hid-multitouch: Filter collections by application usage.

This change fixes two problems.

First, it ensures that the hid-multitouch driver does not incorrectly
map GenericDesktop usages that are intended for other applications,
such as a Mouse.

Second, it sets the appropriate input properties so that user-space
can distinguish TouchScreen devices (INPUT_PROP_DIRECT) from
TouchPad devices (INPUT_PROP_POINTER) and configure them accordingly.

Change-Id: I8c2d947929186ffe7cf04b37c76e29b9abecf8cb
Signed-off-by: jeffbrown@android.com

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 3d664d01305e5ef32301fdcf53a4f3bbee61f027..96759b2703604739f40ff73ebb764276e8c1f44e 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -434,6 +434,16 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
        if ((usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON)
                td->buttons_count++;
 
+       /* Only map fields from TouchScreen or TouchPad collections.
+         * We need to ignore fields that belong to other collections
+         * such as Mouse that might have the same GenericDesktop usages. */
+       if (field->application == HID_DG_TOUCHSCREEN)
+               set_bit(INPUT_PROP_DIRECT, hi->input->propbit);
+       else if (field->application == HID_DG_TOUCHPAD)
+               set_bit(INPUT_PROP_POINTER, hi->input->propbit);
+       else
+               return 0;
+
        if (usage->usage_index)
                prev_usage = &field->usage[usage->usage_index - 1];