If in doubt, say Y.
+config MDIO_SUN4I
+ tristate "Allwinner sun4i MDIO interface support"
+ depends on ARCH_SUNXI
+ select REGULATOR
+ select REGULATOR_FIXED_VOLTAGE
+ help
+ This driver supports the MDIO interface found in the network
+ interface units of the Allwinner SoC that have an EMAC (A10,
+ A12, A10s, etc.)
+
config MDIO_BUS_MUX
tristate
depends on OF_MDIO