[PATCH 2/3] hid: 3m: Convert to MT slots

["Henrik Rydberg" <rydberg@euromail.se>]

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.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
---
 drivers/hid/hid-3m-pct.c |   50 +++++++++++++++++++++++++++++++++++----------
 1 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/drivers/hid/hid-3m-pct.c b/drivers/hid/hid-3m-pct.c
index 1057430..9a3b047 100644
--- a/drivers/hid/hid-3m-pct.c
+++ b/drivers/hid/hid-3m-pct.c
@@ -25,16 +25,22 @@ MODULE_LICENSE("GPL");
 #include "hid-ids.h"
 
 #define MAX_SLOTS		60
-#define MAX_TRKID		59
+#define MAX_TRKID		USHRT_MAX
+#define MAX_EVENTS		360
+#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 +50,10 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		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 +64,20 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		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 +97,19 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		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,
 					1, 1, 0, 0);
 			return 1;
@@ -100,6 +117,11 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 			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 +139,10 @@ static int mmm_input_mapped(struct hid_device *hdev, struct hid_input *hi,
 		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 +163,15 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 		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 +179,6 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 						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 +207,9 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 			--(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;
 	}
 
-- 
1.7.1