of_mdio: add helper to deregister fixed-link PHYs

Add helper to deregister fixed-link PHYs registered using
of_phy_register_fixed_link().

Convert the two drivers that care to deregister their fixed-link PHYs to
use the new helper, but note that most drivers currently fail to do so.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -2459,20 +2459,8 @@ static void cpsw_remove_dt(struct platform_device *pdev)
 		if (strcmp(slave_node->name, "slave"))
 			continue;
 
-		if (of_phy_is_fixed_link(slave_node)) {
-			struct phy_device *phydev;
-
-			phydev = of_phy_find_device(slave_node);
-			if (phydev) {
-				fixed_phy_unregister(phydev);
-				/* Put references taken by
-				 * of_phy_find_device() and
-				 * of_phy_register_fixed_link().
-				 */
-				phy_device_free(phydev);
-				phy_device_free(phydev);
-			}
-		}
+		if (of_phy_is_fixed_link(slave_node))
+			of_phy_deregister_fixed_link(slave_node);
 
 		of_node_put(slave_data->phy_node);
 

drivers/of/of_mdio.c

@@ -490,3 +490,18 @@ int of_phy_register_fixed_link(struct device_node *np)
 	return -ENODEV;
 }
 EXPORT_SYMBOL(of_phy_register_fixed_link);
+
+void of_phy_deregister_fixed_link(struct device_node *np)
+{
+	struct phy_device *phydev;
+
+	phydev = of_phy_find_device(np);
+	if (!phydev)
+		return;
+
+	fixed_phy_unregister(phydev);
+
+	put_device(&phydev->mdio.dev);	/* of_phy_find_device() */
+	phy_device_free(phydev);	/* fixed_phy_register() */
+}
+EXPORT_SYMBOL(of_phy_deregister_fixed_link);

include/linux/of_mdio.h

@@ -29,6 +29,7 @@ struct phy_device *of_phy_attach(struct net_device *dev,
 extern struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np);
 extern int of_mdio_parse_addr(struct device *dev, const struct device_node *np);
 extern int of_phy_register_fixed_link(struct device_node *np);
+extern void of_phy_deregister_fixed_link(struct device_node *np);
 extern bool of_phy_is_fixed_link(struct device_node *np);
 
 #else /* CONFIG_OF */
@@ -83,6 +84,9 @@ static inline int of_phy_register_fixed_link(struct device_node *np)
 {
 	return -ENOSYS;
 }
+static inline void of_phy_deregister_fixed_link(struct device_node *np)
+{
+}
 static inline bool of_phy_is_fixed_link(struct device_node *np)
 {
 	return false;

net/dsa/dsa.c

@@ -506,16 +506,8 @@ dsa_switch_setup(struct dsa_switch_tree *dst, int index,
 
 void dsa_cpu_dsa_destroy(struct device_node *port_dn)
 {
-	struct phy_device *phydev;
-
-	if (of_phy_is_fixed_link(port_dn)) {
-		phydev = of_phy_find_device(port_dn);
-		if (phydev) {
-			fixed_phy_unregister(phydev);
-			put_device(&phydev->mdio.dev);
-			phy_device_free(phydev);
-		}
-	}
+	if (of_phy_is_fixed_link(port_dn))
+		of_phy_deregister_fixed_link(port_dn);
 }
 
 static void dsa_switch_destroy(struct dsa_switch *ds)