I have download and compile the source code of LEDE/OpenWRT in order to make it work with a Raspberry Pi 3 Model B Rev 1.2, but I can't manage to make the SPI work with a ENC28J60 Ethernet module, under raspbian it does work okay but on openwrt I just can't figure it out!
in order to make it work with raspbian I've followed the next tutorial
You must modifie the kernel via overlay. But no idea if it exist now for openwrt.
And them you must build your own makefile for the kernel mudule because it is in the kernelsource but not in the openwrt makefile. For a long time i had the same problem: https://forum.archive.openwrt.org/viewtopic.php?id=58925