projects/linux·blob v6.2 · refs

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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
15static 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 */
39int 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, 0, num_slots - 1, 0, 0);
57 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 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(n2, 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(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
92
93 /* Mark slots as 'unused' */
94 mt->frame = 1;
95
96 dev->mt = mt;
97 return 0;
98err_mem:
99 kfree(mt);
100 return -ENOMEM;
101}
102EXPORT_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 */
111void input_mt_destroy_slots(struct input_dev *dev)
112{
113 if (dev->mt) {
114 kfree(dev->mt->red);
115 kfree(dev->mt);
116 }
117 dev->mt = NULL;
118}
119EXPORT_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 */
135bool 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, -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, id);
158 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
159
160 return true;
161}
162EXPORT_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 */
175void input_mt_report_finger_count(struct input_dev *dev, int count)
176{
177 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
178 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
179 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
180 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
181 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
182}
183EXPORT_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 */
196void 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(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, 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(oldest, ABS_MT_POSITION_X);
243 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
244
245 input_event(dev, EV_ABS, ABS_X, x);
246 input_event(dev, EV_ABS, ABS_Y, y);
247
248 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
249 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
250 input_event(dev, EV_ABS, ABS_PRESSURE, p);
251 }
252 } else {
253 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
254 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
255 }
256}
257EXPORT_SYMBOL(input_mt_report_pointer_emulation);
258
259static 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(&mt->slots[i]) &&
267 !input_mt_is_used(mt, &mt->slots[i])) {
268 input_handle_event(dev, EV_ABS, ABS_MT_SLOT, i);
269 input_handle_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -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 */
280void 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(&dev->event_lock, flags);
293 }
294}
295EXPORT_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 */
303void 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, 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 */
330void 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(&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}
353EXPORT_SYMBOL(input_mt_sync_frame);
354
355static 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
388static 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(w + i, nr, w + i + nrc, nr <= nc, mu);
395 sum = 0;
396 for (i = 0; i < nrc; i += nr)
397 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
398 if (!sum)
399 break;
400 }
401}
402
403static 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(s))
414 continue;
415 x = input_mt_get_value(s, ABS_MT_POSITION_X);
416 y = input_mt_get_value(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
426static 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(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(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 */
480int 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(mt->red, num_pos, nrc / num_pos, nrc, mu);
497 input_mt_set_slots(mt, slots, num_pos);
498
499 return 0;
500}
501EXPORT_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 */
515int 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(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(s) && !input_mt_is_used(mt, s)) {
529 s->key = key;
530 return s - mt->slots;
531 }
532
533 return -1;
534}
535EXPORT_SYMBOL(input_mt_get_slot_by_key);