U-Boot Device Tree for Ethernet on MCIMX6ULL-EVK

[JohnKlug]

In our design, which is similar to Ethernet (ENET1) on MCIMX6ULL-EVK, I am trying to determine a reasonable device tree.  To rule out a hardware issue, I am trying to get the EVK board to work with only ENET1.

I am using U-Boot 2020, and patching file:
arch/arm/dts/imx6ul-14x14-evk.dtsi

I wrote a patch, but the patch causes the MDIO bus to not function:

Net:   FEC: can't find phy-handle
Could not get PHY for FEC0: addr 2
FEC: can't find phy-handle
Could not get PHY for FEC0: addr 2
No ethernet found.

Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0 
=> 
=> mdio list
No MDIO bus found

When I take my patch out, I get both ports successfully, but I am trying to simulate having only one port.  Why would removing enet2 cause mdio not to work?

I added the mdio signals with the pin control for ENET1:

 			MX6UL_PAD_ENET1_TX_DATA1__ENET1_TDATA01	0x1b0b0
 			MX6UL_PAD_ENET1_TX_CLK__ENET1_REF_CLK1	0x4001b031
+			MX6UL_PAD_GPIO1_IO07__ENET2_MDC		0x1b0b0
+			MX6UL_PAD_GPIO1_IO06__ENET2_MDIO	0x1b0b0
 		>;

I moved the phy section for ENET1 into fec1:

 	phy-handle = <&ethphy0>;
 	status = "okay";
+	ethphy0: ethernet-phy@2 {
+            reg = <2>;
+	    micrel,led-mode = <1>;
+	    clocks = <&clks IMX6UL_CLK_ENET_REF>;
+	    clock-names = "rmii-ref";
+	};

I created a dummy enet2 that replaced the original:

+&fec2 {
+	status = "disabled";
+};

[JohnKlug · Accepted solution]

Thinking about this some more, it probably didn't make sense to disable ENET2, yet use the ENET2 MDIO path.  I changed the pad for IO06 and IO07 to ENET1, and the MDIO worked, and Ethernet worked as well.