summaryrefslogtreecommitdiffstats
path: root/drivers/input/input-mt.c
blob: cb150a1dbaff9c9e788885747113e83e8f1dbe52 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
/*
 * Input Multitouch Library
 *
 * Copyright (c) 2008-2010 Henrik Rydberg
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/input/mt.h>
#include <linux/export.h>
#include <linux/slab.h>

#define TRKID_SGN	((TRKID_MAX + 1) >> 1)

static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src)
{
	if (dev->absinfo && test_bit(src, dev->absbit)) {
		dev->absinfo[dst] = dev->absinfo[src];
		dev->absinfo[dst].fuzz = 0;
		dev->absbit[BIT_WORD(dst)] |= BIT_MASK(dst);
	}
}

/**
 * input_mt_init_slots() - initialize MT input slots
 * @dev: input device supporting MT events and finger tracking
 * @num_slots: number of slots used by the device
 * @flags: mt tasks to handle in core
 *
 * This function allocates all necessary memory for MT slot handling
 * in the input device, prepares the ABS_MT_SLOT and
 * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
 * Depending on the flags set, it also performs pointer emulation and
 * frame synchronization.
 *
 * May be called repeatedly. Returns -EINVAL if attempting to
 * reinitialize with a different number of slots.
 */
int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
			unsigned int flags)
{
	struct input_mt *mt = dev->mt;
	int i;

	if (!num_slots)
		return 0;
	if (mt)
		return mt->num_slots != num_slots ? -EINVAL : 0;

	mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
	if (!mt)
		goto err_mem;

	mt->num_slots = num_slots;
	mt->flags = flags;
	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);

	if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
		__set_bit(EV_KEY, dev->evbit);
		__set_bit(BTN_TOUCH, dev->keybit);

		copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
		copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
		copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
	}
	if (flags & INPUT_MT_POINTER) {
		__set_bit(BTN_TOOL_FINGER, dev->keybit);
		__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
		if (num_slots >= 3)
			__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
		if (num_slots >= 4)
			__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
		if (num_slots >= 5)
			__set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
		__set_bit(INPUT_PROP_POINTER, dev->propbit);
	}
	if (flags & INPUT_MT_DIRECT)
		__set_bit(INPUT_PROP_DIRECT, dev->propbit);
	if (flags & INPUT_MT_SEMI_MT)
		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
	if (flags & INPUT_MT_TRACK) {
		unsigned int n2 = num_slots * num_slots;
		mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
		if (!mt->red)
			goto err_mem;
	}

	/* Mark slots as 'unused' */
	for (i = 0; i < num_slots; i++)
		input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);

	dev->mt = mt;
	return 0;
err_mem:
	kfree(mt);
	return -ENOMEM;
}
EXPORT_SYMBOL(input_mt_init_slots);

/**
 * input_mt_destroy_slots() - frees the MT slots of the input device
 * @dev: input device with allocated MT slots
 *
 * This function is only needed in error path as the input core will
 * automatically free the MT slots when the device is destroyed.
 */
void input_mt_destroy_slots(struct input_dev *dev)
{
	if (dev->mt) {
		kfree(dev->mt->red);
		kfree(dev->mt);
	}
	dev->mt = NULL;
}
EXPORT_SYMBOL(input_mt_destroy_slots);

/**
 * input_mt_report_slot_state() - report contact state
 * @dev: input device with allocated MT slots
 * @tool_type: the tool type to use in this slot
 * @active: true if contact is active, false otherwise
 *
 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
 * inactive, or if the tool type is changed, a new tracking id is
 * assigned to the slot. The tool type is only reported if the
 * corresponding absbit field is set.
 */
void input_mt_report_slot_state(struct input_dev *dev,
				unsigned int tool_type, bool active)
{
	struct input_mt *mt = dev->mt;
	struct input_mt_slot *slot;
	int id;

	if (!mt)
		return;

	slot = &mt->slots[mt->slot];
	slot->frame = mt->frame;

	if (!active) {
		input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
		return;
	}

	id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
	if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
		id = input_mt_new_trkid(mt);

	input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
	input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
}
EXPORT_SYMBOL(input_mt_report_slot_state);

