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: I2927c0a12a04a72c0c567f4844f499ab3621cca7
Signed-off-by: jeffbrown@android.com

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index ee01e65..852bc85 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -165,6 +165,16 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
        struct mt_class *cls = td->mtclass;
        __s32 quirks = cls->quirks;
 
+       /* 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;
+
        switch (usage->hid & HID_USAGE_PAGE) {
 
        case HID_UP_GENDESK: