What:		/sys/class/leds/<led>/brightness
Date:		March 2006
KernelVersion:	2.6.17
Contact:	Richard Purdie <rpurdie@rpsys.net>
Description:
		Set the brightness of the LED. Most LEDs don't
		have hardware brightness support, so will just be turned on for
		non-zero brightness settings. The value is between 0 and
		/sys/class/leds/<led>/max_brightness.

		Writing 0 to this file clears active trigger.

		Writing non-zero to this file while trigger is active changes the
		top brightness trigger is going to use.

What:		/sys/class/leds/<led>/max_brightness
Date:		March 2006
KernelVersion:	2.6.17
Contact:	Richard Purdie <rpurdie@rpsys.net>
Description:
		Maximum brightness level for this LED, default is 255 (LED_FULL).

		If the LED does not support different brightness levels, this
		should be 1.

What:		/sys/class/leds/<led>/trigger
Date:		March 2006
KernelVersion:	2.6.17
Contact:	Richard Purdie <rpurdie@rpsys.net>
Description:
		Set the trigger for this LED. A trigger is a kernel based source
		of LED events.
		You can change triggers in a similar manner to the way an IO
		scheduler is chosen. Trigger specific parameters can appear in
		/sys/class/leds/<led> once a given trigger is selected. For
		their documentation see sysfs-class-led-trigger-*.

What:		/sys/class/leds/<led>/inverted
Date:		January 2011
KernelVersion:	2.6.38
Contact:	Richard Purdie <rpurdie@rpsys.net>
Description:
		Invert the LED on/off state. This parameter is specific to
		gpio and backlight triggers. In case of the backlight trigger,
		it is useful when driving a LED which is intended to indicate
		a device in a standby like state.