net: phy: Add phy_interface_is_sgmii to phy.h

Add a helper to phy.h to identify whether the
phy is configured for SGMII all variables.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Mugunthan V N <mugunthanvnm@ti.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

include/phy.h

@@ -289,6 +289,17 @@ static inline bool phy_interface_is_rgmii(struct phy_device *phydev)
 		phydev->interface <= PHY_INTERFACE_MODE_RGMII_TXID;
 }
 
+/**
+ * phy_interface_is_sgmii - Convenience function for testing if a PHY interface
+ * is SGMII (all variants)
+ * @phydev: the phy_device struct
+ */
+static inline bool phy_interface_is_sgmii(struct phy_device *phydev)
+{
+	return phydev->interface >= PHY_INTERFACE_MODE_SGMII &&
+		phydev->interface <= PHY_INTERFACE_MODE_QSGMII;
+}
+
 /* PHY UIDs for various PHYs that are referenced in external code */
 #define PHY_UID_CS4340  0x13e51002
 #define PHY_UID_TN2020	0x00a19410