usb: dwc2: gadget: use soft-disconnect udc feature in pullup() method

This patch moves udc initialization from pullup() method to
s3c_hsotg_udc_start(), so that method ends with hardware fully
initialized and left in soft-disconnected state. After this change, the
pullup() method simply clears soft-disconnect start() when called with
is_on=1. For completeness, a call to s3c_hsotg_core_disconnect() has
been added when pullup() method is called with is_on=0, what puts the
udc hardware back to soft-disconnected state.
Acked-by: NPaul Zimmerman <paulz@synopsys.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/dwc2/gadget.c

@@ -2880,6 +2880,7 @@ static int s3c_hsotg_udc_start(struct usb_gadget *gadget,
 			   struct usb_gadget_driver *driver)
 {
 	struct s3c_hsotg *hsotg = to_hsotg(gadget);
+	unsigned long flags;
 	int ret;
 
 	if (!hsotg) {
@@ -2918,7 +2919,13 @@ static int s3c_hsotg_udc_start(struct usb_gadget *gadget,
 
 	s3c_hsotg_phy_enable(hsotg);
 
+	spin_lock_irqsave(&hsotg->lock, flags);
+	s3c_hsotg_init(hsotg);
+	s3c_hsotg_core_init_disconnected(hsotg);
+	spin_unlock_irqrestore(&hsotg->lock, flags);
+
 	dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
+
 	return 0;
 
 err:
@@ -2990,9 +2997,9 @@ static int s3c_hsotg_pullup(struct usb_gadget *gadget, int is_on)
 	spin_lock_irqsave(&hsotg->lock, flags);
 	if (is_on) {
 		clk_enable(hsotg->clk);
-		s3c_hsotg_core_init_disconnected(hsotg);
 		s3c_hsotg_core_connect(hsotg);
 	} else {
+		s3c_hsotg_core_disconnect(hsotg);
 		clk_disable(hsotg->clk);
 	}