+static int search_roland_implicit_fb(struct usb_device *dev, int ifnum,
+ unsigned int altsetting,
+ struct usb_host_interface **alts,
+ unsigned int *ep)
+{
+ struct usb_interface *iface;
+ struct usb_interface_descriptor *altsd;
+ struct usb_endpoint_descriptor *epd;
+
+ iface = usb_ifnum_to_if(dev, ifnum);
+ if (!iface || iface->num_altsetting < altsetting + 1)
+ return -ENOENT;
+ *alts = &iface->altsetting[altsetting];
+ altsd = get_iface_desc(*alts);
+ if (altsd->bAlternateSetting != altsetting ||
+ altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
+ (altsd->bInterfaceSubClass != 2 &&
+ altsd->bInterfaceProtocol != 2 ) ||
+ altsd->bNumEndpoints < 1)
+ return -ENOENT;
+ epd = get_endpoint(*alts, 0);
+ if (!usb_endpoint_is_isoc_in(epd) ||
+ (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
+ USB_ENDPOINT_USAGE_IMPLICIT_FB)
+ return -ENOENT;
+ *ep = epd->bEndpointAddress;
+ return 0;
+}
+