/**
 * input_mt_report_finger_count() - report contact count
 * @dev: input device with allocated MT slots
 * @count: the number of contacts
 *
 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
 *
 * The input core ensures only the KEY events already setup for
 * this device will produce output.
 */
void input_mt_report_finger_count(struct input_dev *dev, int count)
{
	input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
	input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
	input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
	input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
	input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
}
EXPORT_SYMBOL(input_mt_report_finger_count);

/**
 * input_mt_report_pointer_emulation() - common pointer emulation
 * @dev: input device with allocated MT slots
 * @use_count: report number of active contacts as finger count
 *
 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
 *
 * The input core ensures only the KEY and ABS axes already setup for
 * this device will produce output.
 */
void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
{
	struct input_mt *mt = dev->mt;
	struct input_mt_slot *oldest;
	int oldid, count, i;

	if (!mt)
		return;

	oldest = NULL;
	oldid = mt->trkid;
	count = 0;

	for (i = 0; i < mt->num_slots; ++i) {
		struct input_mt_slot *ps = &mt->slots[i];
		int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);

		if (id < 0)
			continue;
		if ((id - oldid) & TRKID_SGN) {
			oldest = ps;
			oldid = id;
		}
		count++;
	}

	input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
	if (use_count)
		input_mt_report_finger_count(dev, count);

	if (oldest) {
		int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
		int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);

		input_event(dev, EV_ABS, ABS_X, x);
		input_event(dev, EV_ABS, ABS_Y, y);

		if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
			int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
			input_event(dev, EV_ABS, ABS_PRESSURE, p);
		}
	} else {
		if (test_bit(ABS_MT_PRESSURE, dev->absbit))
			input_event(dev, EV_ABS, ABS_PRESSURE, 0);
	}
}
EXPORT_SYMBOL(input_mt_report_pointer_emulation);

static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
{
	int i;

	for (i = 0; i < mt->num_slots; i++) {
		if (!input_mt_is_used(mt, &mt->slots[i])) {
			input_mt_slot(dev, i);
			input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
		}
	}
}

/**
 * input_mt_drop_unused() - Inactivate slots not seen in this frame
 * @dev: input device with allocated MT slots
 *
 * Lift all slots not seen since the last call to this function.
 */
void input_mt_drop_unused(struct input_dev *dev)
{
	struct input_mt *mt = dev->mt;

	if (mt) {
		__input_mt_drop_unused(dev, mt);
		mt->frame++;
	}
}
EXPORT_SYMBOL(input_mt_drop_unused);

/**
 * input_mt_sync_frame() - synchronize mt frame
 * @dev: input device with allocated MT slots
 *
 * Close the frame and prepare the internal state for a new one.
 * Depending on the flags, marks unused slots as inactive and performs
 * pointer emulation.
 */
void input_mt_sync_frame(struct input_dev *dev)
{
	struct input_mt *mt = dev->mt;
	bool use_count = false;

	if (!mt)
		return;

	if (mt->flags & INPUT_MT_DROP_UNUSED)
		__input_mt_drop_unused(dev, mt);

	if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
		use_count = true;

	input_mt_report_pointer_emulation(dev, use_count);

	mt->frame++;
}
EXPORT_SYMBOL(input_mt_sync_frame);

static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
{
	int f, *p, s, c;

	if (begin == end)
		return 0;

	f = *begin;
	p = begin + step;
	s = p == end ? f + 1 : *p;

	for (; p != end; p += step)
		if (*p < f)
			s = f, f = *p;
		else if (*p < s)
			s = *p;

