[PATCH] scanner.c: Support for devices with only one bulk-in endpoint

This patch (originally from Sergey Vlasov) adds support for scanners
with only one bulk-in endpoint. It's needed by all the GT-6801 based
scanners like the Artec Ultima 2000 or some of the Mustek BearPaws.

drivers/usb/image/scanner.c

@@ -323,6 +323,8 @@
  *      Ed Hamrick <EdHamrick@aol.com>, Oliver Schwartz
  *	<Oliver.Schwartz@gmx.de> and everyone else who sent ids.
  *    - Some Benq, Genius and Plustek ids are identified now.
+ *    - Accept scanners with only one bulk (in) endpoint (thanks to Sergey
+ *      Vlasov <vsu@mivlgu.murom.ru>).
  *
  * TODO
  *    - Remove the 2/3 endpoint limitation
@@ -513,6 +515,12 @@ write_scanner(struct file * file, const char * buffer,
 
 	down(&(scn->sem));
 
+	if (!scn->bulk_out_ep) {
+		/* This scanner does not have a bulk-out endpoint */
+		up(&(scn->sem));
+		return -EINVAL;
+	}
+
 	scn_minor = scn->scn_minor;
 
 	obuf = scn->obuf;
@@ -907,15 +915,15 @@ probe_scanner(struct usb_interface *intf,
 	interface = intf->altsetting;
 
 /*
- * Start checking for two bulk endpoints OR two bulk endpoints *and* one
+ * Start checking for one or two bulk endpoints and an optional
  * interrupt endpoint. If we have an interrupt endpoint go ahead and
  * setup the handler. FIXME: This is a future enhancement...
  */
 
 	dbg("probe_scanner: Number of Endpoints:%d", (int) interface->desc.bNumEndpoints);
 
-	if ((interface->desc.bNumEndpoints != 2) && (interface->desc.bNumEndpoints != 3)) {
-		info("probe_scanner: Only two or three endpoints supported.");
+	if ((interface->desc.bNumEndpoints < 1) || (interface->desc.bNumEndpoints > 3)) {
+		info("probe_scanner: Only 1, 2, or 3 endpoints supported.");
 		return -ENODEV;
 	}
 
@@ -955,6 +963,12 @@ probe_scanner(struct usb_interface *intf,
  */
 
 	switch(interface->desc.bNumEndpoints) {
+	case 1:
+		if (!have_bulk_in) {
+			info("probe_scanner: One bulk-in endpoint required.");
+			return -EIO;
+		}
+		break;
 	case 2:
 		if (!have_bulk_in || !have_bulk_out) {
 			info("probe_scanner: Two bulk endpoints required.");