net: phy: Add gmiitorgmii converter support

This patch adds support for gmiitorgmii converter.
This converter sits between the MAC and the external phy
MAC <==> GMII2RGMII <==> RGMII_PHY.
The ethernet driver probes this bridge and this bridge driver
probes real phy driver and invokes the real phy functionalities
as requested. This bridge just needs to be configured based on
real phy negotiated speed and duplex.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/include/phy.h b/include/phy.h
index f4530fa..e50f56b 100644
--- a/include/phy.h
+++ b/include/phy.h
@@ -17,6 +17,11 @@
 #include <phy_interface.h>
 
 #define PHY_FIXED_ID		0xa5a55a5a
+/*
+ * There is no actual id for this.
+ * This is just a dummy id for gmii2rgmmi converter.
+ */
+#define PHY_GMII2RGMII_ID	0x5a5a5a5a
 
 #define PHY_MAX_ADDR 32
 
@@ -391,6 +396,7 @@
 int phy_xilinx_init(void);
 int phy_mscc_init(void);
 int phy_fixed_init(void);
+int phy_xilinx_gmii2rgmii_init(void);
 
 int board_phy_config(struct phy_device *phydev);
 int get_phy_id(struct mii_dev *bus, int addr, int devad, u32 *phy_id);