projects/linux·blob v4.13 · refs

491 lines · 12.5 KiB

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(sizeof(*mt) + num_slots * sizeof(*mt->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 */
135void 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;
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;
151 }
152
153 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
154 if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
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}
160EXPORT_SYMBOL(input_mt_report_slot_state);
161
162/**
163 * input_mt_report_finger_count() - report contact count
164 * @dev: input device with allocated MT slots
165 * @count: the number of contacts
166 *
167 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
168 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
169 *
170 * The input core ensures only the KEY events already setup for
171 * this device will produce output.
172 */
173void input_mt_report_finger_count(struct input_dev *dev, int count)
174{
175 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
176 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
177 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
178 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
179 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
180}
181EXPORT_SYMBOL(input_mt_report_finger_count);
182
183/**
184 * input_mt_report_pointer_emulation() - common pointer emulation
185 * @dev: input device with allocated MT slots
186 * @use_count: report number of active contacts as finger count
187 *
188 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
189 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
190 *
191 * The input core ensures only the KEY and ABS axes already setup for
192 * this device will produce output.
193 */
194void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
195{
196 struct input_mt *mt = dev->mt;
197 struct input_mt_slot *oldest;
198 int oldid, count, i;
199
200 if (!mt)
201 return;
202
203 oldest = NULL;
204 oldid = mt->trkid;
205 count = 0;
206
207 for (i = 0; i < mt->num_slots; ++i) {
208 struct input_mt_slot *ps = &mt->slots[i];
209 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
210
211 if (id < 0)
212 continue;
213 if ((id - oldid) & TRKID_SGN) {
214 oldest = ps;
215 oldid = id;
216 }
217 count++;
218 }
219
220 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
221
222 if (use_count) {
223 if (count == 0 &&
224 !test_bit(ABS_MT_DISTANCE, dev->absbit) &&
225 test_bit(ABS_DISTANCE, dev->absbit) &&
226 input_abs_get_val(dev, ABS_DISTANCE) != 0) {
227 /*
228 * Force reporting BTN_TOOL_FINGER for devices that
229 * only report general hover (and not per-contact
230 * distance) when contact is in proximity but not
231 * on the surface.
232 */
233 count = 1;
234 }
235
236 input_mt_report_finger_count(dev, count);
237 }
238
239 if (oldest) {
240 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
241 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
242
243 input_event(dev, EV_ABS, ABS_X, x);
244 input_event(dev, EV_ABS, ABS_Y, y);
245
246 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
247 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
248 input_event(dev, EV_ABS, ABS_PRESSURE, p);
249 }
250 } else {
251 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
252 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
253 }
254}
255EXPORT_SYMBOL(input_mt_report_pointer_emulation);
256
257static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
258{
259 int i;
260
261 for (i = 0; i < mt->num_slots; i++) {
262 if (!input_mt_is_used(mt, &mt->slots[i])) {
263 input_mt_slot(dev, i);
264 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
265 }
266 }
267}
268
269/**
270 * input_mt_drop_unused() - Inactivate slots not seen in this frame
271 * @dev: input device with allocated MT slots
272 *
273 * Lift all slots not seen since the last call to this function.
274 */
275void input_mt_drop_unused(struct input_dev *dev)
276{
277 struct input_mt *mt = dev->mt;
278
279 if (mt) {
280 __input_mt_drop_unused(dev, mt);
281 mt->frame++;
282 }
283}
284EXPORT_SYMBOL(input_mt_drop_unused);
285
286/**
287 * input_mt_sync_frame() - synchronize mt frame
288 * @dev: input device with allocated MT slots
289 *
290 * Close the frame and prepare the internal state for a new one.
291 * Depending on the flags, marks unused slots as inactive and performs
292 * pointer emulation.
