diff --git a/Documentation/devicetree/bindings/net/mdio-mux.txt b/Documentation/devicetree/bindings/net/mdio-mux.txt
new file mode 100644
index 0000000000000000000000000000000000000000..f65606f8d632b86bab2af28eb4a198d426a378ab
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/mdio-mux.txt
@@ -0,0 +1,136 @@
+Common MDIO bus multiplexer/switch properties.
+
+An MDIO bus multiplexer/switch will have several child busses that are
+numbered uniquely in a device dependent manner. The nodes for an MDIO
+bus multiplexer/switch will have one child node for each child bus.
+
+Required properties:
+- mdio-parent-bus : phandle to the parent MDIO bus.
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Optional properties:
+- Other properties specific to the multiplexer/switch hardware.
+
+Required properties for child nodes:
+- #address-cells = <1>;
+- #size-cells = <0>;
+- reg : The sub-bus number.
+
+
+Example :
+
+ /* The parent MDIO bus. */
+ smi1: mdio@1180000001900 {
+ compatible = "cavium,octeon-3860-mdio";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ reg = <0x11800 0x00001900 0x0 0x40>;
+ };
+
+ /*
+ An NXP sn74cbtlv3253 dual 1-of-4 switch controlled by a
+ pair of GPIO lines. Child busses 2 and 3 populated with 4
+ PHYs each.
+ */
+ mdio-mux {
+ compatible = "mdio-mux-gpio";
+ gpios = <&gpio1 3 0>, <&gpio1 4 0>;
+ mdio-parent-bus = <&smi1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ mdio@2 {
+ reg = <2>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ phy11: ethernet-phy@1 {
+ reg = <1>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ phy12: ethernet-phy@2 {
+ reg = <2>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ phy13: ethernet-phy@3 {
+ reg = <3>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ phy14: ethernet-phy@4 {
+ reg = <4>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <10 8>; /* Pin 10, active low */
+ };
+ };
+
+ mdio@3 {
+ reg = <3>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ phy21: ethernet-phy@1 {
+ reg = <1>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ phy22: ethernet-phy@2 {
+ reg = <2>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ phy23: ethernet-phy@3 {
+ reg = <3>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ phy24: ethernet-phy@4 {
+ reg = <4>;
+ compatible = "marvell,88e1149r";
+ marvell,reg-init = <3 0x10 0 0x5777>,
+ <3 0x11 0 0x00aa>,
+ <3 0x12 0 0x4105>,
+ <3 0x13 0 0x0a60>;
+ interrupt-parent = <&gpio>;
+ interrupts = <12 8>; /* Pin 12, active low */
+ };
+ };
+ };
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 0e01f4e5cd64d9474450c5da7249485b6447b3b7..99c0674a593512bc201374a1d8e30e4182b638fe 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -135,6 +135,15 @@ config MDIO_OCTEON
If in doubt, say Y.
+config MDIO_BUS_MUX
+ tristate
+ depends on OF_MDIO
+ help
+ This module provides a driver framework for MDIO bus
+ multiplexers which connect one of several child MDIO busses
+ to a parent bus. Switching between child busses is done by
+ device specific drivers.
+
endif # PHYLIB
config MICREL_KS8995MA
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index b7438b1b94b9100df5e78c48a8ccc6cb2d57209f..a6b50e7715d0d55ccaaf85dafdf8ea5ddcb0016f 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_MICREL_PHY) += micrel.o
obj-$(CONFIG_MDIO_OCTEON) += mdio-octeon.o
obj-$(CONFIG_MICREL_KS8995MA) += spi_ks8995.o
obj-$(CONFIG_AMD_PHY) += amd.o
+obj-$(CONFIG_MDIO_BUS_MUX) += mdio-mux.o
diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
new file mode 100644
index 0000000000000000000000000000000000000000..39ea0674dcde8cde6b31d71202b9b81873897ba6
--- /dev/null
+++ b/drivers/net/phy/mdio-mux.c
@@ -0,0 +1,192 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011, 2012 Cavium, Inc.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/mdio-mux.h>
+#include <linux/of_mdio.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define DRV_VERSION "1.0"
+#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
+
+struct mdio_mux_child_bus;
+
+struct mdio_mux_parent_bus {
+ struct mii_bus *mii_bus;
+ int current_child;
+ int parent_id;
+ void *switch_data;
+ int (*switch_fn)(int current_child, int desired_child, void *data);
+
+ /* List of our children linked through their next fields. */
+ struct mdio_mux_child_bus *children;
+};
+
+struct mdio_mux_child_bus {
+ struct mii_bus *mii_bus;
+ struct mdio_mux_parent_bus *parent;
+ struct mdio_mux_child_bus *next;
+ int bus_number;
+ int phy_irq[PHY_MAX_ADDR];
+};
+
+/*
+ * The parent bus' lock is used to order access to the switch_fn.
