linux-kernel - Re: [PATCH V4 4/4] arm64: dts: qcom: sm8550: Add camera clock controller

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Message-ID: <CAA8EJpqjAkdnU+WXoPJs2m4OSZQe10D=Y8nUAofEoEfV139VjA@mail.gmail.com>
Date:   Wed, 14 Jun 2023 15:15:36 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Jagadeesh Kona <quic_jkona@...cinc.com>
Cc:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Taniya Das <quic_tdas@...cinc.com>,
        Satya Priya Kakitapalli <quic_skakitap@...cinc.com>,
        Imran Shaik <quic_imrashai@...cinc.com>,
        Ajit Pandey <quic_ajipan@...cinc.com>
Subject: Re: [PATCH V4 4/4] arm64: dts: qcom: sm8550: Add camera clock controller

On Wed, 14 Jun 2023 at 14:56, Jagadeesh Kona <quic_jkona@...cinc.com> wrote:
>
>
>
> On 6/9/2023 6:22 PM, Konrad Dybcio wrote:
> >
> >
> > On 9.06.2023 13:50, Jagadeesh Kona wrote:
> >> Add device node for camera clock controller on Qualcomm
> >> SM8550 platform.
> >>
> >> Signed-off-by: Taniya Das <quic_tdas@...cinc.com>
> >> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
> >> ---
> >> Changes since V3:
> >>   - No changes
> >> Changes since V2:
> >>   - No changes
> >> Changes since V1:
> >>   - Padded non-zero address part to 8 hex digits
> >>
> >>   arch/arm64/boot/dts/qcom/sm8550.dtsi | 15 +++++++++++++++
> >>   1 file changed, 15 insertions(+)
> >>
> >> diff --git a/arch/arm64/boot/dts/qcom/sm8550.dtsi b/arch/arm64/boot/dts/qcom/sm8550.dtsi
> >> index 75cd374943eb..4d2d610fc66a 100644
> >> --- a/arch/arm64/boot/dts/qcom/sm8550.dtsi
> >> +++ b/arch/arm64/boot/dts/qcom/sm8550.dtsi
> >> @@ -5,6 +5,7 @@
> >>
> >>   #include <dt-bindings/clock/qcom,rpmh.h>
> >>   #include <dt-bindings/clock/qcom,sm8450-videocc.h>
> >> +#include <dt-bindings/clock/qcom,sm8550-camcc.h>
> >>   #include <dt-bindings/clock/qcom,sm8550-gcc.h>
> >>   #include <dt-bindings/clock/qcom,sm8550-gpucc.h>
> >>   #include <dt-bindings/clock/qcom,sm8550-tcsr.h>
> >> @@ -2419,6 +2420,20 @@ videocc: clock-controller@...0000 {
> >>                      #power-domain-cells = <1>;
> >>              };
> >>
> >> +            camcc: clock-controller@...0000 {
> >> +                    compatible = "qcom,sm8550-camcc";
> >> +                    reg = <0 0x0ade0000 0 0x20000>;
> >> +                    clocks = <&gcc GCC_CAMERA_AHB_CLK>,
> >> +                             <&bi_tcxo_div2>,
> >> +                             <&bi_tcxo_ao_div2>,
> >> +                             <&sleep_clk>;
> >> +                    power-domains = <&rpmhpd SM8550_MMCX>;
> > I see that both MMCX ("mmcx.lvl") and MXC ("mxc.lvl") (and MX, FWIW)
> > are consumed on msm-5.15, with the latter one powering camcc PLLs..
> >
> > How are they related? Is that resolved internally or does it need
> > manual intervention?
> >
> > Konrad
>
> These are just different voltage rails, camcc clocks are powered by MMCX
> rail and camcc pll's are powered by MXC rail. Consumer drivers need to
> take care of voting on these rails properly based on the frequency of
> clocks requested.

Which rail powers registers of the camcc? Which rail is required to
read PLL registers?

>
> Thanks,
> Jagadeesh
>
> >> +                    required-opps = <&rpmhpd_opp_low_svs>;
> >> +                    #clock-cells = <1>;
> >> +                    #reset-cells = <1>;
> >> +                    #power-domain-cells = <1>;
> >> +            };
> >> +
> >>              mdss: display-subsystem@...0000 {
> >>                      compatible = "qcom,sm8550-mdss";
> >>                      reg = <0 0x0ae00000 0 0x1000>;



-- 
With best wishes
Dmitry