diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 3c3f31c..acea3f7 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -134,6 +134,14 @@ config U_SERIAL_CONSOLE
 	help
 	   It supports the serial gadget can be used as a console.
 
+config USB_CHARGER
+	bool "USB charger support"
+	select EXTCON
+	help
+	  The usb charger driver based on the usb gadget that makes an
+	  enhancement to a power driver which can set the current limitation
+	  when the usb charger is added or removed.
+
 source "drivers/usb/gadget/udc/Kconfig"
 
 #
diff --git a/drivers/usb/gadget/udc/Makefile b/drivers/usb/gadget/udc/Makefile
index 98e74ed..ede2351 100644
--- a/drivers/usb/gadget/udc/Makefile
+++ b/drivers/usb/gadget/udc/Makefile
@@ -2,6 +2,7 @@
 CFLAGS_trace.o			:= -I$(src)
 
 udc-core-y			:= core.o trace.o
+udc-core-$(CONFIG_USB_CHARGER)	+= charger.o
 
 #
 # USB peripheral controller drivers
diff --git a/drivers/usb/gadget/udc/charger.c b/drivers/usb/gadget/udc/charger.c
new file mode 100644
index 0000000..462faa1
--- /dev/null
+++ b/drivers/usb/gadget/udc/charger.c
@@ -0,0 +1,697 @@
+/*
+ * charger.c -- USB charger driver
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/extcon.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/charger.h>
+#include <linux/power_supply.h>
+
+/* Default current limit by charger type. */
+#define DEFAULT_SDP_CUR_LIMIT		500
+#define DEFAULT_SDP_CUR_LIMIT_SS	900
+#define DEFAULT_DCP_CUR_LIMIT		1500
+#define DEFAULT_CDP_CUR_LIMIT		1500
+#define DEFAULT_ACA_CUR_LIMIT		1500
+
+static DEFINE_IDA(usb_charger_ida);
+static LIST_HEAD(charger_list);
+static DEFINE_MUTEX(charger_lock);
+
+static unsigned int __usb_charger_get_cur_limit(struct usb_charger *uchger);
+
+static struct usb_charger *dev_to_uchger(struct device *dev)
+{
+	return NULL;
+}
+
+/*
+ * charger_current_show() - Show the charger current limit.
+ */
+static ssize_t charger_current_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct usb_charger *uchger = dev_to_uchger(dev);
+
+	return sprintf(buf, "%u\n", __usb_charger_get_cur_limit(uchger));
+}
+static DEVICE_ATTR_RO(charger_current);
+
+/*
+ * charger_type_show() - Show the charger type.
+ *
+ * It can be SDP/DCP/CDP/ACA type, else for unknown type.
+ */
+static ssize_t charger_type_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct usb_charger *uchger = dev_to_uchger(dev);
+	int cnt;
+
+	switch (uchger->type) {
+	case SDP_TYPE:
+		cnt = sprintf(buf, "%s\n", "SDP");
+		break;
+	case DCP_TYPE:
+		cnt = sprintf(buf, "%s\n", "DCP");
+		break;
+	case CDP_TYPE:
+		cnt = sprintf(buf, "%s\n", "CDP");
+		break;
+	case ACA_TYPE:
+		cnt = sprintf(buf, "%s\n", "ACA");
+		break;
+	default:
+		cnt = sprintf(buf, "%s\n", "UNKNOWN");
+		break;
+	}
+
+	return cnt;
+}
+static DEVICE_ATTR_RO(charger_type);
+
+/*
+ * charger_state_show() - Show the charger state.
+ *
+ * Charger state can be present or removed.
