Input: MT - Get slot by key

Some devices use an internal key for tracking which cannot be directly
mapped to slots. This patch provides a key-to-slot mapping, which can
be used by drivers of such devices.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/input/mt.h b/include/linux/input/mt.h
index 6b6f7c8e95bf..cc5cca774bab 100644
--- a/include/linux/input/mt.h
+++ b/include/linux/input/mt.h
@@ -24,10 +24,12 @@
  * struct input_mt_slot - represents the state of an input MT slot
  * @abs: holds current values of ABS_MT axes for this slot
  * @frame: last frame at which input_mt_report_slot_state() was called
+ * @key: optional driver designation of this slot
  */
 struct input_mt_slot {
         int abs[ABS_MT_LAST - ABS_MT_FIRST + 1];
         unsigned int frame;
+        unsigned int key;
 };
 
 /**
@@ -111,4 +113,6 @@ struct input_mt_pos {
 int input_mt_assign_slots(struct input_dev *dev, int *slots,
                           const struct input_mt_pos *pos, int num_pos);
 
+int input_mt_get_slot_by_key(struct input_dev *dev, int key);
+
 #endif