usb: gadget: udc-core: add "new-style" registration interface

udc_start() should only trigger the internal state machine and make
minimal house keeping. Before that call udc-core calls the bind()
callback and after the callback the pullup().

udc_stop() is simillar, udc-core calls pullup(), unbind() and finally
udc_stop().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/udc-core.c

@@ -72,6 +72,26 @@ static inline int usb_gadget_start(struct usb_gadget *gadget,
 	return gadget->ops->start(driver, bind);
 }
 
+/**
+ * usb_gadget_udc_start - tells usb device controller to start up
+ * @gadget: The gadget we want to get started
+ * @driver: The driver we want to bind to @gadget
+ *
+ * This call is issued by the UDC Class driver when it's about
+ * to register a gadget driver to the device controller, before
+ * calling gadget driver's bind() method.
+ *
+ * It allows the controller to be powered off until strictly
+ * necessary to have it powered on.
+ *
+ * Returns zero on success, else negative errno.
+ */
+static inline int usb_gadget_udc_start(struct usb_gadget *gadget,
+		struct usb_gadget_driver *driver)
+{
+	return gadget->ops->udc_start(gadget, driver);
+}
+
 /**
  * usb_gadget_stop - tells usb device controller we don't need it anymore
  * @gadget: The device we want to stop activity
@@ -90,6 +110,24 @@ static inline void usb_gadget_stop(struct usb_gadget *gadget,
 	gadget->ops->stop(driver);
 }
 
+/**
+ * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
+ * @gadget: The device we want to stop activity
+ * @driver: The driver to unbind from @gadget
+ *
+ * This call is issued by the UDC Class driver after calling
+ * gadget driver's unbind() method.
+ *
+ * The details are implementation specific, but it can go as
+ * far as powering off UDC completely and disable its data
+ * line pullups.
+ */
+static inline void usb_gadget_udc_stop(struct usb_gadget *gadget,
+		struct usb_gadget_driver *driver)
+{
+	gadget->ops->udc_stop(gadget, driver);
+}
+
 /**
  * usb_udc_release - release the usb_udc struct
  * @dev: the dev member within usb_udc
@@ -155,6 +193,14 @@ int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
 }
 EXPORT_SYMBOL_GPL(usb_add_gadget_udc);
 
+static int udc_is_newstyle(struct usb_udc *udc)
+{
+	if (udc->gadget->ops->udc_start && udc->gadget->ops->udc_stop)
+		return 1;
+	return 0;
+}
+
+
 static void usb_gadget_remove_driver(struct usb_udc *udc)
 {
 	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
@@ -162,7 +208,14 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
 
 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 
+	if (udc_is_newstyle(udc)) {
+		usb_gadget_disconnect(udc->gadget);
+		udc->driver->unbind(udc->gadget);
+		usb_gadget_udc_stop(udc->gadget, udc->driver);
+
+	} else {
 		usb_gadget_stop(udc->gadget, udc->driver);
+	}
 
 	udc->driver = NULL;
 	udc->dev.driver = NULL;
@@ -232,10 +285,24 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
 	udc->driver = driver;
 	udc->dev.driver = &driver->driver;
 
+	if (udc_is_newstyle(udc)) {
+		ret = bind(udc->gadget);
+		if (ret)
+			goto err1;
+		ret = usb_gadget_udc_start(udc->gadget, driver);
+		if (ret) {
+			driver->unbind(udc->gadget);
+			goto err1;
+		}
+		usb_gadget_connect(udc->gadget);
+	} else {
+
 		ret = usb_gadget_start(udc->gadget, driver, bind);
 		if (ret)
 			goto err1;
 
+	}
+
 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 	mutex_unlock(&udc_lock);
 	return 0;

include/linux/usb/gadget.h

@@ -459,6 +459,12 @@ struct usb_gadget_ops {
 	int	(*ioctl)(struct usb_gadget *,
 				unsigned code, unsigned long param);
 	void	(*get_config_params)(struct usb_dcd_config_params *);
+	int	(*udc_start)(struct usb_gadget *,
+			struct usb_gadget_driver *);
+	int	(*udc_stop)(struct usb_gadget *,
+			struct usb_gadget_driver *);
+
+	/* Those two are deprecated */
 	int	(*start)(struct usb_gadget_driver *,
 			int (*bind)(struct usb_gadget *));
 	int	(*stop)(struct usb_gadget_driver *);