1/*
2 * Input Multitouch Library
3 *
4 * Copyright (c) 2008-2010 Henrik Rydberg
5 *
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.
9 */
10
11#include <linux/input/mt.h>
12#include <linux/export.h>
13#include <linux/slab.h>
14
15#define TRKID_SGN ((TRKID_MAX + 1) >> 1)
16
17static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src)
18{
19 if (dev->absinfo && test_bit(src, dev->absbit)) {
20 dev->absinfo[dst] = dev->absinfo[src];
21 dev->absinfo[dst].fuzz = 0;
22 dev->absbit[BIT_WORD(dst)] |= BIT_MASK(dst);
23 }
24}
25
26/**
27 * input_mt_init_slots() - initialize MT input slots
28 * @dev: input device supporting MT events and finger tracking
29 * @num_slots: number of slots used by the device
30 * @flags: mt tasks to handle in core
31 *
32 * This function allocates all necessary memory for MT slot handling
33 * in the input device, prepares the ABS_MT_SLOT and
34 * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
35 * Depending on the flags set, it also performs pointer emulation and
36 * frame synchronization.
37 *
38 * May be called repeatedly. Returns -EINVAL if attempting to
39 * reinitialize with a different number of slots.
40 */
41int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
42 unsigned int flags)
43{
44 struct input_mt *mt = dev->mt;
45 int i;
46
47 if (!num_slots)
48 return 0;
49 if (mt)
50 return mt->num_slots != num_slots ? -EINVAL : 0;
51
52 mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
53 if (!mt)
54 goto err_mem;
55
56 mt->num_slots = num_slots;
57 mt->flags = flags;
58 input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
59 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
60
61 if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
62 __set_bit(EV_KEY, dev->evbit);
63 __set_bit(BTN_TOUCH, dev->keybit);
64
65 copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
66 copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
67 copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
68 }
69 if (flags & INPUT_MT_POINTER) {
70 __set_bit(BTN_TOOL_FINGER, dev->keybit);
71 __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
72 if (num_slots >= 3)
73 __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
74 if (num_slots >= 4)
75 __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
76 if (num_slots >= 5)
77 __set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
78 __set_bit(INPUT_PROP_POINTER, dev->propbit);
79 }
80 if (flags & INPUT_MT_DIRECT)
81 __set_bit(INPUT_PROP_DIRECT, dev->propbit);
82 if (flags & INPUT_MT_SEMI_MT)
83 __set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
84 if (flags & INPUT_MT_TRACK) {
85 unsigned int n2 = num_slots * num_slots;
86 mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
87 if (!mt->red)
88 goto err_mem;
89 }
90
91 /* Mark slots as 'inactive' */
92 for (i = 0; i < num_slots; i++)
93 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
94
95 /* Mark slots as 'unused' */
96 mt->frame = 1;
97
98 dev->mt = mt;
99 return 0;
100err_mem:
101 kfree(mt);
102 return -ENOMEM;
103}
104EXPORT_SYMBOL(input_mt_init_slots);
105
106/**
107 * input_mt_destroy_slots() - frees the MT slots of the input device
108 * @dev: input device with allocated MT slots
109 *
110 * This function is only needed in error path as the input core will
111 * automatically free the MT slots when the device is destroyed.
112 */
113void input_mt_destroy_slots(struct input_dev *dev)
114{
115 if (dev->mt) {
116 kfree(dev->mt->red);
117 kfree(dev->mt);
118 }
119 dev->mt = NULL;
120}
121EXPORT_SYMBOL(input_mt_destroy_slots);
122
123/**
124 * input_mt_report_slot_state() - report contact state
125 * @dev: input device with allocated MT slots
126 * @tool_type: the tool type to use in this slot
127 * @active: true if contact is active, false otherwise
128 *
129 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
130 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
131 * inactive, or if the tool type is changed, a new tracking id is
132 * assigned to the slot. The tool type is only reported if the
133 * corresponding absbit field is set.
134 *
135 * Returns true if contact is active.
136 */
137bool input_mt_report_slot_state(struct input_dev *dev,
138 unsigned int tool_type, bool active)
139{
140 struct input_mt *mt = dev->mt;
141 struct input_mt_slot *slot;
142 int id;
143
144 if (!mt)
145 return false;
146
147 slot = &mt->slots[mt->slot];
148 slot->frame = mt->frame;
149
150 if (!active) {
151 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
152 return false;
153 }
154
155 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
156 if (id < 0)
157 id = input_mt_new_trkid(mt);
158
159 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
160 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
161
162 return true;
163}
164EXPORT_SYMBOL(input_mt_report_slot_state);
165
166/**
167 * input_mt_report_finger_count() - report contact count
168 * @dev: input device with allocated MT slots
169 * @count: the number of contacts
170 *
171 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
172 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
173 *
174 * The input core ensures only the KEY events already setup for
175 * this device will produce output.
176 */
177void input_mt_report_finger_count(struct input_dev *dev, int count)
178{
179 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
180 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
181 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
182 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
183 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
184}
185EXPORT_SYMBOL(input_mt_report_finger_count);
186
187/**
188 * input_mt_report_pointer_emulation() - common pointer emulation
189 * @dev: input device with allocated MT slots
190 * @use_count: report number of active contacts as finger count
191 *
192 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
193 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
194 *
195 * The input core ensures only the KEY and ABS axes already setup for
196 * this device will produce output.
197 */
198void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
199{
200 struct input_mt *mt = dev->mt;
201 struct input_mt_slot *oldest;
202 int oldid, count, i;
203
204 if (!mt)
205 return;
206
207 oldest = NULL;
208 oldid = mt->trkid;
209 count = 0;
210
211 for (i = 0; i < mt->num_slots; ++i) {
212 struct input_mt_slot *ps = &mt->slots[i];
213 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
214
215 if (id < 0)
216 continue;
217 if ((id - oldid) & TRKID_SGN) {
218 oldest = ps;
219 oldid = id;
220 }
221 count++;
222 }
223
224 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
225
226 if (use_count) {
227 if (count == 0 &&
228 !test_bit(ABS_MT_DISTANCE, dev->absbit) &&
229 test_bit(ABS_DISTANCE, dev->absbit) &&
230 input_abs_get_val(dev, ABS_DISTANCE) != 0) {
231 /*
232 * Force reporting BTN_TOOL_FINGER for devices that
233 * only report general hover (and not per-contact
234 * distance) when contact is in proximity but not
235 * on the surface.
236 */
237 count = 1;
238 }
239
240 input_mt_report_finger_count(dev, count);
241 }
242
243 if (oldest) {
244 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
245 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
246
247 input_event(dev, EV_ABS, ABS_X, x);
248 input_event(dev, EV_ABS, ABS_Y, y);
249
250 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
251 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
252 input_event(dev, EV_ABS, ABS_PRESSURE, p);
253 }
254 } else {
255 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
256 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
257 }
258}
259EXPORT_SYMBOL(input_mt_report_pointer_emulation);
260
261static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
262{
263 int i;
264
265 for (i = 0; i < mt->num_slots; i++) {
266 if (!input_mt_is_used(mt, &mt->slots[i])) {
267 input_mt_slot(dev, i);
268 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
269 }
270 }
271}
272
273/**
274 * input_mt_drop_unused() - Inactivate slots not seen in this frame
275 * @dev: input device with allocated MT slots
276 *
277 * Lift all slots not seen since the last call to this function.
278 */
279void input_mt_drop_unused(struct input_dev *dev)
280{
281 struct input_mt *mt = dev->mt;
282
283 if (mt) {
284 __input_mt_drop_unused(dev, mt);
285 mt->frame++;
286 }
287}
288EXPORT_SYMBOL(input_mt_drop_unused);
289
290/**
291 * input_mt_sync_frame() - synchronize mt frame
292 * @dev: input device with allocated MT slots
293 *
294 * Close the frame and prepare the internal state for a new one.
295 * Depending on the flags, marks unused slots as inactive and performs
296 * pointer emulation.
297 */
298void input_mt_sync_frame(struct input_dev *dev)
299{
300 struct input_mt *mt = dev->mt;
301 bool use_count = false;
302
303 if (!mt)
304 return;
305
306 if (mt->flags & INPUT_MT_DROP_UNUSED)
307 __input_mt_drop_unused(dev, mt);
308
309 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
310 use_count = true;
311
312 input_mt_report_pointer_emulation(dev, use_count);
313
314 mt->frame++;
315}
316EXPORT_SYMBOL(input_mt_sync_frame);
317
318static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
319{
320 int f, *p, s, c;
321
322 if (begin == end)
323 return 0;
324
325 f = *begin;
326 p = begin + step;
327 s = p == end ? f + 1 : *p;
328
329 for (; p != end; p += step)
330 if (*p < f)
331 s = f, f = *p;
332 else if (*p < s)
333 s = *p;
334
335 c = (f + s + 1) / 2;
336 if (c == 0 || (c > mu && (!eq || mu > 0)))
337 return 0;
338 /* Improve convergence for positive matrices by penalizing overcovers */
339 if (s < 0 && mu <= 0)
340 c *= 2;
341
342 for (p = begin; p != end; p += step)
343 *p -= c;
344
345 return (c < s && s <= 0) || (f >= 0 && f < c);
346}
347
348static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
349{
350 int i, k, sum;
351
352 for (k = 0; k < nrc; k++) {
353 for (i = 0; i < nr; i++)
354 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
355 sum = 0;
356 for (i = 0; i < nrc; i += nr)
357 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
358 if (!sum)
359 break;
360 }
361}
362
363static int input_mt_set_matrix(struct input_mt *mt,
364 const struct input_mt_pos *pos, int num_pos,
365 int mu)
366{
367 const struct input_mt_pos *p;
368 struct input_mt_slot *s;
369 int *w = mt->red;
370 int x, y;
371
372 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
373 if (!input_mt_is_active(s))
374 continue;
375 x = input_mt_get_value(s, ABS_MT_POSITION_X);
376 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
377 for (p = pos; p != pos + num_pos; p++) {
378 int dx = x - p->x, dy = y - p->y;
379 *w++ = dx * dx + dy * dy - mu;
380 }
381 }
382
383 return w - mt->red;
384}
385
386static void input_mt_set_slots(struct input_mt *mt,
387 int *slots, int num_pos)
388{
389 struct input_mt_slot *s;
390 int *w = mt->red, j;
391
392 for (j = 0; j != num_pos; j++)
393 slots[j] = -1;
394
395 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
396 if (!input_mt_is_active(s))
397 continue;
398
399 for (j = 0; j != num_pos; j++) {
400 if (w[j] < 0) {
401 slots[j] = s - mt->slots;
402 break;
403 }
404 }
405
406 w += num_pos;
407 }
408
409 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
410 if (input_mt_is_active(s))
411 continue;
412
413 for (j = 0; j != num_pos; j++) {
414 if (slots[j] < 0) {
415 slots[j] = s - mt->slots;
416 break;
417 }
418 }
419 }
420}
421
422/**
423 * input_mt_assign_slots() - perform a best-match assignment
424 * @dev: input device with allocated MT slots
425 * @slots: the slot assignment to be filled
426 * @pos: the position array to match
427 * @num_pos: number of positions
428 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
429 *
430 * Performs a best match against the current contacts and returns
431 * the slot assignment list. New contacts are assigned to unused
432 * slots.
433 *
434 * The assignments are balanced so that all coordinate displacements are
435 * below the euclidian distance dmax. If no such assignment can be found,
436 * some contacts are assigned to unused slots.
437 *
438 * Returns zero on success, or negative error in case of failure.
439 */
440int input_mt_assign_slots(struct input_dev *dev, int *slots,
441 const struct input_mt_pos *pos, int num_pos,
442 int dmax)
443{
444 struct input_mt *mt = dev->mt;
445 int mu = 2 * dmax * dmax;
446 int nrc;
447
448 if (!mt || !mt->red)
449 return -ENXIO;
450 if (num_pos > mt->num_slots)
451 return -EINVAL;
452 if (num_pos < 1)
453 return 0;
454
455 nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
456 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
457 input_mt_set_slots(mt, slots, num_pos);
458
459 return 0;
460}
461EXPORT_SYMBOL(input_mt_assign_slots);
462
463/**
464 * input_mt_get_slot_by_key() - return slot matching key
465 * @dev: input device with allocated MT slots
466 * @key: the key of the sought slot
467 *
468 * Returns the slot of the given key, if it exists, otherwise
469 * set the key on the first unused slot and return.
470 *
471 * If no available slot can be found, -1 is returned.
472 * Note that for this function to work properly, input_mt_sync_frame() has
473 * to be called at each frame.
474 */
475int input_mt_get_slot_by_key(struct input_dev *dev, int key)
476{
477 struct input_mt *mt = dev->mt;
478 struct input_mt_slot *s;
479
480 if (!mt)
481 return -1;
482
483 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
484 if (input_mt_is_active(s) && s->key == key)
485 return s - mt->slots;
486
487 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
488 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) {
489 s->key = key;
490 return s - mt->slots;
491 }
492
493 return -1;
494}
495EXPORT_SYMBOL(input_mt_get_slot_by_key);
496