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.
Shawn
> };
> };
> };
> --
> 2.17.1
>
