Re: [PATCH RFC 3/7] dt-bindings: mfd: rz-mtu3: Document RZ/G2L MTU3 PWM

[Rob Herring <robh@kernel.org>]

On Thu, Sep 29, 2022 at 11:30:39AM +0100, Biju Das wrote:
> Document RZ/G2L MTU3 PWM support. It supports following pwm modes.
> 	1) PWM mode 1
> 	2) PWM mode 2
> 	3) Reset-synchronized PWM mode
> 	4) Complementary PWM mode 1 (transfer at crest)
> 	5) Complementary PWM mode 2 (transfer at trough)
> 	6) Complementary PWM mode 3 (transfer at crest and trough)

What does 'complementary' mean here?

Mode 1, 2, 3 isn't very meaningful. Do other PWMs have similar modes? No 
way to tell without better descriptions.

> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
>  .../bindings/mfd/renesas,rzg2l-mtu3.yaml      | 50 +++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/renesas,rzg2l-mtu3.yaml b/Documentation/devicetree/bindings/mfd/renesas,rzg2l-mtu3.yaml
> index c4bcf28623d6..362fedf5bedb 100644
> --- a/Documentation/devicetree/bindings/mfd/renesas,rzg2l-mtu3.yaml
> +++ b/Documentation/devicetree/bindings/mfd/renesas,rzg2l-mtu3.yaml
> @@ -223,6 +223,50 @@ patternProperties:
>        - compatible
>        - reg
>  
> +  "^pwm@([0-4]|[6-7])+$":
> +    type: object
> +
> +    properties:
> +      compatible:
> +        const: renesas,rz-mtu3-pwm
> +
> +      reg:
> +        description: Identify pwm channels.
> +        items:
> +          enum: [ 0, 1, 2, 3, 4, 6, 7 ]

At any given level in DT, there is only 1 address space. You've created 
2 with pwms and counters.

> +
> +      "#pwm-cells":
> +        const: 2
> +
> +      renesas,pwm-mode1:
> +        type: boolean
> +        description: Enable PWM mode 1.
> +
> +      renesas,pwm-mode2:
> +        type: boolean
> +        description: Enable PWM mode 2.
> +
> +      renesas,reset-synchronized-pwm-mode:
> +        type: boolean
> +        description: Enable Reset-synchronized PWM mode.
> +
> +      renesas,complementary-pwm-mode1:
> +        type: boolean
> +        description: Complementary PWM mode 1 (transfer at crest).
> +
> +      renesas,complementary-pwm-mode2:
> +        type: boolean
> +        description: Complementary PWM mode 2 (transfer at trough).
> +
> +      renesas,complementary-pwm-mode3:
> +        type: boolean
> +        description: Complementary PWM mode 3 (transfer at crest and trough).

These all look like client configuration and should be either runtime 
config or part of pwm cells args.

> +
> +    required:
> +      - compatible
> +      - reg
> +      - "#pwm-cells"
> +
>  required:
>    - compatible
>    - reg
> @@ -305,6 +349,12 @@ examples:
>          compatible = "renesas,rzg2l-mtu3-counter";
>          reg = <1>;
>        };
> +      pwm@3 {
> +        compatible = "renesas,rz-mtu3-pwm";
> +        reg = <3>;
> +        #pwm-cells = <2>;
> +        renesas,pwm-mode1;
> +      };
>      };
>  
>  ...
> -- 
> 2.25.1
> 
>