a device, i.e. no other LED class device can be assigned the same
label.
+- default-state : The initial state of the LED. Valid values are "on", "off",
+ and "keep". If the LED is already on or off and the default-state property is
+ set the to same value, then no glitch should be produced where the LED
+ momentarily turns off (or on). The "keep" setting will keep the LED at
+ whatever its current state is, without producing a glitch. The default is
+ off if this property is not present.
+
- linux,default-trigger : This parameter, if present, is a
string defining the trigger assigned to the LED. Current triggers are:
"backlight" - LED will act as a back-light, controlled by the framebuffer