usb: musb: gadget: beautify usb_gadget_probe_driver()/usb_gadget_unregister_driver

Just a few cosmetic fixes to usb_gadget_probe_driver()
and usb_gadget_unregister_driver().

Decreased a few indentation levels with goto statements.

While at that, also add the missing call to musb_stop().
If we don't have OTG, there's no point of leaving
MUSB prepared for operation if a gadget driver fails
to probe. The same is valid for usb_gadget_unregister_driver(),
since we are removing the gadget driver and we don't have
OTG, we can completely unconfigure MUSB.
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_gadget.c

@@ -1801,46 +1801,44 @@ void musb_gadget_cleanup(struct musb *musb)
 int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
 		int (*bind)(struct usb_gadget *))
 {
-	int retval;
-	unsigned long flags;
 	struct musb		*musb = the_gadget;
+	unsigned long		flags;
+	int			retval = -EINVAL;
 
 	if (!driver
 			|| driver->speed != USB_SPEED_HIGH
 			|| !bind || !driver->setup)
-		return -EINVAL;
+		goto err0;
 
 	/* driver must be initialized to support peripheral mode */
 	if (!musb) {
 		DBG(1, "%s, no dev??\n", __func__);
-		return -ENODEV;
+		retval = -ENODEV;
+		goto err0;
 	}
 
 	DBG(3, "registering driver %s\n", driver->function);
-	spin_lock_irqsave(&musb->lock, flags);
 
 	if (musb->gadget_driver) {
 		DBG(1, "%s is already bound to %s\n",
 				musb_driver_name,
 				musb->gadget_driver->driver.name);
 		retval = -EBUSY;
-	} else {
+		goto err0;
+	}
+
+	spin_lock_irqsave(&musb->lock, flags);
 	musb->gadget_driver = driver;
 	musb->g.dev.driver = &driver->driver;
 	driver->driver.bus = NULL;
 	musb->softconnect = 1;
-		retval = 0;
-	}
-
 	spin_unlock_irqrestore(&musb->lock, flags);
 
-	if (retval == 0) {
 	retval = bind(&musb->g);
-		if (retval != 0) {
+	if (retval) {
 		DBG(3, "bind to driver %s failed --> %d\n",
 				driver->driver.name, retval);
-			musb->gadget_driver = NULL;
-			musb->g.dev.driver = NULL;
+		goto err1;
 	}
 
 	spin_lock_irqsave(&musb->lock, flags);
@@ -1849,7 +1847,8 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
 	musb->xceiv->state = OTG_STATE_B_IDLE;
 	musb->is_active = 1;
 
-		/* FIXME this ignores the softconnect flag.  Drivers are
+	/*
+	 * FIXME this ignores the softconnect flag.  Drivers are
 	 * allowed hold the peripheral inactive until for example
 	 * userspace hooks up printer hardware or DSP codecs, so
 	 * hosts only see fully functional devices.
@@ -1874,17 +1873,23 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
 		retval = usb_add_hcd(musb_to_hcd(musb), -1, 0);
 		if (retval < 0) {
 			DBG(1, "add_hcd failed, %d\n", retval);
-				spin_lock_irqsave(&musb->lock, flags);
-				otg_set_peripheral(musb->xceiv, NULL);
-				musb->gadget_driver = NULL;
-				musb->g.dev.driver = NULL;
-				spin_unlock_irqrestore(&musb->lock, flags);
-			} else {
-				hcd->self.uses_pio_for_control = 1;
-			}
+			goto err2;
 		}
+
+		hcd->self.uses_pio_for_control = 1;
 	}
 
+	return 0;
+
+err2:
+	if (!is_otg_enabled(musb))
+		musb_stop(musb);
+
+err1:
+	musb->gadget_driver = NULL;
+	musb->g.dev.driver = NULL;
+
+err0:
 	return retval;
 }
 EXPORT_SYMBOL(usb_gadget_probe_driver);
@@ -1939,14 +1944,17 @@ static void stop_activity(struct musb *musb, struct usb_gadget_driver *driver)
  */
 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 {
-	unsigned long	flags;
-	int		retval = 0;
 	struct musb	*musb = the_gadget;
+	unsigned long	flags;
 
 	if (!driver || !driver->unbind || !musb)
 		return -EINVAL;
 
-	/* REVISIT always use otg_set_peripheral() here too;
+	if (!musb->gadget_driver)
+		return -EINVAL;
+
+	/*
+	 * REVISIT always use otg_set_peripheral() here too;
 	 * this needs to shut down the OTG engine.
 	 */
 
@@ -1956,8 +1964,6 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 	musb_hnp_stop(musb);
 #endif
 
-	if (musb->gadget_driver == driver) {
-
 	(void) musb_gadget_vbus_draw(&musb->g, 0);
 
 	musb->xceiv->state = OTG_STATE_UNDEFINED;
@@ -1965,6 +1971,7 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 	otg_set_peripheral(musb->xceiv, NULL);
 
 	DBG(3, "unregistering driver %s\n", driver->function);
+
 	spin_unlock_irqrestore(&musb->lock, flags);
 	driver->unbind(&musb->g);
 	spin_lock_irqsave(&musb->lock, flags);
@@ -1974,11 +1981,9 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 
 	musb->is_active = 0;
 	musb_platform_try_idle(musb, 0);
-	} else
-		retval = -EINVAL;
 	spin_unlock_irqrestore(&musb->lock, flags);
 
-	if (is_otg_enabled(musb) && retval == 0) {
+	if (is_otg_enabled(musb)) {
 		usb_remove_hcd(musb_to_hcd(musb));
 		/* FIXME we need to be able to register another
 		 * gadget driver here and have everything work;
@@ -1986,7 +1991,10 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 		 */
 	}
 
-	return retval;
+	if (!is_otg_enabled(musb))
+		musb_stop(musb);
+
+	return 0;
 }
 EXPORT_SYMBOL(usb_gadget_unregister_driver);