Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rydberg/input-mt into next

Conflicts:
	drivers/input/Makefile

Documentation/DocBook/device-drivers.tmpl

@@ -303,6 +303,10 @@ X!Idrivers/video/console/fonts.c
 !Edrivers/input/input.c
 !Edrivers/input/ff-core.c
 !Edrivers/input/ff-memless.c
+     </sect1>
+     <sect1><title>Multitouch Library</title>
+!Iinclude/linux/input/mt.h
+!Edrivers/input/input-mt.c
      </sect1>
      <sect1><title>Polled input devices</title>
 !Iinclude/linux/input-polldev.h

Documentation/input/multi-touch-protocol.txt

@@ -161,7 +161,8 @@ against the glass. The inner region will increase, and in general, the
 ratio ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR, which is always smaller than
 unity, is related to the contact pressure. For pressure-based devices,
 ABS_MT_PRESSURE may be used to provide the pressure on the contact area
-instead.
+instead. Devices capable of contact hovering can use ABS_MT_DISTANCE to
+indicate the distance between the contact and the surface.
 
 In addition to the MAJOR parameters, the oval shape of the contact can be
 described by adding the MINOR parameters, such that MAJOR and MINOR are the
@@ -213,6 +214,12 @@ The pressure, in arbitrary units, on the contact area. May be used instead
 of TOUCH and WIDTH for pressure-based devices or any device with a spatial
 signal intensity distribution.
 
+ABS_MT_DISTANCE
+
+The distance, in surface units, between the contact and the surface. Zero
+distance means the contact is touching the surface. A positive number means
+the contact is hovering above the surface.
+
 ABS_MT_ORIENTATION
 
 The orientation of the ellipse. The value should describe a signed quarter

MAINTAINERS

@@ -3020,8 +3020,10 @@ F:	drivers/input/
 INPUT MULTITOUCH (MT) PROTOCOL
 M:	Henrik Rydberg <rydberg@euromail.se>
 L:	linux-input@vger.kernel.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rydberg/input-mt.git
 S:	Maintained
 F:	Documentation/input/multi-touch-protocol.txt
+F:	drivers/input/input-mt.c
 K:	\b(ABS|SYN)_MT_
 
 INTEL IDLE DRIVER

drivers/hid/Kconfig

@@ -154,7 +154,8 @@ config HID_EGALAX
 	tristate "eGalax multi-touch panel"
 	depends on USB_HID
 	---help---
-	Support for the eGalax dual-touch panel.
+	Support for the eGalax dual-touch panels, including the
+	Joojoo and Wetab tablets.
 
 config HID_ELECOM
 	tristate "ELECOM BM084 bluetooth mouse"

drivers/hid/hid-3m-pct.c

@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/usb.h>
+#include <linux/input/mt.h>
 
 MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
 MODULE_DESCRIPTION("3M PCT multitouch panels");
@@ -27,8 +28,6 @@ MODULE_LICENSE("GPL");
 #include "hid-ids.h"
 
 #define MAX_SLOTS		60
-#define MAX_TRKID		USHRT_MAX
-#define MAX_EVENTS		360
 
 /* estimated signal-to-noise ratios */
 #define SN_MOVE			2048
@@ -36,14 +35,11 @@ MODULE_LICENSE("GPL");
 
 struct mmm_finger {
 	__s32 x, y, w, h;
-	__u16 id;
-	bool prev_touch;
 	bool touch, valid;
 };
 
 struct mmm_data {
 	struct mmm_finger f[MAX_SLOTS];
-	__u16 id;
 	__u8 curid;
 	__u8 nexp, nreal;
 	bool touch, valid;
@@ -117,14 +113,7 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 					0, 1, 0, 0);
 			return 1;
 		case HID_DG_CONTACTID:
-			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);
+			input_mt_init_slots(hi->input, MAX_SLOTS);
 			return 1;
 		}
 		/* let hid-input decide for the others */
@@ -154,7 +143,6 @@ static int mmm_input_mapped(struct hid_device *hdev, struct hid_input *hi,
  */
 static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 {
-	struct mmm_finger *oldest = 0;
 	int i;
 	for (i = 0; i < MAX_SLOTS; ++i) {
 		struct mmm_finger *f = &md->f[i];
@@ -163,6 +151,7 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 			continue;
 		}
 		input_mt_slot(input, i);
+		input_mt_report_slot_state(input, MT_TOOL_FINGER, f->touch);
 		if (f->touch) {
 			/* this finger is on the screen */
 			int wide = (f->w > f->h);
@@ -170,33 +159,16 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 			int major = max(f->w, f->h) >> 1;
 			int minor = min(f->w, f->h) >> 1;
 
-			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);
 			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
 			input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
-			/* touchscreen emulation: pick the oldest contact */
-			if (!oldest || ((f->id - oldest->id) & (SHRT_MAX + 1)))
-				oldest = f;
-		} else {
-			/* this finger took off the screen */
-			input_event(input, EV_ABS, ABS_MT_TRACKING_ID, -1);
 		}
-		f->prev_touch = f->touch;
 		f->valid = 0;
 	}
 
-	/* touchscreen emulation */
-	if (oldest) {
-		input_event(input, EV_KEY, BTN_TOUCH, 1);
-		input_event(input, EV_ABS, ABS_X, oldest->x);
-		input_event(input, EV_ABS, ABS_Y, oldest->y);
-	} else {
-		input_event(input, EV_KEY, BTN_TOUCH, 0);
-	}
+	input_mt_report_pointer_emulation(input, true);
 	input_sync(input);
 }
 

drivers/hid/hid-core.c

@@ -1300,6 +1300,8 @@ static const struct hid_device_id hid_blacklist[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, 0x0006) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH1) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH2) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH3) },
 	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ELECOM, USB_DEVICE_ID_ELECOM_BM084) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_EZKEY, USB_DEVICE_ID_BTC_8193) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PSX_ADAPTOR) },

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.
  *
  */
 
@@ -16,6 +18,7 @@
 #include <linux/hid.h>
 #include <linux/module.h>
 #include <linux/usb.h>
+#include <linux/input/mt.h>
 #include <linux/slab.h>
 #include "usbhid/usbhid.h"
 
@@ -25,38 +28,53 @@ MODULE_LICENSE("GPL");
 
 #include "hid-ids.h"
 
+#define MAX_SLOTS		2
+
+/* estimated signal-to-noise ratios */
+#define SN_MOVE			4096
+#define SN_PRESSURE		32
+
 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 */
+	int valid;
+	int slot;
+	int touch;
+	int x, y, z;
 };
 
+static void set_abs(struct input_dev *input, unsigned int code,
+		    struct hid_field *field, int snratio)
+{
+	int fmin = field->logical_minimum;
+	int fmax = field->logical_maximum;
+	int fuzz = snratio ? (fmax - fmin) / snratio : 0;
+	input_set_abs_params(input, code, fmin, fmax, fuzz, 0);
+}
+
 static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		struct hid_field *field, struct hid_usage *usage,
 		unsigned long **bit, int *max)
 {
+	struct input_dev *input = hi->input;
+
 	switch (usage->hid & HID_USAGE_PAGE) {
 
