Hi Chanwoo,

quoted

+			input_mt_slot(sdata->input, t_id);
+			input_report_abs(sdata->input, ABS_MT_POSITION_X, x);
+			input_report_abs(sdata->input, ABS_MT_POSITION_Y, y);
+			input_report_abs(sdata->input, ABS_MT_TOUCH_MAJOR, maj);
+			input_report_abs(sdata->input, ABS_MT_TOUCH_MINOR, min);
+			input_report_abs(sdata->input, ABS_MT_PRESSURE, area);
+			input_report_abs(sdata->input, ABS_MT_ORIENTATION,
+								orientation);
+			input_sync(sdata->input);
+

When I tested this patch on TM2 board, It looks like it is not well working.
So, I tried to check the input event by using the evtest tool.
But, the result don't show the proper ABS_MT_TRACKING_ID event.
[1] https://cgit.freedesktop.org/evtest/

According to the mutlti-touch-protocol.txt[2], there are two multi-touch protocol.
As far as I knew, this driver supports the Protocol B which needs
the ABS_MT_TRACKING_ID according to the multi-touch-protocol.txt[2].
[2] Documentation/input/mutlti-touch-protocol.txt
 
In our test, the ABS_MT_TRACKING_ID is showed only one time.
After pressing/releasing finger from touchscreen on first time,
there are no ABS_MT_TRACKING_ID information from second try with finger.

I guess that input_mt_report_slot_state() is not calling properly.

Thanks for testing it, with my own tests indeed I didn't check on
that, there is a logical mistake here:

quoted

+			if (id == STMFTS_EV_MULTI_TOUCH_ENTER) {
+				if (!(sdata->in_touch++))
+					input_mt_report_slot_state(
+							sdata->input,
+							MT_TOOL_FINGER, true);
+			} else if (id == STMFTS_EV_MULTI_TOUCH_LEAVE) {
+				if (!(--sdata->in_touch))
+					input_mt_report_slot_state(
+							sdata->input,
+							MT_TOOL_FINGER, false);
+			}

the inner ifs should be removed, they prevent the
ABS_MT_TRACKING_ID to be sent.

I will fix it.

Thanks a lot,
Andi