diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 1cd604cd1fa1..bde195864c17 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -826,6 +826,100 @@ int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 }
 EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
 
+/**
+ * __mdiobus_c45_read - Unlocked version of the mdiobus_c45_read function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to read
+ *
+ * Read a MDIO bus register. Caller must hold the mdio bus lock.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
+{
+	int retval;
+
+	lockdep_assert_held_once(&bus->mdio_lock);
+
+	if (bus->read_c45)
+		retval = bus->read_c45(bus, addr, devad, regnum);
+	else
+		retval = bus->read(bus, addr, mdiobus_c45_addr(devad, regnum));
+
+	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
+	mdiobus_stats_acct(&bus->stats[addr], true, retval);
+
+	return retval;
+}
+EXPORT_SYMBOL(__mdiobus_c45_read);
+
+/**
+ * __mdiobus_c45_write - Unlocked version of the mdiobus_write function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * Write a MDIO bus register. Caller must hold the mdio bus lock.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
+			u16 val)
+{
+	int err;
+
+	lockdep_assert_held_once(&bus->mdio_lock);
+
+	if (bus->write_c45)
+		err = bus->write_c45(bus, addr, devad, regnum, val);
+	else
+		err = bus->write(bus, addr, mdiobus_c45_addr(devad, regnum),
+				 val);
+
+	trace_mdio_access(bus, 0, addr, regnum, val, err);
+	mdiobus_stats_acct(&bus->stats[addr], false, err);
+
+	return err;
+}
+EXPORT_SYMBOL(__mdiobus_c45_write);
+
+/**
+ * __mdiobus_c45_modify_changed - Unlocked version of the mdiobus_modify function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to modify
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Read, modify, and if any change, write the register value back to the
+ * device. Any error returns a negative number.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+static int __mdiobus_c45_modify_changed(struct mii_bus *bus, int addr,
+					int devad, u32 regnum, u16 mask,
+					u16 set)
+{
+	int new, ret;
+
+	ret = __mdiobus_c45_read(bus, addr, devad, regnum);
+	if (ret < 0)
+		return ret;
+
+	new = (ret & ~mask) | set;
+	if (new == ret)
+		return 0;
+
+	ret = __mdiobus_c45_write(bus, addr, devad, regnum, new);
+
+	return ret < 0 ? ret : 1;
+}
+
 /**
  * mdiobus_read_nested - Nested version of the mdiobus_read function
  * @bus: the mii_bus struct
@@ -873,6 +967,29 @@ int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 }
 EXPORT_SYMBOL(mdiobus_read);
 
+/**
+ * mdiobus_c45_read - Convenience function for reading a given MII mgmt register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to read
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
+{
+	int retval;
+
+	mutex_lock(&bus->mdio_lock);
+	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_c45_read);
+
 /**
  * mdiobus_write_nested - Nested version of the mdiobus_write function
  * @bus: the mii_bus struct
@@ -922,6 +1039,31 @@ int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 }
 EXPORT_SYMBOL(mdiobus_write);
 
+/**
+ * mdiobus_c45_write - Convenience function for writing a given MII mgmt register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
+		      u16 val)
+{
+	int err;
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(mdiobus_c45_write);
+
 /**
  * mdiobus_modify - Convenience function for modifying a given mdio device
  *	register
@@ -943,6 +1085,30 @@ int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
 }
 EXPORT_SYMBOL_GPL(mdiobus_modify);
 
+/**
+ * mdiobus_c45_modify - Convenience function for modifying a given mdio device
+ *	register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to write
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ */
+int mdiobus_c45_modify(struct mii_bus *bus, int addr, int devad, u32 regnum,
+		       u16 mask, u16 set)
+{
+	int err;
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_c45_modify_changed(bus, addr, devad, regnum,
+					   mask, set);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err < 0 ? err : 0;
+}
+EXPORT_SYMBOL_GPL(mdiobus_c45_modify);
+
 /**
  * mdiobus_modify_changed - Convenience function for modifying a given mdio
  *	device register and returning if it changed
@@ -965,6 +1131,29 @@ int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 }
 EXPORT_SYMBOL_GPL(mdiobus_modify_changed);
 
