usb: dwc2: gadget: rework suspend/resume code to correctly restore gadget state

Suspend/resume code assumed that the gadget was always started and
enabled to connect to usb bus. This means that the actual state of the
gadget (started/stopped or connected/disconnected) was not correctly
preserved on suspend/resume cycle. This patch fixes this issue.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/core.h

@@ -688,8 +688,9 @@ struct dwc2_hsotg {
 	u8 ctrl_buff[8];
 
 	struct usb_gadget gadget;
+	unsigned int enabled:1;
 	unsigned int connected:1;
-	unsigned int setup;
+	unsigned int setup:1;
 	unsigned long last_rst;
 	struct s3c_hsotg_ep *eps;
 #endif /* CONFIG_USB_DWC2_PERIPHERAL || CONFIG_USB_DWC2_DUAL_ROLE */

drivers/usb/dwc2/gadget.c

@@ -2889,6 +2889,7 @@ static int s3c_hsotg_udc_start(struct usb_gadget *gadget,
 	spin_lock_irqsave(&hsotg->lock, flags);
 	s3c_hsotg_init(hsotg);
 	s3c_hsotg_core_init_disconnected(hsotg);
+	hsotg->enabled = 0;
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
 	dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
@@ -2929,6 +2930,7 @@ static int s3c_hsotg_udc_stop(struct usb_gadget *gadget)
 
 	hsotg->driver = NULL;
 	hsotg->gadget.speed = USB_SPEED_UNKNOWN;
+	hsotg->enabled = 0;
 
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
@@ -2972,9 +2974,11 @@ 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);
+		hsotg->enabled = 1;
 		s3c_hsotg_core_connect(hsotg);
 	} else {
 		s3c_hsotg_core_disconnect(hsotg);
+		hsotg->enabled = 0;
 		clk_disable(hsotg->clk);
 	}
 
@@ -3585,20 +3589,21 @@ int s3c_hsotg_suspend(struct dwc2_hsotg *hsotg)
 
 	mutex_lock(&hsotg->init_mutex);
 
-	if (hsotg->driver)
+	if (hsotg->driver) {
+		int ep;
+
 		dev_info(hsotg->dev, "suspending usb gadget %s\n",
 			 hsotg->driver->driver.name);
 
-	spin_lock_irqsave(&hsotg->lock, flags);
-	s3c_hsotg_core_disconnect(hsotg);
-	s3c_hsotg_disconnect(hsotg);
-	hsotg->gadget.speed = USB_SPEED_UNKNOWN;
-	spin_unlock_irqrestore(&hsotg->lock, flags);
+		spin_lock_irqsave(&hsotg->lock, flags);
+		if (hsotg->enabled)
+			s3c_hsotg_core_disconnect(hsotg);
+		s3c_hsotg_disconnect(hsotg);
+		hsotg->gadget.speed = USB_SPEED_UNKNOWN;
+		spin_unlock_irqrestore(&hsotg->lock, flags);
 
-	s3c_hsotg_phy_disable(hsotg);
+		s3c_hsotg_phy_disable(hsotg);
 
-	if (hsotg->driver) {
-		int ep;
 		for (ep = 0; ep < hsotg->num_of_eps; ep++)
 			s3c_hsotg_ep_disable(&hsotg->eps[ep].ep);
 
@@ -3626,16 +3631,16 @@ int s3c_hsotg_resume(struct dwc2_hsotg *hsotg)
 
 		clk_enable(hsotg->clk);
 		ret = regulator_bulk_enable(ARRAY_SIZE(hsotg->supplies),
-				      hsotg->supplies);
-	}
-
-	s3c_hsotg_phy_enable(hsotg);
+					    hsotg->supplies);
 
-	spin_lock_irqsave(&hsotg->lock, flags);
-	s3c_hsotg_core_init_disconnected(hsotg);
-	s3c_hsotg_core_connect(hsotg);
-	spin_unlock_irqrestore(&hsotg->lock, flags);
+		s3c_hsotg_phy_enable(hsotg);
 
+		spin_lock_irqsave(&hsotg->lock, flags);
+		s3c_hsotg_core_init_disconnected(hsotg);
+		if (hsotg->enabled)
+			s3c_hsotg_core_connect(hsotg);
+		spin_unlock_irqrestore(&hsotg->lock, flags);
+	}
 	mutex_unlock(&hsotg->init_mutex);
 
 	return ret;