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

[Conor Dooley]

On Mon, Jun 22, 2026 at 11:14:32AM +0200, Krzysztof Kozlowski wrote:
> 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

Ah d'oh. I was hung up on matching the existing property that I didn't
include -hz in my original suggestion, sorry!

> 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
>

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