> Before going into explaining my viewpoint, could someone, please, clarify > which LAN78xx USB-to-Ethernet bridge does this apply to? I already had > a look at a few LAN78xx datasheets, and I'm not sure how the external PHY > becomes exposed over the USB interface, so it needs a driver. https://elixir.bootlin.com/linux/v6.10/source/drivers/net/usb/lan78xx.c#L2049 This is creating an MDIO bus device. The MDIO bus will be scanned and PHYs on the bus found. There are then a few calls to phy_find_first() which will get the PHY. The code itself looks pretty broken, it is directly accessing PHY registers, which a MAC driver should not do. That is a layering violation. Andrew
