1 files changed, 258 insertions, 109 deletions

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 087e480b624c..ae7e9c8b65a6 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -16,6 +16,7 @@
 #include <linux/acpi.h>
 #include <linux/clk/clk-conf.h>
 #include <linux/completion.h>
+#include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/errno.h>
@@ -25,21 +26,22 @@
 #include <linux/idr.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
-#include <linux/irqflags.h>
+#include <linux/irq.h>
 #include <linux/jump_label.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of_device.h>
 #include <linux/of.h>
-#include <linux/of_irq.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/pinctrl/devinfo.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_wakeirq.h>
 #include <linux/property.h>
 #include <linux/rwsem.h>
 #include <linux/slab.h>
+#include <linux/string_choices.h>
 
 #include "i2c-core.h"
 
@@ -66,6 +68,8 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
 static bool is_registered;
 
+static struct dentry *i2c_debugfs_root;
+
 int i2c_transfer_trace_reg(void)
 {
 	static_branch_inc(&i2c_trace_msg_key);
@@ -113,10 +117,29 @@ const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
 }
 EXPORT_SYMBOL_GPL(i2c_match_id);
 
-static int i2c_device_match(struct device *dev, struct device_driver *drv)
+const void *i2c_get_match_data(const struct i2c_client *client)
+{
+	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
+	const struct i2c_device_id *match;
+	const void *data;
+
+	data = device_get_match_data(&client->dev);
+	if (!data) {
+		match = i2c_match_id(driver->id_table, client);
+		if (!match)
+			return NULL;
+
+		data = (const void *)match->driver_data;
+	}
+
+	return data;
+}
+EXPORT_SYMBOL(i2c_get_match_data);
+
+static int i2c_device_match(struct device *dev, const struct device_driver *drv)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
-	struct i2c_driver	*driver;
+	const struct i2c_driver	*driver;
 
 
 	/* Attempt an OF style match */
@@ -136,9 +159,9 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
-static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
+static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
 {
-	struct i2c_client *client = to_i2c_client(dev);
+	const struct i2c_client *client = to_i2c_client(dev);
 	int rc;
 
 	rc = of_device_uevent_modalias(dev, env);
@@ -282,7 +305,9 @@ static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
 {
 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 	struct device *dev = &adap->dev;
-	struct pinctrl *p = bri->pinctrl;
+	struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
+
+	bri->pinctrl = p;
 
 	/*
 	 * we can't change states without pinctrl, so remove the states if
@@ -465,6 +490,7 @@ static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 
 static int i2c_device_probe(struct device *dev)
 {
+	struct fwnode_handle	*fwnode = dev_fwnode(dev);
 	struct i2c_client	*client = i2c_verify_client(dev);
 	struct i2c_driver	*driver;
 	bool do_power_on;
@@ -483,11 +509,11 @@ static int i2c_device_probe(struct device *dev)
 			/* Keep adapter active when Host Notify is required */
 			pm_runtime_get_sync(&client->adapter->dev);
 			irq = i2c_smbus_host_notify_to_irq(client);
-		} else if (dev->of_node) {
-			irq = of_irq_get_byname(dev->of_node, "irq");
+		} else if (is_of_node(fwnode)) {
+			irq = fwnode_irq_get_byname(fwnode, "irq");
 			if (irq == -EINVAL || irq == -ENODATA)
-				irq = of_irq_get(dev->of_node, 0);
-		} else if (ACPI_COMPANION(dev)) {
+				irq = fwnode_irq_get(fwnode, 0);
+		} else if (is_acpi_device_node(fwnode)) {
 			bool wake_capable;
 
 			irq = i2c_acpi_get_irq(client, &wake_capable);
@@ -495,7 +521,7 @@ static int i2c_device_probe(struct device *dev)
 				client->flags |= I2C_CLIENT_WAKE;
 		}
 		if (irq == -EPROBE_DEFER) {
-			status = irq;
+			status = dev_err_probe(dev, irq, "can't get irq\n");
 			goto put_sync_adapter;
 		}
 
@@ -521,9 +547,9 @@ static int i2c_device_probe(struct device *dev)
 	if (client->flags & I2C_CLIENT_WAKE) {
 		int wakeirq;
 
-		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
+		wakeirq = fwnode_irq_get_byname(fwnode, "wakeup");
 		if (wakeirq == -EPROBE_DEFER) {
-			status = wakeirq;
+			status = dev_err_probe(dev, wakeirq, "can't get wakeirq\n");
 			goto put_sync_adapter;
 		}
 
@@ -542,12 +568,13 @@ static int i2c_device_probe(struct device *dev)
 
 	dev_dbg(dev, "probe\n");
 
-	status = of_clk_set_defaults(dev->of_node, false);
+	status = of_clk_set_defaults(to_of_node(fwnode), false);
 	if (status < 0)
 		goto err_clear_wakeup_irq;
 
 	do_power_on = !i2c_acpi_waive_d0_probe(dev);
-	status = dev_pm_domain_attach(&client->dev, do_power_on);
+	status = dev_pm_domain_attach(&client->dev, PD_FLAG_DETACH_POWER_OFF |
+				      (do_power_on ? PD_FLAG_ATTACH_POWER_ON : 0));
 	if (status)
 		goto err_clear_wakeup_irq;
 
@@ -555,18 +582,14 @@ static int i2c_device_probe(struct device *dev)
 						    GFP_KERNEL);
 	if (!client->devres_group_id) {
 		status = -ENOMEM;
-		goto err_detach_pm_domain;
+		goto err_clear_wakeup_irq;
 	}
 
-	/*
-	 * When there are no more users of probe(),
-	 * rename probe_new to probe.
-	 */
-	if (driver->probe_new)
-		status = driver->probe_new(client);
-	else if (driver->probe)
-		status = driver->probe(client,
-				       i2c_match_id(driver->id_table, client));
+	client->debugfs = debugfs_create_dir(dev_name(&client->dev),
+					     client->adapter->debugfs);
+
+	if (driver->probe)
+		status = driver->probe(client);
 	else
 		status = -EINVAL;
 
@@ -584,9 +607,8 @@ static int i2c_device_probe(struct device *dev)
 	return 0;
 
 err_release_driver_resources:
+	debugfs_remove_recursive(client->debugfs);
 	devres_release_group(&client->dev, client->devres_group_id);
-err_detach_pm_domain:
-	dev_pm_domain_detach(&client->dev, do_power_on);
 err_clear_wakeup_irq:
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -609,9 +631,9 @@ static void i2c_device_remove(struct device *dev)
 		driver->remove(client);
 	}
 
-	devres_release_group(&client->dev, client->devres_group_id);
+	debugfs_remove_recursive(client->debugfs);
 
-	dev_pm_domain_detach(&client->dev, true);
+	devres_release_group(&client->dev, client->devres_group_id);
 
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -674,7 +696,7 @@ static struct attribute *i2c_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(i2c_dev);
 
-struct bus_type i2c_bus_type = {
+const struct bus_type i2c_bus_type = {
 	.name		= "i2c",
 	.match		= i2c_device_match,
 	.probe		= i2c_device_probe,
@@ -683,7 +705,7 @@ struct bus_type i2c_bus_type = {
 };
 EXPORT_SYMBOL_GPL(i2c_bus_type);
 
-struct device_type i2c_client_type = {
+const struct device_type i2c_client_type = {
 	.groups		= i2c_dev_groups,
 	.uevent		= i2c_device_uevent,
 	.release	= i2c_client_dev_release,
@@ -897,6 +919,27 @@ int i2c_dev_irq_from_resources(const struct resource *resources,
 	return 0;
 }
 
+/*
+ * Serialize device instantiation in case it can be instantiated explicitly
+ * and by auto-detection
+ */
+static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr,
+			 unsigned short flags)
+{
+	if (!(flags & I2C_CLIENT_TEN) &&
+	    test_and_set_bit(addr, adap->addrs_in_instantiation))
+		return -EBUSY;
+
+	return 0;
+}
+
+static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr,
+			    unsigned short flags)
+{
+	if (!(flags & I2C_CLIENT_TEN))
+		clear_bit(addr, adap->addrs_in_instantiation);
+}
+
 /**
  * i2c_new_client_device - instantiate an i2c device
  * @adap: the adapter managing the device
@@ -916,8 +959,10 @@ int i2c_dev_irq_from_resources(const struct resource *resources,
 struct i2c_client *
 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 {
-	struct i2c_client	*client;
-	int			status;
+	struct fwnode_handle *fwnode = info->fwnode;
+	struct i2c_client *client;
+	bool need_put = false;
+	int status;
 
 	client = kzalloc(sizeof *client, GFP_KERNEL);
 	if (!client)
@@ -943,6 +988,10 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 		goto out_err_silent;
 	}
 
