HID: add autodetection of multitouch devices

As mentioned by http://www.microsoft.com/whdc/device/input/DigitizerDrvs_touch.mspx
multitouch devices are those that have the input report HID_CONTACTID.

This patch detects this and unloads the generic-usb driver.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

3 files changed, 18 insertions, 0 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 956f84968fa4..f869ab35e6d6 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1212,6 +1212,12 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
         if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
                                 connect_mask & HID_CONNECT_HIDINPUT_FORCE))
                 hdev->claimed |= HID_CLAIMED_INPUT;
+        if (hdev->quirks & HID_QUIRK_MULTITOUCH) {
+                /* this device should be handled by hid-multitouch, skip it */
+                hdev->quirks &= ~HID_QUIRK_MULTITOUCH;
+                return -ENODEV;
+        }
+
         if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
                         !hdev->hiddev_connect(hdev,
                                 connect_mask & HID_CONNECT_HIDDEV_FORCE))
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 6559e2e3364e..f333139d1a48 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -474,6 +474,10 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
                         map_key_clear(BTN_STYLUS2);
                         break;
 
+                case 0x51: /* ContactID */
+                        device->quirks |= HID_QUIRK_MULTITOUCH;
+                        goto unknown;
+
                 default:  goto unknown;
                 }
                 break;
@@ -978,6 +982,13 @@ int hidinput_connect(struct hid_device *hid, unsigned int force)
                 }
         }
 
+        if (hid->quirks & HID_QUIRK_MULTITOUCH) {
+                /* generic hid does not know how to handle multitouch devices */
+                if (hidinput)
+                        goto out_cleanup;
+                goto out_unwind;
+        }
+
         if (hidinput && input_register_device(hidinput->input))
                 goto out_cleanup;
 
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 9cf8e7ae7450..6fb743d72bfe 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -312,6 +312,7 @@ struct hid_item {
 #define HID_QUIRK_BADPAD                        0x00000020
 #define HID_QUIRK_MULTI_INPUT                   0x00000040
 #define HID_QUIRK_HIDINPUT_FORCE                0x00000080
+#define HID_QUIRK_MULTITOUCH                    0x00000100
 #define HID_QUIRK_SKIP_OUTPUT_REPORTS           0x00010000
 #define HID_QUIRK_FULLSPEED_INTERVAL            0x10000000
 #define HID_QUIRK_NO_INIT_REPORTS               0x20000000