Documentation/devicetree/bindings/gpio/gpio-fan.txt

   1 Bindings for fan connected to GPIO lines
   2
   3 Required properties:
   4 - compatible : "gpio-fan"
   5
   6 Optional properties:
   7 - gpios: Specifies the pins that map to bits in the control value,
   8   ordered MSB-->LSB.
   9 - gpio-fan,speed-map: A mapping of possible fan RPM speeds and the
  10   control value that should be set to achieve them. This array
  11   must have the RPM values in ascending order.
  12 - alarm-gpios: This pin going active indicates something is wrong with
  13   the fan, and a udev event will be fired.
  14 - cooling-cells: If used as a cooling device, must be <2>
  15   Also see: Documentation/devicetree/bindings/thermal/thermal.txt
  16   min and max states are derived from the speed-map of the fan.
  17
  18 Note: At least one the "gpios" or "alarm-gpios" properties must be set.
  19
  20 Examples:
  21
  22         gpio_fan {
  23                 compatible = "gpio-fan";
  24                 gpios = <&gpio1 14 1
  25                          &gpio1 13 1>;
  26                 gpio-fan,speed-map = <0    0
  27                                       3000 1
  28                                       6000 2>;
  29                 alarm-gpios = <&gpio1 15 1>;
  30         };
  31         gpio_fan_cool: gpio_fan {
  32                 compatible = "gpio-fan";
  33                 gpios = <&gpio2 14 1
  34                          &gpio2 13 1>;
  35                 gpio-fan,speed-map =    <0    0>,
  36                                         <3000 1>,
  37                                         <6000 2>;
  38                 alarm-gpios = <&gpio2 15 1>;
  39                 #cooling-cells = <2>; /* min followed by max */
  40         };