diff --git a/phy.h b/phy.h
new file mode 100644
index 0000000..3918415
--- /dev/null
+++ b/phy.h
@@ -0,0 +1,26 @@
+#ifndef _PHY_H_
+#define _PHY_H_
+
+/*
+ * The RTL8272/RTL8273 appear to comprise an RTL8224 PHY
+ * which in turn is a 4x RTL8221B PHY
+ * These phys are all Clause 45
+ * The defines below are taken from the RTL8221B datasheet
+ */
+
+/*
+ * Define PHY pages
+ */
+#define PHY_MMD_AN	7
+#define PHY_MMD_CTRL	31
+
+
+/*
+ * Define registers in Auto-Negotiation page
+ */
+#define PHY_ANEG_CTRL	0x00
+#define PHY_EEE_ADV	0x3c
+#define PHY_EEE_ABILITY	0x3d
+#define PHY_EEE_ADV2	0x3e
+
+#endif