diff --git a/include/phy.h b/include/phy.h
index ad2096c..0737c4e 100644
--- a/include/phy.h
+++ b/include/phy.h
@@ -412,6 +412,8 @@
 		phydev->interface <= PHY_INTERFACE_MODE_QSGMII;
 }
 
+bool phy_interface_is_ncsi(void);
+
 /* PHY UIDs for various PHYs that are referenced in external code */
 #define PHY_UID_CS4340		0x13e51002
 #define PHY_UID_CS4223		0x03e57003