Realtek MDIO interface driver

modulename: realtek-mdio.ko

configname: CONFIG_NET_DSA_REALTEK_MDIO

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Distributed Switch Architecture drivers
└─>Realtek Ethernet switch family support
└─>Device Tree and Open Firmware support
└─>Realtek MDIO interface driver
In linux kernel since version 5.2 (release Date: 2019-07-07)  
Select to enable support for registering switches configured
through MDIO.

source code:
drivers/net/dsa/realtek/realtek-mdio.c