Re: [PATCH 4/7] arm64: dts: imx8m: configure FEC PHY VDDIO voltage

[Shawn Guo]

On Mon, Dec 06, 2021 at 01:59:18AM +0000, Joakim Zhang wrote:
> 
> Hi Shawn,
> 
> > -----Original Message-----
> > From: Shawn Guo <shawnguo@xxxxxxxxxx>
> > Sent: 2021年12月6日 9:16
> > To: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> > Cc: robh+dt@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> > festevam@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH 4/7] arm64: dts: imx8m: configure FEC PHY VDDIO
> > voltage
> > 
> > On Tue, Nov 23, 2021 at 04:05:03PM +0800, Joakim Zhang wrote:
> > > As commit 2f664823a470 ("net: phy: at803x: add device tree binding")
> > > described, configure FEC PHY VDDIO voltage according to board design.
> > >
> > > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> > > ---
> > >  arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 6 ++++++
> > > arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi | 6 ++++++
> > > arch/arm64/boot/dts/freescale/imx8mq-evk.dts  | 4 ++++
> > >  3 files changed, 16 insertions(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > > b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > > index 50b3bbb662d5..3bac87b7e142 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > > @@ -117,6 +117,12 @@
> > >  			reset-gpios = <&gpio4 22 GPIO_ACTIVE_LOW>;
> > >  			reset-assert-us = <10000>;
> > >  			qca,disable-smarteee;
> > > +			vddio-supply = <&vddio>;
> > > +
> > > +			vddio: vddio-regulator {
> > > +				regulator-min-microvolt = <1800000>;
> > > +				regulator-max-microvolt = <1800000>;
> > > +			};
> > >  		};
> > >  	};
> > >  };
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
> > > b/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
> > > index 342f57e8cf61..c3f15192b76c 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi
> > > @@ -100,6 +100,12 @@
> > >  			reset-gpios = <&gpio4 22 GPIO_ACTIVE_LOW>;
> > >  			reset-assert-us = <10000>;
> > >  			qca,disable-smarteee;
> > > +			vddio-supply = <&vddio>;
> > > +
> > > +			vddio: vddio-regulator {
> > > +				regulator-min-microvolt = <1800000>;
> > > +				regulator-max-microvolt = <1800000>;
> > > +			};
> > >  		};
> > >  	};
> > >  };
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> > > b/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> > > index a9e33548a2f3..c96d23fe3010 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mq-evk.dts
> > > @@ -170,6 +170,10 @@
> > >  			reset-gpios = <&gpio1 9 GPIO_ACTIVE_LOW>;
> > >  			reset-assert-us = <10000>;
> > >  			qca,disable-smarteee;
> > > +			vddio-supply = <&vddh>;
> > > +
> > > +			vddh: vddh-regulator {
> > > +			};
> > 
> > Why does this need to be different from the one on imx8mm-evk and
> > imx8mn-evk?
> 
> It's depend on RGMII_IO voltage out from SoC and PHY reference design.
> 
> For 8MM/MN:
> 	SoC RGMII_IO is 1.8V, and board design use "Reference Design, 1.5/1.8 V RGMII I/O", PHY default work on 1.5V, so we need configure PHY to work on 1.8V.
> For 8MQ:
> 	SoC RGMII_IO is 2.5V, and board design use "Reference Design, 2.5 V/ 3.3 V RGMII I/O", PHY default work on 2.5V.

Hmm, why do you not specify 2.5V with regulator-min[max]-microvolt then?
Also, why is the regulator named vddh instead of vddio?

Shawn

> 
> Best Regards,
> Joakim Zhang
> > Shawn
> > 
> > >  		};
> > >  	};
> > >  };
> > > --
> > > 2.17.1
> > >