Documentation/devicetree/bindings/leds/register-bit-led.txt

   1 Device Tree Bindings for Register Bit LEDs
   2
   3 Register bit leds are used with syscon multifunctional devices
   4 where single bits in a certain register can turn on/off a
   5 single LED. The register bit LEDs appear as children to the
   6 syscon device, with the proper compatible string. For the
   7 syscon bindings see:
   8 Documentation/devicetree/bindings/mfd/syscon.txt
   9
  10 Each LED is represented as a sub-node of the syscon device. Each
  11 node's name represents the name of the corresponding LED.
  12
  13 LED sub-node properties:
  14
  15 Required properties:
  16 - compatible : must be "register-bit-led"
  17 - offset : register offset to the register controlling this LED
  18 - mask : bit mask for the bit controlling this LED in the register
  19   typically 0x01, 0x02, 0x04 ...
  20
  21 Optional properties:
  22 - label : (optional)
  23   see Documentation/devicetree/bindings/leds/common.txt
  24 - linux,default-trigger : (optional)
  25   see Documentation/devicetree/bindings/leds/common.txt
  26 - default-state: (optional) The initial state of the LED. Valid
  27   values are "on", "off", and "keep". If the LED is already on or off
  28   and the default-state property is set the to same value, then no
  29   glitch should be produced where the LED momentarily turns off (or
  30   on). The "keep" setting will keep the LED at whatever its current
  31   state is, without producing a glitch.  The default is off if this
  32   property is not present.
  33
  34 Example:
  35
  36 syscon: syscon@10000000 {
  37         compatible = "arm,realview-pb1176-syscon", "syscon";
  38         reg = <0x10000000 0x1000>;
  39
  40         led@08.0 {
  41                 compatible = "register-bit-led";
  42                 offset = <0x08>;
  43                 mask = <0x01>;
  44                 label = "versatile:0";
  45                 linux,default-trigger = "heartbeat";
  46                 default-state = "on";
  47         };
  48         led@08.1 {
  49                 compatible = "register-bit-led";
  50                 offset = <0x08>;
  51                 mask = <0x02>;
  52                 label = "versatile:1";
  53                 linux,default-trigger = "mmc0";
  54                 default-state = "off";
  55         };
  56         led@08.2 {
  57                 compatible = "register-bit-led";
  58                 offset = <0x08>;
  59                 mask = <0x04>;
  60                 label = "versatile:2";
  61                 linux,default-trigger = "cpu0";
  62                 default-state = "off";
  63         };
  64         led@08.3 {
  65                 compatible = "register-bit-led";
  66                 offset = <0x08>;
  67                 mask = <0x08>;
  68                 label = "versatile:3";
  69                 default-state = "off";
  70         };
  71         led@08.4 {
  72                 compatible = "register-bit-led";
  73                 offset = <0x08>;
  74                 mask = <0x10>;
  75                 label = "versatile:4";
  76                 default-state = "off";
  77         };
  78         led@08.5 {
  79                 compatible = "register-bit-led";
  80                 offset = <0x08>;
  81                 mask = <0x20>;
  82                 label = "versatile:5";
  83                 default-state = "off";
  84         };
  85         led@08.6 {
  86                 compatible = "register-bit-led";
  87                 offset = <0x08>;
  88                 mask = <0x40>;
  89                 label = "versatile:6";
  90                 default-state = "off";
  91         };
  92         led@08.7 {
  93                 compatible = "register-bit-led";
  94                 offset = <0x08>;
  95                 mask = <0x80>;
  96                 label = "versatile:7";
  97                 default-state = "off";
  98         };
  99 };