diff --git a/arch/powerpc/platforms/82xx/ep8248e.c b/arch/powerpc/platforms/82xx/ep8248e.c
index ba93d8ae9b0c..d5770fdf7f09 100644
--- a/arch/powerpc/platforms/82xx/ep8248e.c
+++ b/arch/powerpc/platforms/82xx/ep8248e.c
@@ -138,7 +138,7 @@ static int __devinit ep8248e_mdio_probe(struct of_device *ofdev,
 
 	bus->name = "ep8248e-mdio-bitbang";
 	bus->dev = &ofdev->dev;
-	bus->id = res.start;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%x", res.start);
 
 	return mdiobus_register(bus);
 }
diff --git a/arch/powerpc/platforms/pasemi/gpio_mdio.c b/arch/powerpc/platforms/pasemi/gpio_mdio.c
index b46542990cf8..ab6955412ba4 100644
--- a/arch/powerpc/platforms/pasemi/gpio_mdio.c
+++ b/arch/powerpc/platforms/pasemi/gpio_mdio.c
@@ -241,7 +241,7 @@ static int __devinit gpio_mdio_probe(struct of_device *ofdev,
 	new_bus->reset = &gpio_mdio_reset;
 
 	prop = of_get_property(np, "reg", NULL);
-	new_bus->id = *prop;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", *prop);
 	new_bus->priv = priv;
 
 	new_bus->phy_mask = 0;
diff --git a/arch/powerpc/sysdev/fsl_soc.c b/arch/powerpc/sysdev/fsl_soc.c
index 2c5388ce902a..3581416905ea 100644
--- a/arch/powerpc/sysdev/fsl_soc.c
+++ b/arch/powerpc/sysdev/fsl_soc.c
@@ -341,7 +341,7 @@ static int __init gfar_of_init(void)
 				goto unreg;
 			}
 
-			gfar_data.bus_id = 0;
+			snprintf(gfar_data.bus_id, MII_BUS_ID_SIZE, "0");
 			gfar_data.phy_id = fixed_link[0];
 		} else {
 			phy = of_find_node_by_phandle(*ph);
@@ -362,7 +362,8 @@ static int __init gfar_of_init(void)
 			}
 
 			gfar_data.phy_id = *id;
-			gfar_data.bus_id = res.start;
+			snprintf(gfar_data.bus_id, MII_BUS_ID_SIZE, "%x",
+					res.start);
 
 			of_node_put(phy);
 			of_node_put(mdio);
diff --git a/drivers/net/au1000_eth.c b/drivers/net/au1000_eth.c
index 504b7ce2747d..3634b5fd7919 100644
--- a/drivers/net/au1000_eth.c
+++ b/drivers/net/au1000_eth.c
@@ -701,7 +701,7 @@ static struct net_device * au1000_probe(int port_num)
 	aup->mii_bus.write = mdiobus_write;
 	aup->mii_bus.reset = mdiobus_reset;
 	aup->mii_bus.name = "au1000_eth_mii";
-	aup->mii_bus.id = aup->mac_id;
+	snprintf(aup->mii_bus.id, MII_BUS_ID_SIZE, "%x", aup->mac_id);
 	aup->mii_bus.irq = kmalloc(sizeof(int)*PHY_MAX_ADDR, GFP_KERNEL);
 	for(i = 0; i < PHY_MAX_ADDR; ++i)
 		aup->mii_bus.irq[i] = PHY_POLL;
@@ -709,11 +709,11 @@ static struct net_device * au1000_probe(int port_num)
 	/* if known, set corresponding PHY IRQs */
 #if defined(AU1XXX_PHY_STATIC_CONFIG)
 # if defined(AU1XXX_PHY0_IRQ)
-	if (AU1XXX_PHY0_BUSID == aup->mii_bus.id)
+	if (AU1XXX_PHY0_BUSID == aup->mac_id)
 		aup->mii_bus.irq[AU1XXX_PHY0_ADDR] = AU1XXX_PHY0_IRQ;
 # endif
 # if defined(AU1XXX_PHY1_IRQ)
-	if (AU1XXX_PHY1_BUSID == aup->mii_bus.id)
+	if (AU1XXX_PHY1_BUSID == aup->mac_id)
 		aup->mii_bus.irq[AU1XXX_PHY1_ADDR] = AU1XXX_PHY1_IRQ;
 # endif
 #endif
diff --git a/drivers/net/bfin_mac.c b/drivers/net/bfin_mac.c
index 26b2dd5016cd..717dcc1aa1e9 100644
--- a/drivers/net/bfin_mac.c
+++ b/drivers/net/bfin_mac.c
@@ -969,7 +969,7 @@ static int __init bf537mac_probe(struct net_device *dev)
 	lp->mii_bus.write = mdiobus_write;
 	lp->mii_bus.reset = mdiobus_reset;
 	lp->mii_bus.name = "bfin_mac_mdio";
-	lp->mii_bus.id = 0;
+	snprintf(lp->mii_bus.id, MII_BUS_ID_SIZE, "0");
 	lp->mii_bus.irq = kmalloc(sizeof(int)*PHY_MAX_ADDR, GFP_KERNEL);
 	for (i = 0; i < PHY_MAX_ADDR; ++i)
 		lp->mii_bus.irq[i] = PHY_POLL;
diff --git a/drivers/net/cpmac.c b/drivers/net/cpmac.c
index c85194f2cd2d..9da7ff437031 100644
--- a/drivers/net/cpmac.c
+++ b/drivers/net/cpmac.c
@@ -987,7 +987,7 @@ static int external_switch;
 static int __devinit cpmac_probe(struct platform_device *pdev)
 {
 	int rc, phy_id, i;
-	int mdio_bus_id = cpmac_mii.id;
+	char *mdio_bus_id = "0";
 	struct resource *mem;
 	struct cpmac_priv *priv;
 	struct net_device *dev;
@@ -1008,8 +1008,6 @@ static int __devinit cpmac_probe(struct platform_device *pdev)
 		if (external_switch || dumb_switch) {
 			struct fixed_phy_status status = {};
 
