Based on kernel version 3.7. Page generated on 2012-12-12 10:00 EST.
1 LEDs connected to GPIO lines 2 3 Required properties: 4 - compatible : should be "gpio-leds". 5 6 Each LED is represented as a sub-node of the gpio-leds device. Each 7 node's name represents the name of the corresponding LED. 8 9 LED sub-node properties: 10 - gpios : Should specify the LED's GPIO, see "gpios property" in 11 Documentation/devicetree/bindings/gpio/gpio.txt. Active low LEDs should be 12 indicated using flags in the GPIO specifier. 13 - label : (optional) The label for this LED. If omitted, the label is 14 taken from the node name (excluding the unit address). 15 - linux,default-trigger : (optional) This parameter, if present, is a 16 string defining the trigger assigned to the LED. Current triggers are: 17 "backlight" - LED will act as a back-light, controlled by the framebuffer 18 system 19 "default-on" - LED will turn on, but see "default-state" below 20 "heartbeat" - LED "double" flashes at a load average based rate 21 "ide-disk" - LED indicates disk activity 22 "timer" - LED flashes at a fixed, configurable rate 23 - default-state: (optional) The initial state of the LED. Valid 24 values are "on", "off", and "keep". If the LED is already on or off 25 and the default-state property is set the to same value, then no 26 glitch should be produced where the LED momentarily turns off (or 27 on). The "keep" setting will keep the LED at whatever its current 28 state is, without producing a glitch. The default is off if this 29 property is not present. 30 31 Examples: 32 33 leds { 34 compatible = "gpio-leds"; 35 hdd { 36 label = "IDE Activity"; 37 gpios = <&mcu_pio 0 1>; /* Active low */ 38 linux,default-trigger = "ide-disk"; 39 }; 40 41 fault { 42 gpios = <&mcu_pio 1 0>; 43 /* Keep LED on if BIOS detected hardware fault */ 44 default-state = "keep"; 45 }; 46 }; 47 48 run-control { 49 compatible = "gpio-leds"; 50 red { 51 gpios = <&mpc8572 6 0>; 52 default-state = "off"; 53 }; 54 green { 55 gpios = <&mpc8572 7 0>; 56 default-state = "on"; 57 }; 58 };