Re: [PATCH v5 01/17] spi: dt-bindings: add spi-max-post-config-frequency-hz property

On 20/07/26 15:39, Krzysztof Kozlowski wrote:
> On 20/07/2026 10:48, Santhosh Kumar K wrote:
>>
>>
>> On 20/07/26 13:10, Krzysztof Kozlowski wrote:
>>> On 20/07/2026 09:38, Santhosh Kumar K wrote:
>>>>>> diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
>>>>>> index 880a9f624566..12211f8c9f7d 100644
>>>>>> --- a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
>>>>>> +++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
>>>>>> @@ -45,6 +45,11 @@ properties:
>>>>>>         description:
>>>>>>           Maximum SPI clocking speed of the device in Hz.
>>>>>>     
>>>>>> +  spi-max-post-config-frequency-hz:
>>>>>> +    description:
>>>>>> +      Maximum SPI clock frequency in Hz achievable after controller-side
>>>>>> +      configuration.
>>>>>
>>>>> How did you implement my feedback?
>>>>
>>>> Three points from your feedback:
>>>>
>>>> 1. -hz suffix: added
>>>>
>>>> 2. Array property: I still lean towards keeping this as a scalar for
>>>> now, as we don't have a concrete use case for multiple values today, and
>>>> supporting two frequencies should be sufficient for the foreseeable
>>>> future. I had responded to this in the v4 discussion as well, you may
>>>> have missed that response.
>>>>
>>>> 3. maxItems: Since the property remains a scalar, I have not added maxItems.
>>>
>>> So how did you make this property scalar?
>>
>> The -hz suffix constraints the property to a uint32 scalar through the
>> DT schema framework's property-units.yaml.
> 
> Hm, where? I completely missed that, can you point me to the specific
> line? I see clearly that it is not a scalar.
> 
> 
>>
>> Adding an explicit $ref or maxItems for a unit-suffixed property is
>> rejected by dtbs_check with:
>>    - "Standard unit suffix properties don't need a type $ref"
> 
> This I did not propose - the type is fixed.
> 
>>    - "Scalar properties should not have array keywords"
> 
> Cannot reproduce it.

I overlooked this. You are right, and I apologize for the incorrect
explanation.

The -hz suffix maps to uint32-matrix in property-units.yaml, not a
scalar. Without 'maxItems: 1', the property can accept multiple values.
I should have verified this before responding. Sorry again!

I'll add 'maxItems: 1' in the next version.

Thanks,
Santhosh.

> 
> Best regards,
> Krzysztof