-			mdio_bus_id = 0;
-
 			/*
 			 * FIXME: this should be in the platform code!
 			 * Since there is not platform code at all (that is,
@@ -1143,6 +1141,7 @@ int __devinit cpmac_init(void)
 	}
 
 	cpmac_mii.phy_mask = ~(mask | 0x80000000);
+	snprintf(cpmac_mii.id, MII_BUS_ID_SIZE, "0");
 
 	res = mdiobus_register(&cpmac_mii);
 	if (res)
diff --git a/drivers/net/fec_mpc52xx.c b/drivers/net/fec_mpc52xx.c
index 58b71e60204e..43b5f30743c2 100644
--- a/drivers/net/fec_mpc52xx.c
+++ b/drivers/net/fec_mpc52xx.c
@@ -198,7 +198,7 @@ static int mpc52xx_fec_init_phy(struct net_device *dev)
 	struct phy_device *phydev;
 	char phy_id[BUS_ID_SIZE];
 
-	snprintf(phy_id, BUS_ID_SIZE, PHY_ID_FMT,
+	snprintf(phy_id, BUS_ID_SIZE, "%x:%02x",
 			(unsigned int)dev->base_addr, priv->phy_addr);
 
 	priv->link = PHY_DOWN;
diff --git a/drivers/net/fec_mpc52xx_phy.c b/drivers/net/fec_mpc52xx_phy.c
index 6a3ac4ea97e9..956836fc5ec0 100644
--- a/drivers/net/fec_mpc52xx_phy.c
+++ b/drivers/net/fec_mpc52xx_phy.c
@@ -124,7 +124,7 @@ static int mpc52xx_fec_mdio_probe(struct of_device *of, const struct of_device_i
 		goto out_free;
 	}
 
-	bus->id = res.start;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%x", res.start);
 	bus->priv = priv;
 
 	bus->dev = dev;
diff --git a/drivers/net/fs_enet/fs_enet-main.c b/drivers/net/fs_enet/fs_enet-main.c
index 940e2041ba38..67b4b0728fce 100644
--- a/drivers/net/fs_enet/fs_enet-main.c
+++ b/drivers/net/fs_enet/fs_enet-main.c
@@ -1178,7 +1178,7 @@ static int __devinit find_phy(struct device_node *np,
 
 	data  = of_get_property(np, "fixed-link", NULL);
 	if (data) {
-		snprintf(fpi->bus_id, 16, PHY_ID_FMT, 0, *data);
+		snprintf(fpi->bus_id, 16, "%x:%02x", 0, *data);
 		return 0;
 	}
 
@@ -1202,7 +1202,7 @@ static int __devinit find_phy(struct device_node *np,
 	if (!data || len != 4)
 		goto out_put_mdio;
 
