> -----Original Message-----
> From: Shawn Guo <shawnguo@xxxxxxxxxx>
> Sent: 2021年3月18日 18:48
> To: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> Cc: robh+dt@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; festevam@xxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH V1] arm64: dts: imx8mp: fix FEC can't work when attached
> to generic phy driver
>
> On Thu, Mar 04, 2021 at 07:40:13PM +0800, Joakim Zhang wrote:
> > Some users report that FEC can't work on i.MX8MP EVK board, it brings
> > inconvenience. The root cause should be FEC controller attached to
> > generic phy driver, as Realtek phy driver is built as module in the
> > defconfig file (CONFIG_REALTEK_PHY=m), so it is unavailable. If
> > provide "reset-gpios" property, it will reset phy when probed, and no
> > way to re-config phy since we use the generic phy dirver, which leads
> > FEC can't work.
> >
> > There are two ways to let FEC work:
> >
> > 1. If you want to use generic phy dirver, please delete "reset-gpios"
> > property, keep power-on strapping pins configurations.
> >
> > 2. If you want to use Realtek phy driver, please buildin driver
> > (CONFIG_REALTEK_PHY=y), and had better add another two reset
> > properties:
> > reset-assert-us = <20000>;
> > reset-deassert-us = <150000>;
> > According to RTL8211 serials PHY datasheet, for a complete PHY reset,
> > reset pin must be asserted low for at least 10ms for internal regulator.
> > Wait for at least 72ms (for internal circuits settling time) before
> > accessing the PHY register.
> >
> > This patch selects method 1, since users may waste time to find out
> > FEC failure, in most cases, they just want to use networking to debug
> > other modules.
> >
> > Fixs: commit 9e847693c6f34 ("arm64: dts: freescale: Add i.MX8MP EVK
> > board support")
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> > ---
> > arch/arm64/boot/dts/freescale/imx8mp-evk.dts | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > index 7db4273cc88b..4f5c2fb33eda 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > +++ b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
> > @@ -97,7 +97,6 @@
> > compatible = "ethernet-phy-ieee802.3-c22";
> > reg = <1>;
> > eee-broken-1000t;
> > - reset-gpios = <&gpio4 2 GPIO_ACTIVE_LOW>;
>
> Hmm, DT is describing hardware. If board schematic says there is a reset
> GPIO, we should have it.
Hi Shawn,
Seems you prefer to 2, is it possible to buildin Realtek PHY(CONFIG_REALTEK_PHY=y)? If not, it is going to be tricky.
Best Regards,
Joakim Zhang
> Shawn
>
> > };
> > };
> > };
> > --
> > 2.17.1
> >
