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

index f660afb..1971218 100644
@@ -28,6 +28,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb.h>
+#include <linux/usb/usb_charger.h>
 
 /**
  * struct usb_udc - describes one usb device controller

@@ -129,6 +130,32 @@ void usb_gadget_giveback_request(struct usb_ep *ep,
 }
 EXPORT_SYMBOL_GPL(usb_gadget_giveback_request);
 
+int usb_gadget_register_notify(struct usb_gadget *gadget,
+			       struct notifier_block *nb)
+{
+	int ret;
+
+	mutex_lock(&gadget->lock);
+	ret = raw_notifier_chain_register(&gadget->nh, nb);
+	mutex_unlock(&gadget->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_register_notify);
+
+int usb_gadget_unregister_notify(struct usb_gadget *gadget,
+				 struct notifier_block *nb)
+{
+	int ret;
+
+	mutex_lock(&gadget->lock);
+	ret = raw_notifier_chain_unregister(&gadget->nh, nb);
+	mutex_unlock(&gadget->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_unregister_notify);
+
 /* ------------------------------------------------------------------------- */
 
 /**

@@ -226,6 +253,10 @@ static void usb_gadget_state_work(struct work_struct *work)
 	struct usb_gadget *gadget = work_to_gadget(work);
 	struct usb_udc *udc = gadget->udc;
 
+	mutex_lock(&gadget->lock);
+	raw_notifier_call_chain(&gadget->nh, gadget->state, gadget);
+	mutex_unlock(&gadget->lock);
+
 	if (udc)
 		sysfs_notify(&udc->dev.kobj, NULL, "state");
 }

@@ -364,6 +395,8 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
 
 	dev_set_name(&gadget->dev, "gadget");
 	INIT_WORK(&gadget->work, usb_gadget_state_work);
+	RAW_INIT_NOTIFIER_HEAD(&gadget->nh);
+	mutex_init(&gadget->lock);
 	gadget->dev.parent = parent;
 
 #ifdef	CONFIG_HAS_DMA

@@ -405,8 +438,13 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
 
 	mutex_unlock(&udc_lock);
 
-	return 0;
+	ret = usb_charger_init(gadget);
+	if (ret)
+		goto err5;
 
+	return 0;
+err5:
+	device_del(&udc->dev);
 err4:
 	list_del(&udc->list);
 	mutex_unlock(&udc_lock);

@@ -481,6 +519,7 @@ 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 c14a69b..78cc862 100644
@@ -537,6 +537,7 @@ struct usb_gadget_ops {
 	struct usb_ep *(*match_ep)(struct usb_gadget *,
 			struct usb_endpoint_descriptor *,
 			struct usb_ss_ep_comp_descriptor *);
+	enum usb_charger_type	(*get_charger_type)(struct usb_gadget *);
 };
 
 /**

@@ -609,6 +610,9 @@ struct usb_gadget {
 	unsigned			out_epnum;
 	unsigned			in_epnum;
 	struct usb_otg_caps		*otg_caps;
+	struct raw_notifier_head	nh;
+	struct usb_charger		*uchger;
+	struct mutex			lock;
 
 	unsigned			sg_supported:1;
 	unsigned			is_otg:1;

@@ -1183,6 +1187,22 @@ extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
 
 /*-------------------------------------------------------------------------*/
 
+/**
+ * Register a notifiee to get notified by any attach status changes from
+ * the usb gadget
+ */
+int usb_gadget_register_notify(struct usb_gadget *gadget,
+			       struct notifier_block *nb);
+
+/*-------------------------------------------------------------------------*/
+
+
+/* Unregister a notifiee from the usb gadget */
+int usb_gadget_unregister_notify(struct usb_gadget *gadget,
+				 struct notifier_block *nb);
+
+/*-------------------------------------------------------------------------*/
+
 /* utility to set gadget state properly */
 
 extern void usb_gadget_set_state(struct usb_gadget *gadget,

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138 lines not on this page · raw message

index db11ae6..72c661f 100644
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
+#include <linux/usb/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 miliamps */
+static 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);
+	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 %dmA", wm831x_usb_limits[best]);
+
+	wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
+		        WM831X_USB_ILIM_MASK, best);
+
+	return 0;
+}
+
 /*********************************************************************
  *		Battery properties
  *********************************************************************/

@@ -606,8 +646,31 @@ 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:
+	usb_charger_put(power->usb_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);
+		usb_charger_put(wm831x_power->usb_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];