+ */
+static ssize_t charger_state_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	struct usb_charger *uchger = dev_to_uchger(dev);
+	int cnt;
+
+	switch (uchger->state) {
+	case USB_CHARGER_PRESENT:
+		cnt = sprintf(buf, "%s\n", "PRESENT");
+		break;
+	case USB_CHARGER_REMOVE:
+		cnt = sprintf(buf, "%s\n", "REMOVE");
+		break;
+	default:
+		cnt = sprintf(buf, "%s\n", "UNKNOWN");
+		break;
+	}
+
+	return cnt;
+}
+static DEVICE_ATTR_RO(charger_state);
+
+static struct attribute *usb_charger_attrs[] = {
+	&dev_attr_charger_current.attr,
+	&dev_attr_charger_type.attr,
+	&dev_attr_charger_state.attr,
+	NULL
+};
+
+static const struct attribute_group usb_charger_group = {
+	.name = "charger",
+	.attrs = usb_charger_attrs,
+};
+__ATTRIBUTE_GROUPS(usb_charger);
+
+/*
+ * usb_charger_find_by_name() - Get the usb charger instance by name.
+ * @name - usb charger name.
+ */
+struct usb_charger *usb_charger_find_by_name(const char *name)
+{
+	struct usb_charger *uchger;
+
+	if (WARN(!name, "can't work with NULL name"))
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&charger_lock);
+	list_for_each_entry(uchger, &charger_list, list) {
+		if (!strcmp(uchger->name, name))
+			break;
+	}
+	mutex_unlock(&charger_lock);
+
+	if (WARN(!uchger, "can't find usb charger"))
+		return ERR_PTR(-ENODEV);
+
+	return uchger;
+}
+EXPORT_SYMBOL_GPL(usb_charger_find_by_name);
+
+/*
+ * usb_charger_get_type() - get the usb charger type with lock protection.
+ * @uchger - usb charger instance.
+ *
+ * Users can get the charger type by this safe API, rather than using the
+ * usb_charger structure directly.
+ */
+enum usb_charger_type usb_charger_get_type(struct usb_charger *uchger)
+{
+	enum usb_charger_type type;
+
+	mutex_lock(&uchger->lock);
+	type = uchger->type;
+	mutex_unlock(&uchger->lock);
+
+	return type;
+}
+EXPORT_SYMBOL_GPL(usb_charger_get_type);
+
+/*
+ * usb_charger_get_state() - Get the charger state with lock protection.
+ * @uchger - the usb charger instance.
+ *
+ * Users should get the charger state by this safe API.
+ */
+enum usb_charger_state usb_charger_get_state(struct usb_charger *uchger)
+{
+	enum usb_charger_state state;
+
+	mutex_lock(&uchger->lock);
+	state = uchger->state;
+	mutex_unlock(&uchger->lock);
+
+	return state;
+}
+EXPORT_SYMBOL_GPL(usb_charger_get_state);
+
+/*
+ * usb_charger_detect_type() - detect the charger type manually.
+ * @uchger - usb charger instance.
+ *
+ * Note: You should ensure you need to detect the charger type manually on your
+ * platform.
+ * You should call it at the right gadget state to avoid affecting gadget
+ * enumeration.
+ */
+int usb_charger_detect_type(struct usb_charger *uchger)
+{
+	enum usb_charger_type type;
+
+	if (!uchger->charger_detect)
+		return -EINVAL;
+
+	type = uchger->charger_detect(uchger);
+
+	mutex_lock(&uchger->lock);
+	uchger->type = type;
+	mutex_unlock(&uchger->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_charger_detect_type);
+
+/*
+ * usb_charger_get_type_by_others() - Get the usb charger type by the callback
+ * which is implemented by users.
+ * @uchger - the usb charger instance.
+ *
+ * Note: This function is just used for getting the charger type, not for
+ * detecting charger type which might affect the DP/DM line when gadget is on
+ * enumeration state.
