HID: hid-multitouch: add support for PenMount dual-touch panel

This patch adds PenMount support to hid-multitouch.  A new class
MT_CLS_CONFIDENCE is defined for PenMount, since it uses HID_DG_CONFIDENCE as
the valid flag.

Signed-off-by: John Sung <penmount.touch@gmail.com>
[benjamin.tissoires@enac.fr: rebased on top of last_index_field changes]
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-multitouch.c

@@ -89,6 +89,7 @@ struct mt_class {
 #define MT_CLS_EGALAX				5
 #define MT_CLS_STANTUM				6
 #define MT_CLS_3M				7
+#define MT_CLS_CONFIDENCE			8
 
 #define MT_DEFAULT_MAXCONTACT	10
 
@@ -156,6 +157,8 @@ struct mt_class mt_classes[] = {
 		.sn_move = 2048,
 		.sn_width = 128,
 		.sn_height = 128 },
+	{ .name = MT_CLS_CONFIDENCE,
+		.quirks = MT_QUIRK_VALID_IS_CONFIDENCE },
 
 	{ }
 };
@@ -584,6 +587,11 @@ static const struct hid_device_id mt_devices[] = {
 		HID_USB_DEVICE(USB_VENDOR_ID_IRTOUCHSYSTEMS,
 			USB_DEVICE_ID_IRTOUCH_INFRARED_USB) },
 
+	/* PenMount panels */
+	{ .driver_data = MT_CLS_CONFIDENCE,
+		HID_USB_DEVICE(USB_VENDOR_ID_PENMOUNT,
+			USB_DEVICE_ID_PENMOUNT_PCI) },
+
 	/* PixCir-based panels */
 	{ .driver_data = MT_CLS_DUAL_INRANGE_CONTACTID,
 		HID_USB_DEVICE(USB_VENDOR_ID_HANVON,