	c = (f + s + 1) / 2;
	if (c == 0 || (c > mu && (!eq || mu > 0)))
		return 0;
	/* Improve convergence for positive matrices by penalizing overcovers */
	if (s < 0 && mu <= 0)
		c *= 2;

	for (p = begin; p != end; p += step)
		*p -= c;

	return (c < s && s <= 0) || (f >= 0 && f < c);
}

static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
{
	int i, k, sum;

	for (k = 0; k < nrc; k++) {
		for (i = 0; i < nr; i++)
			adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
		sum = 0;
		for (i = 0; i < nrc; i += nr)
			sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
		if (!sum)
			break;
	}
}

static int input_mt_set_matrix(struct input_mt *mt,
			       const struct input_mt_pos *pos, int num_pos,
			       int mu)
{
	const struct input_mt_pos *p;
	struct input_mt_slot *s;
	int *w = mt->red;
	int x, y;

	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
		if (!input_mt_is_active(s))
			continue;
		x = input_mt_get_value(s, ABS_MT_POSITION_X);
		y = input_mt_get_value(s, ABS_MT_POSITION_Y);
		for (p = pos; p != pos + num_pos; p++) {
			int dx = x - p->x, dy = y - p->y;
			*w++ = dx * dx + dy * dy - mu;
		}
	}

	return w - mt->red;
}

static void input_mt_set_slots(struct input_mt *mt,
			       int *slots, int num_pos)
{
	struct input_mt_slot *s;
	int *w = mt->red, *p;

	for (p = slots; p != slots + num_pos; p++)
		*p = -1;

	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
		if (!input_mt_is_active(s))
			continue;
		for (p = slots; p != slots + num_pos; p++)
			if (*w++ < 0)
				*p = s - mt->slots;
	}

	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
		if (input_mt_is_active(s))
			continue;
		for (p = slots; p != slots + num_pos; p++)
			if (*p < 0) {
				*p = s - mt->slots;
				break;
			}
	}
}

/**
 * input_mt_assign_slots() - perform a best-match assignment
 * @dev: input device with allocated MT slots
 * @slots: the slot assignment to be filled
 * @pos: the position array to match
 * @num_pos: number of positions
 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
 *
 * Performs a best match against the current contacts and returns
 * the slot assignment list. New contacts are assigned to unused
 * slots.
 *
 * The assignments are balanced so that all coordinate displacements are
 * below the euclidian distance dmax. If no such assignment can be found,
 * some contacts are assigned to unused slots.
 *
 * Returns zero on success, or negative error in case of failure.
 */
int input_mt_assign_slots(struct input_dev *dev, int *slots,
			  const struct input_mt_pos *pos, int num_pos,
			  int dmax)
{
	struct input_mt *mt = dev->mt;
	int mu = 2 * dmax * dmax;
	int nrc;

	if (!mt || !mt->red)
		return -ENXIO;
	if (num_pos > mt->num_slots)
		return -EINVAL;
	if (num_pos < 1)
		return 0;

	nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
	find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
	input_mt_set_slots(mt, slots, num_pos);

	return 0;
}
EXPORT_SYMBOL(input_mt_assign_slots);

/**
 * input_mt_get_slot_by_key() - return slot matching key
 * @dev: input device with allocated MT slots
 * @key: the key of the sought slot
 *
 * Returns the slot of the given key, if it exists, otherwise
 * set the key on the first unused slot and return.
 *
 * If no available slot can be found, -1 is returned.
 */
int input_mt_get_slot_by_key(struct input_dev *dev, int key)
{
	struct input_mt *mt = dev->mt;
	struct input_mt_slot *s;

	if (!mt)
		return -1;

	for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
		if (input_mt_is_active(s) && s->key == key)
			return s - mt->slots;

	for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
		if (!input_mt_is_active(s)) {
			s->key = key;
			return s - mt->slots;
		}

	return -1;
}
EXPORT_SYMBOL(input_mt_get_slot_by_key);