HID: 3m: Convert to MT slots

The Microtouch controller is capable of doing finger tracking on
up to 60 fingers. To reduce bandwidth and cpu usage, convert the
driver to use the MT slots protocol. On Stephane's suggestion, also
insert the additional copyright lines.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Acked-by: Stephane Chatty <chatty@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-3m-pct.c b/drivers/hid/hid-3m-pct.c
index d2fda78..3c380e1 100644
--- a/drivers/hid/hid-3m-pct.c
+++ b/drivers/hid/hid-3m-pct.c
@@ -2,6 +2,8 @@
  *  HID driver for 3M PCT multitouch panels
  *
  *  Copyright (c) 2009-2010 Stephane Chatty <chatty@enac.fr>
+ *  Copyright (c) 2010      Henrik Rydberg <rydberg@euromail.se>
+ *  Copyright (c) 2010      Canonical, Ltd.
  *
  */
 
@@ -25,16 +27,24 @@
 #include "hid-ids.h"
 
 #define MAX_SLOTS		60
-#define MAX_TRKID		59
+#define MAX_TRKID		USHRT_MAX
+#define MAX_EVENTS		360
+
+/* estimated signal-to-noise ratios */
+#define SN_MOVE			2048
+#define SN_WIDTH		128
 
 struct mmm_finger {
 	__s32 x, y, w, h;
+	__u16 id;
 	__u8 rank;
+	bool prev_touch;
 	bool touch, valid;
 };
 
 struct mmm_data {
 	struct mmm_finger f[MAX_SLOTS];
+	__u16 id;
 	__u8 curid, num;
 	__u8 nexp, nreal;
 	bool touch, valid;
@@ -44,6 +54,10 @@
 		struct hid_field *field, struct hid_usage *usage,
 		unsigned long **bit, int *max)
 {
+	int f1 = field->logical_minimum;
+	int f2 = field->logical_maximum;
+	int df = f2 - f1;
+
 	switch (usage->hid & HID_USAGE_PAGE) {
 
 	case HID_UP_BUTTON:
@@ -54,18 +68,20 @@
 		case HID_GD_X:
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_POSITION_X);
+			input_set_abs_params(hi->input, ABS_MT_POSITION_X,
+					     f1, f2, df / SN_MOVE, 0);
 			/* touchscreen emulation */
 			input_set_abs_params(hi->input, ABS_X,
-						field->logical_minimum,
-						field->logical_maximum, 0, 0);
+					     f1, f2, df / SN_MOVE, 0);
 			return 1;
 		case HID_GD_Y:
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_POSITION_Y);
+			input_set_abs_params(hi->input, ABS_MT_POSITION_Y,
+					     f1, f2, df / SN_MOVE, 0);
 			/* touchscreen emulation */
 			input_set_abs_params(hi->input, ABS_Y,
-						field->logical_minimum,
-						field->logical_maximum, 0, 0);
+					     f1, f2, df / SN_MOVE, 0);
 			return 1;
 		}
 		return 0;
@@ -85,14 +101,19 @@
 		case HID_DG_TIPSWITCH:
 			/* touchscreen emulation */
 			hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+			input_set_capability(hi->input, EV_KEY, BTN_TOUCH);
 			return 1;
 		case HID_DG_WIDTH:
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_TOUCH_MAJOR);
+			input_set_abs_params(hi->input, ABS_MT_TOUCH_MAJOR,
+					     f1, f2, df / SN_WIDTH, 0);
 			return 1;
 		case HID_DG_HEIGHT:
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_TOUCH_MINOR);
+			input_set_abs_params(hi->input, ABS_MT_TOUCH_MINOR,
+					     f1, f2, df / SN_WIDTH, 0);
 			input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
 					0, 1, 0, 0);
 			return 1;
@@ -100,6 +121,11 @@
 			field->logical_maximum = MAX_TRKID;
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_TRACKING_ID);
+			input_set_abs_params(hi->input, ABS_MT_TRACKING_ID,
+					     0, MAX_TRKID, 0, 0);
+			if (!hi->input->mt)
+				input_mt_create_slots(hi->input, MAX_SLOTS);
+			input_set_events_per_packet(hi->input, MAX_EVENTS);
 			return 1;
 		}
 		/* let hid-input decide for the others */
@@ -117,10 +143,10 @@
 		struct hid_field *field, struct hid_usage *usage,
 		unsigned long **bit, int *max)
 {
+	/* tell hid-input to skip setup of these event types */
 	if (usage->type == EV_KEY || usage->type == EV_ABS)
-		clear_bit(usage->code, *bit);
-
-	return 0;
+		set_bit(usage->type, hi->input->evbit);
+	return -1;
 }
 
 /*
@@ -141,10 +167,15 @@
 		struct mmm_finger *f = &md->f[i];
 		if (!f->valid) {
 			/* this finger is just placeholder data, ignore */
-		} else if (f->touch) {
+			continue;
+		}
+		input_mt_slot(input, i);
+		if (f->touch) {
 			/* this finger is on the screen */
 			int wide = (f->w > f->h);
-			input_event(input, EV_ABS, ABS_MT_TRACKING_ID, i);
+			if (!f->prev_touch)
+				f->id = md->id++;
+			input_event(input, EV_ABS, ABS_MT_TRACKING_ID, f->id);
 			input_event(input, EV_ABS, ABS_MT_POSITION_X, f->x);
 			input_event(input, EV_ABS, ABS_MT_POSITION_Y, f->y);
 			input_event(input, EV_ABS, ABS_MT_ORIENTATION, wide);
@@ -152,7 +183,6 @@
 						wide ? f->w : f->h);
 			input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR,
 						wide ? f->h : f->w);
-			input_mt_sync(input);
 			/*
 			 * touchscreen emulation: maintain the age rank
 			 * of this finger, decide if we have a press
@@ -181,7 +211,9 @@
 			--(md->num);
 			if (md->num == 0)
 				released = true;
+			input_event(input, EV_ABS, ABS_MT_TRACKING_ID, -1);
 		}
+		f->prev_touch = f->touch;
 		f->valid = 0;
 	}