[RESEND PATCH v5 4/5] dt-bindings: input: Add docs for ADC driven joystick.

Artur Rojek
2020-04-17T20:20:43Z

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>
Reviewed-by: Rob Herring <robh@kernel.org>
---

Changes:

v2: - Add `reg` property to axis subnode in order to enumerate the axes,
- rename `linux,abs-code` property to `linux,code`,
- drop `linux,` prefix from the remaining properties of axis subnode

v3: no change

v4: - remove "bindings" from the unique identifier string,
- replace `|` with `>` for all description properties,
- specify the number of items for `io-channels`,
- correct the regex pattern of `axis` property,
- specify the value range of `reg` property for each axis,
- put `abs-range` properties under `allOf`

v5: add `a-f` to the regex pattern of `axis` property

.../bindings/input/adc-joystick.yaml | 121 ++++++++++++++++++
1 file changed, 121 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..054406bbd22b
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/adc-joystick.yaml
@@ -0,0 +1,121 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019-2020 Artur Rojek
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/input/adc-joystick.yaml#"
+$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:
+ minItems: 1
+ maxItems: 1024
+ 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.
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+required:
+ - compatible
+ - io-channels
+ - '#address-cells'
+ - '#size-cells'
+
+additionalProperties: false
+
+patternProperties:
+ "^axis@[0-9a-f]+$":
+ 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
+ reg property must be specified.
+
+ properties:
+ reg:
+ minimum: 0
+ maximum: 1023
+ description: Index of an io-channels list entry bound to this axis.
+
+ linux,code:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: EV_ABS specific event code generated by the axis.
+
+ abs-range:
+ allOf:
+ - $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.
+
+ abs-fuzz:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: >
+ Amount of noise in the input value.
+ Omitting this property indicates the axis is precise.
+
+ 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:
+ - reg
+ - linux,code
+ - 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>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ axis@0 {
+ reg = <0>;
+ linux,code = <ABS_X>;
+ abs-range = <3300 0>;
+ abs-fuzz = <4>;
+ abs-flat = <200>;
+ };
+ axis@1 {
+ reg = <1>;
+ linux,code = <ABS_Y>;
+ abs-range = <0 3300>;
+ abs-fuzz = <4>;
+ abs-flat = <200>;
+ };
+ };
--
2.26.1