MDIO bus device drivers

modulename: mdio-bus.ko

configname: CONFIG_MDIO_DEVICE

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>MDIO bus device drivers
In linux kernel since version 3.10 (release Date: 2013-06-30)  
MDIO devices and driver infrastructure code.

source code:
drivers/net/phy/