net: phy: probe for C45 PHYs that return PHY ID of zero in C22 space

PHY devices such as the Marvell Alaska 88E2110 does not return a valid
PHY ID when probed using Clause-22. The current implementation treats
PHY ID of zero as a non-error and valid PHY ID, and causing the PHY
device failed to bind to the Marvell driver.

For such devices, we do an additional probe in the Clause-45 space,
if a valid PHY ID is returned, we then proceed to attach the PHY
device to the matching PHY ID driver.
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy_device.c

@@ -870,6 +870,18 @@ struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45)
 	if (r)
 		return ERR_PTR(r);
 
+	/* PHY device such as the Marvell Alaska 88E2110 will return a PHY ID
+	 * of 0 when probed using get_phy_c22_id() with no error. Proceed to
+	 * probe with C45 to see if we're able to get a valid PHY ID in the C45
+	 * space, if successful, create the C45 PHY device.
+	 */
+	if (!is_c45 && phy_id == 0 && bus->probe_capabilities >= MDIOBUS_C45) {
+		r = get_phy_c45_ids(bus, addr, &c45_ids);
+		if (!r)
+			return phy_device_create(bus, addr, phy_id,
+						 true, &c45_ids);
+	}
+
 	return phy_device_create(bus, addr, phy_id, is_c45, &c45_ids);
 }
 EXPORT_SYMBOL(get_phy_device);