Re: [PATCH v4 4/4] dt-bindings: firmware: arm,scmi: Add support for pinctrl protocol

[AKASHI Takahiro]

On Tue, Aug 08, 2023 at 06:25:36PM +0000, Oleksii Moisieiev wrote:
> Add new SCMI v3.2 pinctrl protocol bindings definitions and example.
> 
> Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx>
> 
> ---
> Changes v3 -> v4
>   - reworked protocol@19 format
> ---
>  .../bindings/firmware/arm,scmi.yaml           | 53 +++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> index 5824c43e9893..5318fe72354e 100644
> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> @@ -233,6 +233,39 @@ properties:
>        reg:
>          const: 0x18
>  
> +  protocol@19:
> +    type: object
> +    allOf:
> +      - $ref: "#/$defs/protocol-node"
> +      - $ref: "../pinctrl/pinctrl.yaml"

Does this rule require that the node name start with "pinctrl" or "pinmux"?
If so, it doesn't match with "protocol@19".

> +    unevaluatedProperties: false
> +
> +    properties:
> +      reg:
> +        const: 0x19
> +
> +      '#pinctrl-cells':
> +        const: 0
> +
> +    patternProperties:
> +      '-pins$':

Is this restriction necessary?
(Most pinctrl's do so, though.)

> +        type: object
> +        allOf:
> +          - $ref: "../pinctrl/pincfg-node.yaml#"
> +          - $ref: "../pinctrl/pinmux-node.yaml#"
> +        unevaluatedProperties: false
> +
> +        description:

I think the description may be a bit ambiguous.

> +          A pin multiplexing sub-node describe how to configure a
> +          set of pins is some desired function.

Even a sub-node that has pin multiplexing definitions may have
pin property/parameter definitions. Right?

> +          A single sub-node may define several pin configurations.

Do you not allow for having a sub-node under a sub-node?

> +          This sub-node is using default pinctrl bindings to configure

Does "default pinctrl bindings" refer to "pinctrl-bindings.txt"?
Is it necessary to specifically mention it here as it is for client devices?


> +          pin multiplexing and using SCMI protocol to apply specified

Again, not only multiplexing but also pin property/parameters.

Thanks,
-Takahiro Akashi

> +          configuration using SCMI protocol.
> +
> +    required:
> +      - reg
> +
>  additionalProperties: false
>  
>  $defs:
> @@ -384,6 +417,26 @@ examples:
>              scmi_powercap: protocol@18 {
>                  reg = <0x18>;
>              };
> +
> +            scmi_pinctrl: protocol@19 {
> +                reg = <0x19>;
> +                #pinctrl-cells = <0>;
> +
> +                i2c2-pins {
> +                    groups = "i2c2_a", "i2c2_b";
> +                    function = "i2c2";
> +                };
> +
> +                mdio-pins {
> +                    groups = "avb_mdio";
> +                    drive-strength = <24>;
> +                };
> +
> +                keys_pins: keys-pins {
> +                    pins = "GP_5_17", "GP_5_20", "GP_5_22", "GP_2_1";
> +                    bias-pull-up;
> +                };
> +            };
>          };
>      };
>  
> -- 
> 2.25.1