1 files changed, 362 insertions, 386 deletions

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 58d602985877..afdf1ad6c0e6 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -8,15 +8,12 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
-#include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/init.h>
-#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/mii.h>
@@ -24,49 +21,19 @@
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/of_device.h>
-#include <linux/of_gpio.h>
 #include <linux/of_mdio.h>
 #include <linux/phy.h>
 #include <linux/reset.h>
-#include <linux/skbuff.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
 #include <linux/unistd.h>
+#include "mdio-private.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/mdio.h>
 
-#include "mdio-boardinfo.h"
-
-static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
-{
-	/* Deassert the optional reset signal */
-	mdiodev->reset_gpio = gpiod_get_optional(&mdiodev->dev,
-						 "reset", GPIOD_OUT_LOW);
-	if (IS_ERR(mdiodev->reset_gpio))
-		return PTR_ERR(mdiodev->reset_gpio);
-
-	if (mdiodev->reset_gpio)
-		gpiod_set_consumer_name(mdiodev->reset_gpio, "PHY reset");
-
-	return 0;
-}
-
-static int mdiobus_register_reset(struct mdio_device *mdiodev)
-{
-	struct reset_control *reset;
-
-	reset = reset_control_get_optional_exclusive(&mdiodev->dev, "phy");
-	if (IS_ERR(reset))
-		return PTR_ERR(reset);
-
-	mdiodev->reset_ctrl = reset;
-
-	return 0;
-}
-
 int mdiobus_register_device(struct mdio_device *mdiodev)
 {
 	int err;
@@ -75,11 +42,7 @@ int mdiobus_register_device(struct mdio_device *mdiodev)
 		return -EBUSY;
 
 	if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY) {
-		err = mdiobus_register_gpiod(mdiodev);
-		if (err)
-			return err;
-
-		err = mdiobus_register_reset(mdiodev);
+		err = mdio_device_register_reset(mdiodev);
 		if (err)
 			return err;
 
@@ -98,7 +61,7 @@ int mdiobus_unregister_device(struct mdio_device *mdiodev)
 	if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
 		return -EINVAL;
 
-	reset_control_put(mdiodev->reset_ctrl);
+	mdio_device_unregister_reset(mdiodev);
 
 	mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
 
@@ -106,10 +69,21 @@ int mdiobus_unregister_device(struct mdio_device *mdiodev)
 }
 EXPORT_SYMBOL(mdiobus_unregister_device);
 
+static struct mdio_device *mdiobus_find_device(struct mii_bus *bus, int addr)
+{
+	bool addr_valid = addr >= 0 && addr < ARRAY_SIZE(bus->mdio_map);
+
+	if (WARN_ONCE(!addr_valid, "addr %d out of range\n", addr))
+		return NULL;
+
+	return bus->mdio_map[addr];
+}
+
 struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
 {
-	struct mdio_device *mdiodev = bus->mdio_map[addr];
+	struct mdio_device *mdiodev;
 
+	mdiodev = mdiobus_find_device(bus, addr);
 	if (!mdiodev)
 		return NULL;
 
@@ -122,50 +96,11 @@ EXPORT_SYMBOL(mdiobus_get_phy);
 
 bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
 {
-	return bus->mdio_map[addr];
+	return mdiobus_find_device(bus, addr) != NULL;
 }
 EXPORT_SYMBOL(mdiobus_is_registered_device);
 
