leds: flash: document sysfs interface

Add a documentation of LED Flash class specific 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>

diff --git a/Documentation/ABI/testing/sysfs-class-led-flash b/Documentation/ABI/testing/sysfs-class-led-flash
new file mode 100644 (file)
index 0000000..220a027
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-flash
@@ -0,0 +1,80 @@
+What:          /sys/class/leds/<led>/flash_brightness
+Date:          March 2015
+KernelVersion: 4.0
+Contact:       Jacek Anaszewski <j.anaszewski@samsung.com>
+Description:   read/write
+               Set the brightness of this LED in the flash strobe mode, in
+               microamperes. The file is created only for the flash LED devices
+               that support setting flash brightness.
+
+               The value is between 0 and
+               /sys/class/leds/<led>/max_flash_brightness.
+
+What:          /sys/class/leds/<led>/max_flash_brightness
+Date:          March 2015
+KernelVersion: 4.0
+Contact:       Jacek Anaszewski <j.anaszewski@samsung.com>
+Description:   read only
+               Maximum brightness level for this LED in the flash strobe mode,
+               in microamperes.
+
+What:          /sys/class/leds/<led>/flash_timeout
+Date:          March 2015
+KernelVersion: 4.0
+Contact:       Jacek Anaszewski <j.anaszewski@samsung.com>
+Description:   read/write
+               Hardware timeout for flash, in microseconds. The flash strobe
+               is stopped after this period of time has passed from the start
+               of the strobe. The file is created only for the flash LED
+               devices that support setting flash timeout.
+
+What:          /sys/class/leds/<led>/max_flash_timeout
+Date:          March 2015
+KernelVersion: 4.0
+Contact:       Jacek Anaszewski <j.anaszewski@samsung.com>
+Description:   read only
+               Maximum flash timeout for this LED, in microseconds.
+
+What:          /sys/class/leds/<led>/flash_strobe
+Date:          March 2015
+KernelVersion: 4.0
+Contact:       Jacek Anaszewski <j.anaszewski@samsung.com>
+Description:   read/write
+               Flash strobe state. When written with 1 it triggers flash strobe
+               and when written with 0 it turns the flash off.
+
+               On read 1 means that flash is currently strobing and 0 means
+               that flash is off.
+
+What:          /sys/class/leds/<led>/flash_fault
+Date:          March 2015
+KernelVersion: 4.0
+Contact:       Jacek Anaszewski <j.anaszewski@samsung.com>
+Description:   read only
+               Space separated list of flash faults that may have occurred.
+               Flash faults are re-read after strobing the flash. Possible
+               flash faults:
+
+               * led-over-voltage - flash controller voltage to the flash LED
+                       has exceeded the limit specific to the flash controller
+               * flash-timeout-exceeded - 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
+               * controller-over-temperature - the flash controller has
+                       overheated
+               * controller-short-circuit - the short circuit protection
+                       of the flash controller has been triggered
+               * led-power-supply-over-current - current in the LED power
+                       supply has exceeded the limit specific to the flash
+                       controller
+               * indicator-led-fault - the flash controller has detected
+                       a short or open circuit condition on the indicator LED
+               * led-under-voltage - flash controller voltage to the flash
+                       LED has been below the minimum limit specific to
+                       the flash
+               * controller-under-voltage - 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
+               * led-over-temperature - the temperature of the LED has exceeded
+                       its allowed upper limit