Re: [PATCH v10 08/11] dt-bindings: ufs: Add NXP S32N79 UFS host controller

[Krzysztof Kozlowski <krzk@kernel.org>]

On 09/11/2026 21:47, Larisa Ileana Grigore wrote:
> On 11/5/2026 8:28 PM, Krzysztof Kozlowski wrote:
>> On 04/11/2026 10:41, Larisa Ileana Grigore wrote:
>>> On 11/4/2026 10:40 AM, Krzysztof Kozlowski wrote:
>>> v8:
>>> https://lore.kernel.org/all/20261013103003.373156-1-larisa.grigore@oss.nxp.com/
>>> v9:
>>> https://lore.kernel.org/all/20261024122533.3609180-1-larisa.grigore@oss.nxp.com/
>>> v10:
>>> https://lore.kernel.org/all/20261103133215.1385823-1-larisa.grigore@oss.nxp.com
>>>
>>> Regarding your comments on v9:
>>>
>>> Frank's Reviewed-by was given publicly on v8 [1]. The series only looked
>>> like a v1 because of the wrong version number.
>>> The tag ordering was changed in v10 since the patch was changed.
>>> The single 0 Hz OPP entry: as discussed on v8 [2][3], the clock rate is
>>> set outside Linux and is not scaled. The OPP table lets the UFS core
>>
>> That is not the purpose of OPP table. OPP defines performance point.
>> Performance point of 0 makes no sense. You cannot use Linux limitations
>> as reason to add some DTS, because answer is simple: fix your Linux
>> limitations.
>>
> 
> Hi Krzysztof,
> 
> Thanks for the clarification. I understand that an OPP table is not 
> appropriate here.
> 
> Existing platform DTs, such as Hi3660 and MT8195, define freq-table-hz 
> containing only <0 0> pairs. This allows the UFS core to manage clock 
> enable/disable without setting their rates. With freq-table-hz 
> deprecated, there seems to be a gap for this use case, beyond S32N.
> 

Instead of passing 0, properties should be rather missing and that would
be hint for Linux. Is there a difference between missing properties and
some non-valid state (like freq=0)?


Best regards,
Krzysztof