linux-kernel - Re: [PATCH] dt-bindings: clock: qcom,a53pll: drop operating-points-v2

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Date:   Thu, 19 Jan 2023 11:33:40 +0000
From:   Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>
Cc:     Stephen Boyd <sboyd@...nel.org>, Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, fabien.parent@...aro.org
Subject: Re: [PATCH] dt-bindings: clock: qcom,a53pll: drop operating-points-v2

On 19/01/2023 11:04, Krzysztof Kozlowski wrote:
> On 19/01/2023 11:55, Bryan O'Donoghue wrote:
>> On 19/01/2023 03:11, Bjorn Andersson wrote:
>>> On Wed, Jan 18, 2023 at 11:11:00AM -0800, Stephen Boyd wrote:
>>>> Quoting Krzysztof Kozlowski (2023-01-15 06:35:23)
>>>>> On 13/01/2023 21:28, Stephen Boyd wrote:
>>>>>> Quoting Krzysztof Kozlowski (2023-01-13 06:58:59)
>>>>>>> The CPU PLL clock node does not use OPP tables (neither driver).
>>>>>>
>>>>>> What device is qcom_a53pll_get_freq_tbl() operating on?
>>>>>
>>>>> On its own, internal table. While of course driver could be converted to
>>>>> operating-points-v2, no one did it within last 5 years, so why it should
>>>>> happen now?
>>>>>
>>>>
>>>> The property was added mid 2021 by Shawn[1], that's not 5 years ago. I
>>>> guess there were plans to add an OPP table that never happened[2]? Is
>>>> Shawn still working on this? If not, we should revert the OPP code out
>>>> of the driver.
>>>>
>>>
>>> @Bryan, what do you think about this?
>>
>> I'd be in favour of starting the CPR patchset instead, which depends on
>> the opps.
>>
>> I think @Fabien has been waiting on the core 8939 dtsi, I also think the
>> dtsi is close enough to merge that we could reasonably initiate the CPR
>> stuff.
> 
> So you would make use of operating-points-v2 property? Then probably we
> also miss opp-table, but anyway this patch can be dropped then.
> 
> Best regards,
> Krzysztof
> 


Yep.

Looks something like this.

CPU2: cpu@102 {
     device_type = "cpu";
     compatible = "arm,cortex-a53", "arm,armv8";
     reg = <0x102>;
     next-level-cache = <&L2_1>;
     enable-method = "qcom,kpss-acc-v2";
     qcom,acc = <&acc2>;
     qcom,saw = <&saw2>;
     clocks = <&apcs1>;
     operating-points-v2 = <&cluster1_opp_table>;
     power-domains = <&cpr>;
     power-domain-names = "cpr";
     #cooling-cells = <2>;
     capacity-dmips-mhz = <1024>;
};

cluster1_opp_table: cluster1-opp-table {
     compatible = "operating-points-v2-qcom-cpu";
     opp-shared;

     /* Used by qcom-cpufreq-nvmem.c */
     nvmem-cells = <&cpr_efuse_speedbin_pvs>;
     nvmem-cell-names = "cpr_efuse_speedbin_pvs";

     opp-200000000 {
         opp-hz = /bits/ 64 <200000000>;
         opp-supported-hw = <0x3f>;
         required-opps = <&cpr_opp3>;
     };

     opp-345600000 {
         opp-hz = /bits/ 64 <345600000>;
         opp-supported-hw = <0x3f>;
         required-opps = <&cpr_opp3>;
     };
};

cpr_opp_table: cpr-opp-table {
     compatible = "operating-points-v2-qcom-level";

     cpr_opp1: opp1 {
         opp-hz = /bits/ 64 <200000000>;
             opp-level = <1>;
             qcom,opp-fuse-level = <1>;
         };
     cpr_opp2: opp2 {
         opp-hz = /bits/ 64 <345600000>;
             opp-level = <2>;
             qcom,opp-fuse-level = <1>;
          };
          cpr_opp3: opp3 {
             opp-hz = /bits/ 64 <400000000>;
             opp-level = <3>;
             qcom,opp-fuse-level = <1>;
          };
     };
     /* etc */
};

---
bod