net: dsa: microchip: lan937x: register mdio-bus

This patch register mdio-bus for the lan937x series switch. mdio read
and write uses the vphy for accessing the phy register.
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/lan937x_main.c

@@ -7,6 +7,7 @@
 #include <linux/iopoll.h>
 #include <linux/phy.h>
 #include <linux/of_net.h>
+#include <linux/of_mdio.h>
 #include <linux/if_bridge.h>
 #include <linux/math.h>
 #include <net/dsa.h>
@@ -136,6 +137,73 @@ void lan937x_w_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 val)
 	lan937x_internal_phy_write(dev, addr, reg, val);
 }
 
+static int lan937x_sw_mdio_read(struct mii_bus *bus, int addr, int regnum)
+{
+	struct ksz_device *dev = bus->priv;
+	u16 val;
+	int ret;
+
+	if (regnum & MII_ADDR_C45)
+		return -EOPNOTSUPP;
+
+	ret = lan937x_internal_phy_read(dev, addr, regnum, &val);
+	if (ret < 0)
+		return ret;
+
+	return val;
+}
+
+static int lan937x_sw_mdio_write(struct mii_bus *bus, int addr, int regnum,
+				 u16 val)
+{
+	struct ksz_device *dev = bus->priv;
+
+	if (regnum & MII_ADDR_C45)
+		return -EOPNOTSUPP;
+
+	return lan937x_internal_phy_write(dev, addr, regnum, val);
+}
+
+static int lan937x_mdio_register(struct ksz_device *dev)
+{
+	struct dsa_switch *ds = dev->ds;
+	struct device_node *mdio_np;
+	struct mii_bus *bus;
+	int ret;
+
+	mdio_np = of_get_child_by_name(dev->dev->of_node, "mdio");
+	if (!mdio_np) {
+		dev_err(ds->dev, "no MDIO bus node\n");
+		return -ENODEV;
+	}
+
+	bus = devm_mdiobus_alloc(ds->dev);
+	if (!bus) {
+		of_node_put(mdio_np);
+		return -ENOMEM;
+	}
+
+	bus->priv = dev;
+	bus->read = lan937x_sw_mdio_read;
+	bus->write = lan937x_sw_mdio_write;
+	bus->name = "lan937x slave smi";
+	snprintf(bus->id, MII_BUS_ID_SIZE, "SMI-%d", ds->index);
+	bus->parent = ds->dev;
+	bus->phy_mask = ~ds->phys_mii_mask;
+
+	ds->slave_mii_bus = bus;
+
+	ret = devm_of_mdiobus_register(ds->dev, bus, mdio_np);
+	if (ret) {
+		dev_err(ds->dev, "unable to register MDIO bus %s\n",
+			bus->id);
+	}
+
+	of_node_put(mdio_np);
+
+	return ret;
+}
+
 int lan937x_reset_switch(struct ksz_device *dev)
 {
 	u32 data32;
@@ -228,6 +296,12 @@ int lan937x_setup(struct dsa_switch *ds)
 		return ret;
 	}
 
+	ret = lan937x_mdio_register(dev);
+	if (ret < 0) {
+		dev_err(dev->dev, "failed to register the mdio");
+		return ret;
+	}
+
 	/* The VLAN aware is a global setting. Mixed vlan
 	 * filterings are not supported.
 	 */