1 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/hwmon/gpio-fan.txt b/Documentation/devicetree/bindings/hwmon/gpio-fan.txt
new file mode 100644
index 000000000..2becdcfdc
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/gpio-fan.txt
@@ -0,0 +1,40 @@
+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 */
+	};