[PATCH v13 0/4] Introduce usb charger framework to deal with the usb gadget power negotation

[PATCH v13 0/4] Introduce usb charger framework to deal with the usb gadget power negotation

[Baolin Wang]

Currently the Linux kernel does not provide any standard integration of this
feature that integrates the USB subsystem with the system power regulation
provided by PMICs meaning that either vendors must add this in their kernels
or USB gadget devices based on Linux (such as mobile phones) may not behave
as they should. Thus provide a standard framework for doing this in kernel.

Now introduce one user with wm831x_power to support and test the usb charger,
which is pending testing. Moreover there may be other potential users will use
it in future.

Changes since v12:
 - Remove the class and device things.
 - Link usb charger to udc-core.ko.
 - Create one "charger" subdirectory which holds all charger-related attributes.

Changes since v11:
 - Reviewed and tested by Li Jun.

Changes since v10:
 - Introduce usb_charger_get_state() function to check charger state.
 - Remove the mutex lock in usb_charger_set_cur_limit_by_type() function
 in case will be issued in atomic context.

Baolin Wang (4):
  usb: gadget: Introduce the usb charger framework
  usb: gadget: Support for the usb charger framework
  usb: gadget: Integrate with the usb gadget supporting for usb charger
  power: wm831x_power: Support USB charger current limit management

 drivers/power/wm831x_power.c      |   69 ++++
 drivers/usb/gadget/Kconfig        |    8 +
 drivers/usb/gadget/udc/Makefile   |    4 +-
 drivers/usb/gadget/udc/charger.c  |  723 +++++++++++++++++++++++++++++++++++++
 drivers/usb/gadget/udc/udc-core.c |   11 +
 include/linux/mfd/wm831x/pdata.h  |    3 +
 include/linux/usb/charger.h       |  166 +++++++++
 include/linux/usb/gadget.h        |   11 +
 include/uapi/linux/usb/charger.h  |   31 ++
 9 files changed, 1025 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/gadget/udc/charger.c
 create mode 100644 include/linux/usb/charger.h
 create mode 100644 include/uapi/linux/usb/charger.h

-- 
1.7.9.5

[PATCH v13 1/4] usb: gadget: Introduce the usb charger framework

[Baolin Wang]

This patch introduces the usb charger driver based on usb gadget that
makes an enhancement to a power driver. It works well in practice but
that requires a system with suitable hardware.

The basic conception of the usb charger is that, when one usb charger
is added or removed by reporting from the usb gadget state change or
the extcon device state change, the usb charger will report to power
user to set the current limitation.

The usb charger will register notifiees on the usb gadget or the extcon
device to get notified the usb charger state. It also supplies the
notification mechanism to userspace When the usb charger state is changed.

Power user will register a notifiee on the usb charger to get notified
by status changes from the usb charger. It will report to power user
to set the current limitation when detecting the usb charger is added
or removed from extcon device state or usb gadget state.

This patch doesn't yet integrate with the gadget code, so some functions
which rely on the 'gadget' are not completed, that will be implemented
in the following patches.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Li Jun <jun.li@nxp.com>
Tested-by: Li Jun <jun.li@nxp.com>
---
 drivers/usb/gadget/Kconfig       |    8 +
 drivers/usb/gadget/udc/Makefile  |    4 +-
 drivers/usb/gadget/udc/charger.c |  665 ++++++++++++++++++++++++++++++++++++++
 include/linux/usb/charger.h      |  166 ++++++++++
 include/uapi/linux/usb/charger.h |   31 ++
 5 files changed, 873 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/gadget/udc/charger.c
 create mode 100644 include/linux/usb/charger.h
 create mode 100644 include/uapi/linux/usb/charger.h

