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/drivers/hid/wacom_wac.h b/drivers/hid/wacom_wac.h
index 72f9ca8..f472eac 100644
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h
@@ -113,6 +113,7 @@
 	MTSCREEN,
 	MTTPC,
 	MTTPC_B,
+	HID_GENERIC,
 	MAX_TYPE
 };
 
@@ -154,6 +155,12 @@
 	struct input_dev *touch_input;
 };
 
+struct hid_data {
+	bool inrange_state;
+	bool invert_state;
+	bool tipswitch;
+};
+
 struct wacom_wac {
 	char name[WACOM_NAME_MAX];
 	char pad_name[WACOM_NAME_MAX];
@@ -175,6 +182,7 @@
 	int ps_connected;
 	u8 bt_features;
 	u8 bt_high_speed;
+	struct hid_data hid_data;
 };
 
 #endif