 	case HID_UP_GENDESK:
 		switch (usage->hid) {
 		case HID_GD_X:
+			field->logical_maximum = 32760;
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_POSITION_X);
+			set_abs(input, ABS_MT_POSITION_X, field, SN_MOVE);
 			/* touchscreen emulation */
-			input_set_abs_params(hi->input, ABS_X,
-						field->logical_minimum,
-						field->logical_maximum, 0, 0);
+			set_abs(input, ABS_X, field, SN_MOVE);
 			return 1;
 		case HID_GD_Y:
+			field->logical_maximum = 32760;
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_POSITION_Y);
+			set_abs(input, ABS_MT_POSITION_Y, field, SN_MOVE);
 			/* touchscreen emulation */
-			input_set_abs_params(hi->input, ABS_Y,
-						field->logical_minimum,
-						field->logical_maximum, 0, 0);
+			set_abs(input, ABS_Y, field, SN_MOVE);
 			return 1;
 		}
 		return 0;
@@ -66,6 +84,7 @@ static int egalax_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(input, EV_KEY, BTN_TOUCH);
 			return 1;
 		case HID_DG_INRANGE:
 		case HID_DG_CONFIDENCE:
@@ -73,16 +92,15 @@ static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		case HID_DG_CONTACTMAX:
 			return -1;
 		case HID_DG_CONTACTID:
-			hid_map_usage(hi, usage, bit, max,
-					EV_ABS, ABS_MT_TRACKING_ID);
+			input_mt_init_slots(input, MAX_SLOTS);
 			return 1;
 		case HID_DG_TIPPRESSURE:
+			field->logical_minimum = 0;
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_PRESSURE);
+			set_abs(input, ABS_MT_PRESSURE, field, SN_PRESSURE);
 			/* touchscreen emulation */
-			input_set_abs_params(hi->input, ABS_PRESSURE,
-						field->logical_minimum,
-						field->logical_maximum, 0, 0);
+			set_abs(input, ABS_PRESSURE, field, SN_PRESSURE);
 			return 1;
 		}
 		return 0;
@@ -96,10 +114,10 @@ static int egalax_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;
 }
 
 /*
@@ -108,58 +126,16 @@ static int egalax_input_mapped(struct hid_device *hdev, struct hid_input *hi,
  */
 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_mt_slot(input, td->slot);
+	input_mt_report_slot_state(input, MT_TOOL_FINGER, td->touch);
+	if (td->touch) {
+		input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x);
+		input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y);
 		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;
-		}
-		return;
-	}
-
-
-	/* touchscreen emulation: if no previous activity, emit touch event */
-	if (!td->activity) {
-		input_event(input, EV_KEY, BTN_TOUCH, 1);
-		td->activity = true;
 	}
+	input_mt_report_pointer_emulation(input, true);
 }
 
-
 static int egalax_event(struct hid_device *hid, struct hid_field *field,
 				struct hid_usage *usage, __s32 value)
 {
@@ -169,25 +145,26 @@ 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->touch = value;
 			break;
 		case HID_DG_TIPPRESSURE:
 			td->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;
@@ -195,11 +172,11 @@ static int egalax_event(struct hid_device *hid, struct hid_field *field,
 		case HID_GD_Y:
 			td->y = value;
 			/* this is the last field in a finger */
+			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:
@@ -261,6 +238,10 @@ static const struct hid_device_id egalax_devices[] = {
 			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
 			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH1) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
+			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH2) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
+			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH3) },
 	{ }
 };
 MODULE_DEVICE_TABLE(hid, egalax_devices);

drivers/hid/hid-ids.h

@@ -196,6 +196,8 @@
 #define USB_DEVICE_ID_EGALAX_TOUCHCONTROLLER	0x0001
 #define USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH	0x480d
 #define USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH1	0x720c
+#define USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH2	0x72a1
+#define USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH3	0x480e
 
 #define USB_VENDOR_ID_ELECOM		0x056e
 #define USB_DEVICE_ID_ELECOM_BM084	0x0061

drivers/input/Makefile

@@ -5,7 +5,7 @@
 # Each configuration option enables a list of files.
 
