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

From: "Stefan Riedmüller" <s.riedmueller@phytec.de>
To: Marco Felsch <m.felsch@pengutronix.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: Thu, 12 Dec 2019 10:00:00 +0100	[thread overview]
Message-ID: <27152e13-57c6-9668-4500-d79148ecb019@phytec.de> (raw)
In-Reply-To: <20191210090920.a5aswmgihjzvsk25@pengutronix.de>

Hi Marco,

On 10.12.19 10:09, Marco Felsch wrote:
> 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.

That is a reasonable question. But since we can't change this here we need 
to take it as it is. So it is probably best to just drop both regulators.

Regards,
Stefan

> 
> 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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