+ */
+static enum usb_charger_type
+usb_charger_get_type_by_others(struct usb_charger *uchger)
+{
+	if (uchger->type != UNKNOWN_TYPE)
+		return uchger->type;
+
+	if (uchger->psy) {
+		union power_supply_propval val;
+
+		power_supply_get_property(uchger->psy,
+					  POWER_SUPPLY_PROP_CHARGE_TYPE,
+					  &val);
+		switch (val.intval) {
+		case POWER_SUPPLY_TYPE_USB:
+			uchger->type = SDP_TYPE;
+			break;
+		case POWER_SUPPLY_TYPE_USB_DCP:
+			uchger->type = DCP_TYPE;
+			break;
+		case POWER_SUPPLY_TYPE_USB_CDP:
+			uchger->type = CDP_TYPE;
+			break;
+		case POWER_SUPPLY_TYPE_USB_ACA:
+			uchger->type = ACA_TYPE;
+			break;
+		default:
+			uchger->type = UNKNOWN_TYPE;
+			break;
+		}
+	} else if (uchger->get_charger_type) {
+		uchger->type = uchger->get_charger_type(uchger);
+	} else {
+		uchger->type = UNKNOWN_TYPE;
+	}
+
+	return uchger->type;
+}
+
+/*
+ * __usb_charger_set_cur_limit_by_type() - Set the current limitation
+ * by charger type.
+ * @uchger - the usb charger instance.
+ * @type - the usb charger type.
+ * @cur_limit - the current limitation.
+ */
+static int __usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
+					       enum usb_charger_type type,
+					       unsigned int cur_limit)
+{
+	switch (type) {
+	case SDP_TYPE:
+		uchger->cur_limit.sdp_cur_limit = cur_limit;
+		uchger->sdp_default_cur_change = 1;
+		break;
+	case DCP_TYPE:
+		uchger->cur_limit.dcp_cur_limit = cur_limit;
+		break;
+	case CDP_TYPE:
+		uchger->cur_limit.cdp_cur_limit	= cur_limit;
+		break;
+	case ACA_TYPE:
+		uchger->cur_limit.aca_cur_limit	= cur_limit;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * usb_charger_notify_work() - Notify users the current has changed by work.
+ * @work - the work instance.
+ */
+static void usb_charger_notify_work(struct work_struct *work)
+{
+	struct usb_charger *uchger = work_to_charger(work);
+
+	mutex_lock(&uchger->lock);
+
+	if (uchger->state == USB_CHARGER_PRESENT) {
+		usb_charger_get_type_by_others(uchger);
+		raw_notifier_call_chain(&uchger->uchger_nh,
+				__usb_charger_get_cur_limit(uchger),
+				uchger);
+	}
+
+	mutex_unlock(&uchger->lock);
+}
+
+/*
+ * usb_charger_set_cur_limit_by_gadget() - Set the current limitation from
+ * gadget layer.
+ * @gadget - the usb gadget device.
+ * @cur_limit - the current limitation.
+ *
+ * Note: This function is used in atomic contexts without mutex lock.
+ */
+int usb_charger_set_cur_limit_by_gadget(struct usb_gadget *gadget,
+					unsigned int cur_limit)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_charger_set_cur_limit_by_gadget);
+
+/*
+ * usb_charger_set_cur_limit_by_type() - Set the current limitation
+ * by charger type with lock protection.
+ * @uchger - the usb charger instance.
+ * @type - the usb charger type.
+ * @cur_limit - the current limitation.
+ *
+ * Users should set the current limitation by this lock protection API.
+ */
+int usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
+				      enum usb_charger_type type,
+				      unsigned int cur_limit)
+{
+	int ret;
+
+	if (!uchger)
+		return -EINVAL;
+
+	mutex_lock(&uchger->lock);
+	ret = __usb_charger_set_cur_limit_by_type(uchger, type, cur_limit);
+	mutex_unlock(&uchger->lock);
+
+	schedule_work(&uchger->work);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_charger_set_cur_limit_by_type);
+
+/*
+ * usb_charger_set_cur_limit() - Set the current limitation.
