From: Jeffrey Hugo <jhugo@codeaurora.org>
To: Loic Poulain <loic.poulain@linaro.org>
Cc: andy.gross@linaro.org, david.brown@linaro.org,
robh+dt@kernel.org, linux-arm-msm@vger.kernel.org,
bjorn.andersson@linaro.org, devicetree@vger.kernel.org
Subject: Re: [PATCH] arm64: dts: apq8096-db820c: Increase load on l21 for SDCARD
Date: Thu, 13 Dec 2018 07:46:37 -0700 [thread overview]
Message-ID: <aea60b4c-f651-5e5a-c363-f7da9a8ed838@codeaurora.org> (raw)
In-Reply-To: <CAMZdPi8-9d11FXKJinpJkJyhi8fcysbYVDjG8aDwbY3s=mLarw@mail.gmail.com>
On 12/13/2018 12:55 AM, Loic Poulain wrote:
> Hi Jeffrey,
>
>
> On Wed, 12 Dec 2018 at 18:23, Jeffrey Hugo <jhugo@codeaurora.org
> <mailto:jhugo@codeaurora.org>> wrote:
>
> On 12/12/2018 10:13 AM, Loic Poulain wrote:
> > In the same way as for msm8974-hammerhead, l21 load, used for SDCARD
> > VMMC, needs to be increased in order to prevent any voltage drop
> issues
> > (due to limited current) happening with some SDCARDS or during
> specific
> > operations (e.g. write).
> >
> > Fixes: 660a9763c6a9 (arm64: dts: qcom: db820c: Add pm8994
> regulator node)
> > Signed-off-by: Loic Poulain <loic.poulain@linaro.org
> <mailto:loic.poulain@linaro.org>>
> > ---
> > arch/arm64/boot/dts/qcom/apq8096-db820c.dtsi | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/apq8096-db820c.dtsi
> b/arch/arm64/boot/dts/qcom/apq8096-db820c.dtsi
> > index 104cad9..c15e2c0 100644
> > --- a/arch/arm64/boot/dts/qcom/apq8096-db820c.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/apq8096-db820c.dtsi
> > @@ -634,6 +634,8 @@
> > l21 {
> > regulator-min-microvolt =
> <2950000>;
> > regulator-max-microvolt =
> <2950000>;
> > + regulator-allow-set-load;
> > + regulator-system-load =
> <200000>;
> > };
> > l22 {
> > regulator-min-microvolt =
> <3300000>;
> >
>
> I'm curious, why not update sdhci-msm to set the load on the regulator?
>
>
> Yes you're right, and I saw that there is ongoing work:
> https://patchwork.kernel.org/patch/10630731/
>
> Howerver I thought this change would be a quicker fix and easier to
> backport in stable trees.
> I assume all the device-tree vmmc loads will be removed at some point
> when driven from sdhci.
>
I hadn't seen that. Ok, seems good to me.
--
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
next prev parent reply other threads:[~2018-12-13 14:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-12 17:13 [PATCH] arm64: dts: apq8096-db820c: Increase load on l21 for SDCARD Loic Poulain
2018-12-12 17:23 ` Jeffrey Hugo
2018-12-13 7:55 ` Loic Poulain
2018-12-13 14:46 ` Jeffrey Hugo [this message]
2018-12-13 19:14 ` Doug Anderson
2018-12-12 19:46 ` Bjorn Andersson
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