293 */
294void input_mt_sync_frame(struct input_dev *dev)
295{
296 struct input_mt *mt = dev->mt;
297 bool use_count = false;
298
299 if (!mt)
300 return;
301
302 if (mt->flags & INPUT_MT_DROP_UNUSED)
303 __input_mt_drop_unused(dev, mt);
304
305 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
306 use_count = true;
307
308 input_mt_report_pointer_emulation(dev, use_count);
309
310 mt->frame++;
311}
312EXPORT_SYMBOL(input_mt_sync_frame);
313
314static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
315{
316 int f, *p, s, c;
317
318 if (begin == end)
319 return 0;
320
321 f = *begin;
322 p = begin + step;
323 s = p == end ? f + 1 : *p;
324
325 for (; p != end; p += step)
326 if (*p < f)
327 s = f, f = *p;
328 else if (*p < s)
329 s = *p;
330
331 c = (f + s + 1) / 2;
332 if (c == 0 || (c > mu && (!eq || mu > 0)))
333 return 0;
334 /* Improve convergence for positive matrices by penalizing overcovers */
335 if (s < 0 && mu <= 0)
336 c *= 2;
337
338 for (p = begin; p != end; p += step)
339 *p -= c;
340
341 return (c < s && s <= 0) || (f >= 0 && f < c);
342}
343
344static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
345{
346 int i, k, sum;
347
348 for (k = 0; k < nrc; k++) {
349 for (i = 0; i < nr; i++)
350 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
351 sum = 0;
352 for (i = 0; i < nrc; i += nr)
353 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
354 if (!sum)
355 break;
356 }
357}
358
359static int input_mt_set_matrix(struct input_mt *mt,
360 const struct input_mt_pos *pos, int num_pos,
361 int mu)
362{
363 const struct input_mt_pos *p;
364 struct input_mt_slot *s;
365 int *w = mt->red;
366 int x, y;
367
368 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
369 if (!input_mt_is_active(s))
370 continue;
371 x = input_mt_get_value(s, ABS_MT_POSITION_X);
372 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
373 for (p = pos; p != pos + num_pos; p++) {
374 int dx = x - p->x, dy = y - p->y;
375 *w++ = dx * dx + dy * dy - mu;
376 }
377 }
378
379 return w - mt->red;
380}
381
382static void input_mt_set_slots(struct input_mt *mt,
383 int *slots, int num_pos)
384{
385 struct input_mt_slot *s;
386 int *w = mt->red, j;
387
388 for (j = 0; j != num_pos; j++)
389 slots[j] = -1;
390
391 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
392 if (!input_mt_is_active(s))
393 continue;
394
395 for (j = 0; j != num_pos; j++) {
396 if (w[j] < 0) {
397 slots[j] = s - mt->slots;
398 break;
399 }
400 }
401
402 w += num_pos;
403 }
404
405 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
406 if (input_mt_is_active(s))
407 continue;
408
409 for (j = 0; j != num_pos; j++) {
410 if (slots[j] < 0) {
411 slots[j] = s - mt->slots;
412 break;
413 }
414 }
415 }
416}
417
418/**
419 * input_mt_assign_slots() - perform a best-match assignment
420 * @dev: input device with allocated MT slots
421 * @slots: the slot assignment to be filled
422 * @pos: the position array to match
423 * @num_pos: number of positions
424 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
425 *
426 * Performs a best match against the current contacts and returns
427 * the slot assignment list. New contacts are assigned to unused
428 * slots.
429 *
430 * The assignments are balanced so that all coordinate displacements are
431 * below the euclidian distance dmax. If no such assignment can be found,
432 * some contacts are assigned to unused slots.
433 *
434 * Returns zero on success, or negative error in case of failure.
435 */
436int input_mt_assign_slots(struct input_dev *dev, int *slots,
437 const struct input_mt_pos *pos, int num_pos,
438 int dmax)
439{
440 struct input_mt *mt = dev->mt;
441 int mu = 2 * dmax * dmax;
442 int nrc;
443
444 if (!mt || !mt->red)
445 return -ENXIO;
446 if (num_pos > mt->num_slots)
447 return -EINVAL;
448 if (num_pos < 1)
449 return 0;
450
451 nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
452 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
453 input_mt_set_slots(mt, slots, num_pos);
454
455 return 0;
456}
457EXPORT_SYMBOL(input_mt_assign_slots);
458
459/**
460 * input_mt_get_slot_by_key() - return slot matching key
461 * @dev: input device with allocated MT slots
462 * @key: the key of the sought slot
463 *
464 * Returns the slot of the given key, if it exists, otherwise
465 * set the key on the first unused slot and return.
466 *
467 * If no available slot can be found, -1 is returned.
468 * Note that for this function to work properly, input_mt_sync_frame() has
469 * to be called at each frame.
470 */
471int input_mt_get_slot_by_key(struct input_dev *dev, int key)
472{
473 struct input_mt *mt = dev->mt;
474 struct input_mt_slot *s;
475
476 if (!mt)
477 return -1;
478
479 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
480 if (input_mt_is_active(s) && s->key == key)
481 return s - mt->slots;
482
483 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
484 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) {
485 s->key = key;
486 return s - mt->slots;
487 }
488
489 return -1;
490}
491EXPORT_SYMBOL(input_mt_get_slot_by_key);