+ * @uchger - the usb charger instance.
+ * @cur_limit_set - the current limitation.
+ */
+int usb_charger_set_cur_limit(struct usb_charger *uchger,
+			      struct usb_charger_cur_limit *cur_limit_set)
+{
+	if (!uchger || !cur_limit_set)
+		return -EINVAL;
+
+	mutex_lock(&uchger->lock);
+	uchger->cur_limit.sdp_cur_limit = cur_limit_set->sdp_cur_limit;
+	uchger->cur_limit.dcp_cur_limit = cur_limit_set->dcp_cur_limit;
+	uchger->cur_limit.cdp_cur_limit = cur_limit_set->cdp_cur_limit;
+	uchger->cur_limit.aca_cur_limit = cur_limit_set->aca_cur_limit;
+	uchger->sdp_default_cur_change = 1;
+	mutex_unlock(&uchger->lock);
+
+	schedule_work(&uchger->work);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_charger_set_cur_limit);
+
+/*
+ * __usb_charger_get_cur_limit() - Get the current limitation by
+ * different usb charger type.
+ * @uchger - the usb charger instance.
+ *
+ * return the current limitation to set.
+ */
+static unsigned int
+__usb_charger_get_cur_limit(struct usb_charger *uchger)
+{
+	enum usb_charger_type uchger_type =
+		usb_charger_get_type_by_others(uchger);
+	unsigned int cur_limit;
+
+	switch (uchger_type) {
+	case SDP_TYPE:
+		/*
+		 * For super speed gadget, the default charger current should
+		 * be 900 mA.
+		 */
+		if (!uchger->sdp_default_cur_change && uchger->gadget &&
+		    uchger->gadget->speed >= USB_SPEED_SUPER) {
+			uchger->cur_limit.sdp_cur_limit =
+				DEFAULT_SDP_CUR_LIMIT_SS;
+
+			uchger->sdp_default_cur_change = 1;
+		}
+
+		cur_limit = uchger->cur_limit.sdp_cur_limit;
+		break;
+	case DCP_TYPE:
+		cur_limit = uchger->cur_limit.dcp_cur_limit;
+		break;
+	case CDP_TYPE:
+		cur_limit = uchger->cur_limit.cdp_cur_limit;
+		break;
+	case ACA_TYPE:
+		cur_limit = uchger->cur_limit.aca_cur_limit;
+		break;
+	default:
+		return 0;
+	}
+
+	return cur_limit;
+}
+
+/*
+ * usb_charger_get_cur_limit() - Get the charger current with lock protection.
+ * @uchger - the usb charger instance.
+ *
+ * Users should get the charger current by this safe API.
+ */
+unsigned int usb_charger_get_cur_limit(struct usb_charger *uchger)
+{
+	unsigned int cur;
+
+	mutex_lock(&uchger->lock);
+	cur = __usb_charger_get_cur_limit(uchger);
+	mutex_unlock(&uchger->lock);
+
+	return cur;
+}
+EXPORT_SYMBOL_GPL(usb_charger_get_cur_limit);
+
+/*
+ * usb_charger_register_notify() - Register a notifiee to get notified by
+ * any attach status changes from the usb charger detection.
+ * @uchger - the usb charger instance which is monitored.
+ * @nb - a notifier block to be registered.
+ */
+int usb_charger_register_notify(struct usb_charger *uchger,
+				struct notifier_block *nb)
+{
+	int ret;
+
+	if (!uchger || !nb) {
+		pr_err("Charger or nb can not be NULL.\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&uchger->lock);
+	ret = raw_notifier_chain_register(&uchger->uchger_nh, nb);
+	mutex_unlock(&uchger->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_charger_register_notify);
+
+/*
+ * usb_charger_unregister_notify() - Unregister a notifiee from the usb charger.
+ * @uchger - the usb charger instance which is monitored.
+ * @nb - a notifier block to be unregistered.
