net: Add MDIO bus driver for the Allwinner EMAC

This patch adds a separate driver for the MDIO interface of the
Allwinner ethernet controllers.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Tested-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 1e11f2b..3a316b3 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -144,6 +144,16 @@
 
 	  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