linux-kernel - Re: [PATCH 1/3] arm64: dts: qcom: ipq6018: separate CPU OPP tables

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Date: Thu, 1 Feb 2024 05:15:51 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Chukun Pan <amadeus@....edu.cn>
Cc: andersson@...nel.org, conor+dt@...nel.org, devicetree@...r.kernel.org, 
	konrad.dybcio@...aro.org, krzysztof.kozlowski+dt@...aro.org, 
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	robh+dt@...nel.org
Subject: Re: [PATCH 1/3] arm64: dts: qcom: ipq6018: separate CPU OPP tables

On Thu, 1 Feb 2024 at 05:08, Chukun Pan <amadeus@....edu.cn> wrote:
>
> Hi, Dmitry
> > I went on and checked ipq6018.dtsi. It will need to be reworked before
> > we can continue with PMIC-less devices.
>
> > Obviously, the PMIC is not a part of the SoC. So please move the
> > "qcom,rpm-mp5496-regulators" node to the board files together with the
> > cpu-supply properties that reference that regulator.
>
> Thanks a lot for your advice, now things are clearer.
> My idea is as follows:
>
> 1. Add all frequencies supported by SoCs in ipq6018.dtsi
>
> 2. Move cpu-supply and mp5496 nodes to ipq6018-mp5496.dtsi

Straight to the board files, please, no need for additional includes.

>
> &CPU0 {
>         cpu-supply = <&ipq6018_s2>;
> };
> ...
>
> &rpm_requests {
>         regulators {
>                 rpm-mp5496...
>                 ipq6018_s2...
>         };
> };
>
> > The SoC itself supports all listed frequencies, so it is incorrect to
> > split the opp tables from the ipq6018.dtsi. Instead please patch the
> > PMIC-less boards in the following way:
>
> > #include "ipq6018.dtsi"
> > &cpu_opp_table {
> >  /* the board doesn't have a PMIC, disable CPU frequencies which
> > require higher voltages */
> >  /delete-node/ opp-1320000000;
> >  /delete-node/ opp-1440000000;
> >};
>
> Thank you but no need. The CPUFreq NVMEM driver will give the CPU
> maximum frequency based on the cpu_speed_bin and opp-supported-hw.

>From your patches I had the feeling that you still want to limit the
high-frequency OPP entries if there is no PMIC.

>
> Thanks,
> Chukun
>
> --
> 2.25.1
>


-- 
With best wishes
Dmitry