Re: [PATCH V3 2/4] dt-bindings: mmc: controller: Add max-sd-hs-frequency property

[Krzysztof Kozlowski <krzk@kernel.org>]

On 23/06/2025 14:08, Konrad Dybcio wrote:
>>>>
>>>> This might be fine, but your DTS suggests clearly this is SoC compatible
>>>> deducible, which I already said at v1.
>>>
>>> I don't understand why you're rejecting a common solution to a problem
>>> that surely exists outside this one specific chip from one specific
>>> vendor, which may be caused by a multitude of design choices, including
>>> erratic board (not SoC) electrical design
>>
>> No one brought any arguments so far that common solution is needed. The
>> only argument provided - sm8550 - is showing this is soc design.
>>
>> I don't reject common solution. I provided review at v1 to which no one
>> responded, no one argued, no one provided other arguments.
> 
> Okay, so the specific problem that causes this observable limitation
> exists on SM8550 and at least one more platform which is not upstream
> today. It can be caused by various electrical issues, in our specific
> case by something internal to the SoC (but external factors may apply
> too)
> 
> Looking at the docs, a number of platforms have various limitations
> with regards to frequency at specific speed-modes, some of which seem
> to be handled implicitly by rounding in the clock framework's
> round/set_rate().
> 
> I can very easily imagine there are either boards or platforms in the
> wild, where the speed must be limited for various reasons, maybe some
> of them currently don't advertise it (like sm8550 on next/master) to
> hide that

But there are no such now. The only argument (fact) provided in this
patchset is: this is issue specific to SM8550 SoC, not the board. See
last patch. Therefore this is compatible-deducible and this makes
property without any upstream user.


Best regards,
Krzysztof