 /**
- * mdiobus_alloc_size - allocate a mii_bus structure
- * @size: extra amount of memory to allocate for private storage.
- * If non-zero, then bus->priv is points to that memory.
- *
- * Description: called by a bus driver to allocate an mii_bus
- * structure to fill in.
- */
-struct mii_bus *mdiobus_alloc_size(size_t size)
-{
-	struct mii_bus *bus;
-	size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
-	size_t alloc_size;
-	int i;
-
-	/* If we alloc extra space, it should be aligned */
-	if (size)
-		alloc_size = aligned_size + size;
-	else
-		alloc_size = sizeof(*bus);
-
-	bus = kzalloc(alloc_size, GFP_KERNEL);
-	if (!bus)
-		return NULL;
-
-	bus->state = MDIOBUS_ALLOCATED;
-	if (size)
-		bus->priv = (void *)bus + aligned_size;
-
-	/* Initialise the interrupts to polling and 64-bit seqcounts */
-	for (i = 0; i < PHY_MAX_ADDR; i++) {
-		bus->irq[i] = PHY_POLL;
-		u64_stats_init(&bus->stats[i].syncp);
-	}
-
-	return bus;
-}
-EXPORT_SYMBOL(mdiobus_alloc_size);
-
-/**
  * mdiobus_release - mii_bus device release callback
  * @d: the target struct device that contains the mii_bus
  *
@@ -181,6 +116,10 @@ static void mdiobus_release(struct device *d)
 	     bus->state != MDIOBUS_ALLOCATED,
 	     "%s: not in RELEASED or ALLOCATED state\n",
 	     bus->id);
+
+	if (bus->state == MDIOBUS_RELEASED)
+		fwnode_handle_put(dev_fwnode(d));
+
 	kfree(bus);
 }
 
@@ -232,7 +171,7 @@ static ssize_t mdio_bus_stat_field_show(struct device *dev,
 		val = mdio_bus_get_stat(&bus->stats[sattr->addr],
 					sattr->field_offset);
 
-	return sprintf(buf, "%llu\n", val);
+	return sysfs_emit(buf, "%llu\n", val);
 }
 
 static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
@@ -251,7 +190,7 @@ static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
 
 	val = mdio_bus_get_stat(&bus->stats[addr], sattr->field_offset);
 
-	return sprintf(buf, "%llu\n", val);
+	return sysfs_emit(buf, "%llu\n", val);
 }
 
 #define MDIO_BUS_STATS_ATTR_DECL(field, file)				\
@@ -389,17 +328,18 @@ static const struct attribute_group *mdio_bus_groups[] = {
 	NULL,
 };
 
-static struct class mdio_bus_class = {
+const struct class mdio_bus_class = {
 	.name		= "mdio_bus",
 	.dev_release	= mdiobus_release,
 	.dev_groups	= mdio_bus_groups,
 };
+EXPORT_SYMBOL_GPL(mdio_bus_class);
 
 /**
  * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
  * @mdio_name: The name of a mdiobus.
  *
- * Returns a reference to the mii_bus, or NULL if none found.  The
+ * Return: a reference to the mii_bus, or NULL if none found. The
  * embedded struct device will have its reference count incremented,
  * and this must be put_deviced'ed once the bus is finished with.
  */
@@ -417,7 +357,7 @@ EXPORT_SYMBOL(mdio_find_bus);
  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
  * @mdio_bus_np: Pointer to the mii_bus.
  *
- * Returns a reference to the mii_bus, or NULL if none found.  The
+ * Return: a reference to the mii_bus, or NULL if none found. The
  * embedded struct device will have its reference count incremented,
  * and this must be put once the bus is finished with.
  *
@@ -437,382 +377,224 @@ struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
 	return d ? to_mii_bus(d) : NULL;
 }
 EXPORT_SYMBOL(of_mdio_find_bus);
+#endif
 
-/* Walk the list of subnodes of a mdio bus and look for a node that
- * matches the mdio device's address with its 'reg' property. If
- * found, set the of_node pointer for the mdio device. This allows
- * auto-probed phy devices to be supplied with information passed in
- * via DT.
- */
-static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
-				    struct mdio_device *mdiodev)
+static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
 {
-	struct device *dev = &mdiodev->dev;
-	struct device_node *child;
-
-	if (dev->of_node || !bus->dev.of_node)
-		return;
-
-	for_each_available_child_of_node(bus->dev.of_node, child) {
-		int addr;
-
-		addr = of_mdio_parse_addr(dev, child);
-		if (addr < 0)
-			continue;
-
-		if (addr == mdiodev->addr) {
-			device_set_node(dev, of_fwnode_handle(child));
-			/* The refcount on "child" is passed to the mdio
-			 * device. Do _not_ use of_node_put(child) here.
-			 */
-			return;
-		}
+	preempt_disable();
+	u64_stats_update_begin(&stats->syncp);
+
+	u64_stats_inc(&stats->transfers);
+	if (ret < 0) {
+		u64_stats_inc(&stats->errors);
+		goto out;
 	}
+
+	if (op)
+		u64_stats_inc(&stats->reads);
+	else
+		u64_stats_inc(&stats->writes);
+out:
+	u64_stats_update_end(&stats->syncp);
+	preempt_enable();
 }
-#else /* !IS_ENABLED(CONFIG_OF_MDIO) */
-static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
-					   struct mdio_device *mdiodev)
-{
-}
-#endif
 
