usb: dwc2: gadget: Corrected interval calculation

Calculate the interval according to the USB 2.0 specification section
9.6.6.

Tested-by: John Keeping <john@metanate.com>
Signed-off-by: Vardan Mikayelyan <mvardan@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/core.h

@@ -166,7 +166,7 @@ struct dwc2_hsotg_req;
  *          means that it is sending data to the Host.
  * @index: The index for the endpoint registers.
  * @mc: Multi Count - number of transactions per microframe
- * @interval - Interval for periodic endpoints
+ * @interval - Interval for periodic endpoints, in frames or microframes.
  * @name: The name array passed to the USB core.
  * @halted: Set if the endpoint has been halted.
  * @periodic: Set if this is a periodic ep, such as Interrupt

drivers/usb/dwc2/gadget.c

@@ -2693,16 +2693,13 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 	hs_ep->periodic = 0;
 	hs_ep->halted = 0;
 	hs_ep->interval = desc->bInterval;
-	hs_ep->has_correct_parity = 0;
-
-	if (hs_ep->interval > 1 && hs_ep->mc > 1)
-		dev_err(hsotg->dev, "MC > 1 when interval is not 1\n");
 
 	switch (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
 	case USB_ENDPOINT_XFER_ISOC:
 		epctrl |= DXEPCTL_EPTYPE_ISO;
 		epctrl |= DXEPCTL_SETEVENFR;
 		hs_ep->isochronous = 1;
+		hs_ep->interval = 1 << (desc->bInterval - 1);
 		if (dir_in)
 			hs_ep->periodic = 1;
 		break;
@@ -2715,6 +2712,9 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 		if (dir_in)
 			hs_ep->periodic = 1;
 
+		if (hsotg->gadget.speed == USB_SPEED_HIGH)
+			hs_ep->interval = 1 << (desc->bInterval - 1);
+
 		epctrl |= DXEPCTL_EPTYPE_INTERRUPT;
 		break;