CONFIG_MDIO_REGMAP (not configurable)

modulename: mdio-regmap.ko

configname: CONFIG_MDIO_REGMAP

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>MDIO bus device drivers
└─>MDIO_REGMAP
In linux kernel since version 6.5 (release Date: 2023-08-27)  
This driver allows using MDIO devices that are not sitting on a
regular MDIO bus, but still exposes the standard 802.3 register
layout. It's regmap-based so that it can be used on integrated,
memory-mapped PHYs, SPI PHYs and so on. A new virtual MDIO bus is
created, and its read/write operations are mapped to the underlying
regmap. Users willing to use this driver must explicitly select
REGMAP.

source code: