V4L/DVB (9587): Handle changes to endpoint layout in em2874

Empia moved around their endpoint configuration in newer chips, so accommodate
the changes

Thanks for Ray Lu from Empia for providing the em2874 datasheet.
Signed-off-by: Devin Heitmueller <devin.heitmueller@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-video.c

@@ -2149,7 +2149,7 @@ static int em28xx_usb_probe(struct usb_interface *interface,
 	struct usb_interface *uif;
 	struct em28xx *dev = NULL;
 	int retval = -ENODEV;
-	int i, nr, ifnum;
+	int i, nr, ifnum, isoc_pipe;
 
 	udev = usb_get_dev(interface_to_usbdev(interface));
 	ifnum = interface->altsetting[0].desc.bInterfaceNumber;
@@ -2176,9 +2176,18 @@ static int em28xx_usb_probe(struct usb_interface *interface,
 			ifnum,
 			interface->altsetting[0].desc.bInterfaceClass);
 
-	endpoint = &interface->cur_altsetting->endpoint[1].desc;
+	endpoint = &interface->cur_altsetting->endpoint[0].desc;
 
 	/* check if the device has the iso in endpoint at the correct place */
+	if ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
+	    USB_ENDPOINT_XFER_ISOC &&
+	    (interface->altsetting[1].endpoint[0].desc.wMaxPacketSize == 940))
+	{
+		/* It's a newer em2874/em2875 device */
+		isoc_pipe = 0;
+	} else {
+		isoc_pipe = 1;
+		endpoint = &interface->cur_altsetting->endpoint[1].desc;
 		if ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
 		    USB_ENDPOINT_XFER_ISOC) {
 			em28xx_err(DRIVER_NAME " probing error: endpoint is non-ISO endpoint!\n");
@@ -2190,6 +2199,7 @@ static int em28xx_usb_probe(struct usb_interface *interface,
 			em28xx_devused &= ~(1<<nr);
 			return -ENODEV;
 		}
+	}
 
 	if (nr >= EM28XX_MAXBOARDS) {
 		printk(DRIVER_NAME ": Supports only %i em28xx boards.\n",
@@ -2239,7 +2249,7 @@ static int em28xx_usb_probe(struct usb_interface *interface,
 	}
 
 	for (i = 0; i < dev->num_alt ; i++) {
-		u16 tmp = le16_to_cpu(uif->altsetting[i].endpoint[1].desc.
+		u16 tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.
 							wMaxPacketSize);
 		dev->alt_max_pkt_size[i] =
 		    (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);