[PATCH 6/6] hid: egalax: Convert to MT slots

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

The joojoo reports touches sequentially, one per report, which
confuses the current driver. Convert to the MT slots protocol and use
the stored slot information to emulate pointer movement in a stable
manner.

Tested-by: Philipp Merkel <mail@philmerk.de>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
---
 drivers/hid/hid-egalax.c |  133 ++++++++++++++++++++++++---------------------
 1 files changed, 71 insertions(+), 62 deletions(-)

diff --git a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
index b21e7dc..1ca0f84 100644
--- a/drivers/hid/hid-egalax.c
+++ b/drivers/hid/hid-egalax.c
@@ -2,6 +2,8 @@
  *  HID driver for eGalax dual-touch panels
  *
  *  Copyright (c) 2010 Stephane Chatty <chatty@enac.fr>
+ *  Copyright (c) 2010 Henrik Rydberg <rydberg@euromail.se>
+ *  Copyright (c) 2010 Canonical, Ltd.
  *
  */
 
@@ -25,19 +27,25 @@ MODULE_LICENSE("GPL");
 
 #include "hid-ids.h"
 
+#define MAX_SLOTS		2
+#define MAX_TRKID		USHRT_MAX
 #define MAX_EVENTS		120
 
 /* estimated signal-to-noise ratios */
 #define SN_MOVE			1024
 #define SN_PRESSURE		32
 
+struct egalax_contact {
+	int touch;
+	int x, y, z;
+};
+
 struct egalax_data {
-	__u16 x, y, z;
-	__u8 id;
-	bool first;		/* is this the first finger in the frame? */
-	bool valid;		/* valid finger data, or just placeholder? */
-	bool activity;		/* at least one active finger previously? */
-	__u16 lastx, lasty, lastz;	/* latest valid (x, y, z) in the frame */
+	struct egalax_contact contact[MAX_SLOTS];
+	struct egalax_contact single, tmp;
+	int valid;
+	int slot;
+	int trkid;
 };
 
 static void set_abs(struct input_dev *input, unsigned int code,
@@ -91,10 +99,13 @@ static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		case HID_DG_CONTACTMAX:
 			return -1;
 		case HID_DG_CONTACTID:
+			field->logical_maximum = MAX_TRKID;
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_TRACKING_ID);
 			set_abs(input, ABS_MT_TRACKING_ID, field, 0);
 			input_set_events_per_packet(input, MAX_EVENTS);
+			if (!input->mt)
+				input_mt_create_slots(input, MAX_SLOTS);
 			return 1;
 		case HID_DG_TIPPRESSURE:
 			field->logical_minimum = 0;
@@ -122,64 +133,61 @@ static int egalax_input_mapped(struct hid_device *hdev, struct hid_input *hi,
 	return -1;
 }
 
