net: eth: cpsw: Correctly attach to GPIO bitbang MDIO driver

When the GPIO bitbang MDIO driver is used instead of the Davinci MDIO driver
we need to configure the phy_id string differently. Otherwise this string
looks like this "gpio.6" instead of "gpio-0" and the PHY is not found when
phy_connect() is called.
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Lukas Stockmann <lukas.stockmann@siemens.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
Acked-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -1878,8 +1878,18 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
 		mdio_node = of_find_node_by_phandle(be32_to_cpup(parp));
 		phyid = be32_to_cpup(parp+1);
 		mdio = of_find_device_by_node(mdio_node);
-		snprintf(slave_data->phy_id, sizeof(slave_data->phy_id),
-			 PHY_ID_FMT, mdio->name, phyid);
+
+		if (strncmp(mdio->name, "gpio", 4) == 0) {
+			/* GPIO bitbang MDIO driver attached */
+			struct mii_bus *bus = dev_get_drvdata(&mdio->dev);
+
+			snprintf(slave_data->phy_id, sizeof(slave_data->phy_id),
+				 PHY_ID_FMT, bus->id, phyid);
+		} else {
+			/* davinci MDIO driver attached */
+			snprintf(slave_data->phy_id, sizeof(slave_data->phy_id),
+				 PHY_ID_FMT, mdio->name, phyid);
+		}
 
 		mac_addr = of_get_mac_address(slave_node);
 		if (mac_addr)