+ */
+int usb_charger_unregister_notify(struct usb_charger *uchger,
+				  struct notifier_block *nb)
+{
+	int ret;
+
+	if (!uchger || !nb) {
+		pr_err("Charger or nb can not be NULL.\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&uchger->lock);
+	ret = raw_notifier_chain_unregister(&uchger->uchger_nh, nb);
+	mutex_unlock(&uchger->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_charger_unregister_notify);
+
+/*
+ * usb_charger_notifier_others() - It will notify other device registered
+ * on usb charger when the usb charger state is changed.
+ * @uchger - the usb charger instance.
+ * @state - the state of the usb charger.
+ */
+static void
+usb_charger_notify_others(struct usb_charger *uchger,
+			  enum usb_charger_state state)
+{
+	char uchger_state[50] = { 0 };
+	char *envp[] = { uchger_state, NULL };
+
+	mutex_lock(&uchger->lock);
+	if (uchger->state == state) {
+		mutex_unlock(&uchger->lock);
+		return;
+	}
+
+	uchger->state = state;
+
+	switch (state) {
+	case USB_CHARGER_PRESENT:
+		usb_charger_get_type_by_others(uchger);
+		raw_notifier_call_chain(&uchger->uchger_nh,
+			__usb_charger_get_cur_limit(uchger),
+			uchger);
+		snprintf(uchger_state, ARRAY_SIZE(uchger_state),
+			 "USB_CHARGER_STATE=%s", "USB_CHARGER_PRESENT");
+		break;
+	case USB_CHARGER_REMOVE:
+		uchger->type = UNKNOWN_TYPE;
+		raw_notifier_call_chain(&uchger->uchger_nh, 0, uchger);
+		snprintf(uchger_state, ARRAY_SIZE(uchger_state),
+			 "USB_CHARGER_STATE=%s", "USB_CHARGER_REMOVE");
+		break;
+	default:
+		pr_warn("Unknown USB charger state: %d\n", state);
+		mutex_unlock(&uchger->lock);
+		return;
+	}
+
+	kobject_uevent_env(&uchger->gadget->dev.kobj, KOBJ_CHANGE, envp);
+	mutex_unlock(&uchger->lock);
+}
+
+/*
+ * usb_charger_plug_by_extcon() - The notifier call function which is registered
+ * on the extcon device.
+ * @nb - the notifier block that notified by extcon device.
+ * @state - the extcon device state.
+ * @data - here specify a extcon device.
+ *
+ * return the notify flag.
+ */
+static int
+usb_charger_plug_by_extcon(struct notifier_block *nb,
+			   unsigned long state, void *data)
+{
+	struct usb_charger_nb *extcon_nb =
+		container_of(nb, struct usb_charger_nb, nb);
+	struct usb_charger *uchger = extcon_nb->uchger;
+	enum usb_charger_state uchger_state;
+
+	if (WARN(!uchger, "charger can not be NULL"))
+		return NOTIFY_BAD;
+
+	/*
+	 * Report event to power to setting the current limitation
+	 * for this usb charger when one usb charger is added or removed
+	 * with detecting by extcon device.
+	 */
+	if (state)
+		uchger_state = USB_CHARGER_PRESENT;
+	else
+		uchger_state = USB_CHARGER_REMOVE;
+
+	usb_charger_notify_others(uchger, uchger_state);
+
+	return NOTIFY_OK;
+}
+
+/*
+ * usb_charger_plug_by_gadget() - Set the usb charger current limitation
+ * according to the usb gadget device state.
+ * @gadget - the usb gadget device.
+ * @state - the usb gadget state.
+ */
+int usb_charger_plug_by_gadget(struct usb_gadget *gadget,
+			       unsigned long state)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_charger_plug_by_gadget);
+
+/*
+ * usb_charger_register() - Register a new usb charger.
+ * @uchger - the new usb charger instance.