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 2057add..72e0419 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 dfee534..3bdfacd 100644
--- a/drivers/usb/gadget/udc/Makefile
+++ b/drivers/usb/gadget/udc/Makefile
@@ -1,7 +1,9 @@
 #
 # USB peripheral controller drivers
 #
-obj-$(CONFIG_USB_GADGET)	+= udc-core.o
+obj-$(CONFIG_USB_GADGET)	+= udc_core.o
+udc_core-y			:= udc-core.o
+udc_core-$(CONFIG_USB_CHARGER)	+= charger.o
 obj-$(CONFIG_USB_DUMMY_HCD)	+= dummy_hcd.o
 obj-$(CONFIG_USB_NET2272)	+= net2272.o
 obj-$(CONFIG_USB_NET2280)	+= net2280.o
diff --git a/drivers/usb/gadget/udc/charger.c b/drivers/usb/gadget/udc/charger.c
new file mode 100644
index 0000000..a0dd0cf
--- /dev/null
+++ b/drivers/usb/gadget/udc/charger.c
@@ -0,0 +1,665 @@
+/*
+ * charger.c -- USB charger driver
+ *
+ * Copyright (C) 2015 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>
+
+#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 (WARN(!uchger->charger_detect,
+		 "charger detection method should not be NULL"))
+		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.
+ */
+int usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
+				      enum usb_charger_type type,
+				      unsigned int cur_limit)
+{
+	if (WARN(!uchger, "charger can not be NULL"))
+		return -EINVAL;
+
+	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;
+}
+EXPORT_SYMBOL_GPL(usb_charger_set_cur_limit_by_type);
+
+/*
+ * usb_charger_set_current_by_type_lock() - 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_current_by_type_lock(struct usb_charger *uchger,
+					 enum usb_charger_type type,
+					 unsigned int cur_limit)
+{
+	int ret;
+
+	if (WARN(!uchger, "charger can not be NULL"))
+		return -EINVAL;
+
+	mutex_lock(&uchger->lock);
+	ret = usb_charger_set_cur_limit_by_type(uchger, type, cur_limit);
+	mutex_unlock(&uchger->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_charger_set_current_by_type_lock);
+
+/*
+ * 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 (WARN(!uchger || !cur_limit_set, "charger or setting can't be NULL"))
+		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);
+
+	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_current() - 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_current(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_current);
+
+/*
+ * 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 (WARN(!uchger || !nb, "charger or nb can not be NULL"))
+		return -EINVAL;
+
+	mutex_lock(&uchger->lock);
+	ret = raw_notifier_chain_register(&uchger->uchger_nh, nb);
+
+	/* Generate an initial notify so users start in the right state */
+	if (!ret) {
+		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);
+
+	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 (WARN(!uchger || !nb, "charger or nb can not be NULL"))
+		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);
+	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;
+
+	if (WARN(!uchger, "charger can not be NULL"))
+		return -EINVAL;
+
+	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);
+
+	/* 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..b1175bb
--- /dev/null
+++ b/include/linux/usb/charger.h
@@ -0,0 +1,166 @@
+#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
+
+/* 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 {
+	char			name[CHARGER_NAME_MAX];
+	struct list_head	list;
+	struct raw_notifier_head	uchger_nh;
+	/* protect the notifier head and charger */
+	struct mutex		lock;
+	int			id;
+	enum usb_charger_type	type;
+	enum usb_charger_state	state;
+
+	/* for supporting extcon usb gpio */
+	struct extcon_dev	*extcon_dev;
+	struct usb_charger_nb	extcon_nb;
+
+	/* for supporting usb gadget */
+	struct usb_gadget	*gadget;
+	enum usb_device_state	old_gadget_state;
+
+	/* for supporting power supply */
+	struct power_supply	*psy;
+
+	/* user can get charger type by implementing this callback */
+	enum usb_charger_type	(*get_charger_type)(struct usb_charger *);
+	/*
+	 * charger detection method can be implemented if you need to
+	 * manually detect the charger type.
+	 */
+	enum usb_charger_type	(*charger_detect)(struct usb_charger *);
+
+	/* current limitation */
+	struct usb_charger_cur_limit	cur_limit;
+	/* to check if it is needed to change the SDP charger default current */
+	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_current_by_type_lock(struct usb_charger *uchger,
+						enum usb_charger_type type,
+						unsigned int cur_limit);
+extern unsigned int usb_charger_get_current(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_current_by_type_lock(struct usb_charger *uchger,
+				     enum usb_charger_type type,
+				     unsigned int cur_limit)
+{
+	return 0;
+}
+
+static inline unsigned int
+usb_charger_get_current(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 */
-- 
1.7.9.5

[PATCH v13 2/4] usb: gadget: Support for the usb charger framework

[Baolin Wang]

For supporting the usb charger, it adds the usb_charger_init() and
usb_charger_exit() functions for usb charger initialization and exit.

