RE: [PATCH v2 1/2] dt-bindings: mmc: renesas,sdhi: Add mux-states property

[Biju Das]

Hi Josua Mayer,


Thanks for the patch.

> -----Original Message-----
> From: Josua Mayer <josua@xxxxxxxxxxxxx>
> Sent: 01 December 2025 12:31
> Subject: [PATCH v2 1/2] dt-bindings: mmc: renesas,sdhi: Add mux-states property
> 
> Add mux controller support for when sdio lines are muxed between a host and multiple cards.
> 
> There are several devices supporting a choice of eMMC or SD on a single board by both dip switch and
> gpio, e.g. Renesas RZ/G2L SMARC SoM and SolidRun RZ/G2L SoM.
> 
> In-tree dts for the Renesas boards currently rely on preprocessor macros to hog gpios and define the
> card.
> 
> By adding mux-states property to sdio controller description, boards can correctly describe the mux
> that already exists in hardware - and drivers can coordinate between mux selection and probing for
> cards.

> 
> Signed-off-by: Josua Mayer <josua@xxxxxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
> b/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
> index c754ea71f51f7..754ccb1c30efb 100644
> --- a/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
> +++ b/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
> @@ -106,6 +106,11 @@ properties:
>    iommus:
>      maxItems: 1
> 
> +  mux-states:
> +    description:
> +      mux controller node to route the SDIO signals from SoC to cards.

Maybe describe 0 - state for SD and 1 - state for eMMC ??


> +    maxItems: 1

> +
>    power-domains:
>      maxItems: 1
> 
> @@ -275,6 +280,7 @@ examples:
>          max-frequency = <195000000>;
>          power-domains = <&sysc R8A7790_PD_ALWAYS_ON>;
>          resets = <&cpg 314>;
> +        mux-states = <&mux 0>;

On R-Car mmc/sd mux available only on SD2/SD3, so I guess you picked wrong node SD0??

or 

Add separate example with RZ/G2L, as the boards(RZ/G2L SMARC EVK)
use gpio/switch (XOR function) to select the eMMC or SD signals??

Cheers,
Biju