+ */
+static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
+{
+ struct mdio_mux_child_bus *cb = bus->priv;
+ struct mdio_mux_parent_bus *pb = cb->parent;
+ int r;
+
+ mutex_lock(&pb->mii_bus->mdio_lock);
+ r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
+ if (r)
+ goto out;
+
+ pb->current_child = cb->bus_number;
+
+ r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
+out:
+ mutex_unlock(&pb->mii_bus->mdio_lock);
+
+ return r;
+}
+
+/*
+ * The parent bus' lock is used to order access to the switch_fn.
+ */
+static int mdio_mux_write(struct mii_bus *bus, int phy_id,
+ int regnum, u16 val)
+{
+ struct mdio_mux_child_bus *cb = bus->priv;
+ struct mdio_mux_parent_bus *pb = cb->parent;
+
+ int r;
+
+ mutex_lock(&pb->mii_bus->mdio_lock);
+ r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
+ if (r)
+ goto out;
+
+ pb->current_child = cb->bus_number;
+
+ r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
+out:
+ mutex_unlock(&pb->mii_bus->mdio_lock);
+
+ return r;
+}
+
+static int parent_count;
+
+int mdio_mux_init(struct device *dev,
+ int (*switch_fn)(int cur, int desired, void *data),
+ void **mux_handle,
+ void *data)
+{
+ struct device_node *parent_bus_node;
+ struct device_node *child_bus_node;
+ int r, ret_val;
+ struct mii_bus *parent_bus;
+ struct mdio_mux_parent_bus *pb;
+ struct mdio_mux_child_bus *cb;
+
+ if (!dev->of_node)
+ return -ENODEV;
+
+ parent_bus_node = of_parse_phandle(dev->of_node, "mdio-parent-bus", 0);
+
+ if (!parent_bus_node)
+ return -ENODEV;
+
+ parent_bus = of_mdio_find_bus(parent_bus_node);
+ if (parent_bus == NULL) {
+ ret_val = -EPROBE_DEFER;
+ goto err_parent_bus;
+ }
+
+ pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
+ if (pb == NULL) {
+ ret_val = -ENOMEM;
+ goto err_parent_bus;
+ }
+
+ pb->switch_data = data;
+ pb->switch_fn = switch_fn;
+ pb->current_child = -1;
+ pb->parent_id = parent_count++;
+ pb->mii_bus = parent_bus;
+
+ ret_val = -ENODEV;
+ for_each_child_of_node(dev->of_node, child_bus_node) {
+ u32 v;
+
+ r = of_property_read_u32(child_bus_node, "reg", &v);
+ if (r)
+ continue;
+
+ cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
+ if (cb == NULL) {
+ dev_err(dev,
+ "Error: Failed to allocate memory for child\n");
+ ret_val = -ENOMEM;
+ break;
+ }
+ cb->bus_number = v;
+ cb->parent = pb;
+ cb->mii_bus = mdiobus_alloc();
+ cb->mii_bus->priv = cb;
+
+ cb->mii_bus->irq = cb->phy_irq;
+ cb->mii_bus->name = "mdio_mux";
+ snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
+ pb->parent_id, v);
+ cb->mii_bus->parent = dev;
+ cb->mii_bus->read = mdio_mux_read;
+ cb->mii_bus->write = mdio_mux_write;
+ r = of_mdiobus_register(cb->mii_bus, child_bus_node);
+ if (r) {
+ mdiobus_free(cb->mii_bus);
+ devm_kfree(dev, cb);
+ } else {
+ of_node_get(child_bus_node);
+ cb->next = pb->children;
+ pb->children = cb;
+ }
+ }
+ if (pb->children) {
+ *mux_handle = pb;
+ dev_info(dev, "Version " DRV_VERSION "\n");
+ return 0;
+ }
+err_parent_bus:
+ of_node_put(parent_bus_node);
+ return ret_val;
+}
+EXPORT_SYMBOL_GPL(mdio_mux_init);
+
+void mdio_mux_uninit(void *mux_handle)
+{
+ struct mdio_mux_parent_bus *pb = mux_handle;
+ struct mdio_mux_child_bus *cb = pb->children;
+
+ while (cb) {
+ mdiobus_unregister(cb->mii_bus);
+ mdiobus_free(cb->mii_bus);
+ cb = cb->next;
+ }
+}
+EXPORT_SYMBOL_GPL(mdio_mux_uninit);
+
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_VERSION(DRV_VERSION);
+MODULE_AUTHOR("David Daney");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mdio-mux.h b/include/linux/mdio-mux.h
new file mode 100644
index 0000000000000000000000000000000000000000..a243dbba8659a750cde5a23374184fe36def6734
--- /dev/null
+++ b/include/linux/mdio-mux.h
@@ -0,0 +1,21 @@
+/*
+ * MDIO bus multiplexer framwork.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011, 2012 Cavium, Inc.
+ */
+#ifndef __LINUX_MDIO_MUX_H
+#define __LINUX_MDIO_MUX_H
+#include <linux/device.h>
+
+int mdio_mux_init(struct device *dev,
+ int (*switch_fn) (int cur, int desired, void *data),
+ void **mux_handle,
+ void *data);
+
+void mdio_mux_uninit(void *mux_handle);
+
+#endif /* __LINUX_MDIO_MUX_H */