netdev/phy/of: Handle IEEE802.3 clause 45 Ethernet PHYs in of_mdiobus_register()

Define two new "compatible" values for Ethernet
PHYs. "ethernet-phy-ieee802.3-c22" and "ethernet-phy-ieee802.3-c45"
are used to indicate a PHY uses the corresponding protocol.

If a PHY is "compatible" with "ethernet-phy-ieee802.3-c45", we
indicate this so that get_phy_device() can properly probe the device.

If get_phy_device() fails, it was probably due to failing the probe of
the PHY identifier registers.  Since we have the device tree telling
us the PHY exists, go ahead and add it anyhow with a phy_id of zero.
There may be a driver match based on the "compatible" property.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/phy.txt

@@ -14,10 +14,20 @@ Required properties:
  - linux,phandle :  phandle for this node; likely referenced by an
    ethernet controller node.
 
+Optional Properties:
+
+- compatible: Compatible list, may contain
+  "ethernet-phy-ieee802.3-c22" or "ethernet-phy-ieee802.3-c45" for
+  PHYs that implement IEEE802.3 clause 22 or IEEE802.3 clause 45
+  specifications. If neither of these are specified, the default is to
+  assume clause 22. The compatible list may also contain other
+  elements.
+
 Example:
 
 ethernet-phy@0 {
-	linux,phandle = <2452000>
+	compatible = "ethernet-phy-ieee802.3-c22";
+	linux,phandle = <2452000>;
 	interrupt-parent = <40000>;
 	interrupts = <35 1>;
 	reg = <0>;

drivers/of/of_mdio.c

@@ -57,6 +57,7 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
 		const __be32 *paddr;
 		u32 addr;
 		int len;
+		bool is_c45;
 
 		/* A PHY must have a reg property in the range [0-31] */
 		paddr = of_get_property(child, "reg", &len);
@@ -79,12 +80,19 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
 				mdio->irq[addr] = PHY_POLL;
 		}
 
-		phy = get_phy_device(mdio, addr, false);
+		is_c45 = of_device_is_compatible(child,
+						 "ethernet-phy-ieee802.3-c45");
+		phy = get_phy_device(mdio, addr, is_c45);
+
+		if (!phy || IS_ERR(phy)) {
+			phy = phy_device_create(mdio, addr, 0, false, NULL);
 			if (!phy || IS_ERR(phy)) {
-			dev_err(&mdio->dev, "error probing PHY at address %i\n",
+				dev_err(&mdio->dev,
+					"error creating PHY at address %i\n",
 					addr);
 				continue;
 			}
+		}
 
 		/* Associate the OF node with the device structure so it
 		 * can be looked up later */