 /**
- * mdiobus_create_device - create a full MDIO device given
- * a mdio_board_info structure
- * @bus: MDIO bus to create the devices on
- * @bi: mdio_board_info structure describing the devices
+ * __mdiobus_read - Unlocked version of the mdiobus_read function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to read
+ *
+ * Return: The register value if successful, negative error code on failure
+ *
+ * Read a MDIO bus register. Caller must hold the mdio bus lock.
  *
- * Returns 0 on success or < 0 on error.
+ * NOTE: MUST NOT be called from interrupt context.
  */
-static int mdiobus_create_device(struct mii_bus *bus,
-				 struct mdio_board_info *bi)
+int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 {
-	struct mdio_device *mdiodev;
-	int ret = 0;
+	int retval;
 
-	mdiodev = mdio_device_create(bus, bi->mdio_addr);
-	if (IS_ERR(mdiodev))
-		return -ENODEV;
+	lockdep_assert_held_once(&bus->mdio_lock);
 
-	strncpy(mdiodev->modalias, bi->modalias,
-		sizeof(mdiodev->modalias));
-	mdiodev->bus_match = mdio_device_bus_match;
-	mdiodev->dev.platform_data = (void *)bi->platform_data;
+	if (addr >= PHY_MAX_ADDR)
+		return -ENXIO;
 
-	ret = mdio_device_register(mdiodev);
-	if (ret)
-		mdio_device_free(mdiodev);
+	if (bus->read)
+		retval = bus->read(bus, addr, regnum);
+	else
+		retval = -EOPNOTSUPP;
 
-	return ret;
+	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
+	mdiobus_stats_acct(&bus->stats[addr], true, retval);
+
+	return retval;
 }
+EXPORT_SYMBOL(__mdiobus_read);
 
 /**
- * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
- * @bus: target mii_bus
- * @owner: module containing bus accessor functions
+ * __mdiobus_write - Unlocked version of the mdiobus_write function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to write
+ * @val: value to write to @regnum
  *
- * Description: Called by a bus driver to bring up all the PHYs
- *   on a given bus, and attach them to the bus. Drivers should use
- *   mdiobus_register() rather than __mdiobus_register() unless they
- *   need to pass a specific owner module. MDIO devices which are not
- *   PHYs will not be brought up by this function. They are expected
- *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
+ * Return: Zero if successful, negative error code on failure
  *
- * Returns 0 on success or < 0 on error.
+ * Write a MDIO bus register. Caller must hold the mdio bus lock.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
  */
-int __mdiobus_register(struct mii_bus *bus, struct module *owner)
+int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 {
-	struct mdio_device *mdiodev;
-	int i, err;
-	struct gpio_desc *gpiod;
-
-	if (NULL == bus || NULL == bus->name ||
-	    NULL == bus->read || NULL == bus->write)
-		return -EINVAL;
-
-	if (bus->parent && bus->parent->of_node)
-		bus->parent->of_node->fwnode.flags |=
-					FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;
-
-	WARN(bus->state != MDIOBUS_ALLOCATED &&
-	     bus->state != MDIOBUS_UNREGISTERED,
-	     "%s: not in ALLOCATED or UNREGISTERED state\n", bus->id);
-
-	bus->owner = owner;
-	bus->dev.parent = bus->parent;
-	bus->dev.class = &mdio_bus_class;
-	bus->dev.groups = NULL;
-	dev_set_name(&bus->dev, "%s", bus->id);
-
-	/* We need to set state to MDIOBUS_UNREGISTERED to correctly release
-	 * the device in mdiobus_free()
-	 *
-	 * State will be updated later in this function in case of success
-	 */
-	bus->state = MDIOBUS_UNREGISTERED;
-
-	err = device_register(&bus->dev);
-	if (err) {
-		pr_err("mii_bus %s failed to register\n", bus->id);
-		return -EINVAL;
-	}
-
-	mutex_init(&bus->mdio_lock);
-	mutex_init(&bus->shared_lock);
-
-	/* assert bus level PHY GPIO reset */
-	gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH);
-	if (IS_ERR(gpiod)) {
-		err = dev_err_probe(&bus->dev, PTR_ERR(gpiod),
-				    "mii_bus %s couldn't get reset GPIO\n",
-				    bus->id);
-		device_del(&bus->dev);
-		return err;
-	} else	if (gpiod) {
-		bus->reset_gpiod = gpiod;
-		fsleep(bus->reset_delay_us);
-		gpiod_set_value_cansleep(gpiod, 0);
-		if (bus->reset_post_delay_us > 0)
-			fsleep(bus->reset_post_delay_us);
-	}
-
-	if (bus->reset) {
-		err = bus->reset(bus);
-		if (err)
-			goto error_reset_gpiod;
-	}
-
-	for (i = 0; i < PHY_MAX_ADDR; i++) {
-		if ((bus->phy_mask & (1 << i)) == 0) {
-			struct phy_device *phydev;
-
-			phydev = mdiobus_scan(bus, i);
-			if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV)) {
-				err = PTR_ERR(phydev);
-				goto error;
-			}
-		}
-	}
+	int err;
 
