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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Wed, 10 May 2023 17:11:24 +0300
Message-ID: <CAA8EJppgkHREJrBzhSDn9VT--RRcpcxMYvTWoYfkXkv4XFtK6Q@mail.gmail.com>
Subject: Re: [PATCH v11 8/9] arm64: dts: qcom: ipq9574: Add LDO regulator node
To:     Varadarajan Narayanan <quic_varada@quicinc.com>
Cc:     agross@kernel.org, andersson@kernel.org, konrad.dybcio@linaro.org,
        vkoul@kernel.org, kishon@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        gregkh@linuxfoundation.org, mturquette@baylibre.com,
        sboyd@kernel.org, quic_wcheng@quicinc.com,
        linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-usb@vger.kernel.org, linux-clk@vger.kernel.org
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Precedence: bulk

On Wed, 10 May 2023 at 13:23, Varadarajan Narayanan
<quic_varada@quicinc.com> wrote:
>
> On Tue, May 09, 2023 at 04:08:59PM +0300, Dmitry Baryshkov wrote:
> > On Tue, 9 May 2023 at 14:56, Varadarajan Narayanan
> > <quic_varada@quicinc.com> wrote:
> > >
> > > Add LDO regulator node
> > >
> > > Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
> > > ---
> > >  Changes in v10:
> > >         - Add LDO regulator node
> > > ---
> > >  arch/arm64/boot/dts/qcom/ipq9574-rdp433.dts | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> >
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >
> > Minor question below:
> >
> > >
> > > diff --git a/arch/arm64/boot/dts/qcom/ipq9574-rdp433.dts b/arch/arm64/boot/dts/qcom/ipq9574-rdp433.dts
> > > index bdc1434..1f5d14f 100644
> > > --- a/arch/arm64/boot/dts/qcom/ipq9574-rdp433.dts
> > > +++ b/arch/arm64/boot/dts/qcom/ipq9574-rdp433.dts
> > > @@ -60,6 +60,13 @@
> > >                         regulator-min-microvolt = <725000>;
> > >                         regulator-max-microvolt = <1075000>;
> > >                 };
> > > +
> > > +               mp5496_l2: l2 {
> > > +                       regulator-min-microvolt = <1800000>;
> > > +                       regulator-max-microvolt = <1800000>;
> > > +                       regulator-boot-on;
> > > +                       regulator-always-on;
> >
> > This usually points out that there are other users which are not yet
> > enabled/properly specified. What users are there for this supply which
> > demand it to be always on?
>
> The 1.8v rail is used by PCIe PHY, PLL for Ethernet SerDes
> interface and PLLs that generate SoC clocks. The voting for this
> rail is managed by the RPM f/w.

Then I'm looking forward to seeing the patch which declares all the
actual users of the lane. Please do not declare power lanes as
boot-on/always-on unless there is a strong reason for doing it.

>
> Thanks
> Varada
>
> > > +               };
> > >         };
> > >  };
> > >
> > > --
> > > 2.7.4
> > >
> >
> >
> > --
> > With best wishes
> > Dmitry


-- 
With best wishes
Dmitry