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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>;
+ };
+ };