…er writer can write phy_driver first .when mac driver need to use phy they can register phy_device and pjhy_devie will serach for driver which match by uid and mask,if no driver match with the device that you register,phy_bus will return the genphy to you device,the genphy driver is the general driver for phy,so you can use it but it can not support the capcity of chip it may be cause performance is not up to peak