phylib: Add Clause 45 read/write functions

Need an extra parameter to read or write Clause 45 PHYs, so
need a different API with the extra parameter.

Signed-off-by: Andy Fleming <afleming@gmail.com>
Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/phy.h

@@ -487,6 +487,24 @@ struct phy_fixup {
 	int (*run)(struct phy_device *phydev);
 };
 
+/**
+ * phy_read_mmd - Convenience function for reading a register
+ * from an MMD on a given PHY.
+ * @phydev: The phy_device struct
+ * @devad: The MMD to read from
+ * @regnum: The register on the MMD to read
+ *
+ * Same rules as for phy_read();
+ */
+static inline int phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum)
+{
+	if (!phydev->is_c45)
+		return -EOPNOTSUPP;
+
+	return mdiobus_read(phydev->bus, phydev->addr,
+			    MII_ADDR_C45 | (devad << 16) | (regnum & 0xffff));
+}
+
 /**
  * phy_read - Convenience function for reading a given PHY register
  * @phydev: the phy_device struct
@@ -537,6 +555,27 @@ static inline bool phy_is_internal(struct phy_device *phydev)
 	return phydev->is_internal;
 }
 
+/**
+ * phy_write_mmd - Convenience function for writing a register
+ * on an MMD on a given PHY.
+ * @phydev: The phy_device struct
+ * @devad: The MMD to read from
+ * @regnum: The register on the MMD to read
+ * @val: value to write to @regnum
+ *
+ * Same rules as for phy_write();
+ */
+static inline int phy_write_mmd(struct phy_device *phydev, int devad,
+				u32 regnum, u16 val)
+{
+	if (!phydev->is_c45)
+		return -EOPNOTSUPP;
+
+	regnum = MII_ADDR_C45 | ((devad & 0x1f) << 16) | (regnum & 0xffff);
+
+	return mdiobus_write(phydev->bus, phydev->addr, regnum, val);
+}
+
 struct phy_device *phy_device_create(struct mii_bus *bus, int addr, int phy_id,
 				     bool is_c45,
 				     struct phy_c45_device_ids *c45_ids);