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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Thu, 4 Apr 2024 08:30:07 +0300
Message-ID: <CAA8EJprfaALkQe-wUrBow6B1A66ro0AoVpfnQJLXgqFmL8isNQ@mail.gmail.com>
Subject: Re: [PATCH V2 RESEND 6/6] arm64: dts: qcom: sm8650: Add video and
 camera clock controllers
To: Jagadeesh Kona <quic_jkona@quicinc.com>
Cc: Bjorn Andersson <andersson@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, 
	Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, 
	Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>, linux-arm-msm@vger.kernel.org, 
	linux-clk@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Taniya Das <quic_tdas@quicinc.com>, 
	Satya Priya Kakitapalli <quic_skakitap@quicinc.com>, Ajit Pandey <quic_ajipan@quicinc.com>, 
	Imran Shaik <quic_imrashai@quicinc.com>
Content-Type: text/plain; charset="UTF-8"

On Thu, 4 Apr 2024 at 08:13, Jagadeesh Kona <quic_jkona@quicinc.com> wrote:
>
>
>
> On 4/3/2024 9:24 PM, Dmitry Baryshkov wrote:
> > On Wed, 3 Apr 2024 at 10:16, Jagadeesh Kona <quic_jkona@quicinc.com> wrote:
> >>
> >>
> >>
> >> On 3/25/2024 11:38 AM, Jagadeesh Kona wrote:
> >>>
> >>>
> >>> On 3/21/2024 6:43 PM, Dmitry Baryshkov wrote:
> >>>> On Thu, 21 Mar 2024 at 11:27, Jagadeesh Kona <quic_jkona@quicinc.com>
> >>>> wrote:
> >>>>>
> >>>>> Add device nodes for video and camera clock controllers on Qualcomm
> >>>>> SM8650 platform.
> >>>>>
> >>>>> Signed-off-by: Jagadeesh Kona <quic_jkona@quicinc.com>
> >>>>> ---
> >>>>>    arch/arm64/boot/dts/qcom/sm8650.dtsi | 28 ++++++++++++++++++++++++++++
> >>>>>    1 file changed, 28 insertions(+)
> >>>>>
> >>>>> diff --git a/arch/arm64/boot/dts/qcom/sm8650.dtsi
> >>>>> b/arch/arm64/boot/dts/qcom/sm8650.dtsi
> >>>>> index 32c0a7b9aded..d862aa6be824 100644
> >>>>> --- a/arch/arm64/boot/dts/qcom/sm8650.dtsi
> >>>>> +++ b/arch/arm64/boot/dts/qcom/sm8650.dtsi
> >>>>> @@ -4,6 +4,8 @@
> >>>>>     */
> >>>>>
> >>>>>    #include <dt-bindings/clock/qcom,rpmh.h>
> >>>>> +#include <dt-bindings/clock/qcom,sm8450-videocc.h>
> >>>>> +#include <dt-bindings/clock/qcom,sm8650-camcc.h>
> >>>>>    #include <dt-bindings/clock/qcom,sm8650-dispcc.h>
> >>>>>    #include <dt-bindings/clock/qcom,sm8650-gcc.h>
> >>>>>    #include <dt-bindings/clock/qcom,sm8650-gpucc.h>
> >>>>> @@ -3110,6 +3112,32 @@ opp-202000000 {
> >>>>>                           };
> >>>>>                   };
> >>>>>
> >>>>> +               videocc: clock-controller@aaf0000 {
> >>>>> +                       compatible = "qcom,sm8650-videocc";
> >>>>> +                       reg = <0 0x0aaf0000 0 0x10000>;
> >>>>> +                       clocks = <&bi_tcxo_div2>,
> >>>>> +                                <&gcc GCC_VIDEO_AHB_CLK>;
> >>>>> +                       power-domains = <&rpmhpd RPMHPD_MMCX>;
> >>>>> +                       required-opps = <&rpmhpd_opp_low_svs>;
> >>>>
> >>>> The required-opps should no longer be necessary.
> >>>>
> >>>
> >>> Sure, will check and remove this if not required.
> >>
> >>
> >> I checked further on this and without required-opps, if there is no vote
> >> on the power-domain & its peer from any other consumers, when runtime
> >> get is called on device, it enables the power domain just at the minimum
> >> non-zero level. But in some cases, the minimum non-zero level of
> >> power-domain could be just retention and is not sufficient for clock
> >> controller to operate, hence required-opps property is needed to specify
> >> the minimum level required on power-domain for this clock controller.
> >
> > In which cases? If it ends up with the retention vote, it is a bug
> > which must be fixed.
> >
>
> The minimum non-zero level(configured from bootloaders) of MMCX is
> retention on few chipsets but it can vary across the chipsets. Hence to
> be on safer side from our end, it is good to have required-opps in DT to
> specify the minimum level required for this clock controller.

We are discussing sm8650, not some abstract chipset. Does it list
retention or low_svs as a minimal level for MMCX?

>
> Thanks,
> Jagadeesh
>
> >>
> >> Thanks,
> >> Jagadeesh
> >>
> >>>
> >>>>> +                       #clock-cells = <1>;
> >>>>> +                       #reset-cells = <1>;
> >>>>> +                       #power-domain-cells = <1>;
> >>>>> +               };
> >>>>> +
> >>>>> +               camcc: clock-controller@ade0000 {
> >>>>> +                       compatible = "qcom,sm8650-camcc";
> >>>>> +                       reg = <0 0x0ade0000 0 0x20000>;
> >>>>> +                       clocks = <&gcc GCC_CAMERA_AHB_CLK>,
> >>>>> +                                <&bi_tcxo_div2>,
> >>>>> +                                <&bi_tcxo_ao_div2>,
> >>>>> +                                <&sleep_clk>;
> >>>>> +                       power-domains = <&rpmhpd RPMHPD_MMCX>;
> >>>>> +                       required-opps = <&rpmhpd_opp_low_svs>;
> >>>>> +                       #clock-cells = <1>;
> >>>>> +                       #reset-cells = <1>;
> >>>>> +                       #power-domain-cells = <1>;
> >>>>> +               };
> >>>>> +
> >>>>>                   mdss: display-subsystem@ae00000 {
> >>>>>                           compatible = "qcom,sm8650-mdss";
> >>>>>                           reg = <0 0x0ae00000 0 0x1000>;
> >>>>> --
> >>>>> 2.43.0
> >>>>>
> >>>>>
> >>>>
> >>>>
> >
> >
> >


-- 
With best wishes
Dmitry