Added support for the Avision AV210D2+ scanner

Added support for the Avision AV210D2+ scanner.  This is the first scanner
to require the use of the gray filter bits, so code was added to enable them.
Regenerated description file to reflect this change.

backend/avision.c

@@ -238,6 +238,13 @@ static Avision_HWEntry Avision_Device_List [] =
     /* comment="sheetfed scanner" */
     /* status="complete" */
 
+    { NULL, NULL,
+      0x0638, 0x1A35,
+      "Avision", "AV210D2+",
+      AV_INT_BUTTON, AV_USE_GRAY_FILTER},
+    /* comment="sheetfed scanner" */
+    /* status="complete" */
+
     { NULL, NULL,
       0x0638, 0x0A23,
       "Avision", "AV220",
@@ -3172,6 +3179,7 @@ string_for_button (Avision_Scanner* s, int button)
     }
   
   if (strcmp (dev->sane.model, "AV210C2") == 0 ||
+      strcmp (dev->sane.model, "AV210D2+") == 0 ||
       strcmp (dev->sane.model, "AV220C2") == 0 ||
       strcmp (dev->sane.model, "AV610C2") == 0
       )
@@ -5680,6 +5688,8 @@ set_window (Avision_Scanner* s)
   else {
     if (dev->hw->feature_type & AV_FASTER_WITH_FILTER)
       cmd.window.avision.bitset1 |= AVISION_FILTER_GREEN;
+    else if (dev->hw->feature_type2 & AV_USE_GRAY_FILTER)
+      cmd.window.avision.bitset1 |= AVISION_FILTER_GRAY;
     else
       cmd.window.avision.bitset1 |= AVISION_FILTER_NONE;
   }

backend/avision.h

@@ -199,7 +199,10 @@ typedef struct Avision_HWEntry {
   /*second enum cause 32 bit int above is full*/
   enum {
     /* force no calibration */
-    AV_NO_TUNE_SCAN_LENGTH = (1<<0)
+    AV_NO_TUNE_SCAN_LENGTH = (1<<0),
+
+    /* for gray scans, set grey filter */
+    AV_USE_GRAY_FILTER = (1<<1)
   } feature_type2;
 
 } Avision_HWEntry;

doc/descriptions/avision.desc

@@ -89,6 +89,12 @@
 :comment "sheetfed scanner"
 :status :complete
 
+:model "AV210D2+"
+:interface "USB"
+:usbid "0x0638" "0x1a35"
+:comment "sheetfed scanner"
+:status :complete
+
 :model "AV220"
 :interface "USB"
 :usbid "0x0638" "0x0a23"