Live OF reconfiguration needs to create the same PHY and generic MDIO
devices as initial bus population, including legacy PHY nodes that need
address scanning.

Factor fixed-address child registration and PHY address scanning into
helpers. The old scan loop also visited every free address for a child
without a reg property even when the child was not a PHY. Reject that case
before scanning while preserving enumeration of valid PHY and generic MDIO
children.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 drivers/net/mdio/of_mdio.c | 66 ++++++++++++++++++++++++++++------------------
 1 file changed, 40 insertions(+), 26 deletions(-)

diff --git a/drivers/net/mdio/of_mdio.c b/drivers/net/mdio/of_mdio.c
index b8d298c04d3f..051e449bbe7c 100644
--- a/drivers/net/mdio/of_mdio.c
+++ b/drivers/net/mdio/of_mdio.c
@@ -77,6 +77,15 @@ static int of_mdiobus_register_device(struct mii_bus *mdio,
 	return 0;
 }
 
+static int of_mdiobus_register_child(struct mii_bus *mdio,
+				     struct device_node *child, u32 addr)
+{
+	if (of_mdiobus_child_is_phy(child))
+		return of_mdiobus_register_phy(mdio, child, addr);
+
+	return of_mdiobus_register_device(mdio, child, addr);
+}
+
 /* The following is a list of PHY compatible strings which appear in
  * some DTBs. The compatible string is never matched against a PHY
  * driver, so is pointless. We only expect devices which are not PHYs
@@ -136,6 +145,32 @@ bool of_mdiobus_child_is_phy(struct device_node *child)
 }
 EXPORT_SYMBOL(of_mdiobus_child_is_phy);
 
+static int of_mdiobus_scan_phy(struct mii_bus *mdio,
+			       struct device_node *child)
+{
+	int addr, rc;
+
+	if (!of_mdiobus_child_is_phy(child))
+		return -ENODEV;
+
+	for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
+		if (mdiobus_is_registered_device(mdio, addr))
+			continue;
+
+		dev_info(&mdio->dev, "scan phy %pOFn at address %i\n",
+			 child, addr);
+
+		/* -ENODEV means that scanning should continue. */
+		rc = of_mdiobus_register_child(mdio, child, addr);
+		if (!rc)
+			return 0;
+		if (rc != -ENODEV)
+			return rc;
+	}
+
+	return -ENODEV;
+}
+
 static int __of_mdiobus_parse_phys(struct mii_bus *mdio, struct device_node *np,
 				   bool *scanphys)
 {
@@ -164,10 +199,7 @@ static int __of_mdiobus_parse_phys(struct mii_bus *mdio, struct device_node *np,
 			continue;
 		}
 
-		if (of_mdiobus_child_is_phy(child))
-			rc = of_mdiobus_register_phy(mdio, child, addr);
-		else
-			rc = of_mdiobus_register_device(mdio, child, addr);
+		rc = of_mdiobus_register_child(mdio, child, addr);
 
 		if (rc == -ENODEV)
 			dev_err(&mdio->dev,
@@ -197,7 +229,7 @@ int __of_mdiobus_register(struct mii_bus *mdio, struct device_node *np,
 {
 	struct device_node *child;
 	bool scanphys = false;
-	int addr, rc;
+	int rc;
 
 	if (!np)
 		return __mdiobus_register(mdio, owner);
@@ -238,27 +270,9 @@ int __of_mdiobus_register(struct mii_bus *mdio, struct device_node *np,
 		    of_node_name_eq(child, "ethernet-phy-package"))
 			continue;
 
-		for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
-			/* skip already registered PHYs */
-			if (mdiobus_is_registered_device(mdio, addr))
-				continue;
-
-			/* be noisy to encourage people to set reg property */
-			dev_info(&mdio->dev, "scan phy %pOFn at address %i\n",
-				 child, addr);
-
-			if (of_mdiobus_child_is_phy(child)) {
-				/* -ENODEV is the return code that PHYLIB has
-				 * standardized on to indicate that bus
-				 * scanning should continue.
-				 */
-				rc = of_mdiobus_register_phy(mdio, child, addr);
-				if (!rc)
-					break;
-				if (rc != -ENODEV)
-					goto put_unregister;
-			}
-		}
+		rc = of_mdiobus_scan_phy(mdio, child);
+		if (rc && rc != -ENODEV)
+			goto put_unregister;
 	}
 
 	return 0;

-- 
2.53.0