+	status = i2c_lock_addr(adap, client->addr, client->flags);
+	if (status)
+		goto out_err_silent;
+
 	/* Check for address business */
 	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 	if (status)
@@ -951,11 +1000,10 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 	client->dev.parent = &client->adapter->dev;
 	client->dev.bus = &i2c_bus_type;
 	client->dev.type = &i2c_client_type;
-	client->dev.of_node = of_node_get(info->of_node);
-	client->dev.fwnode = info->fwnode;
 
 	device_enable_async_suspend(&client->dev);
-	i2c_dev_set_name(adap, client, info);
+
+	device_set_node(&client->dev, fwnode_handle_get(fwnode));
 
 	if (info->swnode) {
 		status = device_add_software_node(&client->dev, info->swnode);
@@ -963,10 +1011,11 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 			dev_err(&adap->dev,
 				"Failed to add software node to client %s: %d\n",
 				client->name, status);
-			goto out_err_put_of_node;
+			goto out_err_put_fwnode;
 		}
 	}
 
+	i2c_dev_set_name(adap, client, info);
 	status = device_register(&client->dev);
 	if (status)
 		goto out_remove_swnode;
@@ -974,18 +1023,25 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 		client->name, dev_name(&client->dev));
 
+	i2c_unlock_addr(adap, client->addr, client->flags);
+
 	return client;
 
 out_remove_swnode:
 	device_remove_software_node(&client->dev);
-out_err_put_of_node:
-	of_node_put(info->of_node);
+	need_put = true;
+out_err_put_fwnode:
+	fwnode_handle_put(fwnode);
 out_err:
 	dev_err(&adap->dev,
 		"Failed to register i2c client %s at 0x%02x (%d)\n",
 		client->name, client->addr, status);
+	i2c_unlock_addr(adap, client->addr, client->flags);
 out_err_silent:
-	kfree(client);
+	if (need_put)
+		put_device(&client->dev);
+	else
+		kfree(client);
 	return ERR_PTR(status);
 }
 EXPORT_SYMBOL_GPL(i2c_new_client_device);
@@ -997,25 +1053,63 @@ EXPORT_SYMBOL_GPL(i2c_new_client_device);
  */
 void i2c_unregister_device(struct i2c_client *client)
 {
+	struct fwnode_handle *fwnode;
+
 	if (IS_ERR_OR_NULL(client))
 		return;
 
-	if (client->dev.of_node) {
-		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
-		of_node_put(client->dev.of_node);
-	}
+	fwnode = dev_fwnode(&client->dev);
+	if (is_of_node(fwnode))
+		of_node_clear_flag(to_of_node(fwnode), OF_POPULATED);
+	else if (is_acpi_device_node(fwnode))
+		acpi_device_clear_enumerated(to_acpi_device_node(fwnode));
+
+	/*
+	 * If the primary fwnode is a software node it is free-ed by
+	 * device_remove_software_node() below, avoid double-free.
+	 */
+	if (!is_software_node(fwnode))
+		fwnode_handle_put(fwnode);
 
-	if (ACPI_COMPANION(&client->dev))
-		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 	device_remove_software_node(&client->dev);
 	device_unregister(&client->dev);
 }
 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 
+/**
+ * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
+ * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
+ *
+ * Look up and return the &struct i2c_client corresponding to the @fwnode.
+ * If no client can be found, or @fwnode is NULL, this returns NULL.
+ *
+ * The user must call put_device(&client->dev) once done with the i2c client.
+ */
+struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct i2c_client *client;
+	struct device *dev;
+
+	if (!fwnode)
+		return NULL;
+
+	dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
+	if (!dev)
+		return NULL;
+
+	client = i2c_verify_client(dev);
+	if (!client)
+		put_device(dev);
+
+	return client;
+}
+EXPORT_SYMBOL(i2c_find_device_by_fwnode);
+
 
 static const struct i2c_device_id dummy_id[] = {
-	{ "dummy", 0 },
-	{ },
+	{ "dummy", },
+	{ "smbus_host_notify", },
+	{ }
 };
 
 static int dummy_probe(struct i2c_client *client)
@@ -1025,7 +1119,7 @@ static int dummy_probe(struct i2c_client *client)
 
 static struct i2c_driver dummy_driver = {
 	.driver.name	= "dummy",
-	.probe_new	= dummy_probe,
+	.probe		= dummy_probe,
 	.id_table	= dummy_id,
 };
 
@@ -1121,11 +1215,9 @@ struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
 	u32 addr = default_addr;
 	int i;
 
-	if (np) {
-		i = of_property_match_string(np, "reg-names", name);
-		if (i >= 0)
-			of_property_read_u32_index(np, "reg", i, &addr);
-	}
+	i = of_property_match_string(np, "reg-names", name);
+	if (i >= 0)
+		of_property_read_u32_index(np, "reg", i, &addr);
 
