Re: [PATCH V4 2/4] dt-bindings: mmc: controller: Add max-sd-hs-frequency property

[Krzysztof Kozlowski <krzk@kernel.org>]

On 01/08/2025 10:45, Sarthak Garg wrote:
> Some platforms may require limiting the maximum frequency used in SD
> High-Speed (HS) mode due to board-level hardware constraints. For
> example, certain boards may include level shifters or other components
> that cannot reliably operate at the default 50 MHz HS frequency.
> 
> Introduce a new optional device tree property max-sd-hs-frequency to
> limit the maximum frequency (in Hz) used for SD cards operating in
> High-Speed (HS) mode.
> 
> Signed-off-by: Sarthak Garg <quic_sartgarg@quicinc.com>
> ---
>  .../devicetree/bindings/mmc/mmc-controller-common.yaml | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> index 9a7235439759..6c2529b976d1 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> @@ -93,6 +93,16 @@ properties:
>      minimum: 400000
>      maximum: 384000000
>  
> +  max-sd-hs-frequency:

Use standard unit suffixes. s/frequency/hz/



> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Maximum frequency (in Hz) to be used for SD cards operating in
> +      High-Speed (HS) mode. This is useful for board-specific limitations,
> +      such as level shifters or others where the card cannot reliably
> +      operate at the default 50 MHz HS frequency.

Don't repeat constraints in free form text.

default: