2 * Input Multitouch Library
4 * Copyright (c) 2008-2010 Henrik Rydberg
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
11 #include <linux/input/mt.h>
12 #include <linux/export.h>
13 #include <linux/slab.h>
15 #define TRKID_SGN ((TRKID_MAX + 1) >> 1)
17 static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src)
19 if (dev->absinfo && test_bit(src, dev->absbit)) {
20 dev->absinfo[dst] = dev->absinfo[src];
21 dev->absbit[BIT_WORD(dst)] |= BIT_MASK(dst);
26 * input_mt_init_slots() - initialize MT input slots
27 * @dev: input device supporting MT events and finger tracking
28 * @num_slots: number of slots used by the device
30 * This function allocates all necessary memory for MT slot handling
31 * in the input device, prepares the ABS_MT_SLOT and
32 * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
33 * May be called repeatedly. Returns -EINVAL if attempting to
34 * reinitialize with a different number of slots.
36 int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
39 struct input_mt *mt = dev->mt;
45 return mt->num_slots != num_slots ? -EINVAL : 0;
47 mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
51 mt->num_slots = num_slots;
53 input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
54 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
56 if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
57 __set_bit(EV_KEY, dev->evbit);
58 __set_bit(BTN_TOUCH, dev->keybit);
60 copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
61 copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
62 copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
64 if (flags & INPUT_MT_POINTER) {
65 __set_bit(BTN_TOOL_FINGER, dev->keybit);
66 __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
68 __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
70 __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
72 __set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
73 __set_bit(INPUT_PROP_POINTER, dev->propbit);
75 if (flags & INPUT_MT_DIRECT)
76 __set_bit(INPUT_PROP_DIRECT, dev->propbit);
77 if (flags & INPUT_MT_TRACK) {
78 unsigned int n2 = num_slots * num_slots;
79 mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
84 /* Mark slots as 'unused' */
85 for (i = 0; i < num_slots; i++)
86 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
94 EXPORT_SYMBOL(input_mt_init_slots);
97 * input_mt_destroy_slots() - frees the MT slots of the input device
98 * @dev: input device with allocated MT slots
100 * This function is only needed in error path as the input core will
101 * automatically free the MT slots when the device is destroyed.
103 void input_mt_destroy_slots(struct input_dev *dev)
111 EXPORT_SYMBOL(input_mt_destroy_slots);
114 * input_mt_report_slot_state() - report contact state
115 * @dev: input device with allocated MT slots
116 * @tool_type: the tool type to use in this slot
117 * @active: true if contact is active, false otherwise
119 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
120 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
121 * inactive, or if the tool type is changed, a new tracking id is
122 * assigned to the slot. The tool type is only reported if the
123 * corresponding absbit field is set.
125 void input_mt_report_slot_state(struct input_dev *dev,
126 unsigned int tool_type, bool active)
128 struct input_mt *mt = dev->mt;
129 struct input_mt_slot *slot;
135 slot = &mt->slots[mt->slot];
136 slot->frame = mt->frame;
139 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
143 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
144 if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
145 id = input_mt_new_trkid(mt);
147 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
148 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
150 EXPORT_SYMBOL(input_mt_report_slot_state);
153 * input_mt_report_finger_count() - report contact count
154 * @dev: input device with allocated MT slots
155 * @count: the number of contacts
157 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
158 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
160 * The input core ensures only the KEY events already setup for
161 * this device will produce output.
163 void input_mt_report_finger_count(struct input_dev *dev, int count)
165 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
166 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
167 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
168 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
169 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
171 EXPORT_SYMBOL(input_mt_report_finger_count);
174 * input_mt_report_pointer_emulation() - common pointer emulation
175 * @dev: input device with allocated MT slots
176 * @use_count: report number of active contacts as finger count
178 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
179 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
181 * The input core ensures only the KEY and ABS axes already setup for
182 * this device will produce output.
184 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
186 struct input_mt *mt = dev->mt;
187 struct input_mt_slot *oldest;
197 for (i = 0; i < mt->num_slots; ++i) {
198 struct input_mt_slot *ps = &mt->slots[i];
199 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
203 if ((id - oldid) & TRKID_SGN) {
210 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
212 input_mt_report_finger_count(dev, count);
215 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
216 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
218 input_event(dev, EV_ABS, ABS_X, x);
219 input_event(dev, EV_ABS, ABS_Y, y);
221 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
222 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
223 input_event(dev, EV_ABS, ABS_PRESSURE, p);
226 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
227 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
230 EXPORT_SYMBOL(input_mt_report_pointer_emulation);
233 * input_mt_sync_frame() - synchronize mt frame
234 * @dev: input device with allocated MT slots
236 * Close the frame and prepare the internal state for a new one.
237 * Depending on the flags, marks unused slots as inactive and performs
240 void input_mt_sync_frame(struct input_dev *dev)
242 struct input_mt *mt = dev->mt;
243 struct input_mt_slot *s;
248 if (mt->flags & INPUT_MT_DROP_UNUSED) {
249 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
250 if (s->frame == mt->frame)
252 input_mt_slot(dev, s - mt->slots);
253 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
257 input_mt_report_pointer_emulation(dev, (mt->flags & INPUT_MT_POINTER));
261 EXPORT_SYMBOL(input_mt_sync_frame);
263 static int adjust_dual(int *begin, int step, int *end, int eq)
272 s = p == end ? f + 1 : *p;
274 for (; p != end; p += step)
281 if (c == 0 || (c > 0 && !eq))
286 for (p = begin; p != end; p += step)
289 return (c < s && s <= 0) || (f >= 0 && f < c);
292 static void find_reduced_matrix(int *w, int nr, int nc, int nrc)
296 for (k = 0; k < nrc; k++) {
297 for (i = 0; i < nr; i++)
298 adjust_dual(w + i, nr, w + i + nrc, nr <= nc);
300 for (i = 0; i < nrc; i += nr)
301 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr);
307 static int input_mt_set_matrix(struct input_mt *mt,
308 const struct input_mt_pos *pos, int num_pos)
310 const struct input_mt_pos *p;
311 struct input_mt_slot *s;
315 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
316 if (!input_mt_is_active(s))
318 x = input_mt_get_value(s, ABS_MT_POSITION_X);
319 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
320 for (p = pos; p != pos + num_pos; p++) {
321 int dx = x - p->x, dy = y - p->y;
322 *w++ = dx * dx + dy * dy;
329 static void input_mt_set_slots(struct input_mt *mt,
330 int *slots, int num_pos)
332 struct input_mt_slot *s;
333 int *w = mt->red, *p;
335 for (p = slots; p != slots + num_pos; p++)
338 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
339 if (!input_mt_is_active(s))
341 for (p = slots; p != slots + num_pos; p++)
346 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
347 if (input_mt_is_active(s))
349 for (p = slots; p != slots + num_pos; p++)
358 * input_mt_assign_slots() - perform a best-match assignment
359 * @dev: input device with allocated MT slots
360 * @slots: the slot assignment to be filled
361 * @pos: the position array to match
362 * @num_pos: number of positions
364 * Performs a best match against the current contacts and returns
365 * the slot assignment list. New contacts are assigned to unused
368 * Returns zero on success, or negative error in case of failure.
370 int input_mt_assign_slots(struct input_dev *dev, int *slots,
371 const struct input_mt_pos *pos, int num_pos)
373 struct input_mt *mt = dev->mt;
378 if (num_pos > mt->num_slots)
383 nrc = input_mt_set_matrix(mt, pos, num_pos);
384 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc);
385 input_mt_set_slots(mt, slots, num_pos);
389 EXPORT_SYMBOL(input_mt_assign_slots);
392 * input_mt_get_slot_by_key() - return slot matching key
393 * @dev: input device with allocated MT slots
394 * @key: the key of the sought slot
396 * Returns the slot of the given key, if it exists, otherwise
397 * set the key on the first unused slot and return.
399 * If no available slot can be found, -1 is returned.
401 int input_mt_get_slot_by_key(struct input_dev *dev, int key)
403 struct input_mt *mt = dev->mt;
404 struct input_mt_slot *s;
409 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
410 if (input_mt_is_active(s) && s->key == key)
411 return s - mt->slots;
413 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
414 if (!input_mt_is_active(s)) {
416 return s - mt->slots;
421 EXPORT_SYMBOL(input_mt_get_slot_by_key);