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

   1 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
   2 # Copyright 2019-2020 Artur Rojek
   3 %YAML 1.2
   4 ---
   5 $id: "http://devicetree.org/schemas/input/adc-joystick.yaml#"
   6 $schema: "http://devicetree.org/meta-schemas/core.yaml#"
   7
   8 title: ADC attached joystick
   9
  10 maintainers:
  11   - Artur Rojek <contact@artur-rojek.eu>
  12
  13 description: >
  14   Bindings for joystick devices connected to ADC controllers supporting
  15   the Industrial I/O subsystem.
  16
  17 properties:
  18   compatible:
  19     const: adc-joystick
  20
  21   io-channels:
  22     minItems: 1
  23     maxItems: 1024
  24     description: >
  25       List of phandle and IIO specifier pairs.
  26       Each pair defines one ADC channel to which a joystick axis is connected.
  27       See
  28       https://github.com/devicetree-org/dt-schema/blob/master/schemas/iio/iio-consumer.yaml
  29       for details.
  30
  31   '#address-cells':
  32     const: 1
  33
  34   '#size-cells':
  35     const: 0
  36
  37 required:
  38   - compatible
  39   - io-channels
  40   - '#address-cells'
  41   - '#size-cells'
  42
  43 additionalProperties: false
  44
  45 patternProperties:
  46   "^axis@[0-9a-f]+$":
  47     type: object
  48     description: >
  49       Represents a joystick axis bound to the given ADC channel.
  50       For each entry in the io-channels list, one axis subnode with a matching
  51       reg property must be specified.
  52
  53     properties:
  54       reg:
  55         minimum: 0
  56         maximum: 1023
  57         description: Index of an io-channels list entry bound to this axis.
  58
  59       linux,code:
  60         $ref: /schemas/types.yaml#/definitions/uint32
  61         description: EV_ABS specific event code generated by the axis.
  62
  63       abs-range:
  64         allOf:
  65           - $ref: /schemas/types.yaml#/definitions/uint32-array
  66           - items:
  67               - description: minimum value
  68               - description: maximum value
  69         description: >
  70           Minimum and maximum values produced by the axis.
  71           For an ABS_X axis this will be the left-most and right-most
  72           inclination of the joystick. If min > max, it is left to userspace to
  73           treat the axis as inverted.
  74           This property is interpreted as two signed 32 bit values.
  75
  76       abs-fuzz:
  77         $ref: /schemas/types.yaml#/definitions/uint32
  78         description: >
  79           Amount of noise in the input value.
  80           Omitting this property indicates the axis is precise.
  81
  82       abs-flat:
  83         $ref: /schemas/types.yaml#/definitions/uint32
  84         description: >
  85           Axial "deadzone", or area around the center position, where the axis
  86           is considered to be at rest.
  87           Omitting this property indicates the axis always returns to exactly
  88           the center position.
  89
  90     required:
  91       - reg
  92       - linux,code
  93       - abs-range
  94
  95     additionalProperties: false
  96
  97 examples:
  98   - |
  99     #include <dt-bindings/iio/adc/ingenic,adc.h>
 100     #include <dt-bindings/input/input.h>
 101
 102     joystick: adc-joystick {
 103       compatible = "adc-joystick";
 104       io-channels = <&adc INGENIC_ADC_TOUCH_XP>,
 105                     <&adc INGENIC_ADC_TOUCH_YP>;
 106       #address-cells = <1>;
 107       #size-cells = <0>;
 108
 109       axis@0 {
 110               reg = <0>;
 111               linux,code = <ABS_X>;
 112               abs-range = <3300 0>;
 113               abs-fuzz = <4>;
 114               abs-flat = <200>;
 115       };
 116       axis@1 {
 117               reg = <1>;
 118               linux,code = <ABS_Y>;
 119               abs-range = <0 3300>;
 120               abs-fuzz = <4>;
 121               abs-flat = <200>;
 122       };
 123     };