linux-kernel - Re: [PATCH 5/5] arm64: dts: qcom: x1e80100: Enable cpufreq

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Message-ID: <a1623b86-6ab1-12cb-9bf8-37f7e09a0566@quicinc.com>
Date: Thu, 4 Apr 2024 12:02:39 +0530
From: Sibi Sankar <quic_sibis@...cinc.com>
To: Ulf Hansson <ulf.hansson@...aro.org>, Sudeep Holla <sudeep.holla@....com>
CC: <cristian.marussi@....com>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <jassisinghbrar@...il.com>,
        <robh+dt@...nel.org>, <krzysztof.kozlowski+dt@...aro.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <quic_rgottimu@...cinc.com>,
        <quic_kshivnan@...cinc.com>, <conor+dt@...nel.org>,
        <quic_gkohli@...cinc.com>, <quic_nkela@...cinc.com>,
        <quic_psodagud@...cinc.com>
Subject: Re: [PATCH 5/5] arm64: dts: qcom: x1e80100: Enable cpufreq



On 4/3/24 16:50, Ulf Hansson wrote:
> On Tue, 2 Apr 2024 at 13:10, Sudeep Holla <sudeep.holla@....com> wrote:
>>
>> On Thu, Mar 28, 2024 at 03:20:44PM +0530, Sibi Sankar wrote:
>>> Enable cpufreq on X1E80100 SoCs through the SCMI perf protocol node.
>>>
>>> Signed-off-by: Sibi Sankar <quic_sibis@...cinc.com>
>>> ---
>>>   arch/arm64/boot/dts/qcom/x1e80100.dtsi | 27 ++++++++++++++++++++++++++
>>>   1 file changed, 27 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/x1e80100.dtsi b/arch/arm64/boot/dts/qcom/x1e80100.dtsi
>>> index 4e0ec859ed61..d1d232cd1f25 100644
>>> --- a/arch/arm64/boot/dts/qcom/x1e80100.dtsi
>>> +++ b/arch/arm64/boot/dts/qcom/x1e80100.dtsi
>>> @@ -68,6 +68,7 @@ CPU0: cpu@0 {
>>>                        compatible = "qcom,oryon";
>>>                        reg = <0x0 0x0>;
>>>                        enable-method = "psci";
>>> +                     clocks = <&scmi_dvfs 0>;
>>>                        next-level-cache = <&L2_0>;
>>>                        power-domains = <&CPU_PD0>;
>>>                        power-domain-names = "psci";
>>
>>
>> Any reason why you wouldn't want to use the new genpd based perf controls.
>> IIRC it was added based on mainly Qcom platform requirements.
>>
>> -                     clocks = <&scmi_dvfs 0>;
>>                        next-level-cache = <&L2_0>;
>> -                     power-domains = <&CPU_PD0>;
>> -                     power-domain-names = "psci";
>> +                     power-domains = <&CPU_PD0>, <&scmi_dvfs 0>;
>> +                     power-domain-names = "psci", "perf";
>>
>>
>> And the associated changes in the scmi dvfs node for cells property.
>>
>> This change is OK but just wanted to check the reasoning for the choice.
> 
> To me, it seems reasonable to move to the new binding with
> #power-domain-cells for protocol@13. This becomes more future proof,
> as it can then easily be extended to be used beyond CPUs.
> 
> That said, I just submitted a patch [1] to update the examples in the
> scmi DT doc to use  #power-domain-cells in favor of #clock-cells. I
> don't know if there is a better way to promote the new bindings?
> Perhaps moving Juno to use this too?
> 
> Kind regards
> Uffe

Sudeep/Ulfe,

Thanks I'll move to the new recommendation.

-Sibi

> 
> [1]
> https://lore.kernel.org/all/20240403111106.1110940-1-ulf.hansson@linaro.org/