--- /dev/null
+#ifndef _MICREL_H
+
+#define MII_KSZ9021_EXT_COMMON_CTRL 0x100
+#define MII_KSZ9021_EXT_STRAP_STATUS 0x101
+#define MII_KSZ9021_EXT_OP_STRAP_OVERRIDE 0x102
+#define MII_KSZ9021_EXT_OP_STRAP_STATUS 0x103
+#define MII_KSZ9021_EXT_RGMII_CLOCK_SKEW 0x104
+#define MII_KSZ9021_EXT_RGMII_RX_DATA_SKEW 0x105
+#define MII_KSZ9021_EXT_RGMII_TX_DATA_SKEW 0x106
+#define MII_KSZ9021_EXT_ANALOG_TEST 0x107
+/* Register operations */
+#define MII_KSZ9031_MOD_REG 0x0000
+/* Data operations */
+#define MII_KSZ9031_MOD_DATA_NO_POST_INC 0x4000
+#define MII_KSZ9031_MOD_DATA_POST_INC_RW 0x8000
+#define MII_KSZ9031_MOD_DATA_POST_INC_W 0xC000
+
+#define MII_KSZ9031_EXT_RGMII_CTRL_SIG_SKEW 0x4
+#define MII_KSZ9031_EXT_RGMII_RX_DATA_SKEW 0x5
+#define MII_KSZ9031_EXT_RGMII_TX_DATA_SKEW 0x6
+#define MII_KSZ9031_EXT_RGMII_CLOCK_SKEW 0x8
+
+struct phy_device;
+int ksz9021_phy_extended_write(struct phy_device *phydev, int regnum, u16 val);
+int ksz9021_phy_extended_read(struct phy_device *phydev, int regnum);
+
+int ksz9031_phy_extended_write(struct phy_device *phydev, int devaddr,
+ int regnum, u16 mode, u16 val);
+int ksz9031_phy_extended_read(struct phy_device *phydev, int devaddr,
+ int regnum, u16 mode);
+
+#endif