1 files changed, 49 insertions, 0 deletions
diff --git a/Bindings/input/adc-keys.txt b/Bindings/input/adc-keys.txt
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+ADC attached resistor ladder buttons
+------------------------------------
+
+Required properties:
+ - compatible: "adc-keys"
+ - io-channels: Phandle to an ADC channel
+ - io-channel-names = "buttons";
+ - keyup-threshold-microvolt: Voltage at which all the keys are considered up.
+
+Optional properties:
+	- poll-interval: Poll interval time in milliseconds
+	- autorepeat: Boolean, Enable auto repeat feature of Linux input
+	  subsystem.
+
+Each button (key) is represented as a sub-node of "adc-keys":
+
+Required subnode-properties:
+	- label: Descriptive name of the key.
+	- linux,code: Keycode to emit.
+	- press-threshold-microvolt: Voltage ADC input when this key is pressed.
+
+Example:
+
+#include <dt-bindings/input/input.h>
+
+	adc-keys {
+		compatible = "adc-keys";
+		io-channels = <&lradc 0>;
+		io-channel-names = "buttons";
+		keyup-threshold-microvolt = <2000000>;
+
+		button-up {
+			label = "Volume Up";
+			linux,code = <KEY_VOLUMEUP>;
+			press-threshold-microvolt = <1500000>;
+		};
+
+		button-down {
+			label = "Volume Down";
+			linux,code = <KEY_VOLUMEDOWN>;
+			press-threshold-microvolt = <1000000>;
+		};
+
+		button-enter {
+			label = "Enter";
+			linux,code = <KEY_ENTER>;
+			press-threshold-microvolt = <500000>;
+		};
+	};