1Bindings for fan connected to GPIO lines
2
3Required properties:
4- compatible : "gpio-fan"
5
6Optional 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:
16  Documentation/devicetree/bindings/thermal/thermal-cooling-devices.yaml
17  min and max states are derived from the speed-map of the fan.
18
19Note: At least one the "gpios" or "alarm-gpios" properties must be set.
20
21Examples:
22
23	gpio_fan {
24		compatible = "gpio-fan";
25		gpios = <&gpio1 14 1
26			 &gpio1 13 1>;
27		gpio-fan,speed-map = <0    0
28				      3000 1
29				      6000 2>;
30		alarm-gpios = <&gpio1 15 1>;
31	};
32	gpio_fan_cool: gpio_fan {
33		compatible = "gpio-fan";
34		gpios = <&gpio2 14 1
35			 &gpio2 13 1>;
36		gpio-fan,speed-map =	<0    0>,
37					<3000 1>,
38					<6000 2>;
39		alarm-gpios = <&gpio2 15 1>;
40		#cooling-cells = <2>; /* min followed by max */
41	};
42