Linux Device Tree Config and External ADIN1300 PHY

[tractor-rover]

Hi,

I am attempting to configure the device tree to get an external ADIN1300 phy managed by a MDIO on our custom hardware board working. The SOM is the iMX8MP and the carrier board is our in-house design. The link LEDs for both Ethernets light up but no connection is established with the test laptop. FULL DISCLOSURE I am relatively new to the Linux Device Tree stuff.

This is what the relevant parts of the device tree look like: 

reg_fec_phy: regulator-fec-phy {
compatible = "regulator-fixed";
regulator-name = "fec-phy";
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <1800000>;
regulator-enable-ramp-delay = <20000>;
gpios = <&gpio_exp1 16 GPIO_ACTIVE_LOW>; // EXP_MDIO_EN
regulator-always-on;
regulator-boot-on;
};

vddio1: vddio-regulator {
compatible = "regulator-fixed";
regulator-name = "vddio1";
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <1800000>;
regulator-always-on;
regulator-boot-on;
};

&fec {
compatible = "fsl,imx8mp-fec", "fsl,imx8mq-fec", "fsl,imx6sx-fec";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_fec>;
phy-mode = "rgmii";
phy-handle = <&ethphy1>;
phy-supply = <&reg_fec_phy>;
status = "okay";

mdio {
#address-cells = <1>;
#size-cells = <0>;

ethphy1: ethernet-phy@5 {
compatible = "adi,adin1300", "ethernet-phy-ieee802.3-c22";
reg = <5>;
eee-broken-100tx;
eee-broken-1000t;
reset-gpios = <&gpio_exp1 15 GPIO_ACTIVE_LOW>; // EXP_ENET1_RESET_B
reset-assert-us = <10000>;
reset-deassert-us = <20000>;
vddio-supply = <&vddio1>;
};
};
};

pinctrl_fec: fecgrp {
fsl,pins = <
MX8MP_IOMUXC_SAI1_RXD2__ENET1_MDC 0x140
MX8MP_IOMUXC_SAI1_RXD3__ENET1_MDIO 0x140
MX8MP_IOMUXC_SAI1_RXD4__ENET1_RGMII_RD0 0x91 // SCHMITT, FAST
MX8MP_IOMUXC_SAI1_RXD5__ENET1_RGMII_RD1 0x91 // SCHMITT, FAST
MX8MP_IOMUXC_SAI1_RXD6__ENET1_RGMII_RD2 0x91
MX8MP_IOMUXC_SAI1_RXD7__ENET1_RGMII_RD3 0x91
MX8MP_IOMUXC_SAI1_TXC__ENET1_RGMII_RXC 0x91
MX8MP_IOMUXC_SAI1_TXFS__ENET1_RGMII_RX_CTL 0x91
MX8MP_IOMUXC_SAI1_TXD0__ENET1_RGMII_TD0 0x1f
MX8MP_IOMUXC_SAI1_TXD1__ENET1_RGMII_TD1 0x1f
MX8MP_IOMUXC_SAI1_TXD2__ENET1_RGMII_TD2 0x1f
MX8MP_IOMUXC_SAI1_TXD3__ENET1_RGMII_TD3 0x1f
MX8MP_IOMUXC_SAI1_TXD4__ENET1_RGMII_TX_CTL 0x1f
MX8MP_IOMUXC_SAI1_TXD5__ENET1_RGMII_TXC 0x1f
MX8MP_IOMUXC_SAI1_MCLK__ENET1_TX_CLK 0x4000001f
>;
};

Any assistance is appreciated.

[Zhiming_Liu]

Hi @tractor-rover 

Please refer 3.3.2 RGMII mode in below application note about default RGMII setting.

Alternatively, you can refer to the settings in other device tree(arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi)

ENET1_TX_CLK is for RMII mode, so you should remove it if you are using RGMII. For other settings, please ensure that they meet the hardware requirements, such as reset behavior, etc.

Best Regards,
Zhiming