Re: [PATCH 1/2] dt-bindings: mmc: Add post-power-off-delay-ms property

On Fri, Jul 17, 2026 at 1:26 AM Judith Mendez <[email protected]> wrote:
>
> Add post-power-off-delay-ms property to MMC controller common.
>
> This property shall be used to specify delay if needed after
> deasserting power during MMC power cycles.

Please clarify with some additional information from the cover-letter,
like "specify custom delays after MMC power off to work around
hardware issues such as slow RC circuites on MMC VDD rails."

>
> Signed-off-by: Judith Mendez <[email protected]>
> ---
>  .../devicetree/bindings/mmc/mmc-controller-common.yaml    | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> index 3d7195e9461c3..3ff68d32a308f 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> @@ -275,6 +275,14 @@ properties:
>        not available.
>      default: 10
>
> +  post-power-off-delay-ms:

For mmc-pwrseq-simple we already have "power-off-delay-us", perhaps
better to re-use that name instead.

> +    description:
> +      The presence of this property indicates that the card requires a
> +      delay (in milliseconds) after power off before the next power on.

Again, maybe something to indicate this is specific like "specify
custom delays after MMC power off to work around
hardware issues such as slow RC circuites on MMC VDD rails."

> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    minimum: 0
> +    maximum: 10000

Are the above limits needed at all?

I suggest we add a "default: 1", as that would correspond to the
hardcoded value that the mmc core currently uses for this delay.

> +
>    supports-cqe:
>      $ref: /schemas/types.yaml#/definitions/flag
>      description:
> --
> 2.54.0
>

Kind regards
Uffe