HID: lenovo-tpkbd: remove usb dependency

lenovo tpkbd currently relies on the usb interface number to detect
if it is dealing with the touchpad interface or not.
As the report descriptors of the interface 0 does not contain the
button 3, we can use this to remove the need to check for usb.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/Kconfig

@@ -322,7 +322,7 @@ config HID_LCPOWER
 
 config HID_LENOVO_TPKBD
 	tristate "Lenovo ThinkPad USB Keyboard with TrackPoint"
-	depends on USB_HID
+	depends on HID
 	select NEW_LEDS
 	select LEDS_CLASS
 	---help---

drivers/hid/hid-lenovo-tpkbd.c

@@ -14,11 +14,9 @@
 #include <linux/module.h>
 #include <linux/sysfs.h>
 #include <linux/device.h>
-#include <linux/usb.h>
 #include <linux/hid.h>
 #include <linux/input.h>
 #include <linux/leds.h>
-#include "usbhid/usbhid.h"
 
 #include "hid-ids.h"
 
@@ -41,10 +39,9 @@ static int tpkbd_input_mapping(struct hid_device *hdev,
 		struct hid_input *hi, struct hid_field *field,
 		struct hid_usage *usage, unsigned long **bit, int *max)
 {
-	struct usbhid_device *uhdev;
-
-	uhdev = (struct usbhid_device *) hdev->driver_data;
-	if (uhdev->ifnum == 1 && usage->hid == (HID_UP_BUTTON | 0x0010)) {
+	if (usage->hid == (HID_UP_BUTTON | 0x0010)) {
+		/* mark the device as pointer */
+		hid_set_drvdata(hdev, (void *)1);
 		map_key_clear(KEY_MICMUTE);
 		return 1;
 	}
@@ -398,7 +395,6 @@ static int tpkbd_probe(struct hid_device *hdev,
 		const struct hid_device_id *id)
 {
 	int ret;
-	struct usbhid_device *uhdev;
 
 	ret = hid_parse(hdev);
 	if (ret) {
@@ -412,9 +408,8 @@ static int tpkbd_probe(struct hid_device *hdev,
 		goto err;
 	}
 
-	uhdev = (struct usbhid_device *) hdev->driver_data;
-
-	if (uhdev->ifnum == 1) {
+	if (hid_get_drvdata(hdev)) {
+		hid_set_drvdata(hdev, NULL);
 		ret = tpkbd_probe_tp(hdev);
 		if (ret)
 			goto err_hid;
@@ -442,10 +437,7 @@ static void tpkbd_remove_tp(struct hid_device *hdev)
 
 static void tpkbd_remove(struct hid_device *hdev)
 {
-	struct usbhid_device *uhdev;
-
-	uhdev = (struct usbhid_device *) hdev->driver_data;
-	if (uhdev->ifnum == 1)
+	if (hid_get_drvdata(hdev))
 		tpkbd_remove_tp(hdev);
 
 	hid_hw_stop(hdev);