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.

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).

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.

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 usefull when driving a LED which is intended to indicate
		a device in a standby like state.