Re: [PATCH v4 1/2] dt-bindings: pwm: Document clk based PWM controller

[Krzysztof Kozlowski <krzk@kernel.org>]

On 26/01/2022 13:58, Nikita Travkin wrote:
> Add YAML devicetree binding for clk based PWM controller
> 
> Signed-off-by: Nikita Travkin <nikita@trvn.ru>
> --
> Changes in v2:
>  - fix the file name.
> Changes in v4:
>  - Use generic node name in the dt bindings example.
> ---
>  .../devicetree/bindings/pwm/clk-pwm.yaml      | 45 +++++++++++++++++++
>  1 file changed, 45 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/clk-pwm.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pwm/clk-pwm.yaml b/Documentation/devicetree/bindings/pwm/clk-pwm.yaml
> new file mode 100644
> index 000000000000..d3416ba549b5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/clk-pwm.yaml
> @@ -0,0 +1,45 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pwm/clk-pwm.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Clock based PWM controller
> +
> +maintainers:
> +  - Nikita Travkin <nikita@trvn.ru>
> +
> +description: |
> +  Some systems have clocks that can be exposed to external devices.
> +  (e.g. by muxing them to GPIO pins)
> +  It's often possible to control duty-cycle of such clocks which makes them
> +  suitable for generating PWM signal.
> +
> +allOf:
> +  - $ref: pwm.yaml#
> +
> +properties:
> +  compatible:
> +    const: clk-pwm
> +
> +  clocks:
> +    description: Clock used to generate the signal.
> +    maxItems: 1
> +
> +  "#pwm-cells":
> +    const: 2
> +
> +unevaluatedProperties: false
> +
> +required:

You need a compatible. pwm-cells can be skipped as pwm.yaml will require
them.

> +  - clocks
> +
> +examples:
> +  - |
> +    pwm {
> +      compatible = "clk-pwm";
> +      #pwm-cells = <2>;
> +      clocks = <&gcc 0>;
> +      pinctrl-names = "default";
> +      pinctrl-0 = <&pwm_clk_flash_default>;
> +    };


Best regards,
Krzysztof