linux-kernel - Re: [PATCH v1 07/10] arm64: dts: qcom: ipq5332: populate the opp table based on the eFuse

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Message-ID: <CAA8EJppNsgUNgwadq9oM0_KyORNR5PBZGVZukN6MzAm2KPzC9g@mail.gmail.com>
Date:   Thu, 7 Sep 2023 16:59:28 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Varadarajan Narayanan <quic_varada@...cinc.com>
Cc:     ilia.lin@...nel.org, agross@...nel.org, andersson@...nel.org,
        konrad.dybcio@...aro.org, rafael@...nel.org,
        viresh.kumar@...aro.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        mturquette@...libre.com, sboyd@...nel.org,
        quic_kathirav@...cinc.com, linux-pm@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org
Subject: Re: [PATCH v1 07/10] arm64: dts: qcom: ipq5332: populate the opp
 table based on the eFuse

On Thu, 7 Sept 2023 at 08:23, Varadarajan Narayanan
<quic_varada@...cinc.com> wrote:
>
> IPQ53xx have different OPPs available for the CPU based on
> SoC variant. This can be determined through use of an eFuse
> register present in the silicon.
>
> Add support to read the eFuse and populate the OPPs based on it.
>
> Signed-off-by: Kathiravan T <quic_kathirav@...cinc.com>
> Signed-off-by: Varadarajan Narayanan <quic_varada@...cinc.com>
> ---
>  arch/arm64/boot/dts/qcom/ipq5332.dtsi | 34 +++++++++++++++++++++++++++++++---
>  1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/qcom/ipq5332.dtsi b/arch/arm64/boot/dts/qcom/ipq5332.dtsi
> index 82761ae..3ca3f34 100644
> --- a/arch/arm64/boot/dts/qcom/ipq5332.dtsi
> +++ b/arch/arm64/boot/dts/qcom/ipq5332.dtsi
> @@ -91,11 +91,34 @@
>         };
>
>         cpu_opp_table: opp-table-cpu {
> -               compatible = "operating-points-v2";
> +               compatible = "operating-points-v2-kryo-cpu";
>                 opp-shared;
> +               nvmem-cells = <&cpu_speed_bin>;
> +               nvmem-cell-names = "speed_bin";
> +
> +               /*
> +                * Listed all supported CPU frequencies and opp-supported-hw
> +                * values to select CPU frequencies based on the limits fused.
> +                * ------------------------------------------------------------
> +                * Frequency     BIT3   BIT2   BIT1    BIT0    opp-supported-hw
> +                *              1.0GHz 1.2GHz 1.5GHz No Limit
> +                * ------------------------------------------------------------
> +                * 1100000000     1      1      1       1            0xF
> +                * 1500000000     0      0      1       1            0x3
> +                * -----------------------------------------------------------
> +                */

This can probably go to the commit message instead.

> +
> +               opp-1100000000 {
> +                       opp-hz = /bits/ 64 <1100000000>;

But your table shows 1.0 GHz and 1.2 GHz instead of 1.1 GHz

> +                       opp-microvolt = <850000>;
> +                       opp-supported-hw = <0xF>;
> +                       clock-latency-ns = <200000>;
> +               };
>
> -               opp-1488000000 {
> -                       opp-hz = /bits/ 64 <1488000000>;
> +               opp-1500000000 {
> +                       opp-hz = /bits/ 64 <1500000000>;

So, 1.488 GHz or 1.5 GHz?

> +                       opp-microvolt = <950000>;

Which regulator is controlled by this microvolt?

> +                       opp-supported-hw = <0x3>;
>                         clock-latency-ns = <200000>;
>                 };
>         };
> @@ -150,6 +173,11 @@
>                         reg = <0x000a4000 0x721>;
>                         #address-cells = <1>;
>                         #size-cells = <1>;
> +
> +                       cpu_speed_bin: cpu_speed_bin@1d {
> +                               reg = <0x1d 0x2>;
> +                               bits = <7 2>;
> +                       };
>                 };
>
>                 rng: rng@...00 {
> --
> 2.7.4
>


-- 
With best wishes
Dmitry