Re: [PATCH v2 1/8] arm64: dts: imx8mm-nitrogen-r2: add wifi/bt chip

From: Adrien Grassein <adrien.grassein@gmail.com>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Sascha Hauer <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	dl-linux-imx <linux-imx@nxp.com>,
	catalin.marinas@arm.com, will@kernel.org,
	DTML <devicetree@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/8] arm64: dts: imx8mm-nitrogen-r2: add wifi/bt chip
Date: Mon, 22 Feb 2021 00:46:57 +0100	[thread overview]
Message-ID: <CABkfQAGyr_ntKMR3Ht0CVZY7zLiBcRN3-WeWiZQ-BTzXHqSF3w@mail.gmail.com> (raw)
In-Reply-To: <20210220191914.pir3ep3utz6uwyrb@kozik-lap>

Le sam. 20 févr. 2021 à 20:19, Krzysztof Kozlowski <krzk@kernel.org> a écrit :
>
> On Fri, Feb 19, 2021 at 03:03:55PM +0100, Adrien Grassein wrote:
> > Le ven. 19 févr. 2021 à 14:18, Krzysztof Kozlowski <krzk@kernel.org> a écrit :
> > >
> > > On Wed, Feb 17, 2021 at 05:10:45PM +0100, Adrien Grassein wrote:
> > > > Add usdhc3 description which corresponds to the wifi/bt chip
> > > >
> > > > Signed-off-by: Adrien Grassein <adrien.grassein@gmail.com>
> > > > ---
> > > >  .../boot/dts/freescale/imx8mm-nitrogen-r2.dts | 31 +++++++++++++++++++
> > > >  1 file changed, 31 insertions(+)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/freescale/imx8mm-nitrogen-r2.dts b/arch/arm64/boot/dts/freescale/imx8mm-nitrogen-r2.dts
> > > > index c0c384d76147..212dc9e5e85d 100644
> > > > --- a/arch/arm64/boot/dts/freescale/imx8mm-nitrogen-r2.dts
> > > > +++ b/arch/arm64/boot/dts/freescale/imx8mm-nitrogen-r2.dts
> > > > @@ -9,6 +9,17 @@
> > > >  / {
> > > >       model = "Boundary Devices i.MX8MMini Nitrogen8MM Rev2";
> > > >       compatible = "boundary,imx8mm-nitrogen8mm", "fsl,imx8mm";
> > > > +
> > > > +     reg_wlan_vmmc: regulator-wlan-vmmc {
> > > > +             compatible = "regulator-fixed";
> > > > +             pinctrl-names = "default";
> > > > +             pinctrl-0 = <&pinctrl_reg_wlan_vmmc>;
> > > > +             regulator-name = "reg_wlan_vmmc";
> > > > +             regulator-min-microvolt = <3300000>;
> > > > +             regulator-max-microvolt = <3300000>;
> > > > +             gpio = <&gpio3 20 GPIO_ACTIVE_HIGH>;
> > > > +             enable-active-high;
> > > > +     };
> > > >  };
> > > >
> > > >  &A53_0 {
> > > > @@ -206,6 +217,20 @@ &usdhc2 {
> > > >       status = "okay";
> > > >  };
> > > >
> > > > +/* wlan */
> > > > +&usdhc3 {
> > > > +     bus-width = <4>;
> > > > +     sdhci-caps-mask = <0x2 0x0>;
> > > > +     non-removable;
> > > > +     pinctrl-names = "default", "state_100mhz", "state_200mhz";
> > > > +     pinctrl-0 = <&pinctrl_usdhc3>;
> > > > +     pinctrl-1 = <&pinctrl_usdhc3_100mhz>;
> > > > +     pinctrl-2 = <&pinctrl_usdhc3_200mhz>;
> > > > +     vmmc-supply = <&reg_wlan_vmmc>;
> > > > +     vqmmc-1-8-v;
> > >
> > > There is no such property in the bindings.
> > >
> >
> > Sorry, I copied a property from the FSL kernel.
> > I will fix this with a "fixed-regulator".
>
> I would assume this goes from PMIC, so check your schematics. There is
> little point in adding a fixed regulator which is non-controllable.

No, the 1.8V is issued directly from the alimentation stage.
So we can't control it.

> I think bindings don't require it.
After reading some code, I can say that vqmmc is not mandatory but it
helped to find out
the caps of the mmc host. In this case, we only support 1.8V on vqmmc.
It avoids driver to guess it (and avoid bad behaviour on any future change).

>
> Best regards,
> Krzysztof
>

Thanks,
Adrien