> +subsystem. In order to enable this CONFIG_V4L2_FLASH_LED_CLASS symbol has to
> +be defined in the kernel config. The driver must call the v4l2_flash_init
> +function to get registered in the V4L2 subsystem. On remove the
> +v4l2_flash_release function has to be called (see <media/v4l2-flash.h>).
> +
> +After proper initialization a V4L2 Flash sub-device is created. The sub-device
> +exposes a number of V4L2 controls, which allow for controlling a LED Flash class
> +device with use of its internal kernel API.
> +Opening the V4L2 Flash sub-device makes the LED subsystem sysfs interface
> +unavailable. The interface is re-enabled after the V4L2 Flash sub-device
> +is closed.
> --
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