1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Input Multitouch Library |
4 | * |
5 | * Copyright (c) 2008-2010 Henrik Rydberg |
6 | */ |
7 | |
8 | #include <linux/input/mt.h> |
9 | #include <linux/export.h> |
10 | #include <linux/slab.h> |
11 | #include "input-core-private.h" |
12 | |
13 | #define TRKID_SGN ((TRKID_MAX + 1) >> 1) |
14 | |
15 | static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src) |
16 | { |
17 | if (dev->absinfo && test_bit(src, dev->absbit)) { |
18 | dev->absinfo[dst] = dev->absinfo[src]; |
19 | dev->absinfo[dst].fuzz = 0; |
20 | __set_bit(dst, dev->absbit); |
21 | } |
22 | } |
23 | |
24 | /** |
25 | * input_mt_init_slots() - initialize MT input slots |
26 | * @dev: input device supporting MT events and finger tracking |
27 | * @num_slots: number of slots used by the device |
28 | * @flags: mt tasks to handle in core |
29 | * |
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 | * Depending on the flags set, it also performs pointer emulation and |
34 | * frame synchronization. |
35 | * |
36 | * May be called repeatedly. Returns -EINVAL if attempting to |
37 | * reinitialize with a different number of slots. |
38 | */ |
39 | int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots, |
40 | unsigned int flags) |
41 | { |
42 | struct input_mt *mt = dev->mt; |
43 | int i; |
44 | |
45 | if (!num_slots) |
46 | return 0; |
47 | if (mt) |
48 | return mt->num_slots != num_slots ? -EINVAL : 0; |
49 | |
50 | mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL); |
51 | if (!mt) |
52 | goto err_mem; |
53 | |
54 | mt->num_slots = num_slots; |
55 | mt->flags = flags; |
56 | input_set_abs_params(dev, ABS_MT_SLOT, min: 0, max: num_slots - 1, fuzz: 0, flat: 0); |
57 | input_set_abs_params(dev, ABS_MT_TRACKING_ID, min: 0, TRKID_MAX, fuzz: 0, flat: 0); |
58 | |
59 | if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) { |
60 | __set_bit(EV_KEY, dev->evbit); |
61 | __set_bit(BTN_TOUCH, dev->keybit); |
62 | |
63 | copy_abs(dev, ABS_X, ABS_MT_POSITION_X); |
64 | copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y); |
65 | copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE); |
66 | } |
67 | if (flags & INPUT_MT_POINTER) { |
68 | __set_bit(BTN_TOOL_FINGER, dev->keybit); |
69 | __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit); |
70 | if (num_slots >= 3) |
71 | __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit); |
72 | if (num_slots >= 4) |
73 | __set_bit(BTN_TOOL_QUADTAP, dev->keybit); |
74 | if (num_slots >= 5) |
75 | __set_bit(BTN_TOOL_QUINTTAP, dev->keybit); |
76 | __set_bit(INPUT_PROP_POINTER, dev->propbit); |
77 | } |
78 | if (flags & INPUT_MT_DIRECT) |
79 | __set_bit(INPUT_PROP_DIRECT, dev->propbit); |
80 | if (flags & INPUT_MT_SEMI_MT) |
81 | __set_bit(INPUT_PROP_SEMI_MT, dev->propbit); |
82 | if (flags & INPUT_MT_TRACK) { |
83 | unsigned int n2 = num_slots * num_slots; |
84 | mt->red = kcalloc(n: n2, size: sizeof(*mt->red), GFP_KERNEL); |
85 | if (!mt->red) |
86 | goto err_mem; |
87 | } |
88 | |
89 | /* Mark slots as 'inactive' */ |
90 | for (i = 0; i < num_slots; i++) |
91 | input_mt_set_value(slot: &mt->slots[i], ABS_MT_TRACKING_ID, value: -1); |
92 | |
93 | /* Mark slots as 'unused' */ |
94 | mt->frame = 1; |
95 | |
96 | dev->mt = mt; |
97 | return 0; |
98 | err_mem: |
99 | kfree(objp: mt); |
100 | return -ENOMEM; |
101 | } |
102 | EXPORT_SYMBOL(input_mt_init_slots); |
103 | |
104 | /** |
105 | * input_mt_destroy_slots() - frees the MT slots of the input device |
106 | * @dev: input device with allocated MT slots |
107 | * |
108 | * This function is only needed in error path as the input core will |
109 | * automatically free the MT slots when the device is destroyed. |
110 | */ |
111 | void input_mt_destroy_slots(struct input_dev *dev) |
112 | { |
113 | if (dev->mt) { |
114 | kfree(objp: dev->mt->red); |
115 | kfree(objp: dev->mt); |
116 | } |
117 | dev->mt = NULL; |
118 | } |
119 | EXPORT_SYMBOL(input_mt_destroy_slots); |
120 | |
121 | /** |
122 | * input_mt_report_slot_state() - report contact state |
123 | * @dev: input device with allocated MT slots |
124 | * @tool_type: the tool type to use in this slot |
125 | * @active: true if contact is active, false otherwise |
126 | * |
127 | * Reports a contact via ABS_MT_TRACKING_ID, and optionally |
128 | * ABS_MT_TOOL_TYPE. If active is true and the slot is currently |
129 | * inactive, or if the tool type is changed, a new tracking id is |
130 | * assigned to the slot. The tool type is only reported if the |
131 | * corresponding absbit field is set. |
132 | * |
133 | * Returns true if contact is active. |
134 | */ |
135 | bool input_mt_report_slot_state(struct input_dev *dev, |
136 | unsigned int tool_type, bool active) |
137 | { |
138 | struct input_mt *mt = dev->mt; |
139 | struct input_mt_slot *slot; |
140 | int id; |
141 | |
142 | if (!mt) |
143 | return false; |
144 | |
145 | slot = &mt->slots[mt->slot]; |
146 | slot->frame = mt->frame; |
147 | |
148 | if (!active) { |
149 | input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, value: -1); |
150 | return false; |
151 | } |
152 | |
153 | id = input_mt_get_value(slot, ABS_MT_TRACKING_ID); |
154 | if (id < 0) |
155 | id = input_mt_new_trkid(mt); |
156 | |
157 | input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, value: id); |
158 | input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, value: tool_type); |
159 | |
160 | return true; |
161 | } |
162 | EXPORT_SYMBOL(input_mt_report_slot_state); |
163 | |
164 | /** |
165 | * input_mt_report_finger_count() - report contact count |
166 | * @dev: input device with allocated MT slots |
167 | * @count: the number of contacts |
168 | * |
169 | * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP, |
170 | * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP. |
171 | * |
172 | * The input core ensures only the KEY events already setup for |
173 | * this device will produce output. |
174 | */ |
175 | void input_mt_report_finger_count(struct input_dev *dev, int count) |
176 | { |
177 | input_event(dev, EV_KEY, BTN_TOOL_FINGER, value: count == 1); |
178 | input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, value: count == 2); |
179 | input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, value: count == 3); |
180 | input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, value: count == 4); |
181 | input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, value: count == 5); |
182 | } |
183 | EXPORT_SYMBOL(input_mt_report_finger_count); |
184 | |
185 | /** |
186 | * input_mt_report_pointer_emulation() - common pointer emulation |
187 | * @dev: input device with allocated MT slots |
188 | * @use_count: report number of active contacts as finger count |
189 | * |
190 | * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and |
191 | * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true. |
192 | * |
193 | * The input core ensures only the KEY and ABS axes already setup for |
194 | * this device will produce output. |
195 | */ |
196 | void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count) |
197 | { |
198 | struct input_mt *mt = dev->mt; |
199 | struct input_mt_slot *oldest; |
200 | int oldid, count, i; |
201 | |
202 | if (!mt) |
203 | return; |
204 | |
205 | oldest = NULL; |
206 | oldid = mt->trkid; |
207 | count = 0; |
208 | |
209 | for (i = 0; i < mt->num_slots; ++i) { |
210 | struct input_mt_slot *ps = &mt->slots[i]; |
211 | int id = input_mt_get_value(slot: ps, ABS_MT_TRACKING_ID); |
212 | |
213 | if (id < 0) |
214 | continue; |
215 | if ((id - oldid) & TRKID_SGN) { |
216 | oldest = ps; |
217 | oldid = id; |
218 | } |
219 | count++; |
220 | } |
221 | |
222 | input_event(dev, EV_KEY, BTN_TOUCH, value: count > 0); |
223 | |
224 | if (use_count) { |
225 | if (count == 0 && |
226 | !test_bit(ABS_MT_DISTANCE, dev->absbit) && |
227 | test_bit(ABS_DISTANCE, dev->absbit) && |
228 | input_abs_get_val(dev, ABS_DISTANCE) != 0) { |
229 | /* |
230 | * Force reporting BTN_TOOL_FINGER for devices that |
231 | * only report general hover (and not per-contact |
232 | * distance) when contact is in proximity but not |
233 | * on the surface. |
234 | */ |
235 | count = 1; |
236 | } |
237 | |
238 | input_mt_report_finger_count(dev, count); |
239 | } |
240 | |
241 | if (oldest) { |
242 | int x = input_mt_get_value(slot: oldest, ABS_MT_POSITION_X); |
243 | int y = input_mt_get_value(slot: oldest, ABS_MT_POSITION_Y); |
244 | |
245 | input_event(dev, EV_ABS, ABS_X, value: x); |
246 | input_event(dev, EV_ABS, ABS_Y, value: y); |
247 | |
248 | if (test_bit(ABS_MT_PRESSURE, dev->absbit)) { |
249 | int p = input_mt_get_value(slot: oldest, ABS_MT_PRESSURE); |
250 | input_event(dev, EV_ABS, ABS_PRESSURE, value: p); |
251 | } |
252 | } else { |
253 | if (test_bit(ABS_MT_PRESSURE, dev->absbit)) |
254 | input_event(dev, EV_ABS, ABS_PRESSURE, value: 0); |
255 | } |
256 | } |
257 | EXPORT_SYMBOL(input_mt_report_pointer_emulation); |
258 | |
259 | static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt) |
260 | { |
261 | int i; |
262 | |
263 | lockdep_assert_held(&dev->event_lock); |
264 | |
265 | for (i = 0; i < mt->num_slots; i++) { |
266 | if (input_mt_is_active(slot: &mt->slots[i]) && |
267 | !input_mt_is_used(mt, slot: &mt->slots[i])) { |
268 | input_handle_event(dev, EV_ABS, ABS_MT_SLOT, value: i); |
269 | input_handle_event(dev, EV_ABS, ABS_MT_TRACKING_ID, value: -1); |
270 | } |
271 | } |
272 | } |
273 | |
274 | /** |
275 | * input_mt_drop_unused() - Inactivate slots not seen in this frame |
276 | * @dev: input device with allocated MT slots |
277 | * |
278 | * Lift all slots not seen since the last call to this function. |
279 | */ |
280 | void input_mt_drop_unused(struct input_dev *dev) |
281 | { |
282 | struct input_mt *mt = dev->mt; |
283 | |
284 | if (mt) { |
285 | unsigned long flags; |
286 | |
287 | spin_lock_irqsave(&dev->event_lock, flags); |
288 | |
289 | __input_mt_drop_unused(dev, mt); |
290 | mt->frame++; |
291 | |
292 | spin_unlock_irqrestore(lock: &dev->event_lock, flags); |
293 | } |
294 | } |
295 | EXPORT_SYMBOL(input_mt_drop_unused); |
296 | |
297 | /** |
298 | * input_mt_release_slots() - Deactivate all slots |
299 | * @dev: input device with allocated MT slots |
300 | * |
301 | * Lift all active slots. |
302 | */ |
303 | void input_mt_release_slots(struct input_dev *dev) |
304 | { |
305 | struct input_mt *mt = dev->mt; |
306 | |
