[PATCH] usb: dwc3: gadget: call gadget driver's ->suspend/->resume

[David Cohen <david.a.cohen@linux.intel.com>]

From: Felipe Balbi <balbi@ti.com>

When going into bus suspend/resume we _must_
call gadget driver's ->suspend/->resume callbacks
accordingly. This patch implements that very feature
which has been missing forever.

Cc: <stable@vger.kernel.org> # 3.14
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
---

Hi,

This patch was introduced on v3.15.
But the issue it fixes already existed on v3.14 and v3.14 is a long term
support version.
I propose to backport it over there as well.

BR, David
---

 drivers/usb/dwc3/gadget.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8f6738d46b14..1bb752736c32 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2012,6 +2012,24 @@ static void dwc3_disconnect_gadget(struct dwc3 *dwc)
 	}
 }
 
+static void dwc3_suspend_gadget(struct dwc3 *dwc)
+{
+	if (dwc->gadget_driver && dwc->gadget_driver->disconnect) {
+		spin_unlock(&dwc->lock);
+		dwc->gadget_driver->suspend(&dwc->gadget);
+		spin_lock(&dwc->lock);
+	}
+}
+
+static void dwc3_resume_gadget(struct dwc3 *dwc)
+{
+	if (dwc->gadget_driver && dwc->gadget_driver->disconnect) {
+		spin_unlock(&dwc->lock);
+		dwc->gadget_driver->resume(&dwc->gadget);
+		spin_lock(&dwc->lock);
+	}
+}
+
 static void dwc3_stop_active_transfer(struct dwc3 *dwc, u32 epnum)
 {
 	struct dwc3_ep *dep;
@@ -2391,6 +2409,23 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
 
 	dwc->link_state = next;
 
+	switch (next) {
+	case DWC3_LINK_STATE_U1:
+		if (dwc->speed == USB_SPEED_SUPER)
+			dwc3_suspend_gadget(dwc);
+		break;
+	case DWC3_LINK_STATE_U2:
+	case DWC3_LINK_STATE_U3:
+		dwc3_suspend_gadget(dwc);
+		break;
+	case DWC3_LINK_STATE_RESUME:
+		dwc3_resume_gadget(dwc);
+		break;
+	default:
+		/* do nothing */
+		break;
+	}
+
 	dev_vdbg(dwc->dev, "%s link %d\n", __func__, dwc->link_state);
 }
 
-- 
2.1.4