Added sanei_usb_get_descriptor() to retrieve more info about a

device descriptor

include/sane/sanei_usb.h

@@ -162,6 +162,18 @@
 #define USB_DIR_IN                      0x80
 /* @} */
 
+/** */
+struct sanei_usb_dev_descriptor
+{
+	SANE_Byte    desc_type;
+	unsigned int bcd_usb;
+	unsigned int bcd_dev;
+	SANE_Byte    dev_class;
+	SANE_Byte    dev_sub_class;
+	SANE_Byte    dev_protocol;
+	SANE_Byte    max_packet_size;
+};
+
 /** Initialize sanei_usb.
  *
  * Call this before any other sanei_usb function.
@@ -416,5 +428,24 @@ sanei_usb_release_interface (SANE_Int dn, SANE_Int interface_number);
 extern SANE_Status
 sanei_usb_set_altinterface (SANE_Int dn, SANE_Int alternate);
 
+/** Get some information from the device descriptor
+ *
+ * Sometimes it's useful to know something about revisions and
+ * other stuff reported by the USB system
+ *
+ * @param dn device number
+ * @param desc, where to put the information to
+ *
+ * @return 
+ * - SANE_STATUS_GOOD - on succes
+ * - SANE_STATUS_UNSUPPORTED - if the feature is not supported by the OS or
+ *   SANE.
+ * - SANE_STATUS_INVAL - on every other error
+ *
+ */
+
+extern SANE_Status
+sanei_usb_get_descriptor( SANE_Int dn, struct sanei_usb_dev_descriptor *desc );
+
 /*------------------------------------------------------*/
 #endif /* sanei_usb_h */

sanei/sanei_usb.c

@@ -1922,3 +1922,38 @@ sanei_usb_set_altinterface (SANE_Int dn, SANE_Int alternate)
       return SANE_STATUS_UNSUPPORTED;
     }
 }
+
+extern SANE_Status
+sanei_usb_get_descriptor( SANE_Int dn, struct sanei_usb_dev_descriptor *desc )
+{
+  if (dn >= MAX_DEVICES || dn < 0)
+    {
+      DBG (1,
+	   "sanei_usb_get_descriptor: dn >= MAX_DEVICES || dn < 0, dn=%d\n",
+	   dn);
+      return SANE_STATUS_INVAL;
+    }
+
+  DBG (5, "sanei_usb_get_descriptor\n");
+#ifdef HAVE_LIBUSB
+    {
+	  struct usb_device_descriptor *usb_descr;
+
+	  usb_descr = &(devices[dn].libusb_device->descriptor);
+	  desc->desc_type = usb_descr->bDescriptorType;
+	  desc->bcd_usb   = usb_descr->bcdUSB;
+	  desc->bcd_dev   = usb_descr->bcdDevice;
+	  desc->dev_class = usb_descr->bDeviceClass;
+
+	  desc->dev_sub_class   = usb_descr->bDeviceSubClass;
+	  desc->dev_protocol    = usb_descr->bDeviceProtocol;
+	  desc->max_packet_size = usb_descr->bMaxPacketSize0;
+	  return SANE_STATUS_GOOD;
+    }
+#else /* not HAVE_LIBUSB */
+    {
+      DBG (1, "sanei_usb_get_descriptor: libusb support missing\n");
+      return SANE_STATUS_UNSUPPORTED;
+    }
+#endif /* not HAVE_LIBUSB */
+}