Re: [PATCH v4 01/16] spi: dt-bindings: add spi-max-post-config-frequency property

[Krzysztof Kozlowski]

On Thu, Jun 18, 2026 at 01:07:10PM +0530, Santhosh Kumar K wrote:
> Add spi-max-post-config-frequency, a generic uint32 property for SPI
> peripherals that support two distinct clock rates: a conservative rate
> always reachable without controller configuration, and a higher rate
> reachable only after controller-side configuration such as PHY tuning.
> 
> When both properties are present, spi-max-frequency gives the
> conservative pre-configuration rate and spi-max-post-config-frequency
> gives the higher post-configuration target.
> 
> Signed-off-by: Santhosh Kumar K <s-k6@xxxxxx>
> ---
>  .../devicetree/bindings/spi/spi-peripheral-props.yaml       | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
> index 880a9f624566..ece86f65930f 100644
> --- a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
> +++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
> @@ -45,6 +45,12 @@ properties:
>      description:
>        Maximum SPI clocking speed of the device in Hz.
>  
> +  spi-max-post-config-frequency:

-hz
https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml

and you need maxItems: 1.

Now, please take time and think if this should not be an array instead
(maxItems: ...) to cover other possible cases, e.g. different tuning
levels? IOW, having single spi-max-frequency turned out to be
insufficient. You address that insufficiency with one more frequency,
but what if this is going to be insufficient next month as well?

I don't know, answer is rather for domain experts.

> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Maximum SPI clock frequency in Hz achievable post controller-side
> +      configuration.

Best regards,
Krzysztof