+/**
+ * mdiobus_c45_modify_changed - Convenience function for modifying a given mdio
+ *	device register and returning if it changed
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @regnum: register number to write
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ */
+int mdiobus_c45_modify_changed(struct mii_bus *bus, int devad, int addr,
+			       u32 regnum, u16 mask, u16 set)
+{
+	int err;
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_c45_modify_changed(bus, addr, devad, regnum, mask, set);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(mdiobus_c45_modify_changed);
+
 /**
  * mdio_bus_match - determine if given MDIO driver supports the given
  *		    MDIO device
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index f7fbbf3069e7..1e78c8410b21 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -423,6 +423,17 @@ int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask,
 		   u16 set);
 int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 			   u16 mask, u16 set);
+int __mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum);
+int mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum);
+int __mdiobus_c45_write(struct mii_bus *bus, int addr,  int devad, u32 regnum,
+			u16 val);
+int mdiobus_c45_write(struct mii_bus *bus, int addr,  int devad, u32 regnum,
+		      u16 val);
+int mdiobus_c45_modify(struct mii_bus *bus, int addr, int devad, u32 regnum,
+		       u16 mask, u16 set);
+
+int mdiobus_c45_modify_changed(struct mii_bus *bus, int addr, int devad,
+			       u32 regnum, u16 mask, u16 set);
 
 static inline int mdiodev_read(struct mdio_device *mdiodev, u32 regnum)
 {
@@ -463,29 +474,19 @@ static inline u16 mdiobus_c45_devad(u32 regnum)
 	return FIELD_GET(MII_DEVADDR_C45_MASK, regnum);
 }
 
-static inline int __mdiobus_c45_read(struct mii_bus *bus, int prtad, int devad,
-				     u16 regnum)
+static inline int mdiodev_c45_modify(struct mdio_device *mdiodev, int devad,
+				     u32 regnum, u16 mask, u16 set)
 {
-	return __mdiobus_read(bus, prtad, mdiobus_c45_addr(devad, regnum));
+	return mdiobus_c45_modify(mdiodev->bus, mdiodev->addr, devad, regnum,
+				  mask, set);
 }
 
-static inline int __mdiobus_c45_write(struct mii_bus *bus, int prtad, int devad,
-				      u16 regnum, u16 val)
+static inline int mdiodev_c45_modify_changed(struct mdio_device *mdiodev,
+					     int devad, u32 regnum, u16 mask,
+					     u16 set)
 {
-	return __mdiobus_write(bus, prtad, mdiobus_c45_addr(devad, regnum),
-			       val);
-}
-
-static inline int mdiobus_c45_read(struct mii_bus *bus, int prtad, int devad,
-				   u16 regnum)
-{
-	return mdiobus_read(bus, prtad, mdiobus_c45_addr(devad, regnum));
-}
-
-static inline int mdiobus_c45_write(struct mii_bus *bus, int prtad, int devad,
-				    u16 regnum, u16 val)
-{
-	return mdiobus_write(bus, prtad, mdiobus_c45_addr(devad, regnum), val);
+	return mdiobus_c45_modify_changed(mdiodev->bus, mdiodev->addr, devad,
+					  regnum, mask, set);
 }
 
 static inline int mdiodev_c45_read(struct mdio_device *mdiodev, int devad,
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 71eeb4e3b1fd..c33ad3255e3a 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -364,6 +364,11 @@ struct mii_bus {
 	int (*read)(struct mii_bus *bus, int addr, int regnum);
 	/** @write: Perform a write transfer on the bus */
 	int (*write)(struct mii_bus *bus, int addr, int regnum, u16 val);
+	/** @read: Perform a C45 read transfer on the bus */
+	int (*read_c45)(struct mii_bus *bus, int addr, int devnum, int regnum);
+	/** @write: Perform a C45 write transfer on the bus */
+	int (*write_c45)(struct mii_bus *bus, int addr, int devnum,
+			 int regnum, u16 val);
 	/** @reset: Perform a reset of the bus */
 	int (*reset)(struct mii_bus *bus);
 
