[PATCH/RFC v10 16/19] Documentation: leds: Add description of v4l2-flash sub-device
From: Jacek Anaszewski <hidden>
Date: 2015-01-09 15:25:01
Also in:
linux-leds, linux-media, lkml
Subsystem:
documentation, led subsystem, the rest · Maintainers:
Jonathan Corbet, Lee Jones, Pavel Machek, Linus Torvalds
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@linux.intel.com> 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 d80096b..2f38627 100644
--- a/Documentation/leds/leds-class-flash.txt
+++ b/Documentation/leds/leds-class-flash.txt@@ -55,3 +55,16 @@ Following sysfs attributes are exposed for controlling flash led devices: upper limit Flash faults are cleared, if possible, by reading the attribute. + +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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1.7.9.5