CONFIG_MDIO (not configurable)

modulename: mdio.ko

configname: CONFIG_MDIO

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>MDIO
In linux kernel since version 2.6.31 (release Date: 2009-09-09)  
source code:
drivers/net/mdio.c