 	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 	return i2c_new_dummy_device(client->adapter, addr);
@@ -1145,9 +1237,11 @@ static void i2c_adapter_dev_release(struct device *dev)
 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 {
 	unsigned int depth = 0;
+	struct device *parent;
 
-	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
-		depth++;
+	for (parent = adapter->dev.parent; parent; parent = parent->parent)
+		if (parent->type == &i2c_adapter_type)
+			depth++;
 
 	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 		  "adapter depth exceeds lockdep subclass limit\n");
@@ -1289,7 +1383,7 @@ static struct attribute *i2c_adapter_attrs[] = {
 };
 ATTRIBUTE_GROUPS(i2c_adapter);
 
-struct device_type i2c_adapter_type = {
+const struct device_type i2c_adapter_type = {
 	.groups		= i2c_adapter_groups,
 	.release	= i2c_adapter_dev_release,
 };
@@ -1312,10 +1406,6 @@ struct i2c_adapter *i2c_verify_adapter(struct device *dev)
 }
 EXPORT_SYMBOL(i2c_verify_adapter);
 
-#ifdef CONFIG_I2C_COMPAT
-static struct class_compat *i2c_adapter_compat_class;
-#endif
-
 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
 {
 	struct i2c_devinfo	*devinfo;
@@ -1414,6 +1504,8 @@ int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
 	if (!adap)
 		return -EINVAL;
 
+	dev_dbg(&adap->dev, "Detected HostNotify from address 0x%02x", addr);
+
 	irq = irq_find_mapping(adap->host_notify_domain, addr);
 	if (irq <= 0)
 		return -ENXIO;
@@ -1467,35 +1559,36 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
 	adap->dev.bus = &i2c_bus_type;
 	adap->dev.type = &i2c_adapter_type;
-	res = device_register(&adap->dev);
+	device_initialize(&adap->dev);
+
+	/*
+	 * This adapter can be used as a parent immediately after device_add(),
+	 * setup runtime-pm (especially ignore-children) before hand.
+	 */
+	device_enable_async_suspend(&adap->dev);
+	pm_runtime_no_callbacks(&adap->dev);
+	pm_suspend_ignore_children(&adap->dev, true);
+	pm_runtime_enable(&adap->dev);
+
+	res = device_add(&adap->dev);
 	if (res) {
 		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
+		put_device(&adap->dev);
 		goto out_list;
 	}
 
+	adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
+
 	res = i2c_setup_smbus_alert(adap);
 	if (res)
 		goto out_reg;
 
-	device_enable_async_suspend(&adap->dev);
-	pm_runtime_no_callbacks(&adap->dev);
-	pm_suspend_ignore_children(&adap->dev, true);
-	pm_runtime_enable(&adap->dev);
-
 	res = i2c_init_recovery(adap);
 	if (res == -EPROBE_DEFER)
 		goto out_reg;
 
 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
 
-#ifdef CONFIG_I2C_COMPAT
-	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
-				       adap->dev.parent);
-	if (res)
-		dev_warn(&adap->dev,
-			 "Failed to create compatibility class link\n");
-#endif
-
 	/* create pre-declared device nodes */
 	of_i2c_register_devices(adap);
 	i2c_acpi_install_space_handler(adap);
@@ -1512,6 +1605,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	return 0;
 
 out_reg:
+	debugfs_remove_recursive(adap->debugfs);
 	init_completion(&adap->dev_released);
 	device_unregister(&adap->dev);
 	wait_for_completion(&adap->dev_released);
@@ -1561,12 +1655,10 @@ int i2c_add_adapter(struct i2c_adapter *adapter)
 	struct device *dev = &adapter->dev;
 	int id;
 
-	if (dev->of_node) {
-		id = of_alias_get_id(dev->of_node, "i2c");
-		if (id >= 0) {
-			adapter->nr = id;
-			return __i2c_add_numbered_adapter(adapter);
-		}
+	id = of_alias_get_id(dev->of_node, "i2c");
+	if (id >= 0) {
+		adapter->nr = id;
+		return __i2c_add_numbered_adapter(adapter);
 	}
 
 	mutex_lock(&core_lock);
@@ -1701,11 +1793,6 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 	device_for_each_child(&adap->dev, NULL, __unregister_client);
 	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
 
-#ifdef CONFIG_I2C_COMPAT
-	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
-				 adap->dev.parent);
-#endif
-
 	/* device name is gone after device_unregister */
 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
 
@@ -1713,6 +1800,8 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 
 	i2c_host_notify_irq_teardown(adap);
 