+ */
+static int usb_charger_register(struct usb_charger *uchger)
+{
+	int ret;
+
+	ret = ida_simple_get(&usb_charger_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0) {
+		pr_err("Failed to register usb charger: %d\n", ret);
+		return ret;
+	}
+
+	uchger->id = ret;
+	scnprintf(uchger->name, CHARGER_NAME_MAX, "usb-charger.%d", uchger->id);
+
+	ret = sysfs_create_groups(&uchger->gadget->dev.kobj,
+				  usb_charger_groups);
+	if (ret) {
+		pr_err("Failed to create usb charger attributes: %d\n", ret);
+		goto fail;
+	}
+
+	mutex_lock(&charger_lock);
+	list_add_tail(&uchger->list, &charger_list);
+	mutex_unlock(&charger_lock);
+
+	return 0;
+
+fail:
+	ida_simple_remove(&usb_charger_ida, uchger->id);
+	uchger->id = -1;
+	return ret;
+}
+
+int usb_charger_init(struct usb_gadget *ugadget)
+{
+	struct usb_charger *uchger;
+	struct extcon_dev *edev;
+	struct power_supply *psy;
+	int ret;
+
+	uchger = kzalloc(sizeof(struct usb_charger), GFP_KERNEL);
+	if (!uchger)
+		return -ENOMEM;
+
+	uchger->type = UNKNOWN_TYPE;
+	uchger->state = USB_CHARGER_DEFAULT;
+	uchger->id = -1;
+	uchger->sdp_default_cur_change = 0;
+
+	uchger->cur_limit.sdp_cur_limit = DEFAULT_SDP_CUR_LIMIT;
+	uchger->cur_limit.dcp_cur_limit = DEFAULT_DCP_CUR_LIMIT;
+	uchger->cur_limit.cdp_cur_limit = DEFAULT_CDP_CUR_LIMIT;
+	uchger->cur_limit.aca_cur_limit = DEFAULT_ACA_CUR_LIMIT;
+
+	mutex_init(&uchger->lock);
+	RAW_INIT_NOTIFIER_HEAD(&uchger->uchger_nh);
+	INIT_WORK(&uchger->work, usb_charger_notify_work);
+
+	/* register a notifier on a extcon device if it is exsited */
+	edev = extcon_get_edev_by_phandle(ugadget->dev.parent, 0);
+	if (!IS_ERR_OR_NULL(edev)) {
+		uchger->extcon_dev = edev;
+		uchger->extcon_nb.nb.notifier_call = usb_charger_plug_by_extcon;
+		uchger->extcon_nb.uchger = uchger;
+		extcon_register_notifier(edev, EXTCON_USB,
+					 &uchger->extcon_nb.nb);
+	}
+
+	/* to check if the usb charger is link to a power supply */
+	psy = devm_power_supply_get_by_phandle(ugadget->dev.parent,
+					       "power-supplies");
+	if (!IS_ERR_OR_NULL(psy))
+		uchger->psy = psy;
+	else
+		uchger->psy = NULL;
+
+	/* register a notifier on a usb gadget device */
+	uchger->gadget = ugadget;
+	uchger->old_gadget_state = USB_STATE_NOTATTACHED;
+
+	/* register a new usb charger */
+	ret = usb_charger_register(uchger);
+	if (ret)
+		goto fail;
+
+	return 0;
+
+fail:
+	if (uchger->extcon_dev) {
+		extcon_unregister_notifier(uchger->extcon_dev,
+					   EXTCON_USB,
+					   &uchger->extcon_nb.nb);
+	}
+
+	kfree(uchger);
+	return ret;
+}
+
+int usb_charger_exit(struct usb_gadget *ugadget)
+{
+	return 0;
+}
+
+MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
+MODULE_DESCRIPTION("USB charger driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/usb/charger.h b/include/linux/usb/charger.h
new file mode 100644
index 0000000..fb5b994
--- /dev/null
+++ b/include/linux/usb/charger.h
@@ -0,0 +1,186 @@
+#ifndef __LINUX_USB_CHARGER_H__
+#define __LINUX_USB_CHARGER_H__
+
+#include <uapi/linux/usb/ch9.h>
+#include <uapi/linux/usb/charger.h>
+
+#define CHARGER_NAME_MAX	30
+#define work_to_charger(w)	(container_of((w), struct usb_charger, work))
+
+/* Current limitation by charger type */
+struct usb_charger_cur_limit {
+	unsigned int sdp_cur_limit;
+	unsigned int dcp_cur_limit;
+	unsigned int cdp_cur_limit;
+	unsigned int aca_cur_limit;
+};
+
+struct usb_charger_nb {
+	struct notifier_block	nb;
+	struct usb_charger	*uchger;
+};
+
+/**
+ * struct usb_charger - describe one usb charger
+ * @name: Charger name.
