Re: [PATCH 4/4] dt-bindings: input: mt-matrix-keypad: add guardian mt matrix keypad bindings definition

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 04/05/2022 12:52, Gireesh.Hiremath@in.bosch.com wrote:
> From: Gireesh Hiremath <Gireesh.Hiremath@in.bosch.com>
> 
> Add binding definition for the support of the Guardian
> mt matrix keypad driver.
> 
> Signed-off-by: Gireesh Hiremath <Gireesh.Hiremath@in.bosch.com>
> ---
>  .../bindings/input/mt-matrix-keypad.yaml      | 134 ++++++++++++++++++
>  1 file changed, 134 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/mt-matrix-keypad.yaml
> 
> diff --git a/Documentation/devicetree/bindings/input/mt-matrix-keypad.yaml b/Documentation/devicetree/bindings/input/mt-matrix-keypad.yaml
> new file mode 100644
> index 000000000000..b52cd478f638
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/mt-matrix-keypad.yaml
> @@ -0,0 +1,134 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/input/mt-matrix-keypad.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: GPIO driven mt matrix keypad device tree bindings
> +
> +maintainers:
> +  - vinay <VinayKumar.Shettar@in.bosch.com>
> +
> +description: |
> +  GPIO driven mt matrix keypad is used to interface a SoC with a mt matrix
> +  keypad. The mt matrix keypad supports multiple gpio line, all gpio line act

s/line/lines/

> +  as row as wel as column lines, a key can be placed at each intersection

s/wel/well/

> +  of a unique row number not equal to a unique column and they are diagonally
> +  symmetric.
> +

What is "mt" in the "mt matrix"?

> +  Example- For 5 gpio lines, possible matrix is 5x5 and maximum possible
> +        keys are 10.
> +
> +        Sample matrix table for 7 button and 5 gpio line
> +
> +        ------------------------------------------------------
> +        |Row\Col |GPIO 0 | GPIO 1 | GPIO 2 | GPIO 3 | GPIO 4 |
> +        ------------------------------------------------------
> +        | GPIO 0 |  X    | KEY_9  | KEY_2  |   X    | KEY_1  |
> +        ------------------------------------------------------
> +        | GPIO 1 | KEY_9 |  X     | KEY_6  |   X    |  X     |
> +        ------------------------------------------------------
> +        | GPIO 2 | KEY_2 | KEY_6  |  X     | KEY_4  | KEY_7  |
> +        ------------------------------------------------------
> +        | GPIO 3 |  X    |  X     | KEY_4  |  X     | KEY_8  |
> +        ------------------------------------------------------
> +        | GPIO 4 | KEY_1 |  X     | KEY_7  | KEY_8  |  X     |
> +        ------------------------------------------------------
> +        X - invalid key
> +        KEY_x - preferred key code
> +
> +  The mt matrix keypad can sense a key-press and key-release by means of GPIO
> +  lines and report the event using GPIO interrupts to the cpu.
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: gpio-mt-matrix-keypad
> +      - items:
> +          - enum:
> +              - gpio-mt-matrix-keypad
> +          - const: gpio-mt-matrix-keypad

Aren't all these compatibles the same?

> +
> +  debounce-delay-ms:
> +    description: Delay after the first bounce of button.
> +    default: 0
> +
> +  col-scan-delay-us:
> +    description: Delay before scanning next active line.
> +    default: 0
> +
> +  number-of-button:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: Number of button connected to the keypad controller.

s/button/buttons/ I presume.

> +
> +  linux,no-autorepeat:
> +    description: |
> +      Disable the Linux input system's autorepeat feature on the input device.
> +
> +  gpio-activelow:
> +    description: Gpio line are active low.

No, GPIOs should instead use common flags.

> +
> +  line-gpios:
> +    description: |
> +      Gpio lines connected to keypad controller.
> +      all gpio line act as row as wel as column lines.
> +
> +  linux,keymap:
> +    $ref: '/schemas/types.yaml#/definitions/uint32-array'
> +    description: |
> +      An array of packed 1-cell entries containing the equivalent of row,
> +      column and linux key-code. The 32-bit big endian cell is packed as:
> +          row << 24 | column << 16 | key-code

But anyway this should be just merged into matrix-keypad. It's a simpler
set of that binding.

> +
> +required:
> +  - compatible
> +  - number-of-button
> +  - line-gpios
> +  - linux,keymap
> +
> +additionalProperties: true

This cannot be true.

> +
> +examples:
> +  - |
> +    mt_matrix_keypad {

No underscores in node names. Generic node name, so just "keypad".



Best regards,
Krzysztof