Re: [PATCH/RFC v13 10/13] Documentation: leds: Add description of v4l2-flash sub-device
From: Sakari Ailus <sakari.ailus@iki.fi>
Date: 2015-03-18 12:40:34
Also in:
linux-leds, linux-media, lkml
Hi Jacek, On Thu, Mar 12, 2015 at 04:45:11PM +0100, Jacek Anaszewski wrote:
quoted hunk ↗ jump to hunk
This patch extends LED Flash class documention by the description of interactions with v4l2-flash sub-device. Signed-off-by: Jacek Anaszewski <redacted> Acked-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Sakari Ailus <sakari.ailus@iki.fi> Cc: Bryan Wu <redacted> Cc: Richard Purdie <redacted> --- 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 19bb673..8623413 100644 --- a/Documentation/leds/leds-class-flash.txt +++ b/Documentation/leds/leds-class-flash.txt@@ -20,3 +20,16 @@ Following sysfs attributes are exposed for controlling flash LED devices: - max_flash_timeout - flash_strobe - flash_fault + +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
Over 80 characters per line. With this fixed, Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
+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.
-- Kind regards, Sakari Ailus e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk