Kernel-4.18.0-80.el8_gpio-fan

Bindings for fan connected to GPIO lines

Required properties:

• compatible : “gpio-fan”

Optional properties:

• gpios: Specifies the pins that map to bits in the control value,
  ordered MSB–>LSB.
• gpio-fan,speed-map: A mapping of possible fan RPM speeds and the
  control value that should be set to achieve them. This array
  must have the RPM values in ascending order.
• alarm-gpios: This pin going active indicates something is wrong with
  the fan, and a udev event will be fired.
• #cooling-cells: If used as a cooling device, must be <2>
  Also see: Documentation/devicetree/bindings/thermal/thermal.txt
  min and max states are derived from the speed-map of the fan.

Note: At least one the “gpios” or “alarm-gpios” properties must be set.

Examples:

gpio_fan {
    compatible = "gpio-fan";
    gpios = <&gpio1 14 1
         &gpio1 13 1>;
    gpio-fan,speed-map = <0    0
                  3000 1
                  6000 2>;
    alarm-gpios = <&gpio1 15 1>;
};
gpio_fan_cool: gpio_fan {
    compatible = "gpio-fan";
    gpios = <&gpio2 14 1
         &gpio2 13 1>;
    gpio-fan,speed-map =    <0    0>,
                <3000 1>,
                <6000 2>;
    alarm-gpios = <&gpio2 15 1>;
    #cooling-cells = <2>; /* min followed by max */
};