+	debugfs_remove_recursive(adap->debugfs);
+
 	/* wait until all references to the device are gone
 	 *
 	 * FIXME: This is old code and should ideally be replaced by an
@@ -1761,6 +1850,75 @@ int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
 }
 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
 
+static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
+{
+	if (dev_fwnode(dev) == data)
+		return 1;
+
+	if (dev->parent && dev_fwnode(dev->parent) == data)
+		return 1;
+
+	return 0;
+}
+
+/**
+ * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
+ * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
+ *
+ * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
+ * If no adapter can be found, or @fwnode is NULL, this returns NULL.
+ *
+ * The user must call put_device(&adapter->dev) once done with the i2c adapter.
+ */
+struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct i2c_adapter *adapter;
+	struct device *dev;
+
+	if (!fwnode)
+		return NULL;
+
+	dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
+			      i2c_dev_or_parent_fwnode_match);
+	if (!dev)
+		return NULL;
+
+	adapter = i2c_verify_adapter(dev);
+	if (!adapter)
+		put_device(dev);
+
+	return adapter;
+}
+EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
+
+/**
+ * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
+ * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
+ *
+ * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
+ * and increment the adapter module's use count. If no adapter can be found,
+ * or @fwnode is NULL, this returns NULL.
+ *
+ * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
+ * Note that this is different from i2c_find_adapter_by_node().
+ */
+struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct i2c_adapter *adapter;
+
+	adapter = i2c_find_adapter_by_fwnode(fwnode);
+	if (!adapter)
+		return NULL;
+
+	if (!try_module_get(adapter->owner)) {
+		put_device(&adapter->dev);
+		adapter = NULL;
+	}
+
+	return adapter;
+}
+EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
+
 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
 			    u32 def_val, bool use_def)
 {
@@ -1941,13 +2099,8 @@ static int __init i2c_init(void)
 
 	is_registered = true;
 
-#ifdef CONFIG_I2C_COMPAT
-	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
-	if (!i2c_adapter_compat_class) {
-		retval = -ENOMEM;
-		goto bus_err;
-	}
-#endif
+	i2c_debugfs_root = debugfs_create_dir("i2c", NULL);
+
 	retval = i2c_add_driver(&dummy_driver);
 	if (retval)
 		goto class_err;
@@ -1960,10 +2113,6 @@ static int __init i2c_init(void)
 	return 0;
 
 class_err:
-#ifdef CONFIG_I2C_COMPAT
-	class_compat_unregister(i2c_adapter_compat_class);
-bus_err:
-#endif
 	is_registered = false;
 	bus_unregister(&i2c_bus_type);
 	return retval;
@@ -1976,9 +2125,7 @@ static void __exit i2c_exit(void)
 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
 		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
 	i2c_del_driver(&dummy_driver);
-#ifdef CONFIG_I2C_COMPAT
-	class_compat_unregister(i2c_adapter_compat_class);
-#endif
+	debugfs_remove_recursive(i2c_debugfs_root);
 	bus_unregister(&i2c_bus_type);
 	tracepoint_synchronize_unregister();
 }
@@ -2001,7 +2148,7 @@ static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *
 {
 	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
 			    err_msg, msg->addr, msg->len,
-			    msg->flags & I2C_M_RD ? "read" : "write");
+			    str_read_write(msg->flags & I2C_M_RD));
 	return -EOPNOTSUPP;
 }
 
@@ -2069,13 +2216,18 @@ static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs,
  * Returns negative errno, else the number of messages executed.
  *
  * Adapter lock must be held when calling this function. No debug logging
- * takes place. adap->algo->master_xfer existence isn't checked.
+ * takes place.
  */
 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	unsigned long orig_jiffies;
 	int ret, try;
 
+	if (!adap->algo->master_xfer) {
+		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
+		return -EOPNOTSUPP;
+	}
+
 	if (WARN_ON(!msgs || num < 1))
 		return -EINVAL;
 
@@ -2142,11 +2294,6 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	int ret;
 
-	if (!adap->algo->master_xfer) {
-		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
-		return -EOPNOTSUPP;
-	}
-
 	/* REVISIT the fault reporting model here is weak:
 	 *
 	 *  - When we get an error after receiving N bytes from a slave,
@@ -2382,9 +2529,10 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
 		return 0;
 
 	/* Set up a temporary client to help detect callback */
-	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+	temp_client = kzalloc(sizeof(*temp_client), GFP_KERNEL);
 	if (!temp_client)
 		return -ENOMEM;
+
 	temp_client->adapter = adapter;
 
 	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
@@ -2398,6 +2546,7 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
 	}
 
 	kfree(temp_client);
+
 	return err;
 }