Re: [PATCH 2/3] ARM: dts: imx6: phycore-som: fix emmc supply

From: Marco Felsch <m.felsch@pengutronix.de>
To: "Stefan Riedmüller" <s.riedmueller@phytec.de>
Cc: s.christ@phytec.de, chf.fritz@googlemail.com, robh+dt@kernel.org,
	linux-imx@nxp.com, kernel@pengutronix.de, c.hemp@phytec.de,
	shawnguo@kernel.org, festevam@gmail.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/3] ARM: dts: imx6: phycore-som: fix emmc supply
Date: Tue, 10 Dec 2019 10:09:20 +0100	[thread overview]
Message-ID: <20191210090920.a5aswmgihjzvsk25@pengutronix.de> (raw)
In-Reply-To: <6eece2d7-4695-ef2a-7376-cff39aaef8be@phytec.de>

Hi Stefan,

On 19-12-05 13:00, Stefan Riedmüller wrote:
> Hi Marco,
> 
> On 29.11.19 17:48, Marco Felsch wrote:
> > Currently the vmmc is supplied by the 1.8V pmic rail but this is wrong.
> > The 1.8V pmic rail is connected to the emmc vccq (vqmmc).
> 
> I just checked the schematics again and actually both VCC and VCCQ are
> connected to the 3.3V power rail. VCCQ can be connected to the 1.8V PMIC
> power rail by solder jumper but default is 3.3V.

That's right.

> So I think either both should be connected to a fixed 3.3V regulator or
> removed, since the default system does not support switching these voltages.

The question is why the regulator output isn't the default case and
setting regulator-max-microvolt to 3.3V and regulator-min-microvolt to
1.8V? The PMIC LDO4 supports output voltages up to 3.6V so this should
be okay.

Anyway dropping both regulators and using dummy-regulators should be
fine too. I only want to remove this issue.

Regards,
  Marco 

> Regards,
> Stefan
> 
> > 
> > Fixes: ddec5d1c0047 ("ARM: dts: imx6: Add initial support for phyCORE-i.MX 6 SOM")
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > ---
> >   arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi b/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi
> > index 46d4953c5588..44e333848b4d 100644
> > --- a/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi
> > +++ b/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi
> > @@ -183,7 +183,7 @@
> >   	pinctrl-0 = <&pinctrl_usdhc4>;
> >   	bus-width = <8>;
> >   	non-removable;
> > -	vmmc-supply = <&vdd_emmc_1p8>;
> > +	vqmmc-supply = <&vdd_emmc_1p8>;
> >   	status = "disabled";
> >   };
> > 
> 

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