+static void emulate_pointer(struct egalax_data *td, struct input_dev *input)
+{
+	struct egalax_contact *s = &td->single;
+	struct egalax_contact *best = 0;
+	int dbest, i;
+
+	for (i = 0; i < MAX_SLOTS; i++) {
+		struct egalax_contact *f = &td->contact[i];
+		if (f->touch) {
+			int d = abs(f->x - s->x) + abs(f->y - s->y);
+			if (!best || d < dbest) {
+				best = f;
+				dbest = d;
+			}
+		}
+	}
+
+	if (best) {
+		input_event(input, EV_KEY, BTN_TOUCH, 1);
+		input_event(input, EV_ABS, ABS_X, best->x);
+		input_event(input, EV_ABS, ABS_Y, best->y);
+		input_event(input, EV_ABS, ABS_PRESSURE, best->z);
+		*s = *best;
+	} else {
+		input_event(input, EV_KEY, BTN_TOUCH, 0);
+	}
+}
+
+
 /*
  * this function is called when a whole finger has been parsed,
  * so that it can decide what to send to the input layer.
  */
 static void egalax_filter_event(struct egalax_data *td, struct input_dev *input)
 {
-	td->first = !td->first; /* touchscreen emulation */
-
-	if (td->valid) {
-		/* emit multitouch events */
-		input_event(input, EV_ABS, ABS_MT_TRACKING_ID, td->id);
-		input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x >> 3);
-		input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y >> 3);
-		input_event(input, EV_ABS, ABS_MT_PRESSURE, td->z);
-
-		input_mt_sync(input);
-
-		/*
-		 * touchscreen emulation: store (x, y) as
-		 * the last valid values in this frame
-		 */
-		td->lastx = td->x;
-		td->lasty = td->y;
-		td->lastz = td->z;
-	}
-
-	/*
-	 * touchscreen emulation: if this is the second finger and at least
-	 * one in this frame is valid, the latest valid in the frame is
-	 * the oldest on the panel, the one we want for single touch
-	 */
-	if (!td->first && td->activity) {
-		input_event(input, EV_ABS, ABS_X, td->lastx >> 3);
-		input_event(input, EV_ABS, ABS_Y, td->lasty >> 3);
- 		input_event(input, EV_ABS, ABS_PRESSURE, td->lastz);
-	}
-
-	if (!td->valid) {
-		/*
-		 * touchscreen emulation: if the first finger is invalid
-		 * and there previously was finger activity, this is a release
-		 */ 
-		if (td->first && td->activity) {
-			input_event(input, EV_KEY, BTN_TOUCH, 0);
-			td->activity = false;
+	struct egalax_contact *old = &td->contact[td->slot];
+	struct egalax_contact *f = &td->tmp;
+
+	input_mt_slot(input, td->slot);
+	if (f->touch) {
+		if (!old->touch) {
+			int id = td->trkid++ & MAX_TRKID;
+			input_event(input, EV_ABS, ABS_MT_TRACKING_ID, id);
 		}
-		return;
+		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_PRESSURE, f->z);
+	} else {
+		input_event(input, EV_ABS, ABS_MT_TRACKING_ID, -1);
 	}
+	*old = *f;
 
-
-	/* touchscreen emulation: if no previous activity, emit touch event */
-	if (!td->activity) {
-		input_event(input, EV_KEY, BTN_TOUCH, 1);
-		td->activity = true;
-	}
+	emulate_pointer(td, input);
 }
 
-
 static int egalax_event(struct hid_device *hid, struct hid_field *field,
 				struct hid_usage *usage, __s32 value)
 {
@@ -189,37 +197,38 @@ static int egalax_event(struct hid_device *hid, struct hid_field *field,
 	 * uses a standard parallel multitouch protocol (product ID ==
 	 * 48xx).  The second is capacitive and uses an unusual "serial"
 	 * protocol with a different message for each multitouch finger
-	 * (product ID == 72xx).  We do not yet generate a correct event
-	 * sequence for the capacitive/serial protocol.
+	 * (product ID == 72xx).
 	 */
 	if (hid->claimed & HID_CLAIMED_INPUT) {
 		struct input_dev *input = field->hidinput->input;
 
 		switch (usage->hid) {
 		case HID_DG_INRANGE:
+			td->valid = value;
+			break;
 		case HID_DG_CONFIDENCE:
 			/* avoid interference from generic hidinput handling */
 			break;
 		case HID_DG_TIPSWITCH:
-			td->valid = value;
+			td->tmp.touch = value;
 			break;
 		case HID_DG_TIPPRESSURE:
-			td->z = value;
+			td->tmp.z = value;
 			break;
 		case HID_DG_CONTACTID:
-			td->id = value;
+			td->slot = clamp_val(value, 0, MAX_SLOTS - 1);
 			break;
 		case HID_GD_X:
-			td->x = value;
+			td->tmp.x = value;
 			break;
 		case HID_GD_Y:
-			td->y = value;
+			td->tmp.y = value;
 			/* this is the last field in a finger */
-			egalax_filter_event(td, input);
+			if (td->valid)
+				egalax_filter_event(td, input);
 			break;
 		case HID_DG_CONTACTCOUNT:
 			/* touch emulation: this is the last field in a frame */
-			td->first = false;
 			break;
 
 		default:
-- 
1.7.1