linux-kernel - Re: [PATCH v2] arm64: dts: qcom: sm8550: Correct the min/max voltages for vreg_l6n

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Message-ID: <05a443b5-628e-4bd8-a189-7f5a7ccb7b2c@oss.qualcomm.com>
Date: Thu, 26 Jun 2025 16:14:32 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Neil Armstrong <neil.armstrong@...aro.org>
Subject: Re: [PATCH v2] arm64: dts: qcom: sm8550: Correct the min/max voltages
 for vreg_l6n_3p3

On 6/26/25 1:39 PM, Kamal Wadhwa wrote:
> Hi Konrad,
> 
> On Mon, Jun 23, 2025 at 4:53 PM Konrad Dybcio
> <konrad.dybcio@....qualcomm.com> wrote:
>>
>> On 6/20/25 5:29 PM, Kamal Wadhwa wrote:
>>> Voltage regulator 'vreg_l6n_3p3' max-microvolt prop is currently
>>> configured at 3304000uV in different sm8550 board files. However this
>>> is not a valid voltage value for 'pmic5_pldo502ln' type voltage
>>> regulators.
>>>
>>> Check below the max value(3200mV) in the regulator summary for min/max
>>> used as 2800mV/3304mV in DT:-
>>>
>>> logs:
>>>
>>> [    0.294781] vreg_l6n_3p3: Setting 2800000-3304000uV
>>>
>>> regulator summary:
>>>
>>> regulator     use open bypass  opmode   voltage current  min     max
>>> ---------------------------------------------------------------------
>>> ..
>>> vreg_l6n_3p3   0    0    0     normal   2800mV   0mA  2800mV  3200mV
>>> ..
>>>
>>> Correct the min/max value to 3200000uV, as that is the closest valid
>>> value to 3.3V and Hardware team has also confirmed that its good to
>>> support the consumers(camera sensors) of this regulator.
>>>
>>> Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>
>>> Signed-off-by: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
>>> ---
>>
>> FWIW it seems like 3.312v (which is slightly above the previous
>> value) is also supported:
>>
>> static const struct rpmh_vreg_hw_data pmic5_pldo502ln = {
>>         .regulator_type = VRM,
>>         .ops = &rpmh_regulator_vrm_ops,
>>         .voltage_ranges = (struct linear_range[]) {
>>                 REGULATOR_LINEAR_RANGE(1800000, 0,  2,  200000),
>>                 REGULATOR_LINEAR_RANGE(2608000, 3,  28, 16000),
>>                 REGULATOR_LINEAR_RANGE(3104000, 29, 30, 96000),
>>                 REGULATOR_LINEAR_RANGE(3312000, 31, 31, 0),
>>         },
>>         .n_linear_ranges = 4,
>>         .n_voltages = 32,
>>         .pmic_mode_map = pmic_mode_map_pmic5_ldo_hpm,
>>         .of_map_mode = rpmh_regulator_pmic4_ldo_of_map_mode,
>> };
> 
> Yes, originally I was planning to share the change for 3304mV -> 3312mV.
> However, while testing, I realized that I would also need changes in
> firmware( to allow for a 3312mV max limit). so during internal discussion
> it was clarified that all the consumers on L6N can work fine with 3.2v.
> 
> 
>>
>> but if the hw folks say we can do with the lower value, it's probably
>> even better
> 
> Yes. Thanks for affirming.

Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Konrad