 obj-$(CONFIG_INPUT)		+= input-core.o
-input-core-y := input.o input-compat.o ff-core.o
+input-core-y := input.o input-compat.o input-mt.o ff-core.o
 
 obj-$(CONFIG_INPUT_FF_MEMLESS)	+= ff-memless.o
 obj-$(CONFIG_INPUT_POLLDEV)	+= input-polldev.o

drivers/input/input-mt.c

+/*
+ * Input Multitouch Library
+ *
+ * Copyright (c) 2008-2010 Henrik Rydberg
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/input/mt.h>
+#include <linux/slab.h>
+
+#define TRKID_SGN	((TRKID_MAX + 1) >> 1)
+
+/**
+ * input_mt_init_slots() - initialize MT input slots
+ * @dev: input device supporting MT events and finger tracking
+ * @num_slots: number of slots used by the device
+ *
+ * This function allocates all necessary memory for MT slot handling
+ * in the input device, prepares the ABS_MT_SLOT and
+ * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
+ * May be called repeatedly. Returns -EINVAL if attempting to
+ * reinitialize with a different number of slots.
+ */
+int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots)
+{
+	int i;
+
+	if (!num_slots)
+		return 0;
+	if (dev->mt)
+		return dev->mtsize != num_slots ? -EINVAL : 0;
+
+	dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
+	if (!dev->mt)
+		return -ENOMEM;
+
+	dev->mtsize = num_slots;
+	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
+	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
+	input_set_events_per_packet(dev, 6 * num_slots);
+
+	/* Mark slots as 'unused' */
+	for (i = 0; i < num_slots; i++)
+		input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
+
+	return 0;
+}
+EXPORT_SYMBOL(input_mt_init_slots);
+
+/**
+ * input_mt_destroy_slots() - frees the MT slots of the input device
+ * @dev: input device with allocated MT slots
+ *
+ * This function is only needed in error path as the input core will
+ * automatically free the MT slots when the device is destroyed.
+ */
+void input_mt_destroy_slots(struct input_dev *dev)
+{
+	kfree(dev->mt);
+	dev->mt = NULL;
+	dev->mtsize = 0;
+	dev->slot = 0;
+	dev->trkid = 0;
+}
+EXPORT_SYMBOL(input_mt_destroy_slots);
+
+/**
+ * input_mt_report_slot_state() - report contact state
+ * @dev: input device with allocated MT slots
+ * @tool_type: the tool type to use in this slot
+ * @active: true if contact is active, false otherwise
+ *
+ * Reports a contact via ABS_MT_TRACKING_ID, and optionally
+ * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
+ * inactive, or if the tool type is changed, a new tracking id is
+ * assigned to the slot. The tool type is only reported if the
+ * corresponding absbit field is set.
+ */
+void input_mt_report_slot_state(struct input_dev *dev,
+				unsigned int tool_type, bool active)
+{
+	struct input_mt_slot *mt;
+	int id;
+
+	if (!dev->mt || !active) {
+		input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
+		return;
+	}
+
+	mt = &dev->mt[dev->slot];
+	id = input_mt_get_value(mt, ABS_MT_TRACKING_ID);
+	if (id < 0 || input_mt_get_value(mt, ABS_MT_TOOL_TYPE) != tool_type)
+		id = input_mt_new_trkid(dev);
+
+	input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
+	input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
+}
+EXPORT_SYMBOL(input_mt_report_slot_state);
+
+/**
+ * input_mt_report_finger_count() - report contact count
+ * @dev: input device with allocated MT slots
+ * @count: the number of contacts
+ *
+ * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
+ * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
+ *
+ * The input core ensures only the KEY events already setup for
+ * this device will produce output.
+ */
+void input_mt_report_finger_count(struct input_dev *dev, int count)
+{
+	input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
+	input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
+	input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
+	input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
+}
+EXPORT_SYMBOL(input_mt_report_finger_count);
+
+/**
+ * input_mt_report_pointer_emulation() - common pointer emulation
+ * @dev: input device with allocated MT slots
+ * @use_count: report number of active contacts as finger count
+ *
+ * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
+ * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
+ *
+ * The input core ensures only the KEY and ABS axes already setup for
+ * this device will produce output.
+ */
+void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
+{
+	struct input_mt_slot *oldest = 0;
+	int oldid = dev->trkid;
+	int count = 0;
+	int i;
+
+	for (i = 0; i < dev->mtsize; ++i) {
+		struct input_mt_slot *ps = &dev->mt[i];
+		int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
+
+		if (id < 0)
+			continue;
+		if ((id - oldid) & TRKID_SGN) {
+			oldest = ps;
+			oldid = id;
+		}
+		count++;
+	}
+
+	input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
+	if (use_count)
+		input_mt_report_finger_count(dev, count);
+
+	if (oldest) {
+		int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
+		int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
+		int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
+
+		input_event(dev, EV_ABS, ABS_X, x);
+		input_event(dev, EV_ABS, ABS_Y, y);
+		input_event(dev, EV_ABS, ABS_PRESSURE, p);
+	} else {
+		input_event(dev, EV_ABS, ABS_PRESSURE, 0);
+	}
+}
+EXPORT_SYMBOL(input_mt_report_pointer_emulation);

