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_sys.c b/drivers/hid/wacom_sys.c
index 21ac2ba..dd288b2 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -13,7 +13,6 @@
 
 #include "wacom_wac.h"
 #include "wacom.h"
-#include <linux/hid.h>
 
 #define WAC_MSG_RETRIES		5
 
@@ -215,6 +214,9 @@
 			features->pressure_max = field->logical_maximum;
 		break;
 	}
+
+	if (features->type == HID_GENERIC)
+		wacom_wac_usage_mapping(hdev, field, usage);
 }
 
 static void wacom_parse_hid(struct hid_device *hdev,
@@ -1318,6 +1320,7 @@
 	struct wacom_wac *wacom_wac;
 	struct wacom_features *features;
 	int error;
+	unsigned int connect_mask = HID_CONNECT_HIDRAW;
 
 	if (!id->driver_data)
 		return -EINVAL;
@@ -1451,8 +1454,11 @@
 	/* Note that if query fails it is not a hard failure */
 	wacom_query_tablet_data(hdev, features);
 
+	if (features->type == HID_GENERIC)
+		connect_mask |= HID_CONNECT_DRIVER;
+
 	/* Regular HID work starts now */
-	error = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	error = hid_hw_start(hdev, connect_mask);
 	if (error) {
 		hid_err(hdev, "hw start failed\n");
 		goto fail_hw_start;
@@ -1532,6 +1538,8 @@
 	.id_table =	wacom_ids,
 	.probe =	wacom_probe,
 	.remove =	wacom_remove,
+	.event =	wacom_wac_event,
+	.report =	wacom_wac_report,
 #ifdef CONFIG_PM
 	.resume =	wacom_resume,
 	.reset_resume =	wacom_reset_resume,