of_mdio: move of_mdio_parse_addr to header file

The of_mdio_parse_addr() helper function is useful to other code, but
the module dependency chain causes issues.  To work around this, we can
move of_mdio_parse_addr() to be an inline function in the header file.
This gets rid of the dependencies and still allows for the reuse of
code.

Reported-by: Liviu Dudau <liviu@dudau.co.uk>
Signed-off-by: Jon Mason <jon.mason@broadcom.com>
Fixes: 342fa1964439 ("mdio: mux: make child bus walking more permissive and errors more verbose")
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/of_mdio.h b/include/linux/of_mdio.h
index ba35ba5..f5db93b 100644
--- a/include/linux/of_mdio.h
+++ b/include/linux/of_mdio.h
@@ -27,11 +27,33 @@ struct phy_device *of_phy_attach(struct net_device *dev,
 				 phy_interface_t iface);
 
 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);
 
+
+static inline int of_mdio_parse_addr(struct device *dev,
+				     const struct device_node *np)
+{
+	u32 addr;
+	int ret;
+
+	ret = of_property_read_u32(np, "reg", &addr);
+	if (ret < 0) {
+		dev_err(dev, "%s has invalid PHY address\n", np->full_name);
+		return ret;
+	}
+
+	/* A PHY must have a reg property in the range [0-31] */
+	if (addr >= PHY_MAX_ADDR) {
+		dev_err(dev, "%s PHY address %i is too large\n",
+			np->full_name, addr);
+		return -EINVAL;
+	}
+
+	return addr;
+}
+
 #else /* CONFIG_OF_MDIO */
 static inline int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
 {