drivers/input/input.c

@@ -14,7 +14,7 @@
 
 #include <linux/init.h>
 #include <linux/types.h>
-#include <linux/input.h>
+#include <linux/input/mt.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/random.h>
@@ -1725,52 +1725,6 @@ void input_free_device(struct input_dev *dev)
 }
 EXPORT_SYMBOL(input_free_device);
 
-/**
- * input_mt_create_slots() - create MT input slots
- * @dev: input device supporting MT events and finger tracking
- * @num_slots: number of slots used by the device
- *
- * This function allocates all necessary memory for MT slot handling in the
- * input device, and adds ABS_MT_SLOT to the device capabilities. All slots
- * are initially marked as unused by setting ABS_MT_TRACKING_ID to -1.
- */
-int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots)
-{
-	int i;
-
-	if (!num_slots)
-		return 0;
-
-	dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
-	if (!dev->mt)
-		return -ENOMEM;
-
-	dev->mtsize = num_slots;
-	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
-
-	/* Mark slots as 'unused' */
-	for (i = 0; i < num_slots; i++)
-		dev->mt[i].abs[ABS_MT_TRACKING_ID - ABS_MT_FIRST] = -1;
-
-	return 0;
-}
-EXPORT_SYMBOL(input_mt_create_slots);
-
-/**
- * input_mt_destroy_slots() - frees the MT slots of the input device
- * @dev: input device with allocated MT slots
- *
- * This function is only needed in error path as the input core will
- * automatically free the MT slots when the device is destroyed.
- */
-void input_mt_destroy_slots(struct input_dev *dev)
-{
-	kfree(dev->mt);
-	dev->mt = NULL;
-	dev->mtsize = 0;
-}
-EXPORT_SYMBOL(input_mt_destroy_slots);
-
 /**
  * input_set_capability - mark device as capable of a certain event
  * @dev: device that is capable of emitting or accepting event

drivers/input/misc/uinput.c

@@ -37,6 +37,7 @@
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
 #include <linux/uinput.h>
+#include <linux/input/mt.h>
 #include "../input-compat.h"
 
 static int uinput_dev_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
@@ -406,8 +407,7 @@ static int uinput_setup_device(struct uinput_device *udev, const char __user *bu
 			goto exit;
 		if (test_bit(ABS_MT_SLOT, dev->absbit)) {
 			int nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
-			input_mt_create_slots(dev, nslot);
-			input_set_events_per_packet(dev, 6 * nslot);
+			input_mt_init_slots(dev, nslot);
 		} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
 			input_set_events_per_packet(dev, 60);
 		}

drivers/input/tablet/wacom_wac.c

@@ -14,6 +14,7 @@
 
 #include "wacom_wac.h"
 #include "wacom.h"
+#include <linux/input/mt.h>
 
 static int wacom_penpartner_irq(struct wacom_wac *wacom)
 {
@@ -862,19 +863,21 @@ static int wacom_bpt_touch(struct wacom_wac *wacom)
 	struct wacom_features *features = &wacom->features;
 	struct input_dev *input = wacom->input;
 	unsigned char *data = wacom->data;
-	int sp = 0, sx = 0, sy = 0, count = 0;
 	int i;
 