-	snprintf(fpi->bus_id, 16, PHY_ID_FMT, res.start, *data);
+	snprintf(fpi->bus_id, 16, "%x:%02x", res.start, *data);
 
 out_put_mdio:
 	of_node_put(mdionode);
diff --git a/drivers/net/fs_enet/mii-bitbang.c b/drivers/net/fs_enet/mii-bitbang.c
index b8e4a736a130..1620030cd33c 100644
--- a/drivers/net/fs_enet/mii-bitbang.c
+++ b/drivers/net/fs_enet/mii-bitbang.c
@@ -130,7 +130,7 @@ static int __devinit fs_mii_bitbang_init(struct mii_bus *bus,
 	 * we get is an int, and the odds of multiple bitbang mdio buses
 	 * is low enough that it's not worth going too crazy.
 	 */
-	bus->id = res.start;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%x", res.start);
 
 	data = of_get_property(np, "fsl,mdio-pin", &len);
 	if (!data || len != 4)
@@ -307,7 +307,7 @@ static int __devinit fs_enet_mdio_probe(struct device *dev)
 		return -ENOMEM;
 
 	new_bus->name = "BB MII Bus",
-	new_bus->id = pdev->id;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", pdev->id);
 
 	new_bus->phy_mask = ~0x9;
 	pdata = (struct fs_mii_bb_platform_info *)pdev->dev.platform_data;
diff --git a/drivers/net/fs_enet/mii-fec.c b/drivers/net/fs_enet/mii-fec.c
index a89cf15090b8..ba75efc9f5b5 100644
--- a/drivers/net/fs_enet/mii-fec.c
+++ b/drivers/net/fs_enet/mii-fec.c
@@ -196,7 +196,7 @@ static int __devinit fs_enet_mdio_probe(struct of_device *ofdev,
 	if (ret)
 		return ret;
 
-	new_bus->id = res.start;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", res.start);
 
 	fec->fecp = ioremap(res.start, res.end - res.start + 1);
 	if (!fec->fecp)
@@ -309,7 +309,7 @@ static int __devinit fs_enet_fec_mdio_probe(struct device *dev)
 	new_bus->read = &fs_enet_fec_mii_read,
 	new_bus->write = &fs_enet_fec_mii_write,
 	new_bus->reset = &fs_enet_fec_mii_reset,
-	new_bus->id = pdev->id;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", pdev->id);
 
 	pdata = (struct fs_mii_fec_platform_info *)pdev->dev.platform_data;
 
diff --git a/drivers/net/gianfar_mii.c b/drivers/net/gianfar_mii.c
index 24327629bf03..b8898927236a 100644
--- a/drivers/net/gianfar_mii.c
+++ b/drivers/net/gianfar_mii.c
@@ -173,7 +173,7 @@ int gfar_mdio_probe(struct device *dev)
 	new_bus->read = &gfar_mdio_read,
 	new_bus->write = &gfar_mdio_write,
 	new_bus->reset = &gfar_mdio_reset,
-	new_bus->id = pdev->id;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", pdev->id);
 
 	pdata = (struct gianfar_mdio_data *)pdev->dev.platform_data;
 
diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 489c7c3b90d9..d513bb8a4902 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -246,7 +246,7 @@ static int macb_mii_init(struct macb *bp)
 	bp->mii_bus.read = &macb_mdio_read;
 	bp->mii_bus.write = &macb_mdio_write;
 	bp->mii_bus.reset = &macb_mdio_reset;
-	bp->mii_bus.id = bp->pdev->id;
+	snprintf(bp->mii_bus.id, MII_BUS_ID_SIZE, "%x", bp->pdev->id);
 	bp->mii_bus.priv = bp;
 	bp->mii_bus.dev = &bp->dev->dev;
 	pdata = bp->pdev->dev.platform_data;
diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index 2e39e0285d8f..bcd7f9814ed8 100644
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -1012,7 +1012,7 @@ static int pasemi_mac_phy_init(struct net_device *dev)
 		goto err;
 
 	phy_id = *prop;
-	snprintf(mac->phy_id, BUS_ID_SIZE, PHY_ID_FMT, (int)r.start, phy_id);
+	snprintf(mac->phy_id, BUS_ID_SIZE, "%x:%02x", (int)r.start, phy_id);
 
 	of_node_put(phy_dn);
 
diff --git a/drivers/net/phy/fixed.c b/drivers/net/phy/fixed.c
index ca9b040f9ad9..4e07956a483b 100644
--- a/drivers/net/phy/fixed.c
+++ b/drivers/net/phy/fixed.c
@@ -213,7 +213,7 @@ static int __init fixed_mdio_bus_init(void)
 		goto err_pdev;
 	}
 
