linux-kernel - Re: [PATCH v2 13/15] arm64: dts: qcom: sm6125: Add dispcc node

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Message-ID: <9118315e-7280-a8b9-d65f-c1c3026909bd@linaro.org>
Date:   Fri, 30 Jun 2023 03:08:25 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Krishna Manikandan <quic_mkrishn@...cinc.com>,
        Loic Poulain <loic.poulain@...aro.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        ~postmarketos/upstreaming@...ts.sr.ht,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Martin Botka <martin.botka@...ainline.org>,
        Jami Kettunen <jami.kettunen@...ainline.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-clk@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, Lux Aliaga <they@...t.lgbt>
Subject: Re: [PATCH v2 13/15] arm64: dts: qcom: sm6125: Add dispcc node

On 29/06/2023 22:53, Konrad Dybcio wrote:
> On 29.06.2023 14:24, Dmitry Baryshkov wrote:
>> On Thu, 29 Jun 2023 at 15:14, Marijn Suijten
>> <marijn.suijten@...ainline.org> wrote:
>>>
>>> On 2023-06-29 13:56:25, Dmitry Baryshkov wrote:
>>>> On 27/06/2023 23:14, Marijn Suijten wrote:
>>>>> Enable and configure the dispcc node on SM6125 for consumption by MDSS
>>>>> later on.
>>>>>
>>>>> Signed-off-by: Marijn Suijten <marijn.suijten@...ainline.org>
>>>>> ---
>>>>>    arch/arm64/boot/dts/qcom/sm6125.dtsi | 25 +++++++++++++++++++++++++
>>>>>    1 file changed, 25 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm64/boot/dts/qcom/sm6125.dtsi b/arch/arm64/boot/dts/qcom/sm6125.dtsi
>>>>> index edb03508dba3..a5cc0d43d2d9 100644
>>>>> --- a/arch/arm64/boot/dts/qcom/sm6125.dtsi
>>>>> +++ b/arch/arm64/boot/dts/qcom/sm6125.dtsi
>>>>> @@ -3,6 +3,7 @@
>>>>>     * Copyright (c) 2021, Martin Botka <martin.botka@...ainline.org>
>>>>>     */
>>>>>
>>>>> +#include <dt-bindings/clock/qcom,dispcc-sm6125.h>
>>>>>    #include <dt-bindings/clock/qcom,gcc-sm6125.h>
>>>>>    #include <dt-bindings/clock/qcom,rpmcc.h>
>>>>>    #include <dt-bindings/dma/qcom-gpi.h>
>>>>> @@ -1203,6 +1204,30 @@ sram@...0000 {
>>>>>                      reg = <0x04690000 0x10000>;
>>>>>              };
>>>>>
>>>>> +           dispcc: clock-controller@...0000 {
>>>>> +                   compatible = "qcom,sm6125-dispcc";
>>>>> +                   reg = <0x05f00000 0x20000>;
>>>>> +                   clocks = <&rpmcc RPM_SMD_XO_CLK_SRC>,
>>>>> +                            <0>,
>>>>> +                            <0>,
>>>>> +                            <0>,
>>>>> +                            <0>,
>>>>> +                            <0>,
>>>>> +                            <&gcc GCC_DISP_AHB_CLK>,
>>>>> +                            <&gcc GCC_DISP_GPLL0_DIV_CLK_SRC>;
>>>>> +                   clock-names = "bi_tcxo",
>>>>> +                                 "dsi0_phy_pll_out_byteclk",
>>>>> +                                 "dsi0_phy_pll_out_dsiclk",
>>>>> +                                 "dsi1_phy_pll_out_dsiclk",
>>>>> +                                 "dp_phy_pll_link_clk",
>>>>> +                                 "dp_phy_pll_vco_div_clk",
>>>>> +                                 "cfg_ahb_clk",
>>>>> +                                 "gcc_disp_gpll0_div_clk_src";
>>>>> +                   power-domains = <&rpmpd SM6125_VDDCX>;
>>>>
>>>> Would it be logical to specify the required-opps too?
>>>
>>> Perhaps, but barely any other SoC aside from sm8x50 sets it on dispcc.
>>> What should it be, rpmhpd_opp_low_svs?  IIRC we used "svs" for the DSI
>>> PHY despite not having a reference value downstream (it sets a range of
>>> NOM-TURBO_NO_CPR, and RETENTION when it's off).
>>
>> Then for DSI PHY the required-opps should be rpmpd_opp_nom.
> Yes
> 
>>
>> For the dispcc I think the rpmpd_opp_ret, the lowest possible vote,
>> should be enough.
> I'm not 100% sure but not specifying an opp and turning on the domain
> *******probably******* just sticks with the lowest vote

I think so too. But I think it might be better to be explicit rather 
than being implicit here. Both of us are describing Linux behaviour 
(=set lowest possible value), while DT should describe the hardware.

> 
> Konrad
>>
>>>
>>> - Marijn
>>>
>>>>
>>>>> +                   #clock-cells = <1>;
>>>>> +                   #power-domain-cells = <1>;
>>>>> +           };
>>>>> +
>>>>>              apps_smmu: iommu@...0000 {
>>>>>                      compatible = "qcom,sm6125-smmu-500", "qcom,smmu-500", "arm,mmu-500";
>>>>>                      reg = <0x0c600000 0x80000>;
>>>>>
>>>>
>>>> --
>>>> With best wishes
>>>> Dmitry
>>>>
>>
>>
>>

-- 
With best wishes
Dmitry