307 | lockdep_assert_held(&dev->event_lock); |
308 | |
309 | if (mt) { |
310 | /* This will effectively mark all slots unused. */ |
311 | mt->frame++; |
312 | |
313 | __input_mt_drop_unused(dev, mt); |
314 | |
315 | if (test_bit(ABS_PRESSURE, dev->absbit)) |
316 | input_handle_event(dev, EV_ABS, ABS_PRESSURE, value: 0); |
317 | |
318 | mt->frame++; |
319 | } |
320 | } |
321 | |
322 | /** |
323 | * input_mt_sync_frame() - synchronize mt frame |
324 | * @dev: input device with allocated MT slots |
325 | * |
326 | * Close the frame and prepare the internal state for a new one. |
327 | * Depending on the flags, marks unused slots as inactive and performs |
328 | * pointer emulation. |
329 | */ |
330 | void input_mt_sync_frame(struct input_dev *dev) |
331 | { |
332 | struct input_mt *mt = dev->mt; |
333 | bool use_count = false; |
334 | |
335 | if (!mt) |
336 | return; |
337 | |
338 | if (mt->flags & INPUT_MT_DROP_UNUSED) { |
339 | unsigned long flags; |
340 | |
341 | spin_lock_irqsave(&dev->event_lock, flags); |
342 | __input_mt_drop_unused(dev, mt); |
343 | spin_unlock_irqrestore(lock: &dev->event_lock, flags); |
344 | } |
345 | |
346 | if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT)) |
347 | use_count = true; |
348 | |
349 | input_mt_report_pointer_emulation(dev, use_count); |
350 | |
351 | mt->frame++; |
352 | } |
353 | EXPORT_SYMBOL(input_mt_sync_frame); |
354 | |
355 | static int adjust_dual(int *begin, int step, int *end, int eq, int mu) |
356 | { |
357 | int f, *p, s, c; |
358 | |
359 | if (begin == end) |
360 | return 0; |
361 | |
362 | f = *begin; |
363 | p = begin + step; |
364 | s = p == end ? f + 1 : *p; |
365 | |
366 | for (; p != end; p += step) { |
367 | if (*p < f) { |
368 | s = f; |
369 | f = *p; |
370 | } else if (*p < s) { |
371 | s = *p; |
372 | } |
373 | } |
374 | |
375 | c = (f + s + 1) / 2; |
376 | if (c == 0 || (c > mu && (!eq || mu > 0))) |
377 | return 0; |
378 | /* Improve convergence for positive matrices by penalizing overcovers */ |
379 | if (s < 0 && mu <= 0) |
380 | c *= 2; |
381 | |
382 | for (p = begin; p != end; p += step) |
383 | *p -= c; |
384 | |
385 | return (c < s && s <= 0) || (f >= 0 && f < c); |
386 | } |
387 | |
388 | static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu) |
389 | { |
390 | int i, k, sum; |
391 | |
392 | for (k = 0; k < nrc; k++) { |
393 | for (i = 0; i < nr; i++) |
394 | adjust_dual(begin: w + i, step: nr, end: w + i + nrc, eq: nr <= nc, mu); |
395 | sum = 0; |
396 | for (i = 0; i < nrc; i += nr) |
397 | sum += adjust_dual(begin: w + i, step: 1, end: w + i + nr, eq: nc <= nr, mu); |
398 | if (!sum) |
399 | break; |
400 | } |
401 | } |
402 | |
403 | static int input_mt_set_matrix(struct input_mt *mt, |
404 | const struct input_mt_pos *pos, int num_pos, |
405 | int mu) |
406 | { |
407 | const struct input_mt_pos *p; |
408 | struct input_mt_slot *s; |
409 | int *w = mt->red; |
410 | int x, y; |
411 | |
412 | for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { |
413 | if (!input_mt_is_active(slot: s)) |
414 | continue; |
415 | x = input_mt_get_value(slot: s, ABS_MT_POSITION_X); |
416 | y = input_mt_get_value(slot: s, ABS_MT_POSITION_Y); |
417 | for (p = pos; p != pos + num_pos; p++) { |
418 | int dx = x - p->x, dy = y - p->y; |
419 | *w++ = dx * dx + dy * dy - mu; |
420 | } |
421 | } |
422 | |
423 | return w - mt->red; |
424 | } |
425 | |
426 | static void input_mt_set_slots(struct input_mt *mt, |
427 | int *slots, int num_pos) |
