Re: [PATCH 04/10] dt-bindings: pinctrl: add Ambarella CV75 pinctrl

Hi Long,

thanks for your patch!

On Thu, Jul 30, 2026 at 12:44=E2=80=AFPM Long Zhao <[email protected]>=
 wrote:

> +  "^[a-z0-9-]+-pins$":
> +    type: object
> +    allOf:
> +      - $ref: pinmux-node.yaml#
> +      - $ref: pincfg-node.yaml#
> +    additionalProperties: false
> +
> +    properties:
> +      function: true
> +
> +      pinmux:
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +        minItems: 1
> +        maxItems: 96
> +
> +      bias-disable: true
> +      bias-pull-down: true
> +      bias-pull-up: true
> +
> +      drive-strength:
> +        enum: [3, 4, 5, 6, 7, 8, 9, 12]
> +
> +    required:
> +      - function
> +      - pinmux

Usually either (function + group) OR pinmux is used, so this looks
slightly confusing to me.

> +        uart0-pins {
> +            function =3D "uart0";
> +            pinmux =3D <AMBA_PINMUX(44, 1)>,
> +                     <AMBA_PINMUX(45, 1)>;
> +            bias-disable;
> +            drive-strength =3D <8>;
> +        };
> +    };

So I take it that "pinmux" is used for all the muxing while the function "u=
art0"
is actually only used for the pin configs, right?

It would be better to encode the groups into the driver I think and then it
would look like this:

       uart0-pins {
           function =3D "uart0";
           groups =3D "uart0tx", "uart0rx";
           bias-disable;
           drive-strength =3D <8>;
       };

As you can see "uart0tx" is easier to read and understand than
<AMBA_PINMUX(44, 1)>.

Also it hides constants nicely in the driver. I know this is a lot of work.

I know a lot of companies like "pinmux" because it's simple and
convenient, but it really
isn't the best for developers writing device trees and debugging.

Yours,
Linus Walleij