Re: [PATCH V2 RESEND 6/6] arm64: dts: qcom: sm8650: Add video and camera clock controllers

[Vladimir Zapolskiy]

Hi Konrad,

On 3/23/24 02:33, Konrad Dybcio wrote:
> On 21.03.2024 14:07, Vladimir Zapolskiy wrote:
> > Hello Jagadeesh,
> >
> > On 3/21/24 11:25, Jagadeesh Kona wrote:
> > > Add device nodes for video and camera clock controllers on Qualcomm
> > > SM8650 platform.
> > >
> > > Signed-off-by: Jagadeesh Kona <quic_jkona@xxxxxxxxxxx>
> > > ---
> > >    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>;
> >
> > Please add default status = "disabled";
> >
> > > +            #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>;
> >
> > Please add default status = "disabled";
> >
> > > +            #clock-cells = <1>;
> > > +            #reset-cells = <1>;
> > > +            #power-domain-cells = <1>;
> > > +        };
> > > +
> > >            mdss: display-subsystem@ae00000 {
> > >                compatible = "qcom,sm8650-mdss";
> > >                reg = <0 0x0ae00000 0 0x1000>;
> >
> > After disabling the clock controllers
>
> Clock controllers should never be disabled period, that defeats the
> entire point of having unused clk/pd cleanup.

hm, that's very sane, I didn't think about it from this point, thanks!

> The only reason for them to be disabled is for cases where platform
> crashes on access due to stinky "security" settings (like with audio
> clocks), or when people are too lazy to upstream panel drivers and
> end up partially upstreaming display-related changes and continue
> using the bootloader-initialized framebuffer. This takes away from
> the very little determinism we have.

--
Best wishes,
Vladimir