Input: mt: add input_mt_is_used

This patch extracts the test (slot->frame == mt->frame) so that it can
be used in third party drivers.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 7 insertions, 1 deletions

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index c0ec7d42c3be..475b9d424eed 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -247,7 +247,7 @@ void input_mt_sync_frame(struct input_dev *dev)
 
         if (mt->flags & INPUT_MT_DROP_UNUSED) {
                 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
-                        if (s->frame == mt->frame)
+                        if (input_mt_is_used(mt, s))
                                 continue;
                         input_mt_slot(dev, s - mt->slots);
                         input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
diff --git a/include/linux/input/mt.h b/include/linux/input/mt.h
index cc5cca774bab..2e86bd0bfba1 100644
--- a/include/linux/input/mt.h
+++ b/include/linux/input/mt.h
@@ -69,6 +69,12 @@ static inline bool input_mt_is_active(const struct input_mt_slot *slot)
         return input_mt_get_value(slot, ABS_MT_TRACKING_ID) >= 0;
 }
 
+static inline bool input_mt_is_used(const struct input_mt *mt,
+                                    const struct input_mt_slot *slot)
+{
+        return slot->frame == mt->frame;
+}
+
 int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
                         unsigned int flags);
 void input_mt_destroy_slots(struct input_dev *dev);