It will report to the usb charger when the gadget state is changed,
then the usb charger can do the power things.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Li Jun <jun.li@nxp.com>
Tested-by: Li Jun <jun.li@nxp.com>
---
 drivers/usb/gadget/udc/udc-core.c |   11 +++++++++++
 include/linux/usb/gadget.h        |   11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
index 6e8300d..84c098c 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -28,6 +28,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb.h>
+#include <linux/usb/charger.h>
 
 /**
  * struct usb_udc - describes one usb device controller
@@ -242,6 +243,9 @@ static void usb_gadget_state_work(struct work_struct *work)
 	struct usb_gadget *gadget = work_to_gadget(work);
 	struct usb_udc *udc = gadget->udc;
 
+	/* when the gadget state is changed, then report to USB charger */
+	usb_charger_plug_by_gadget(gadget, gadget->state);
+
 	if (udc)
 		sysfs_notify(&udc->dev.kobj, NULL, "state");
 }
@@ -411,6 +415,10 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
 	if (ret)
 		goto err4;
 
+	ret = usb_charger_init(gadget);
+	if (ret)
+		goto err5;
+
 	usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
 	udc->vbus = true;
 
@@ -431,6 +439,8 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
 
 	return 0;
 
+err5:
+	device_del(&udc->dev);
 err4:
 	list_del(&udc->list);
 	mutex_unlock(&udc_lock);
@@ -539,6 +549,7 @@ void usb_del_gadget_udc(struct usb_gadget *gadget)
 	kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
 	flush_work(&gadget->work);
 	device_unregister(&udc->dev);
+	usb_charger_exit(gadget);
 	device_unregister(&gadget->dev);
 }
 EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 457651b..40390ec 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -24,6 +24,7 @@
 #include <linux/types.h>
 #include <linux/workqueue.h>
 #include <linux/usb/ch9.h>
+#include <linux/usb/charger.h>
 
 struct usb_ep;
 
@@ -639,6 +640,8 @@ struct usb_gadget {
 	unsigned			out_epnum;
 	unsigned			in_epnum;
 	struct usb_otg_caps		*otg_caps;
+	/* negotiate the power with the usb charger */
+	struct usb_charger		*charger;
 
 	unsigned			sg_supported:1;
 	unsigned			is_otg:1;
@@ -855,10 +858,18 @@ static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
  * reporting how much power the device may consume.  For example, this
  * could affect how quickly batteries are recharged.
  *
+ * It will also notify the USB charger how much power the device may
+ * consume if there is a USB charger linking with the gadget.
+ *
  * Returns zero on success, else negative errno.
  */
 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
 {
+	if (gadget->charger)
+		usb_charger_set_cur_limit_by_type(gadget->charger,
+						  gadget->charger->type,
+						  mA);
+
 	if (!gadget->ops->vbus_draw)
 		return -EOPNOTSUPP;
 	return gadget->ops->vbus_draw(gadget, mA);
-- 
1.7.9.5

[PATCH v13 3/4] usb: gadget: Integrate with the usb gadget supporting for usb charger

[Baolin Wang]

