linux-kernel - Re: [PATCH v7 06/11] arm64: dts: mediatek: set vmc regulator as always on

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Message-ID: <CAFGrd9owtGmE7xPVRG7VwN5vrKtnq42q6ydSgex+Xocz-Oc16w@mail.gmail.com>
Date:   Mon, 22 May 2023 16:24:37 +0200
From:   Alexandre Mergnat <amergnat@...libre.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Conor Dooley <conor+dt@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
        linux-mediatek@...ts.infradead.org,
        Fabien Parent <fparent@...libre.com>,
        Kevin Hilman <khilman@...libre.com>
Subject: Re: [PATCH v7 06/11] arm64: dts: mediatek: set vmc regulator as
 always on

Hi Angelo

Le lun. 15 mai 2023 à 13:44, AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com> a écrit :
>
> Il 11/05/23 18:29, amergnat@...libre.com ha scritto:
> > From: Fabien Parent <fparent@...libre.com>
> >
> > On downstream, we observe that the MSDC IP (used by the emmc, the micro
> > SD card and the WiFi) isn't working properly if the VMC regulator is
> > shutdown.
> >
> > Make sure it is always on.
>
> I don't understand the power tree of this board: if your VQMMC is VIO18 and
> *not* VMC, why is that required?

I don't have the full history of the downstream, but I think there is
a schematic
issue or HW conception issue because I see an extra pin "MSDC1_INSI" (which
isn't part of MSDC IP) with VIO18 pull-up. That's why, I guess, VQMMC = VIO18
for MMC1. But since DVDD28_MSDC1 = VMC, VQMMC should be equal
to VMC.

The always-on will be removed.

Regards,
Alexandre