+ * @list: For linking usb charger instances into one global list.
+ * @uchger_nh: Notifier head for users to register.
+ * @lock: Protect the notifier head and charger.
+ * @id: The charger id.
+ * @type: The charger type, it can be SDP_TYPE, DCP_TYPE, CDP_TYPE or
+ * ACA_TYPE.
+ * @state: Indicate the charger state.
+ * @work: Workqueue to be used for reporting users current has changed.
+ * @extcon_dev: For supporting extcon usb gpio device to detect usb cable
+ * event (plugin or not).
+ * @extcon_nb: Report the events to charger from extcon device.
+ * @gadget: One usb charger is always tied to one usb gadget.
+ * @old_gadget_state: Record the previous state of one usb gadget to check if
+ * the gadget state is changed. If gadget state is changed, then notify the
+ * event to charger.
+ * @psy: User can get the charger type from power supply if the power supply
+ * supports POWER_SUPPLY_PROP_CHARGE_TYPE property.
+ * @get_charger_type: User can get charger type by implementing this callback.
+ * @charger_detect: Charger detection method can be implemented if you need to
+ * manually detect the charger type.
+ * @cur_limit: Describe the current limitation by charger type.
+ * @sdp_default_cur_change: Check if it is needed to change the SDP charger
+ * default current.
+ *
+ * Users can set 'get_charger_type' and 'charger_detect' callbacks directly
+ * according to their own requirements. Beyond that, users can not touch
+ * anything else directly in this structure.
+ */
+struct usb_charger {
+	char			name[CHARGER_NAME_MAX];
+	struct list_head	list;
+	struct raw_notifier_head	uchger_nh;
+	struct mutex		lock;
+	int			id;
+	enum usb_charger_type	type;
+	enum usb_charger_state	state;
+	struct work_struct	work;
+
+	struct extcon_dev	*extcon_dev;
+	struct usb_charger_nb	extcon_nb;
+
+	struct usb_gadget	*gadget;
+	enum usb_device_state	old_gadget_state;
+
+	struct power_supply	*psy;
+
+	enum usb_charger_type	(*get_charger_type)(struct usb_charger *);
+	enum usb_charger_type	(*charger_detect)(struct usb_charger *);
+
+	struct usb_charger_cur_limit	cur_limit;
+	unsigned int		sdp_default_cur_change;
+};
+
+#ifdef CONFIG_USB_CHARGER
+extern struct usb_charger *usb_charger_find_by_name(const char *name);
+
+extern int usb_charger_register_notify(struct usb_charger *uchger,
+				       struct notifier_block *nb);
+extern int usb_charger_unregister_notify(struct usb_charger *uchger,
+					 struct notifier_block *nb);
+
+extern int usb_charger_set_cur_limit(struct usb_charger *uchger,
+				struct usb_charger_cur_limit *cur_limit_set);
+extern int usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
+					     enum usb_charger_type type,
+					     unsigned int cur_limit);
+extern int usb_charger_set_cur_limit_by_gadget(struct usb_gadget *gadget,
+					       unsigned int cur_limit);
+extern unsigned int usb_charger_get_cur_limit(struct usb_charger *uchger);