-	mdiobus_setup_mdiodev_from_board_info(bus, mdiobus_create_device);
+	lockdep_assert_held_once(&bus->mdio_lock);
 
-	bus->state = MDIOBUS_REGISTERED;
-	dev_dbg(&bus->dev, "probed\n");
-	return 0;
+	if (addr >= PHY_MAX_ADDR)
+		return -ENXIO;
 
-error:
-	while (--i >= 0) {
-		mdiodev = bus->mdio_map[i];
-		if (!mdiodev)
-			continue;
+	if (bus->write)
+		err = bus->write(bus, addr, regnum, val);
+	else
+		err = -EOPNOTSUPP;
 
-		mdiodev->device_remove(mdiodev);
-		mdiodev->device_free(mdiodev);
-	}
-error_reset_gpiod:
-	/* Put PHYs in RESET to save power */
-	if (bus->reset_gpiod)
-		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
+	trace_mdio_access(bus, 0, addr, regnum, val, err);
+	mdiobus_stats_acct(&bus->stats[addr], false, err);
 
-	device_del(&bus->dev);
 	return err;
 }
-EXPORT_SYMBOL(__mdiobus_register);
-
-void mdiobus_unregister(struct mii_bus *bus)
-{
-	struct mdio_device *mdiodev;
-	int i;
-
-	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
-		return;
-	bus->state = MDIOBUS_UNREGISTERED;
-
-	for (i = 0; i < PHY_MAX_ADDR; i++) {
-		mdiodev = bus->mdio_map[i];
-		if (!mdiodev)
-			continue;
-
-		if (mdiodev->reset_gpio)
-			gpiod_put(mdiodev->reset_gpio);
-
-		mdiodev->device_remove(mdiodev);
-		mdiodev->device_free(mdiodev);
-	}
-
-	/* Put PHYs in RESET to save power */
-	if (bus->reset_gpiod)
-		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
-
-	device_del(&bus->dev);
-}
-EXPORT_SYMBOL(mdiobus_unregister);
+EXPORT_SYMBOL(__mdiobus_write);
 
