I've seen the application notes on manual configuration. Specifically I have a Beagleboard variant that I'm using an ADIN1300 and ADIN1200 on. A U-boot initialization will be a lot cleaner.
These two parts have IEEE 802.3 compliant MII, RMII and RGMII MAC interfaces, also the registers comply.
It should work with the generic PHY driver implementation in u-boot.