altera tse: add support for fixed-links.

Add support for fixed-links in configurations without PHY.
(e.g. connection to a switch, SGMII point to point, SFPs)

Check: Documentation/devicetree/bindings/net/fixed-link.txt.
Signed-off-by: Andreas Oetken <ennoerlangen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/altera/altera_tse_main.c

@@ -777,6 +777,8 @@ static int init_phy(struct net_device *dev)
 	struct altera_tse_private *priv = netdev_priv(dev);
 	struct phy_device *phydev;
 	struct device_node *phynode;
+	bool fixed_link = false;
+	int rc = 0;
 
 	/* Avoid init phy in case of no phy present */
 	if (!priv->phy_iface)
@@ -789,13 +791,32 @@ static int init_phy(struct net_device *dev)
 	phynode = of_parse_phandle(priv->device->of_node, "phy-handle", 0);
 
 	if (!phynode) {
-		netdev_dbg(dev, "no phy-handle found\n");
-		if (!priv->mdio) {
-			netdev_err(dev,
-				   "No phy-handle nor local mdio specified\n");
-			return -ENODEV;
+		/* check if a fixed-link is defined in device-tree */
+		if (of_phy_is_fixed_link(priv->device->of_node)) {
+			rc = of_phy_register_fixed_link(priv->device->of_node);
+			if (rc < 0) {
+				netdev_err(dev, "cannot register fixed PHY\n");
+				return rc;
+			}
+
+			/* In the case of a fixed PHY, the DT node associated
+			 * to the PHY is the Ethernet MAC DT node.
+			 */
+			phynode = of_node_get(priv->device->of_node);
+			fixed_link = true;
+
+			netdev_dbg(dev, "fixed-link detected\n");
+			phydev = of_phy_connect(dev, phynode,
+						&altera_tse_adjust_link,
+						0, priv->phy_iface);
+		} else {
+			netdev_dbg(dev, "no phy-handle found\n");
+			if (!priv->mdio) {
+				netdev_err(dev, "No phy-handle nor local mdio specified\n");
+				return -ENODEV;
+			}
+			phydev = connect_local_phy(dev);
 		}
-		phydev = connect_local_phy(dev);
 	} else {
 		netdev_dbg(dev, "phy-handle found\n");
 		phydev = of_phy_connect(dev, phynode,
@@ -819,10 +840,10 @@ static int init_phy(struct net_device *dev)
 	/* Broken HW is sometimes missing the pull-up resistor on the
 	 * MDIO line, which results in reads to non-existent devices returning
 	 * 0 rather than 0xffff. Catch this here and treat 0 as a non-existent
-	 * device as well.
+	 * device as well. If a fixed-link is used the phy_id is always 0.
 	 * Note: phydev->phy_id is the result of reading the UID PHY registers.
 	 */
-	if (phydev->phy_id == 0) {
+	if ((phydev->phy_id == 0) && !fixed_link) {
 		netdev_err(dev, "Bad PHY UID 0x%08x\n", phydev->phy_id);
 		phy_disconnect(phydev);
 		return -ENODEV;