 /**
- * mdiobus_free - free a struct mii_bus
- * @bus: mii_bus to free
+ * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to modify
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
  *
- * This function releases the reference to the underlying device
- * object in the mii_bus.  If this is the last reference, the mii_bus
- * will be freed.
- */
-void mdiobus_free(struct mii_bus *bus)
-{
-	/* For compatibility with error handling in drivers. */
-	if (bus->state == MDIOBUS_ALLOCATED) {
-		kfree(bus);
-		return;
-	}
-
-	WARN(bus->state != MDIOBUS_UNREGISTERED,
-	     "%s: not in UNREGISTERED state\n", bus->id);
-	bus->state = MDIOBUS_RELEASED;
-
-	put_device(&bus->dev);
-}
-EXPORT_SYMBOL(mdiobus_free);
-
-/**
- * mdiobus_scan - scan a bus for MDIO devices.
- * @bus: mii_bus to scan
- * @addr: address on bus to scan
+ * Return: 1 if the register was modified, 0 if no change was needed,
+ *	   negative on any error condition
  *
- * This function scans the MDIO bus, looking for devices which can be
- * identified using a vendor/product ID in registers 2 and 3. Not all
- * MDIO devices have such registers, but PHY devices typically
- * do. Hence this function assumes anything found is a PHY, or can be
- * treated as a PHY. Other MDIO devices, such as switches, will
- * probably not be found during the scan.
+ * Read, modify, and if any change, write the register value back to the
+ * device.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
  */
-struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
+int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
+			     u16 mask, u16 set)
 {
-	struct phy_device *phydev = ERR_PTR(-ENODEV);
-	int err;
-
-	switch (bus->probe_capabilities) {
-	case MDIOBUS_NO_CAP:
-	case MDIOBUS_C22:
-		phydev = get_phy_device(bus, addr, false);
-		break;
-	case MDIOBUS_C45:
-		phydev = get_phy_device(bus, addr, true);
-		break;
-	case MDIOBUS_C22_C45:
-		phydev = get_phy_device(bus, addr, false);
-		if (IS_ERR(phydev))
-			phydev = get_phy_device(bus, addr, true);
-		break;
-	}
-
-	if (IS_ERR(phydev))
-		return phydev;
-
-	/*
-	 * For DT, see if the auto-probed phy has a correspoding child
-	 * in the bus node, and set the of_node pointer in this case.
-	 */
-	of_mdiobus_link_mdiodev(bus, &phydev->mdio);
-
-	err = phy_device_register(phydev);
-	if (err) {
-		phy_device_free(phydev);
-		return ERR_PTR(-ENODEV);
-	}
+	int new, ret;
 
-	return phydev;
-}
-EXPORT_SYMBOL(mdiobus_scan);
+	ret = __mdiobus_read(bus, addr, regnum);
+	if (ret < 0)
+		return ret;
 
-static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
-{
-	preempt_disable();
-	u64_stats_update_begin(&stats->syncp);
+	new = (ret & ~mask) | set;
+	if (new == ret)
+		return 0;
 
-	u64_stats_inc(&stats->transfers);
-	if (ret < 0) {
-		u64_stats_inc(&stats->errors);
-		goto out;
-	}
+	ret = __mdiobus_write(bus, addr, regnum, new);
 
-	if (op)
-		u64_stats_inc(&stats->reads);
-	else
-		u64_stats_inc(&stats->writes);
-out:
-	u64_stats_update_end(&stats->syncp);
-	preempt_enable();
+	return ret < 0 ? ret : 1;
 }
+EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
 
 /**
- * __mdiobus_read - Unlocked version of the mdiobus_read function
+ * __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
  *
+ * Return: The register value if successful, negative error code on failure
+ *
  * Read a MDIO bus register. Caller must hold the mdio bus lock.
  *
  * NOTE: MUST NOT be called from interrupt context.
  */
-int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
+int __mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
 {
 	int retval;
 
 	lockdep_assert_held_once(&bus->mdio_lock);
 
-	retval = bus->read(bus, addr, regnum);
+	if (addr >= PHY_MAX_ADDR)
+		return -ENXIO;
+
+	if (bus->read_c45)
+		retval = bus->read_c45(bus, addr, devad, regnum);
+	else
+		retval = -EOPNOTSUPP;
 
 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
 
 	return retval;
 }
-EXPORT_SYMBOL(__mdiobus_read);
+EXPORT_SYMBOL(__mdiobus_c45_read);
 
 /**
- * __mdiobus_write - Unlocked version of the mdiobus_write function
+ * __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
  *
+ * Return: Zero if successful, negative error code on failure
+ *
  * Write a MDIO bus register. Caller must hold the mdio bus lock.
  *
  * NOTE: MUST NOT be called from interrupt context.
  */
-int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
+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);
 
