Hi Konrad and all,
On Tue Apr 15, 2025 at 11:13 AM CEST, Konrad Dybcio wrote:
> On 4/15/25 6:05 AM, Taniya Das wrote:
>>
>>
>> On 4/12/2025 12:56 AM, Konrad Dybcio wrote:
>>> On 4/11/25 1:37 PM, Jagadeesh Kona wrote:
>>>>
>>>>
>>>> On 4/11/2025 2:42 PM, Konrad Dybcio wrote:
>>>>> On 4/11/25 9:15 AM, Jagadeesh Kona wrote:
>>>>>>
>>>>>>
>>>>>> On 4/1/2025 10:03 PM, Konrad Dybcio wrote:
>>>>>>> On 3/24/25 9:41 AM, Luca Weiss wrote:
>>>>>>>> Add a node for the videocc found on the SM6350 SoC.
>>>>>>>>
>>>>>>>> Signed-off-by: Luca Weiss <luca.we...@fairphone.com>
>>>>>>>> ---
>>>>>>>> arch/arm64/boot/dts/qcom/sm6350.dtsi | 14 ++++++++++++++
>>>>>>>> 1 file changed, 14 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/arch/arm64/boot/dts/qcom/sm6350.dtsi
>>>>>>>> b/arch/arm64/boot/dts/qcom/sm6350.dtsi
>>>>>>>> index
>>>>>>>> 42f9d16c2fa6da66a8bb524a33c2687a1e4b40e0..4498d6dfd61a7e30a050a8654d54dae2d06c220c
>>>>>>>> 100644
>>>>>>>> --- a/arch/arm64/boot/dts/qcom/sm6350.dtsi
>>>>>>>> +++ b/arch/arm64/boot/dts/qcom/sm6350.dtsi
>>>>>>>> @@ -1952,6 +1952,20 @@ usb_1_dwc3_ss_out: endpoint {
>>>>>>>> };
>>>>>>>> };
>>>>>>>>
>>>>>>>> + videocc: clock-controller@aaf0000 {
>>>>>>>> + compatible = "qcom,sm6350-videocc";
>>>>>>>> + reg = <0x0 0x0aaf0000 0x0 0x10000>;
>>>>>>>> + clocks = <&gcc GCC_VIDEO_AHB_CLK>,
>>>>>>>> + <&rpmhcc RPMH_CXO_CLK>,
>>>>>>>> + <&sleep_clk>;
>>>>>>>> + clock-names = "iface",
>>>>>>>> + "bi_tcxo",
>>>>>>>> + "sleep_clk";
>>>>>>>> + #clock-cells = <1>;
>>>>>>>> + #reset-cells = <1>;
>>>>>>>> + #power-domain-cells = <1>;
>>>>>>>> + };
>>>>>>>
>>>>>>> You'll probably want to hook up some additional power domains here, see
>>>>>>>
>>>>>>> https://lore.kernel.org/linux-arm-msm/20250327-videocc-pll-multi-pd-voting-v3-0-895fafd62...@quicinc.com/
>>>>>>>
>>>>>>
>>>>>> On SM6350, videocc doesn't need multiple power domains at HW level, it
>>>>>> is only on CX rail which would be ON
>>>>>> when system is active, hence power-domains are not mandatory here.
>>>>>
>>>>> 6350 doesn't have either MMCX nor a split MX - shouldn't both normal
>>>>> CX and MX be in there?
>>>>>
>>>>
>>>> All clocks & GDSC's of SM6350 videocc are only on CX rail, so it requires
>>>> only CX power domain. But when HLOS
>>>> is active, CX rail will be ON and operate at a level above retention,
>>>> which is sufficient for videocc to operate.
>>>> Hence clock driver don't need to explicitly vote on CX rail.
>>>>
>>>> The same is not true for other rails like MMCX and Split MX(MXC), hence
>>>> clock drivers had to explicitly vote on
>>>> those rails.
>>>
>>> I'm worried about MX being undervolted for higher OPPs
>>>
>>
>> From a videocc PoV there is no requirement of Mx on SM6350. The CX
>> levels would be taken care by Video SW driver from their defined OPP. Mx
>> at system level would be catered via the BW votes.
>
> So I'm specifically thinking about the videocc (and other) PLLs, which
> have defined vdd levels downstream - currently we're relying on random
> luck rather than ensuring each one of them has its requirements fulfilled
Any further comments than this? Not sure how to proceed.
Regards
Luca