428 | { |
429 | struct input_mt_slot *s; |
430 | int *w = mt->red, j; |
431 | |
432 | for (j = 0; j != num_pos; j++) |
433 | slots[j] = -1; |
434 | |
435 | for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { |
436 | if (!input_mt_is_active(slot: s)) |
437 | continue; |
438 | |
439 | for (j = 0; j != num_pos; j++) { |
440 | if (w[j] < 0) { |
441 | slots[j] = s - mt->slots; |
442 | break; |
443 | } |
444 | } |
445 | |
446 | w += num_pos; |
447 | } |
448 | |
449 | for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { |
450 | if (input_mt_is_active(slot: s)) |
451 | continue; |
452 | |
453 | for (j = 0; j != num_pos; j++) { |
454 | if (slots[j] < 0) { |
455 | slots[j] = s - mt->slots; |
456 | break; |
457 | } |
458 | } |
459 | } |
460 | } |
461 | |
462 | /** |
463 | * input_mt_assign_slots() - perform a best-match assignment |
464 | * @dev: input device with allocated MT slots |
465 | * @slots: the slot assignment to be filled |
466 | * @pos: the position array to match |
467 | * @num_pos: number of positions |
468 | * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite) |
469 | * |
470 | * Performs a best match against the current contacts and returns |
471 | * the slot assignment list. New contacts are assigned to unused |
472 | * slots. |
473 | * |
474 | * The assignments are balanced so that all coordinate displacements are |
475 | * below the euclidian distance dmax. If no such assignment can be found, |
476 | * some contacts are assigned to unused slots. |
477 | * |
478 | * Returns zero on success, or negative error in case of failure. |
479 | */ |
480 | int input_mt_assign_slots(struct input_dev *dev, int *slots, |
481 | const struct input_mt_pos *pos, int num_pos, |
482 | int dmax) |
483 | { |
484 | struct input_mt *mt = dev->mt; |
485 | int mu = 2 * dmax * dmax; |
486 | int nrc; |
487 | |
488 | if (!mt || !mt->red) |
489 | return -ENXIO; |
490 | if (num_pos > mt->num_slots) |
491 | return -EINVAL; |
492 | if (num_pos < 1) |
493 | return 0; |
494 | |
495 | nrc = input_mt_set_matrix(mt, pos, num_pos, mu); |
496 | find_reduced_matrix(w: mt->red, nr: num_pos, nc: nrc / num_pos, nrc, mu); |
497 | input_mt_set_slots(mt, slots, num_pos); |
498 | |
499 | return 0; |
500 | } |
501 | EXPORT_SYMBOL(input_mt_assign_slots); |
502 | |
503 | /** |
504 | * input_mt_get_slot_by_key() - return slot matching key |
505 | * @dev: input device with allocated MT slots |
506 | * @key: the key of the sought slot |
507 | * |
508 | * Returns the slot of the given key, if it exists, otherwise |
509 | * set the key on the first unused slot and return. |
510 | * |
511 | * If no available slot can be found, -1 is returned. |
512 | * Note that for this function to work properly, input_mt_sync_frame() has |
513 | * to be called at each frame. |
514 | */ |
515 | int input_mt_get_slot_by_key(struct input_dev *dev, int key) |
516 | { |
517 | struct input_mt *mt = dev->mt; |
518 | struct input_mt_slot *s; |
519 | |
520 | if (!mt) |
521 | return -1; |
522 | |
523 | for (s = mt->slots; s != mt->slots + mt->num_slots; s++) |
524 | if (input_mt_is_active(slot: s) && s->key == key) |
525 | return s - mt->slots; |
526 | |
527 | for (s = mt->slots; s != mt->slots + mt->num_slots; s++) |
528 | if (!input_mt_is_active(slot: s) && !input_mt_is_used(mt, slot: s)) { |
529 | s->key = key; |
530 | return s - mt->slots; |
531 | } |
532 | |
533 | return -1; |
534 | } |
535 | EXPORT_SYMBOL(input_mt_get_slot_by_key); |
536 | |