-	err = bus->write(bus, addr, regnum, val);
+	if (addr >= PHY_MAX_ADDR)
+		return -ENXIO;
+
+	if (bus->write_c45)
+		err = bus->write_c45(bus, addr, devad, regnum, val);
+	else
+		err = -EOPNOTSUPP;
 
 	trace_mdio_access(bus, 0, addr, regnum, val, err);
 	mdiobus_stats_acct(&bus->stats[addr], false, err);
 
 	return err;
 }
-EXPORT_SYMBOL(__mdiobus_write);
+EXPORT_SYMBOL(__mdiobus_c45_write);
 
 /**
- * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
+ * __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
  *
+ * Return: 1 if the register was modified, 0 if no change was needed,
+ *	   negative on any error condition
+ *
  * 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.
  */
-int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
-			     u16 mask, u16 set)
+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_read(bus, addr, regnum);
+	ret = __mdiobus_c45_read(bus, addr, devad, regnum);
 	if (ret < 0)
 		return ret;
 
@@ -820,11 +602,10 @@ int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 	if (new == ret)
 		return 0;
 
-	ret = __mdiobus_write(bus, addr, regnum, new);
+	ret = __mdiobus_c45_write(bus, addr, devad, regnum, new);
 
 	return ret < 0 ? ret : 1;
 }
-EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
 
 /**
  * mdiobus_read_nested - Nested version of the mdiobus_read function
@@ -832,6 +613,8 @@ EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
  * @addr: the phy address
  * @regnum: register number to read
  *
+ * Return: The register value if successful, negative error code on failure
+ *
  * In case of nested MDIO bus access avoid lockdep false positives by
  * using mutex_lock_nested().
  *
@@ -857,6 +640,8 @@ EXPORT_SYMBOL(mdiobus_read_nested);
  * @addr: the phy address
  * @regnum: register number to read
  *
+ * Return: The register value if successful, negative error code on failure
+ *
  * NOTE: MUST NOT be called from interrupt context,
  * because the bus read/write functions may wait for an interrupt
  * to conclude the operation.
@@ -874,12 +659,68 @@ 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
+ *
+ * Return: The register value if successful, negative error code on failure
+ *
+ * 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_c45_read_nested - Nested 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
+ *
+ * Return: The register value if successful, negative error code on failure
+ *
+ * In case of nested MDIO bus access avoid lockdep false positives by
+ * using mutex_lock_nested().
+ *
+ * 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_nested(struct mii_bus *bus, int addr, int devad,
+			    u32 regnum)
+{
+	int retval;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_c45_read_nested);
+
+/**
  * mdiobus_write_nested - Nested version of the mdiobus_write function
  * @bus: the mii_bus struct
  * @addr: the phy address
  * @regnum: register number to write
  * @val: value to write to @regnum
  *
+ * Return: Zero if successful, negative error code on failure
+ *
  * In case of nested MDIO bus access avoid lockdep false positives by
  * using mutex_lock_nested().
  *
@@ -906,6 +747,8 @@ EXPORT_SYMBOL(mdiobus_write_nested);
  * @regnum: register number to write
  * @val: value to write to @regnum
  *
+ * Return: Zero if successful, negative error code on failure
+ *
  * NOTE: MUST NOT be called from interrupt context,
  * because the bus read/write functions may wait for an interrupt
  * to conclude the operation.
@@ -923,6 +766,85 @@ 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
+ *
+ * Return: Zero if successful, negative error code on failure
+ *
+ * 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_c45_write_nested - Nested version of the mdiobus_c45_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
+ *
+ * Return: Zero if successful, negative error code on failure
+ *
+ * In case of nested MDIO bus access avoid lockdep false positives by
+ * using mutex_lock_nested().
+ *
+ * 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_nested(struct mii_bus *bus, int addr, int devad,
+			     u32 regnum, u16 val)
+{
+	int err;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(mdiobus_c45_write_nested);
+
+/*
+ * __mdiobus_modify - Convenience function for modifying a given mdio device
+ *	register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to write
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Return: 0 on success, negative on any error condition
+ */
+int __mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask,
+		     u16 set)
+{
+	int err;
+
+	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
+
+	return err < 0 ? err : 0;
+}
+EXPORT_SYMBOL_GPL(__mdiobus_modify);
+
+/**
  * mdiobus_modify - Convenience function for modifying a given mdio device
  *	register
  * @bus: the mii_bus struct
@@ -930,20 +852,48 @@ EXPORT_SYMBOL(mdiobus_write);
  * @regnum: register number to write
  * @mask: bit mask of bits to clear
  * @set: bit mask of bits to set
+ *
+ * Return: 0 on success, negative on any error condition
  */
 int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
 {
 	int err;
 