When the usb gadget supporting for usb charger is ready, the usb charger
can implement the usb_charger_plug_by_gadget() function, usb_charger_exit()
function and dev_to_uchger() function by getting 'struct usb_charger' from
'struct gadget'.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Li Jun <jun.li@nxp.com>
Tested-by: Li Jun <jun.li@nxp.com>
---
 drivers/usb/gadget/udc/charger.c |   62 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/charger.c b/drivers/usb/gadget/udc/charger.c
index a0dd0cf..e04273c 100644
--- a/drivers/usb/gadget/udc/charger.c
+++ b/drivers/usb/gadget/udc/charger.c
@@ -35,7 +35,9 @@ static unsigned int usb_charger_get_cur_limit(struct usb_charger *uchger);
 
 static struct usb_charger *dev_to_uchger(struct device *dev)
 {
-	return NULL;
+	struct usb_gadget *gadget = container_of(dev, struct usb_gadget, dev);
+
+	return gadget->charger;
 }
 
 /*
@@ -548,11 +550,55 @@ usb_charger_plug_by_extcon(struct notifier_block *nb,
 int usb_charger_plug_by_gadget(struct usb_gadget *gadget,
 			       unsigned long state)
 {
+	struct usb_charger *uchger = gadget->charger;
+	enum usb_charger_state uchger_state;
+
+	if (WARN(!uchger, "charger can not be NULL"))
+		return -EINVAL;
+
+	/*
+	 * Report event to power to setting the current limitation
+	 * for this usb charger when one usb charger state is changed
+	 * with detecting by usb gadget state.
+	 */
+	if (uchger->old_gadget_state != state) {
+		uchger->old_gadget_state = state;
+
+		if (state >= USB_STATE_ATTACHED)
+			uchger_state = USB_CHARGER_PRESENT;
+		else if (state == USB_STATE_NOTATTACHED)
+			uchger_state = USB_CHARGER_REMOVE;
+		else
+			uchger_state = USB_CHARGER_DEFAULT;
+
+		usb_charger_notify_others(uchger, uchger_state);
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(usb_charger_plug_by_gadget);
 
 /*
+ * usb_charger_unregister() - Unregister a usb charger.
+ * @uchger - the usb charger to be unregistered.
+ */
+static int usb_charger_unregister(struct usb_charger *uchger)
+{
+	if (WARN(!uchger, "charger can not be NULL"))
+		return -EINVAL;
+
+	ida_simple_remove(&usb_charger_ida, uchger->id);
+	sysfs_remove_groups(&uchger->gadget->dev.kobj, usb_charger_groups);
+
+	mutex_lock(&charger_lock);
+	list_del(&uchger->list);
+	mutex_unlock(&charger_lock);
+
+	kfree(uchger);
+	return 0;
+}
+
+/*
  * usb_charger_register() - Register a new usb charger.
  * @uchger - the new usb charger instance.
  */
@@ -635,6 +681,7 @@ int usb_charger_init(struct usb_gadget *ugadget)
 
 	/* register a notifier on a usb gadget device */
 	uchger->gadget = ugadget;
+	ugadget->charger = uchger;
 	uchger->old_gadget_state = USB_STATE_NOTATTACHED;
 
 	/* register a new usb charger */
@@ -657,7 +704,18 @@ fail:
 
 int usb_charger_exit(struct usb_gadget *ugadget)
 {
-	return 0;
+	struct usb_charger *uchger = ugadget->charger;
+
+	if (WARN(!uchger, "charger can not be NULL"))
+		return -EINVAL;
+
+	ugadget->charger = NULL;
+	if (uchger->extcon_dev)
+		extcon_unregister_notifier(uchger->extcon_dev,
+					   EXTCON_USB,
+					   &uchger->extcon_nb.nb);
+
+	return usb_charger_unregister(uchger);
 }
 
 MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
-- 
1.7.9.5

[PATCH v13 4/4] power: wm831x_power: Support USB charger current limit management

[Baolin Wang]

Integrate with the newly added USB charger interface to limit the current
we draw from the USB input based on the input device configuration
identified by the USB stack, allowing us to charge more quickly from high
current inputs without drawing more current than specified from others.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Sebastian Reichel <sre@kernel.org>
---
 drivers/power/wm831x_power.c     |   69 ++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/wm831x/pdata.h |    3 ++
 2 files changed, 72 insertions(+)

diff --git a/drivers/power/wm831x_power.c b/drivers/power/wm831x_power.c
index 7082301..cef1812 100644
--- a/drivers/power/wm831x_power.c
+++ b/drivers/power/wm831x_power.c
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
+#include <linux/usb/charger.h>
 
