Re: [PATCH v2] dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

Hi Wolfram,

On Wed, 26 Aug 2026 at 10:35, Wolfram Sang
<[email protected]> wrote:
> R-Car Gen5 can make use of it.
>
> Signed-off-by: Wolfram Sang <[email protected]>

Thanks for your patch!

> --- a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> +++ b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> @@ -83,14 +83,14 @@ properties:
>
>    dmas:
>      minItems: 2
> -    maxItems: 4
> +    maxItems: 6

Shouldn't this be 8, as there are 4 SYS-DMAC instances, and I couldn't
find a limitation w.r.t. I2C and specific SYS-DMAC instances?

>      description:
>        Must contain a list of pairs of references to DMA specifiers, one for
>        transmission, and one for reception.
>
>    dma-names:
>      minItems: 2
> -    maxItems: 4
> +    maxItems: 6
>      items:
>        enum:
>          - tx
> @@ -137,6 +137,20 @@ allOf:
>          dmas: false
>          dma-names: false
>
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - renesas,rcar-gen3-i2c
> +              - renesas,rcar-gen4-i2c
> +    then:
> +      properties:
> +        dmas:
> +          maxItems: 4
> +        dma-names:
> +          maxItems: 4
> +

I wouldn't bother adding further restrictions, as these are not related
to the actual I2C block, but to on-SoC wiring.  DMARQ is just a single
signal going from the I2C block to one or more DMAC instances.
The number also differs among I2C instances on an SoC.

BTW, all I2C instances on R-Car V3U have one DMA pair ;-)

>    - if:
>        properties:
>          compatible:

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

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