 	mutex_lock(&bus->mdio_lock);
-	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
+	err = __mdiobus_modify(bus, addr, regnum, mask, set);
 	mutex_unlock(&bus->mdio_lock);
 
-	return err < 0 ? err : 0;
+	return err;
 }
 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
+ *
+ * Return: 0 on success, negative on any error condition
+ */
+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
  * @bus: the mii_bus struct
@@ -951,6 +901,9 @@ EXPORT_SYMBOL_GPL(mdiobus_modify);
  * @regnum: register number to write
  * @mask: bit mask of bits to clear
  * @set: bit mask of bits to set
+ *
+ * Return: 1 if the register was modified, 0 if no change was needed,
+ *	   negative on any error condition
  */
 int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 			   u16 mask, u16 set)
@@ -966,19 +919,45 @@ 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
+ *
+ * Return: 1 if the register was modified, 0 if no change was needed,
+ *	   negative on any error condition
+ */
+int mdiobus_c45_modify_changed(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;
+}
+EXPORT_SYMBOL_GPL(mdiobus_c45_modify_changed);
+
+/**
  * mdio_bus_match - determine if given MDIO driver supports the given
  *		    MDIO device
  * @dev: target MDIO device
  * @drv: given MDIO driver
  *
- * Description: Given a MDIO device, and a MDIO driver, return 1 if
- *   the driver supports the device.  Otherwise, return 0. This may
- *   require calling the devices own match function, since different classes
- *   of MDIO devices have different match criteria.
+ * Return: 1 if the driver supports the device, 0 otherwise
+ *
+ * Description: This may require calling the devices own match function,
+ *   since different classes of MDIO devices have different match criteria.
  */
-static int mdio_bus_match(struct device *dev, struct device_driver *drv)
+static int mdio_bus_match(struct device *dev, const struct device_driver *drv)
 {
-	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
+	const struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 	struct mdio_device *mdio = to_mdio_device(dev);
 
 	/* Both the driver and device must type-match */
@@ -995,7 +974,7 @@ static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
-static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
+static int mdio_uevent(const struct device *dev, struct kobj_uevent_env *env)
 {
 	int rc;
 
@@ -1025,7 +1004,7 @@ static const struct attribute_group *mdio_bus_dev_groups[] = {
 	NULL,
 };
 
-struct bus_type mdio_bus_type = {
+const struct bus_type mdio_bus_type = {
 	.name		= "mdio_bus",
 	.dev_groups	= mdio_bus_dev_groups,
 	.match		= mdio_bus_match,
@@ -1033,7 +1012,7 @@ struct bus_type mdio_bus_type = {
 };
 EXPORT_SYMBOL(mdio_bus_type);
 
-int __init mdio_bus_init(void)
+static int __init mdio_bus_init(void)
 {
 	int ret;
 
@@ -1046,18 +1025,15 @@ int __init mdio_bus_init(void)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(mdio_bus_init);
 
-#if IS_ENABLED(CONFIG_PHYLIB)
-void mdio_bus_exit(void)
+static void __exit mdio_bus_exit(void)
 {
 	class_unregister(&mdio_bus_class);
 	bus_unregister(&mdio_bus_type);
 }
-EXPORT_SYMBOL_GPL(mdio_bus_exit);
-#else
-module_init(mdio_bus_init);
-/* no module_exit, intentional */
+
+subsys_initcall(mdio_bus_init);
+module_exit(mdio_bus_exit);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("MDIO bus/device layer");
-#endif