[PATCH/RFC v11 03/20] Documentation: leds: Add description of LED Flash class extension

[Jacek Anaszewski <j.anaszewski@samsung.com>]

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: Bryan Wu <cooloney@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
---
 Documentation/leds/leds-class-flash.txt |   32 +++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/leds/leds-class-flash.txt

diff --git a/Documentation/leds/leds-class-flash.txt b/Documentation/leds/leds-class-flash.txt
new file mode 100644
index 0000000..ff03a66
--- /dev/null
+++ b/Documentation/leds/leds-class-flash.txt
@@ -0,0 +1,32 @@
+
+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 support for flash LEDs CONFIG_LEDS_CLASS_FLASH symbol
+must be defined in the kernel config. A flash LED driver must register
+in the LED subsystem with led_classdev_flash_register function to gain flash
+related capabilities.
+
+There are flash LED devices which can control more than one LED and allow for
+strobing the sub-LEDs synchronously. A LED will be strobed synchronously with
+the one whose identifier is written to the flash_sync_strobe sysfs attribute.
+The list of available sub-LED identifiers can be read from the available_sync_leds
+sysfs attribute. In order to enable the related settings the driver must set
+LED_DEV_CAP_SYNC_STROBE flag.
+
+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
+	- available_sync_leds
+	- flash_sync_strobe
+	- flash_fault
-- 
1.7.9.5