usb: dwc3: support continuous runtime PM with dual role

The DRD module calls dwc3_set_mode() on role switches, i.e. when a device is
being plugged in. In order to support continuous runtime power management when
plugging in / unplugging a cable, we need to call pm_runtime_get_sync() in
this path.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/dwc3/core.c

@@ -121,17 +121,19 @@ static void __dwc3_set_mode(struct work_struct *work)
 	if (dwc->dr_mode != USB_DR_MODE_OTG)
 		return;
 
+	pm_runtime_get_sync(dwc->dev);
+
 	if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_OTG)
 		dwc3_otg_update(dwc, 0);
 
 	if (!dwc->desired_dr_role)
-		return;
+		goto out;
 
 	if (dwc->desired_dr_role == dwc->current_dr_role)
-		return;
+		goto out;
 
 	if (dwc->desired_dr_role == DWC3_GCTL_PRTCAP_OTG && dwc->edev)
-		return;
+		goto out;
 
 	switch (dwc->current_dr_role) {
 	case DWC3_GCTL_PRTCAP_HOST:
@@ -190,6 +192,9 @@ static void __dwc3_set_mode(struct work_struct *work)
 		break;
 	}
 
+out:
+	pm_runtime_mark_last_busy(dwc->dev);
+	pm_runtime_put_autosuspend(dwc->dev);
 }
 
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode)