Based on kernel version 5.19.17
. Page generated on 2023-08-28 22:14 EST
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 | 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 above or equal to 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 above or equal to which this key is considered pressed. No two values of press-threshold-microvolt may be the same. All values of press-threshold-microvolt must be less than keyup-threshold-microvolt. 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>; }; }; +--------------------------------+------------------------+ | 2.000.000 <= value | no key pressed | +--------------------------------+------------------------+ | 1.500.000 <= value < 2.000.000 | KEY_VOLUMEUP pressed | +--------------------------------+------------------------+ | 1.000.000 <= value < 1.500.000 | KEY_VOLUMEDOWN pressed | +--------------------------------+------------------------+ | 500.000 <= value < 1.000.000 | KEY_ENTER pressed | +--------------------------------+------------------------+ | value < 500.000 | no key pressed | +--------------------------------+------------------------+ |