+
+extern int usb_charger_plug_by_gadget(struct usb_gadget *gadget,
+				      unsigned long state);
+extern enum usb_charger_type usb_charger_get_type(struct usb_charger *uchger);
+extern int usb_charger_detect_type(struct usb_charger *uchger);
+extern enum usb_charger_state usb_charger_get_state(struct usb_charger *uchger);
+
+extern int usb_charger_init(struct usb_gadget *ugadget);
+extern int usb_charger_exit(struct usb_gadget *ugadget);
+#else
+static inline struct usb_charger *usb_charger_find_by_name(const char *name)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline int
+usb_charger_register_notify(struct usb_charger *uchger,
+			    struct notifier_block *nb)
+{
+	return 0;
+}
+
+static inline int
+usb_charger_unregister_notify(struct usb_charger *uchger,
+			      struct notifier_block *nb)
+{
+	return 0;
+}
+
+static inline int
+usb_charger_set_cur_limit(struct usb_charger *uchger,
+			  struct usb_charger_cur_limit *cur_limit_set)
+{
+	return 0;
+}
+
+static inline int
+usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
+				  enum usb_charger_type type,
+				  unsigned int cur_limit)
+{
+	return 0;
+}
+
+static inline int
+usb_charger_set_cur_limit_by_gadget(struct usb_gadget *gadget,
+				    unsigned int cur_limit)
+{
+	return 0;
+}
+
+static inline unsigned int
+usb_charger_get_cur_limit(struct usb_charger *uchger)
+{
+	return 0;
+}
+
+static inline enum usb_charger_type
+usb_charger_get_type(struct usb_charger *uchger)
+{
+	return UNKNOWN_TYPE;
+}
+
+static inline enum usb_charger_state
+usb_charger_get_state(struct usb_charger *uchger)
+{
+	return USB_CHARGER_REMOVE;
+}
+
+static inline int usb_charger_detect_type(struct usb_charger *uchger)
+{
+	return 0;
+}
+
+static inline int
+usb_charger_plug_by_gadget(struct usb_gadget *gadget, unsigned long state)
+{
+	return 0;
+}
+
+static inline int usb_charger_init(struct usb_gadget *ugadget)
+{
+	return 0;
+}
+
+static inline int usb_charger_exit(struct usb_gadget *ugadget)
+{
+	return 0;
+}
+#endif
+
+#endif /* __LINUX_USB_CHARGER_H__ */
diff --git a/include/uapi/linux/usb/charger.h b/include/uapi/linux/usb/charger.h
new file mode 100644
index 0000000..3c56ec4
--- /dev/null
+++ b/include/uapi/linux/usb/charger.h
@@ -0,0 +1,31 @@
+/*
+ * This file defines the USB charger type and state that are needed for
+ * USB device APIs.
+ */
+
+#ifndef _UAPI__LINUX_USB_CHARGER_H
+#define _UAPI__LINUX_USB_CHARGER_H
+
+/*
+ * USB charger type:
+ * SDP (Standard Downstream Port)
+ * DCP (Dedicated Charging Port)
+ * CDP (Charging Downstream Port)
+ * ACA (Accessory Charger Adapters)
+ */
+enum usb_charger_type {
+	UNKNOWN_TYPE,
+	SDP_TYPE,
+	DCP_TYPE,
+	CDP_TYPE,
+	ACA_TYPE,
+};
+
+/* USB charger state */
+enum usb_charger_state {
+	USB_CHARGER_DEFAULT,
+	USB_CHARGER_PRESENT,
+	USB_CHARGER_REMOVE,
+};
+
+#endif /* _UAPI__LINUX_USB_CHARGER_H */
