Hi!

The documentation being added contains overall description of the
LED Flash Class and the related sysfs attributes.

Signed-off-by: Jacek Anaszewski <redacted>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Bryan Wu <redacted>
Cc: Richard Purdie <redacted>

+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

sub-LED?

+	- flash_fault - bitmask of flash faults that may have occurred
+			possible flags are:
+		* 0x01 - flash controller voltage to the flash LED has exceeded
+			 the limit specific to the flash controller
+		* 0x02 - the flash strobe was still on when the timeout set by
+			 the user has expired; not all flash controllers may
+			 set this in all such conditions
+		* 0x04 - the flash controller has overheated
+		* 0x08 - the short circuit protection of the flash controller
+			 has been triggered
+		* 0x10 - current in the LED power supply has exceeded the limit
+			 specific to the flash controller
+		* 0x20 - the flash controller has detected a short or open
+			 circuit condition on the indicator LED
+		* 0x40 - flash controller voltage to the flash LED has been
+			 below the minimum limit specific to the flash
+		* 0x80 - the input voltage of the flash controller is below
+			 the limit under which strobing the flash at full
+			 current will not be possible. The condition persists
+			 until this flag is no longer set
+		* 0x100 - the temperature of the LED has exceeded its allowed
+			  upper limit

Did not everyone agree that text strings are preferable to bitmasks?

									Pavel

-- 
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