HID: wacom: implement generic HID handling for pen generic devices

ISDv4 and v5 are plain HID devices. We can directly implement a generic
HID parsing/handling and remove the need to manually add those PID in
the list of supported devices.

This patch implements the pen support only. The finger part will come in
a later patch.

To be properly notified of an .event() and a .report(), we need to force
hid-core to go through the HID parsing. By default, wacom.ko binds only
hidraw, so the hid parsing is not done by hid-core. When a true HID device
is there, we add the flag HID_CLAIMED_DRIVER to hid->claimed which will
force hid-core to parse the incoming reports.
(Note that this can be easily backported by directly setting the .claimed
flag to HID_CLAIMED_DRIVER even if hid-core does not support
HID_CONNECT_DRIVER)

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Jason Gerecke <killertofu@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/include/linux/hid.h b/include/linux/hid.h
index f53c4a9..3dcd004 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -265,6 +265,7 @@
 #define HID_CONNECT_HIDDEV		0x08
 #define HID_CONNECT_HIDDEV_FORCE	0x10
 #define HID_CONNECT_FF			0x20
+#define HID_CONNECT_DRIVER		0x40
 #define HID_CONNECT_DEFAULT	(HID_CONNECT_HIDINPUT|HID_CONNECT_HIDRAW| \
 		HID_CONNECT_HIDDEV|HID_CONNECT_FF)
 
@@ -440,6 +441,7 @@
 #define HID_CLAIMED_INPUT	1
 #define HID_CLAIMED_HIDDEV	2
 #define HID_CLAIMED_HIDRAW	4
+#define HID_CLAIMED_DRIVER	8
 
 #define HID_STAT_ADDED		1
 #define HID_STAT_PARSED		2