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authorJacek Anaszewski <j.anaszewski@samsung.com>2015-03-04 08:14:24 -0800
committerBryan Wu <cooloney@gmail.com>2015-03-09 17:18:00 -0700
commitf6ad395bad57dcd15c6423715d15d91363a62ae8 (patch)
tree66155c15c1c9f5d1fecd6a3e8b07e04be4f03d09 /Documentation/leds
parent9c4a8e138cfe2cc7262d5d2224162add5632b546 (diff)
downloadkernel-f6ad395bad57dcd15c6423715d15d91363a62ae8.tar.gz
Documentation: leds: Add description of LED Flash class extension
The documentation being added contains overall description of the LED Flash Class and the related sysfs attributes. Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> Acked-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Bryan Wu <cooloney@gmail.com>
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+
+Flash LED handling under Linux
+==============================
+
+Some LED devices provide two modes - torch and flash. In the LED subsystem
+those modes are supported by LED class (see Documentation/leds/leds-class.txt)
+and LED Flash class respectively. The torch mode related features are enabled
+by default and the flash ones only if a driver declares it by setting
+LED_DEV_CAP_FLASH flag.
+
+In order to enable the support for flash LEDs CONFIG_LEDS_CLASS_FLASH symbol
+must be defined in the kernel config. A LED Flash class driver must be
+registered in the LED subsystem with led_classdev_flash_register function.
+
+Following sysfs attributes are exposed for controlling flash LED devices:
+(see Documentation/ABI/testing/sysfs-class-led-flash)
+ - flash_brightness
+ - max_flash_brightness
+ - flash_timeout
+ - max_flash_timeout
+ - flash_strobe
+ - flash_fault