dwc3: gadget: Implement the suspend entry event handler

It had changed to be suspend event for BIT6 in DEVT register from
version 2.30a and above. Thus this patch introduces one suspend
event handler to handle the suspend event.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

@@ -2695,6 +2695,17 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
 	dwc->link_state = next;
 }
 
+static void dwc3_gadget_suspend_interrupt(struct dwc3 *dwc,
+					  unsigned int evtinfo)
+{
+	enum dwc3_link_state next = evtinfo & DWC3_LINK_STATE_MASK;
+
+	if (dwc->link_state != next && next == DWC3_LINK_STATE_U3)
+		dwc3_suspend_gadget(dwc);
+
+	dwc->link_state = next;
+}
+
 static void dwc3_gadget_hibernation_interrupt(struct dwc3 *dwc,
 		unsigned int evtinfo)
 {
@@ -2746,7 +2757,20 @@ static void dwc3_gadget_interrupt(struct dwc3 *dwc,
 		dwc3_gadget_linksts_change_interrupt(dwc, event->event_info);
 		break;
 	case DWC3_DEVICE_EVENT_EOPF:
+		/* It changed to be suspend event for version 2.30a and above */
+		if (dwc->revision < DWC3_REVISION_230A) {
 			dwc3_trace(trace_dwc3_gadget, "End of Periodic Frame");
+		} else {
+			dwc3_trace(trace_dwc3_gadget, "U3/L1-L2 Suspend Event");
+
+			/*
+			 * Ignore suspend event until the gadget enters into
+			 * USB_STATE_CONFIGURED state.
+			 */
+			if (dwc->gadget.state >= USB_STATE_CONFIGURED)
+				dwc3_gadget_suspend_interrupt(dwc,
+						event->event_info);
+		}
 		break;
 	case DWC3_DEVICE_EVENT_SOF:
 		dwc3_trace(trace_dwc3_gadget, "Start of Periodic Frame");