Re: [PATCH 4/5] dt-bindings: input: Add docs for ADC driven joystick.

Rob Herring
2020-01-08T20:12:31Z

On Sun, Jan 05, 2020 at 01:16:38AM +0100, Artur Rojek wrote:
> Add documentation for the adc-joystick driver, used to provide support
> for joysticks connected over ADC.
>
> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> Tested-by: Paul Cercueil <paul@crapouillou.net>
> ---
> .../bindings/input/adc-joystick.yaml | 100 ++++++++++++++++++
> 1 file changed, 100 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/input/adc-joystick.yaml
>
> diff --git a/Documentation/devicetree/bindings/input/adc-joystick.yaml b/Documentation/devicetree/bindings/input/adc-joystick.yaml
> new file mode 100644
> index 000000000000..97ae797348c7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/adc-joystick.yaml
> @@ -0,0 +1,100 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2019-2020 Artur Rojek
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/bindings/input/adc-joystick.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: ADC attached joystick
> +
> +maintainers:
> + - Artur Rojek <contact@artur-rojek.eu>
> +
> +description: |
> + Bindings for joystick devices connected to ADC controllers supporting
> + the Industrial I/O subsystem.
> +
> +properties:
> + compatible:
> + const: adc-joystick
> +
> + io-channels:
> + description: |
> + List of phandle and IIO specifier pairs.
> + Each pair defines one ADC channel to which a joystick axis is connected.
> + See Documentation/devicetree/bindings/iio/iio-bindings.txt for details.
> +
> +required:
> + - compatible
> + - io-channels
> +
> +additionalProperties: false
> +
> +patternProperties:
> + "^axis@([0-9])$":

A unit-address means there should be a 'reg' property. I'd just do
axis-x and axis-y instead.

> + type: object
> + description: |
> + Represents a joystick axis bound to the given ADC channel.
> + For each entry in the io-channels list, one axis subnode with a matching
> + index must be specified.
> +
> + properties:
> + linux,abs-code:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: EV_ABS specific event code generated by the axis.

Existing 'linux,code' should be used here.

> +
> + linux,abs-range:

Drop 'linux,' here and on the rest of these.

> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + items:
> + - description: minimum value
> + - description: maximum value
> + description: |
> + Minimum and maximum values produced by the axis.
> + For an ABS_X axis this will be the left-most and right-most
> + inclination of the joystick. If min > max, it is left to userspace to
> + treat the axis as inverted.
> + This property is interpreted as two signed 32 bit values.
> +
> + linux,abs-fuzz:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + Amount of noise in the input value.
> + Omitting this property indicates the axis is precise.
> +
> + linux,abs-flat:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + Axial "deadzone", or area around the center position, where the axis
> + is considered to be at rest.
> + Omitting this property indicates the axis always returns to exactly
> + the center position.
> +
> + required:
> + - linux,abs-code
> + - linux,abs-range
> +
> + additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/iio/adc/ingenic,adc.h>
> + #include <dt-bindings/input/input.h>
> +
> + joystick: adc-joystick {
> + compatible = "adc-joystick";
> + io-channels = <&adc INGENIC_ADC_TOUCH_XP>,
> + <&adc INGENIC_ADC_TOUCH_YP>;
> +
> + axis@0 {
> + linux,abs-code = <ABS_X>;
> + linux,abs-range = <3300 0>;
> + linux,abs-fuzz = <4>;
> + linux,abs-flat = <200>;
> + };
> + axis@1 {
> + linux,abs-code = <ABS_Y>;
> + linux,abs-range = <0 3300>;
> + linux,abs-fuzz = <4>;
> + linux,abs-flat = <200>;
> + };
> + };
> --
> 2.24.1
>