Re: [PATCH 1/2] dt-bindings: cpufreq: qcom-hw: Document Shikra CPUFREQ Hardware

[Krzysztof Kozlowski]

On 05/05/2026 10:50, Imran Shaik wrote:
> 
> 
> On 04-05-2026 03:53 pm, Krzysztof Kozlowski wrote:
>> On Fri, May 01, 2026 at 12:45:44PM +0530, Imran Shaik wrote:
>>> The Qualcomm Shikra cpufreq hardware is functionally identical to EPSS,
>>> but supports only up to 12 frequency lookup table (LUT) entries. Introduce
>>> qcom,cpufreq-epss-lite to represent this constrained EPSS variant.
>>
>> The entire point of having a generic compatible is that it MUST match
>> all devices. If it does not, then it is pointless to push that generic
>> compatible.
>>
>> I am speaking about qcom,cpufreq-epss.
>>
>> That's nothing new, I was arguing about it already, but now you have
>> confirmation of the mess introduced by generic compatibles. Solution is
>> not to add more generic compatibles, because what will be next?
>> qcom,cpufreq-epss-lighter?
>> qcom,cpufreq-epss-more-lite?
>> qcom,cpufreq-epss-high?
>>
>> Same was here:
>> https://lore.kernel.org/all/20240828203721.2751904-17-quic_nkela@xxxxxxxxxxx/
>>
>> So that's second time I object and do object for every new instance. No
>> to generic compatibles, they are proven to be wrong at least for
>> Qualcomm.
>>
>> Best regards,
>> Krzysztof
>>
> 
> Hi Krzysztof,
> 
> There is no functional change to the latest EPSS hardware 
> (qcom,cpufreq-epss) in this case. The Shikra platform uses the CPU 
> frequency scaling block, which is a predecessor of EPSS and is referred 
> to as EPSS‑lite. The only difference between EPSS‑lite and EPSS is the 
> maximum number of frequency look up table (LUT) entries.
> 
> This constrained EPSS block is not specific to Shikra and can be reused 
> by other SoCs that implement the same hardware. Hence, we have added a 
> separate epss-lite compatible and reused the existing bindings, as all 
> other aspects of the hardware behavior and interface remain identical.

I don't understand how any of this is relevant to my comment. I know
what you did.

Best regards,
Krzysztof