linux-kernel - Re: [PATCH v3 5/6] arm64: dts: qcom: sm6150: Add gpu and rgmu nodes

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Message-ID: <ed4b1e3c-bb30-42fd-a171-12121db2dbec@oss.qualcomm.com>
Date: Fri, 5 Dec 2025 19:35:48 +0530
From: Akhil P Oommen <akhilpo@....qualcomm.com>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
        Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Rob Clark <robin.clark@....qualcomm.com>, Sean Paul <sean@...rly.run>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Jessica Zhang <jesszhan0024@...il.com>,
        Dan Carpenter <dan.carpenter@...aro.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, Jie Zhang <quic_jiezh@...cinc.com>
Subject: Re: [PATCH v3 5/6] arm64: dts: qcom: sm6150: Add gpu and rgmu nodes

On 12/5/2025 7:22 PM, Konrad Dybcio wrote:
> On 12/5/25 2:41 PM, Akhil P Oommen wrote:
>> On 12/4/2025 7:01 PM, Konrad Dybcio wrote:
>>> On 12/4/25 11:13 AM, Akhil P Oommen wrote:
>>>> On 11/26/2025 6:12 AM, Dmitry Baryshkov wrote:
>>>>> On Sat, Nov 22, 2025 at 03:03:10PM +0100, Konrad Dybcio wrote:
>>>>>> On 11/21/25 10:52 PM, Akhil P Oommen wrote:
>>>>>>> From: Jie Zhang <quic_jiezh@...cinc.com>
>>>>>>>
>>>>>>> Add gpu and rgmu nodes for qcs615 chipset.
>>>>>>>
>>>>>>> Signed-off-by: Jie Zhang <quic_jiezh@...cinc.com>
>>>>>>> Signed-off-by: Akhil P Oommen <akhilpo@....qualcomm.com>
>>>>>>> ---
>>>>>>
>>>>>> [...]
>>>>>>
>>>>>>> +			gpu_opp_table: opp-table {
>>>>>>> +				compatible = "operating-points-v2";
>>>>>>> +
>>>>>>> +				opp-845000000 {
>>>>>>> +					opp-hz = /bits/ 64 <845000000>;
>>>>>>> +					required-opps = <&rpmhpd_opp_turbo>;
>>>>>>> +					opp-peak-kBps = <7050000>;
>>>>>>> +				};
>>>>>>
>>>>>> I see another speed of 895 @ turbo_l1, perhaps that's for speedbins
>>>>>> or mobile parts specifically?
>>>>>
>>>>> msm-4.14 defines 7 speedbins for SM6150. Akhil, I don't see any of them
>>>>> here.
>>>>
>>>> The IoT/Auto variants have a different frequency plan compared to the
>>>> mobile variant. I reviewed the downstream code and this aligns with that
>>>> except the 290Mhz corner. We can remove that one.
>>>>
>>>> Here we are describing the IoT variant of Talos. So we can ignore the
>>>> speedbins from the mobile variant until that is supported.
>>>
>>> Writing this reply took probably only slightly less time than fixing
>>> the issue.. I really see no point in kicking the can down the road
>>
>> We don't know the speedbin fuse register and the values applicable for
>> this IoT chipset. Currently, there is only a single variant and no SKUs
>> for this chipset. We can add them when those decisions are taken by the
>> relevant folks from Product team.
> 
> If there's only a single variant right now, could you simply read back
> the value and report it where necessary to make sure the internal teams
> are aware?
> 
> There's surely *some* value fused into the cell..

We don't know which register to read at the moment. It could be the hard
fuse register or some soft fuse register at an arbitrary location.

It is better to leave it as it is for now. Who knows, maybe there won't
any SKUs at all.

-Akhil

> 
> Konrad