 	for (i = 0; i < 2; i++) {
 		int p = data[9 * i + 2];
+		bool touch = p && !wacom->shared->stylus_in_proximity;
+
 		input_mt_slot(input, i);
+		input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
 		/*
 		 * Touch events need to be disabled while stylus is
 		 * in proximity because user's hand is resting on touchpad
 		 * and sending unwanted events.  User expects tablet buttons
 		 * to continue working though.
 		 */
-		if (p && !wacom->shared->stylus_in_proximity) {
+		if (touch) {
 			int x = get_unaligned_be16(&data[9 * i + 3]) & 0x7ff;
 			int y = get_unaligned_be16(&data[9 * i + 5]) & 0x7ff;
 			if (features->quirks & WACOM_QUIRK_BBTOUCH_LOWRES) {
@@ -884,23 +887,10 @@ static int wacom_bpt_touch(struct wacom_wac *wacom)
 			input_report_abs(input, ABS_MT_PRESSURE, p);
 			input_report_abs(input, ABS_MT_POSITION_X, x);
 			input_report_abs(input, ABS_MT_POSITION_Y, y);
-			if (wacom->id[i] < 0)
-				wacom->id[i] = wacom->trk_id++ & MAX_TRACKING_ID;
-			if (!count++)
-				sp = p, sx = x, sy = y;
-		} else {
-			wacom->id[i] = -1;
 		}
-		input_report_abs(input, ABS_MT_TRACKING_ID, wacom->id[i]);
 	}
 
-	input_report_key(input, BTN_TOUCH, count > 0);
-	input_report_key(input, BTN_TOOL_FINGER, count == 1);
-	input_report_key(input, BTN_TOOL_DOUBLETAP, count == 2);
-
-	input_report_abs(input, ABS_PRESSURE, sp);
-	input_report_abs(input, ABS_X, sx);
-	input_report_abs(input, ABS_Y, sy);
+	input_mt_report_pointer_emulation(input, true);
 
 	input_report_key(input, BTN_LEFT, (data[1] & 0x08) != 0);
 	input_report_key(input, BTN_FORWARD, (data[1] & 0x04) != 0);
@@ -1272,7 +1262,7 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 			__set_bit(BTN_TOOL_FINGER, input_dev->keybit);
 			__set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
 
-			input_mt_create_slots(input_dev, 2);
+			input_mt_init_slots(input_dev, 2);
 			input_set_abs_params(input_dev, ABS_MT_POSITION_X,
 					     0, features->x_max,
 					     features->x_fuzz, 0);
@@ -1282,8 +1272,6 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 			input_set_abs_params(input_dev, ABS_MT_PRESSURE,
 					     0, features->pressure_max,
 					     features->pressure_fuzz, 0);
-			input_set_abs_params(input_dev, ABS_MT_TRACKING_ID, 0,
-					     MAX_TRACKING_ID, 0, 0);
 		} else if (features->device_type == BTN_TOOL_PEN) {
 			__set_bit(BTN_TOOL_RUBBER, input_dev->keybit);
 			__set_bit(BTN_TOOL_PEN, input_dev->keybit);

drivers/input/tablet/wacom_wac.h

@@ -42,9 +42,6 @@
 #define WACOM_QUIRK_MULTI_INPUT		0x0001
 #define WACOM_QUIRK_BBTOUCH_LOWRES	0x0002
 
-/* largest reported tracking id */
-#define MAX_TRACKING_ID			0xfff
-
 enum {
 	PENPARTNER = 0,
 	GRAPHIRE,
@@ -100,7 +97,6 @@ struct wacom_wac {
 	int id[3];
 	__u32 serial[2];
 	int last_finger;
-	int trk_id;
 	struct wacom_features features;
 	struct wacom_shared *shared;
 	struct input_dev *input;

drivers/input/touchscreen/wacom_w8001.c

@@ -15,7 +15,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
-#include <linux/input.h>
+#include <linux/input/mt.h>
 #include <linux/serio.h>
 #include <linux/init.h>
 #include <linux/ctype.h>
@@ -48,8 +48,6 @@ MODULE_LICENSE("GPL");
 #define W8001_PKTLEN_TPCCTL	11	/* control packet */
 #define W8001_PKTLEN_TOUCH2FG	13
 
