I am trying to get external Ethernet RGMII PHY working (ENET1 pins) on our custom carrier board. I am suspecting Power supply of ENET1 ethernet IOs, VDD_ESAI_SPDIF_1P8_2P5_3P3, ball N25 is not provided or enabled. I do not have Colibri SOM schematics to check.
Would you be able to check if IMX8 ball N25 is routed to somewhere? Some ext. LDO or PMIC power rail?
We have a similar setup and trying to connect an RMII PHY (a TJA1100 for BroadR-Reach) to ENET1 on a custom board. We can talk to the chip via the management bus, have verified the link status etc., so the physical side looks fine.
The PHY tries to send data from the network to the SOM - we see activity on the RX lines when the SOM is not in the socket, but when it is powered up, no activity can be measured on the RX nor TX lines (when pinging the other party, for example).
Based on what I found in fsl-imx8qxp-enet2-tja1100.dtsi, I adapted the device-tree to look like this (fsl-imx8qxp-colibri.dtsi):