linux-kernel - Re: [PATCH v2 1/2] arm64: dts: qcom: sm8650-mtp: add PM8010 regulators

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Message-ID: <884eb509-a997-869a-762b-b4c24ff89c27@quicinc.com>
Date: Wed, 24 Jan 2024 18:52:59 -0800
From: David Collins <quic_collinsd@...cinc.com>
To: Konrad Dybcio <konrad.dybcio@...aro.org>, <quic_fenglinw@...cinc.com>,
        <kernel@...cinc.com>, Bjorn Andersson <andersson@...nel.org>,
        Rob Herring
	<robh+dt@...nel.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>
CC: <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 1/2] arm64: dts: qcom: sm8650-mtp: add PM8010
 regulators

On 1/24/24 15:36, Konrad Dybcio wrote:
> On 1/24/24 20:15, David Collins wrote:
>> On 1/23/24 00:49, Fenglin Wu via B4 Relay wrote:
>>> From: Fenglin Wu <quic_fenglinw@...cinc.com>
>>>
>>> Add PM8010 regulator device nodes for sm8650-mtp board.
>>>
>>> Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>
>>> Signed-off-by: Fenglin Wu <quic_fenglinw@...cinc.com>
..
>>> +
>>> +        vreg_l1m_1p1: ldo1 {
>>> +            regulator-name = "vreg_l1m_1p1";
>>> +            regulator-min-microvolt = <1104000>;
>>> +            regulator-max-microvolt = <1104000>;
>>> +            regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
>>
>> Optional:
>> PM8010 L1 and L2 physically support LPM vs HPM configuration.
>> Therefore, these lines could be added here to allow such configuration
>> by software at runtime:
>>
>> regulator-allow-set-load;
>> regulator-allowed-modes = <RPMH_REGULATOR_MODE_LPM
>>                RPMH_REGULATOR_MODE_HPM>;
> 
> David,
> 
> I was under the impression that *all* RPMh regulators support
> modesetting. Would that be an incorrect assumption to make?
> 
> Konrad

Hello Konrad,

That is generally true.  However, PM8010 LDOs 3-7 are a special case.
These do not support LPM configuration.  The limitation is enforced in
the driver by this change:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2544631faa7f3244c9bcb9b511ca4f1a4f5a3ba0
.

Take care,
David