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Date:   Fri, 15 Oct 2021 12:04:51 +0800
From:   Shawn Guo <shawnguo@kernel.org>
To:     Frieder Schrempf <frieder.schrempf@kontron.de>
Cc:     Frieder Schrempf <frieder@fris.de>, devicetree@vger.kernel.org,
        Krzysztof Kozlowski <krzk@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Rob Herring <robh+dt@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>, stable@vger.kernel.org,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Pengutronix Kernel Team <kernel@pengutronix.de>
Subject: Re: [PATCH 3/8] arm64: dts: imx8mm-kontron: Set VDD_SNVS to 800 mV
Message-ID: <20211015040450.GF22881@dragon>
References: <20210930155633.2745201-1-frieder@fris.de>
 <20210930155633.2745201-4-frieder@fris.de>
 <20211005065641.GA20743@dragon>
 <df454b06-3069-d369-e3c7-f2434d94f4af@kontron.de>
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On Tue, Oct 05, 2021 at 03:14:40PM +0200, Frieder Schrempf wrote:
> On 05.10.21 08:56, Shawn Guo wrote:
> > On Thu, Sep 30, 2021 at 05:56:26PM +0200, Frieder Schrempf wrote:
> >> From: Frieder Schrempf <frieder.schrempf@kontron.de>
> >>
> >> According to the datasheet VDD_SNVS should be 800 mV, so let's
> >> make sure that the voltage won't be different.
> > 
> > Could you share the datasheet?
> 
> Sure, it's here: https://www.nxp.com/docs/en/data-sheet/IMX8MMIEC.pdf.
> See table 10 for the operating voltages.

Thanks for the link!

But datasheet specifies a voltage range. 800 mV is just the typical one.
The only problem I see is that regulator-min-microvolt should be lowered
to 800 mV.  regulator-max-microvolt looks correct to me.

Shawn

> 
> >>
> >> Fixes: 21c4f45b335f ("arm64: dts: Add the Kontron i.MX8M Mini SoMs and baseboards")
> >> Cc: stable@vger.kernel.org
> >> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
> >> ---
> >>  arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-som.dtsi | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-som.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-som.dtsi
> >> index b12fb7ce6686..213014f59b46 100644
> >> --- a/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-som.dtsi
> >> +++ b/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-som.dtsi
> >> @@ -152,8 +152,8 @@ reg_nvcc_snvs: LDO1 {
> >>  
> >>  			reg_vdd_snvs: LDO2 {
> >>  				regulator-name = "ldo2";
> >> -				regulator-min-microvolt = <850000>;
> >> -				regulator-max-microvolt = <900000>;
> >> +				regulator-min-microvolt = <800000>;
> >> +				regulator-max-microvolt = <800000>;
> >>  				regulator-boot-on;
> >>  				regulator-always-on;
> >>  			};
> >> -- 
> >> 2.33.0
> >>