Introduce usb charger framework to deal with the usb gadget power negotation

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166 lines not on this page · raw message

new file mode 100644
index 0000000..3c56ec4
@@ -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 */

index 6e8300d..84c098c 100644
@@ -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);

index 457651b..40390ec 100644
@@ -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);

index a0dd0cf..e04273c 100644
@@ -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 <[email protected]>");

index 7082301..cef1812 100644
@@ -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,

index dcc9631..5af8399 100644
@@ -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];