Device Tree Bindings for Register Bit LEDs Register bit leds are used with syscon multifunctional devices where single bits in a certain register can turn on/off a single LED. The register bit LEDs appear as children to the syscon device, with the proper compatible string. For the syscon bindings see: Documentation/devicetree/bindings/mfd/syscon.txt Each LED is represented as a sub-node of the syscon device. Each node's name represents the name of the corresponding LED. LED sub-node properties: Required properties: - compatible : must be "register-bit-led" - offset : register offset to the register controlling this LED - mask : bit mask for the bit controlling this LED in the register typically 0x01, 0x02, 0x04 ... Optional properties: - label : (optional) see Documentation/devicetree/bindings/leds/common.txt - linux,default-trigger : (optional) see Documentation/devicetree/bindings/leds/common.txt - default-state: (optional) 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. Example: syscon: syscon@10000000 { compatible = "arm,realview-pb1176-syscon", "syscon"; reg = <0x10000000 0x1000>; led@08.0 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x01>; label = "versatile:0"; linux,default-trigger = "heartbeat"; default-state = "on"; }; led@08.1 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x02>; label = "versatile:1"; linux,default-trigger = "mmc0"; default-state = "off"; }; led@08.2 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x04>; label = "versatile:2"; linux,default-trigger = "cpu0"; default-state = "off"; }; led@08.3 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x08>; label = "versatile:3"; default-state = "off"; }; led@08.4 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x10>; label = "versatile:4"; default-state = "off"; }; led@08.5 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x20>; label = "versatile:5"; default-state = "off"; }; led@08.6 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x40>; label = "versatile:6"; default-state = "off"; }; led@08.7 { compatible = "register-bit-led"; offset = <0x08>; mask = <0x80>; label = "versatile:7"; default-state = "off"; }; };