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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>
This commit is contained in:
Jacek Anaszewski 2015-03-04 08:14:23 -08:00 committed by Bryan Wu
parent 94fdec768d
commit 9c4a8e138c
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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