linux-kernel - Re: [PATCH] arm64: dts: qcom: ipq9574: Fix 'l2' regulator min/max voltages

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Message-ID: <aFpA4mk2L/sxlpO1@hu-varada-blr.qualcomm.com>
Date: Tue, 24 Jun 2025 11:38:34 +0530
From: Varadarajan Narayanan <quic_varada@...cinc.com>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
CC: <andersson@...nel.org>, <konradybcio@...nel.org>, <robh@...nel.org>,
        <krzk+dt@...nel.org>, <conor+dt@...nel.org>, <lumag@...nel.org>,
        <linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arm64: dts: qcom: ipq9574: Fix 'l2' regulator min/max
 voltages

On Mon, Jun 23, 2025 at 01:34:22PM +0200, Konrad Dybcio wrote:
> On 6/23/25 1:32 PM, Varadarajan Narayanan wrote:
> > The min and max voltages on l2 regulator is 850000uV. This was
> > incorrectly set at 1800000uV earlier and that affected the
> > stability of the networking subsystem.
> >
> > Fixes: d5506524d9d9 ("arm64: dts: qcom: ipq9574: Add LDO regulator node")
> > Signed-off-by: Varadarajan Narayanan <quic_varada@...cinc.com>
> > ---
>
> Shouldn't there be a consumer for it, instead of it being always-on?

The uniphy block is the consumer of this voltage. The PMIC configures it
to 850000uV based on OTP settings and s/w doesn't change it as uniphy
doesn't do scaling.

-Varada

> >  arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi b/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi
> > index bdb396afb992..21b04a2c629d 100644
> > --- a/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/ipq9574-rdp-common.dtsi
> > @@ -106,8 +106,8 @@ ipq9574_s1: s1 {
> >  		};
> >
> >  		mp5496_l2: l2 {
> > -			regulator-min-microvolt = <1800000>;
> > -			regulator-max-microvolt = <1800000>;
> > +			regulator-min-microvolt = <850000>;
> > +			regulator-max-microvolt = <850000>;
> >  			regulator-always-on;
> >  			regulator-boot-on;
> >  		};
> >
> > base-commit: 5d4809e25903ab8e74034c1f23c787fd26d52934