Input: MT - Add in-kernel tracking
With the INPUT_MT_TRACK flag set, the function input_mt_assign_slots()
can be used to match a new set of contacts against the currently used
slots. The algorithm used is based on Lagrange relaxation, and performs
very well in practice; slower than mtdev for a few corner cases, but
faster in most commonly occuring cases.
Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
diff --git a/include/linux/input/mt.h b/include/linux/input/mt.h
index 9498918..6b6f7c8 100644
--- a/include/linux/input/mt.h
+++ b/include/linux/input/mt.h
@@ -18,6 +18,8 @@
#define INPUT_MT_POINTER 0x0001 /* pointer device, e.g. trackpad */
#define INPUT_MT_DIRECT 0x0002 /* direct device, e.g. touchscreen */
#define INPUT_MT_DROP_UNUSED 0x0004 /* drop contacts not seen in frame */
+#define INPUT_MT_TRACK 0x0008 /* use in-kernel tracking */
+
/**
* struct input_mt_slot - represents the state of an input MT slot
* @abs: holds current values of ABS_MT axes for this slot
@@ -35,6 +37,7 @@
* @slot: MT slot currently being transmitted
* @flags: input_mt operation flags
* @frame: increases every time input_mt_sync_frame() is called
+ * @red: reduced cost matrix for in-kernel tracking
* @slots: array of slots holding current values of tracked contacts
*/
struct input_mt {
@@ -43,6 +46,7 @@
int slot;
unsigned int flags;
unsigned int frame;
+ int *red;
struct input_mt_slot slots[];
};
@@ -58,6 +62,11 @@
return slot->abs[code - ABS_MT_FIRST];
}
+static inline bool input_mt_is_active(const struct input_mt_slot *slot)
+{
+ return input_mt_get_value(slot, ABS_MT_TRACKING_ID) >= 0;
+}
+
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);
@@ -90,4 +99,16 @@
void input_mt_sync_frame(struct input_dev *dev);
+/**
+ * struct input_mt_pos - contact position
+ * @x: horizontal coordinate
+ * @y: vertical coordinate
+ */
+struct input_mt_pos {
+ s16 x, y;
+};
+
+int input_mt_assign_slots(struct input_dev *dev, int *slots,
+ const struct input_mt_pos *pos, int num_pos);
+
#endif