-#define MAX_TRACKING_ID		0xFF	/* arbitrarily chosen */
-
 struct w8001_coord {
 	u8 rdy;
 	u8 tsw;
@@ -87,7 +85,6 @@ struct w8001 {
 	char phys[32];
 	int type;
 	unsigned int pktlen;
-	int trkid[2];
 };
 
 static void parse_data(u8 *data, struct w8001_coord *coord)
@@ -116,28 +113,23 @@ static void parse_data(u8 *data, struct w8001_coord *coord)
 
 static void parse_touch(struct w8001 *w8001)
 {
-	static int trkid;
 	struct input_dev *dev = w8001->dev;
 	unsigned char *data = w8001->data;
 	int i;
 
 	for (i = 0; i < 2; i++) {
-		input_mt_slot(dev, i);
+		bool touch = data[0] & (1 << i);
 
-		if (data[0] & (1 << i)) {
+		input_mt_slot(dev, i);
+		input_mt_report_slot_state(dev, MT_TOOL_FINGER, touch);
+		if (touch) {
 			int x = (data[6 * i + 1] << 7) | (data[6 * i + 2]);
 			int y = (data[6 * i + 3] << 7) | (data[6 * i + 4]);
 			/* data[5,6] and [11,12] is finger capacity */
 
 			input_report_abs(dev, ABS_MT_POSITION_X, x);
 			input_report_abs(dev, ABS_MT_POSITION_Y, y);
-			input_report_abs(dev, ABS_MT_TOOL_TYPE, MT_TOOL_FINGER);
-			if (w8001->trkid[i] < 0)
-				w8001->trkid[i] = trkid++ & MAX_TRACKING_ID;
-		} else {
-			w8001->trkid[i] = -1;
 		}
-		input_report_abs(dev, ABS_MT_TRACKING_ID, w8001->trkid[i]);
 	}
 
 	input_sync(dev);
@@ -318,15 +310,13 @@ static int w8001_setup(struct w8001 *w8001)
 		case 5:
 			w8001->pktlen = W8001_PKTLEN_TOUCH2FG;
 
-			input_mt_create_slots(dev, 2);
-			input_set_abs_params(dev, ABS_MT_TRACKING_ID,
-						0, MAX_TRACKING_ID, 0, 0);
+			input_mt_init_slots(dev, 2);
 			input_set_abs_params(dev, ABS_MT_POSITION_X,
 						0, touch.x, 0, 0);
 			input_set_abs_params(dev, ABS_MT_POSITION_Y,
 						0, touch.y, 0, 0);
 			input_set_abs_params(dev, ABS_MT_TOOL_TYPE,
-						0, 0, 0, 0);
+						0, MT_TOOL_MAX, 0, 0);
 			break;
 		}
 	}
@@ -372,7 +362,6 @@ static int w8001_connect(struct serio *serio, struct serio_driver *drv)
 	w8001->serio = serio;
 	w8001->id = serio->id.id;
 	w8001->dev = input_dev;
-	w8001->trkid[0] = w8001->trkid[1] = -1;
 	init_completion(&w8001->cmd_done);
 	snprintf(w8001->phys, sizeof(w8001->phys), "%s/input0", serio->phys);
 

include/linux/input.h

@@ -733,11 +733,12 @@ struct input_keymap_entry {
 #define ABS_MT_BLOB_ID		0x38	/* Group a set of packets as a blob */
 #define ABS_MT_TRACKING_ID	0x39	/* Unique ID of initiated contact */
 #define ABS_MT_PRESSURE		0x3a	/* Pressure on contact area */
+#define ABS_MT_DISTANCE		0x3b	/* Contact hover distance */
 
