net: phy: clean up get_phy_c22_id() invalid ID handling

Move the ID check from get_phy_device() into get_phy_c22_id(), which
simplifies get_phy_device(). The ID reading functions are now
responsible for indicating whether they found a PHY or not via their
return code - they must return -ENODEV when a PHY is not present.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy_device.c

@@ -761,8 +761,10 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr,
  * @addr: PHY address on the MII bus
  * @phy_id: where to store the ID retrieved.
  *
- * Read the 802.3 clause 22 PHY ID from the PHY at @addr on the @bus.
- * Return the PHY ID read from the PHY in @phy_id on successful access.
+ * Read the 802.3 clause 22 PHY ID from the PHY at @addr on the @bus,
+ * placing it in @phy_id. Return zero on successful read and the ID is
+ * valid, %-EIO on bus access error, or %-ENODEV if no device responds
+ * or invalid ID.
  */
 static int get_phy_c22_id(struct mii_bus *bus, int addr, u32 *phy_id)
 {
@@ -784,6 +786,10 @@ static int get_phy_c22_id(struct mii_bus *bus, int addr, u32 *phy_id)
 
 	*phy_id |= phy_reg;
 
+	/* If the phy_id is mostly Fs, there is no device there */
+	if ((*phy_id & 0x1fffffff) == 0x1fffffff)
+		return -ENODEV;
+
 	return 0;
 }
 
@@ -814,10 +820,6 @@ struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45)
 	if (r)
 		return ERR_PTR(r);
 
-	/* If the phy_id is mostly Fs, there is no device there */
-	if ((phy_id & 0x1fffffff) == 0x1fffffff)
-		return ERR_PTR(-ENODEV);
-
 	return phy_device_create(bus, addr, phy_id, is_c45, &c45_ids);
 }
 EXPORT_SYMBOL(get_phy_device);