quoted

Name         Description                                         Start      End
SWITCH       Ethernet Switch Subsystem                           0x000000   0x3ffffc
100BASE-T1   Internal MDIO bus for 100BASE-T1 PHY (port 5 - 10)  0x704000   0x704ffc
SGMII1       SGMII Port 1                                        0x705000   0x705ffc
SGMII2       SGMII Port 2                                        0x706000   0x706ffc
SGMII3       SGMII Port 3                                        0x707000   0x707ffc
SGMII4       SGMII Port 4                                        0x708000   0x708ffc
100BASE-TX   Internal MDIO bus for 100BASE-TX PHY                0x709000   0x709ffc

All in drivers/net.

I've not been following this conversation too much, but i would like
to point out that what you find in drivers/net is not a uniform set of
drivers, but a collection of different driver types.

SWITCH might belong on drivers/net/dsa
100BASE-T1 might belong on drivers/net/mdio
SGMIIX might belong in drivers/net/pcs
100BASE-TX might belong in drivers/net/mdio

I also expect those T1 and TX PHYs have drivers in drivers/net/phy,
but they are not memory mapped, so not on your list.

Each driver can probe independently, registering with different parts
of the net core. And then the switch driver will link all the parts
together using phandles.

Saying that all the sub drivers are in drivers/net seems an odd
argument it is not an MFD.

	 Andrew