Re: [PATCH RFC v2 1/9] dt-bindings: clock: renesas,cpg-mssr: Support RZ/T2H system controllers

[Geert Uytterhoeven]

Hi Prabhakar,

On Thu, 2 Jul 2026 at 14:31, Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
>
> The RZ/T2H and RZ/N2H SoCs features system controller blocks for low-power
> management and access control that reside within the CPG/MSSR address
> space. To properly represent these hardware modules, allow them to be
> defined as child nodes of the CPG/MSSR controller.
>
> Update the CPG/MSSR binding to support child nodes by adding
> system-controller child nodes using a patternProperty, requiring a reg
> property and a renesas,sys-block property to identify the controller
> instance.
>
> Restrict these new properties to the RZ/T2H and RZ/N2H SoCs to ensure
> existing bindings for other Renesas SoCs remain unaffected.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> ---
> v1->v2:
> - Updated commit message.

Thanks for the update!

> --- a/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.yaml
> +++ b/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.yaml
> @@ -99,6 +99,41 @@ properties:
>        the datasheet.
>      const: 1
>
> +  '#address-cells':
> +    description:
> +      Required for the RZ/T2H SoC to define the address space for child
> +      system-controller nodes.
> +    const: 2
> +
> +  '#size-cells':
> +    description:
> +      Required for the RZ/T2H SoC to define the size of the register
> +      blocks for child system-controller nodes.
> +    const: 2
> +
> +  ranges:
> +    description:
> +      Required for the RZ/T2H SoC to provide 1:1 address translation
> +      from the child system-controller nodes to the CPU address space.
> +
> +patternProperties:
> +  "^system-controller@[0-9a-f]+$":
> +    type: object
> +    description:
> +      System controller child nodes representing sub-blocks for
> +      Low Power Management (LPM) and Access Control.

According to the documentation for the PRCi bit in Section 11.3.1
("PRCRN : Non_Safety Area Protect Register"), the low power consumption
bits are in the xx28_xxxx blocks?

> +    properties:
> +      reg:
> +        maxItems: 1
> +      renesas,sys-block:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description: Index of the system controller instance.
> +        enum: [0, 1]

I am not so fond of such "index" properties.
And of subnodes ;-)

> +    required:
> +      - reg
> +      - renesas,sys-block
> +    additionalProperties: false
> +
>  required:
>    - compatible
>    - reg
> @@ -126,6 +161,10 @@ allOf:
>        properties:
>          reg:
>            maxItems: 1
> +        '#address-cells': false
> +        '#size-cells': false
> +      patternProperties:
> +        "^system-controller@[0-9a-f]+$": false
>    - if:
>        not:
>          properties:

As RZ/T2H and RZ/N2H are rather different than the other (mostly
R-Car) variants, perhaps it makes sense to spin them off to a separate
bindings document?

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds