dts/bindings/input/adc-keys.yaml

# Copyright (c) 2024 Chen Xingyu <hi@xingrz.me>
# SPDX-License-Identifier: Apache-2.0

description: |
  Input driver for ADC attached resistor ladder buttons.

  The driver itself does not calculate each possible combination of resistor
  values. Instead, users are required to specify the voltage for each single
  key press or for combinations of key presses.

  Example:

  #include <dt-bindings/input/input-event-codes.h>

  / {
          buttons {
                  compatible = "adc-keys";
                  io-channels = <&adc 2>;
                  keyup-threshold-mv = <0>;

                  key_0 {
                          press-thresholds-mv = <1650>,  /* KEY0 */
                                                <2536>;  /* KEY0 + KEY1 */
                          zephyr,code = <INPUT_KEY_0>;
                  };

                  key_1 {
                          press-thresholds-mv = <2300>,  /* KEY1 */
                                                <2536>;  /* KEY0 + KEY1 */
                          zephyr,code = <INPUT_KEY_1>;
                  };
          };
  };

compatible: "adc-keys"

include: base.yaml

properties:
  io-channels:
    type: phandle-array
    required: true
    description: Phandle to an ADC channel.

  sample-period-ms:
    type: int
    default: 20
    description: |
       Sample period in milliseconds.
       If not specified defaults to 20.

  keyup-threshold-mv:
    type: int
    required: true
    description: |
      Millivolt value to which all the keys are considered up.

child-binding:
  description: ADC KEYS child node.
  properties:
    press-thresholds-mv:
      type: array
      required: true
      description: |
        Array of millivolt values to consider a key pressed.

    zephyr,code:
      type: int
      required: true
      description: Key code to emit.