Documentation/devicetree/bindings/input/adc-keys.yaml

   1 # SPDX-License-Identifier: GPL-2.0
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/input/adc-keys.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: ADC attached resistor ladder buttons
   8
   9 maintainers:
  10   - Alexandre Belloni <alexandre.belloni@bootlin.com>
  11
  12 allOf:
  13   - $ref: input.yaml#
  14
  15 properties:
  16   compatible:
  17     const: adc-keys
  18
  19   io-channels:
  20     maxItems: 1
  21
  22   io-channel-names:
  23     const: buttons
  24
  25   keyup-threshold-microvolt:
  26     description:
  27       Voltage above or equal to which all the keys are considered up.
  28
  29   poll-interval: true
  30   autorepeat: true
  31
  32 patternProperties:
  33   '^button-':
  34     type: object
  35     $ref: input.yaml#
  36     additionalProperties: false
  37     description:
  38       Each button (key) is represented as a sub-node.
  39
  40     properties:
  41       label: true
  42
  43       linux,code: true
  44
  45       press-threshold-microvolt:
  46         description:
  47           Voltage above or equal to which this key is considered pressed. No
  48           two values of press-threshold-microvolt may be the same. All values
  49           of press-threshold-microvolt must be less than
  50           keyup-threshold-microvolt.
  51
  52     required:
  53       - linux,code
  54       - press-threshold-microvolt
  55
  56 required:
  57   - compatible
  58   - io-channels
  59   - io-channel-names
  60   - keyup-threshold-microvolt
  61
  62 additionalProperties: false
  63
  64 examples:
  65   - |
  66     #include <dt-bindings/input/input.h>
  67     // +--------------------------------+------------------------+
  68     // | 2.000.000 <= value             | no key pressed         |
  69     // +--------------------------------+------------------------+
  70     // | 1.500.000 <= value < 2.000.000 | KEY_VOLUMEUP pressed   |
  71     // +--------------------------------+------------------------+
  72     // | 1.000.000 <= value < 1.500.000 | KEY_VOLUMEDOWN pressed |
  73     // +--------------------------------+------------------------+
  74     // |   500.000 <= value < 1.000.000 | KEY_ENTER pressed      |
  75     // +--------------------------------+------------------------+
  76     // |              value <   500.000 | no key pressed         |
  77     // +--------------------------------+------------------------+
  78
  79     adc-keys {
  80         compatible = "adc-keys";
  81         io-channels = <&lradc 0>;
  82         io-channel-names = "buttons";
  83         keyup-threshold-microvolt = <2000000>;
  84
  85         button-up {
  86             label = "Volume Up";
  87             linux,code = <KEY_VOLUMEUP>;
  88             press-threshold-microvolt = <1500000>;
  89         };
  90
  91         button-down {
  92             label = "Volume Down";
  93             linux,code = <KEY_VOLUMEDOWN>;
  94             press-threshold-microvolt = <1000000>;
  95         };
  96
  97         button-enter {
  98             label = "Enter";
  99             linux,code = <KEY_ENTER>;
 100             press-threshold-microvolt = <500000>;
 101         };
 102     };
 103 ...