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/auxadc.h>
@@ -31,6 +32,8 @@ struct wm831x_power {
 	char usb_name[20];
 	char battery_name[20];
 	bool have_battery;
+	struct usb_charger *usb_charger;
+	struct notifier_block usb_notify;
 };
 
 static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
@@ -125,6 +128,43 @@ static enum power_supply_property wm831x_usb_props[] = {
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 };
 
+/* In milliamps */
+static const unsigned int wm831x_usb_limits[] = {
+	0,
+	2,
+	100,
+	500,
+	900,
+	1500,
+	1800,
+	550,
+};
+
+static int wm831x_usb_limit_change(struct notifier_block *nb,
+				   unsigned long limit, void *data)
+{
+	struct wm831x_power *wm831x_power = container_of(nb,
+							 struct wm831x_power,
+							 usb_notify);
+	unsigned int i, best;
+
+	/* Find the highest supported limit */
+	best = 0;
+	for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
+		if (limit >= wm831x_usb_limits[i] &&
+		    wm831x_usb_limits[best] < wm831x_usb_limits[i])
+			best = i;
+	}
+
+	dev_dbg(wm831x_power->wm831x->dev,
+		"Limiting USB current to %umA", wm831x_usb_limits[best]);
+
+	wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
+		        WM831X_USB_ILIM_MASK, best);
+
+	return 0;
+}
+
 /*********************************************************************
  *		Battery properties
  *********************************************************************/
@@ -607,8 +647,31 @@ static int wm831x_power_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (wm831x_pdata && wm831x_pdata->usb_gadget) {
+		power->usb_charger =
+			usb_charger_find_by_name(wm831x_pdata->usb_gadget);
+		if (IS_ERR(power->usb_charger)) {
+			ret = PTR_ERR(power->usb_charger);
+			dev_err(&pdev->dev,
+				"Failed to find USB gadget: %d\n", ret);
+			goto err_bat_irq;
+		}
+
+		power->usb_notify.notifier_call = wm831x_usb_limit_change;
+
+		ret = usb_charger_register_notify(power->usb_charger,
+						  &power->usb_notify);
+		if (ret != 0) {
+			dev_err(&pdev->dev,
+				"Failed to register notifier: %d\n", ret);
+			goto err_usb_charger;
+		}
+	}
+
 	return ret;
 
+err_usb_charger:
+	/* put_device on charger */
 err_bat_irq:
 	--i;
 	for (; i >= 0; i--) {
@@ -637,6 +700,12 @@ static int wm831x_power_remove(struct platform_device *pdev)
 	struct wm831x *wm831x = wm831x_power->wm831x;
 	int irq, i;
 
+	if (wm831x_power->usb_charger) {
+		usb_charger_unregister_notify(wm831x_power->usb_charger,
+					      &wm831x_power->usb_notify);
+		/* Free charger */
+	}
+
 	for (i = 0; i < ARRAY_SIZE(wm831x_bat_irqs); i++) {
 		irq = wm831x_irq(wm831x, 
 				 platform_get_irq_byname(pdev,
diff --git a/include/linux/mfd/wm831x/pdata.h b/include/linux/mfd/wm831x/pdata.h
index dcc9631..5af8399 100644
--- a/include/linux/mfd/wm831x/pdata.h
+++ b/include/linux/mfd/wm831x/pdata.h
@@ -126,6 +126,9 @@ struct wm831x_pdata {
 	/** The driver should initiate a power off sequence during shutdown */
 	bool soft_shutdown;
 
+	/** dev_name of USB charger gadget to integrate with */
+	const char *usb_gadget;
+
 	int irq_base;
 	int gpio_base;
 	int gpio_defaults[WM831X_GPIO_NUM];
-- 
1.7.9.5