-	fmb->mii_bus.id = 0;
+	snprintf(fmb->mii_bus.id, MII_BUS_ID_SIZE, "0");
 	fmb->mii_bus.name = "Fixed MDIO Bus";
 	fmb->mii_bus.dev = &pdev->dev;
 	fmb->mii_bus.read = &fixed_mdio_read;
diff --git a/drivers/net/sb1250-mac.c b/drivers/net/sb1250-mac.c
index 7b53d658e337..888b7dec9866 100644
--- a/drivers/net/sb1250-mac.c
+++ b/drivers/net/sb1250-mac.c
@@ -2374,7 +2374,7 @@ static int sbmac_init(struct platform_device *pldev, long long base)
 	       dev->name, base, print_mac(mac, eaddr));
 
 	sc->mii_bus.name = sbmac_mdio_string;
-	sc->mii_bus.id = idx;
+	snprintf(sc->mii_bus.id, MII_BUS_ID_SIZE, "%x", idx);
 	sc->mii_bus.priv = sc;
 	sc->mii_bus.read = sbmac_mii_read;
 	sc->mii_bus.write = sbmac_mii_write;
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 0ee4c168e4c0..29a4d650e8a8 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -3954,7 +3954,7 @@ static int ucc_geth_probe(struct of_device* ofdev, const struct of_device_id *ma
 		if (err)
 			return -1;
 
-		ug_info->mdio_bus = res.start;
+		snprintf(ug_info->mdio_bus, MII_BUS_ID_SIZE, "%x", res.start);
 	}
 
 	/* get the phy interface type, or default to MII */
diff --git a/drivers/net/ucc_geth.h b/drivers/net/ucc_geth.h
index 4fb95b3af948..9f8b7580a3a4 100644
--- a/drivers/net/ucc_geth.h
+++ b/drivers/net/ucc_geth.h
@@ -1156,7 +1156,7 @@ struct ucc_geth_info {
 	u16 pausePeriod;
 	u16 extensionField;
 	u8 phy_address;
-	u32 mdio_bus;
+	char mdio_bus[MII_BUS_ID_SIZE];
 	u8 weightfactor[NUM_TX_QUEUES];
 	u8 interruptcoalescingmaxvalue[NUM_RX_QUEUES];
 	u8 l2qt[UCC_GETH_VLAN_PRIORITY_MAX];
diff --git a/drivers/net/ucc_geth_mii.c b/drivers/net/ucc_geth_mii.c
index c69e654d539f..e4d3f330bac3 100644
--- a/drivers/net/ucc_geth_mii.c
+++ b/drivers/net/ucc_geth_mii.c
@@ -157,7 +157,7 @@ static int uec_mdio_probe(struct of_device *ofdev, const struct of_device_id *ma
 	if (err)
 		goto reg_map_fail;
 
-	new_bus->id = res.start;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", res.start);
 
 	new_bus->irq = kmalloc(32 * sizeof(int), GFP_KERNEL);
 
diff --git a/include/linux/fsl_devices.h b/include/linux/fsl_devices.h
index 1831b196c70a..2cad5c67397e 100644
--- a/include/linux/fsl_devices.h
+++ b/include/linux/fsl_devices.h
@@ -50,7 +50,7 @@ struct gianfar_platform_data {
 	u32	device_flags;
 	/* board specific information */
 	u32	board_flags;
-	u32	bus_id;
+	char	bus_id[MII_BUS_ID_SIZE];
 	u32	phy_id;
 	u8	mac_addr[6];
 	phy_interface_t interface;
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 5e43ae751412..6509f377bb10 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -63,8 +63,6 @@ typedef enum {
 	PHY_INTERFACE_MODE_RTBI
 } phy_interface_t;
 
-#define MII_BUS_MAX 4
-
 
 #define PHY_INIT_TIMEOUT	100000
 #define PHY_STATE_TIME		1
@@ -74,13 +72,19 @@ typedef enum {
 #define PHY_MAX_ADDR	32
 
 /* Used when trying to connect to a specific phy (mii bus id:phy device id) */
-#define PHY_ID_FMT "%x:%02x"
+#define PHY_ID_FMT "%s:%02x"
+
+/*
+ * Need to be a little smaller than phydev->dev.bus_id to leave room
+ * for the ":%02x"
+ */
+#define MII_BUS_ID_SIZE	(BUS_ID_SIZE - 3)
 
 /* The Bus class for PHYs.  Devices which provide access to
  * PHYs should register using this structure */
 struct mii_bus {
 	const char *name;
-	int id;
+	char id[MII_BUS_ID_SIZE];
 	void *priv;
 	int (*read)(struct mii_bus *bus, int phy_id, int regnum);
 	int (*write)(struct mii_bus *bus, int phy_id, int regnum, u16 val);