 #ifdef __KERNEL__
 /* Implementation details, userspace should not care about these */
 #define ABS_MT_FIRST		ABS_MT_TOUCH_MAJOR
-#define ABS_MT_LAST		ABS_MT_PRESSURE
+#define ABS_MT_LAST		ABS_MT_DISTANCE
 #endif
 
 #define ABS_MAX			0x3f
@@ -848,6 +849,7 @@ struct input_keymap_entry {
  */
 #define MT_TOOL_FINGER		0
 #define MT_TOOL_PEN		1
+#define MT_TOOL_MAX		1
 
 /*
  * Values describing the status of a force-feedback effect
@@ -1082,14 +1084,6 @@ struct ff_effect {
 #include <linux/timer.h>
 #include <linux/mod_devicetable.h>
 
-/**
- * struct input_mt_slot - represents the state of an input MT slot
- * @abs: holds current values of ABS_MT axes for this slot
- */
-struct input_mt_slot {
-	int abs[ABS_MT_LAST - ABS_MT_FIRST + 1];
-};
-
 /**
  * struct input_dev - represents an input device
  * @name: name of the device
@@ -1130,6 +1124,7 @@ struct input_mt_slot {
  *	of tracked contacts
  * @mtsize: number of MT slots the device uses
  * @slot: MT slot currently being transmitted
+ * @trkid: stores MT tracking ID for the current contact
  * @absinfo: array of &struct absinfo elements holding information
  *	about absolute axes (current value, min, max, flat, fuzz,
  *	resolution)
@@ -1214,6 +1209,7 @@ struct input_dev {
 	struct input_mt_slot *mt;
 	int mtsize;
 	int slot;
+	int trkid;
 
 	struct input_absinfo *absinfo;
 
@@ -1463,11 +1459,6 @@ static inline void input_mt_sync(struct input_dev *dev)
 	input_event(dev, EV_SYN, SYN_MT_REPORT, 0);
 }
 
-static inline void input_mt_slot(struct input_dev *dev, int slot)
-{
-	input_event(dev, EV_ABS, ABS_MT_SLOT, slot);
-}
-
 void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code);
 
 /**
@@ -1580,8 +1571,5 @@ int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file);
 int input_ff_create_memless(struct input_dev *dev, void *data,
 		int (*play_effect)(struct input_dev *, void *, struct ff_effect *));
 
-int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots);
-void input_mt_destroy_slots(struct input_dev *dev);
-
 #endif
 #endif

include/linux/input/mt.h

+#ifndef _INPUT_MT_H
+#define _INPUT_MT_H
+
+/*
+ * Input Multitouch Library
+ *
+ * Copyright (c) 2010 Henrik Rydberg
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/input.h>
+
+#define TRKID_MAX	0xffff
+
+/**
+ * struct input_mt_slot - represents the state of an input MT slot
+ * @abs: holds current values of ABS_MT axes for this slot
+ */
+struct input_mt_slot {
+	int abs[ABS_MT_LAST - ABS_MT_FIRST + 1];
+};
+
+static inline void input_mt_set_value(struct input_mt_slot *slot,
+				      unsigned code, int value)
+{
+	slot->abs[code - ABS_MT_FIRST] = value;
+}
+
+static inline int input_mt_get_value(const struct input_mt_slot *slot,
+				     unsigned code)
+{
+	return slot->abs[code - ABS_MT_FIRST];
+}
+
+int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots);
+void input_mt_destroy_slots(struct input_dev *dev);
+
+static inline int input_mt_new_trkid(struct input_dev *dev)
+{
+	return dev->trkid++ & TRKID_MAX;
+}
+
+static inline void input_mt_slot(struct input_dev *dev, int slot)
+{
+	input_event(dev, EV_ABS, ABS_MT_SLOT, slot);
+}
+
+void input_mt_report_slot_state(struct input_dev *dev,
+				unsigned int tool_type, bool active);
+
+void input_mt_report_finger_count(struct input_dev *dev, int count);
+void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count);
+
+#endif