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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 if (use_count)
222 input_mt_report_finger_count(dev, count);
223
224 if (oldest) {
225 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
226 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
227
228 input_event(dev, EV_ABS, ABS_X, x);
229 input_event(dev, EV_ABS, ABS_Y, y);
230
231 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
232 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
233 input_event(dev, EV_ABS, ABS_PRESSURE, p);
234 }
235 } else {
236 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
237 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
238 }
239}
240EXPORT_SYMBOL(input_mt_report_pointer_emulation);
241
242static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
243{
244 int i;
245
246 for (i = 0; i < mt->num_slots; i++) {
247 if (!input_mt_is_used(mt, &mt->slots[i])) {
248 input_mt_slot(dev, i);
249 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
250 }
251 }
252}
253
254/**
255 * input_mt_drop_unused() - Inactivate slots not seen in this frame
256 * @dev: input device with allocated MT slots
257 *
258 * Lift all slots not seen since the last call to this function.
259 */
260void input_mt_drop_unused(struct input_dev *dev)
261{
262 struct input_mt *mt = dev->mt;
263
264 if (mt) {
265 __input_mt_drop_unused(dev, mt);
266 mt->frame++;
267 }
268}
269EXPORT_SYMBOL(input_mt_drop_unused);
270
271/**
272 * input_mt_sync_frame() - synchronize mt frame
273 * @dev: input device with allocated MT slots
274 *
275 * Close the frame and prepare the internal state for a new one.
276 * Depending on the flags, marks unused slots as inactive and performs
277 * pointer emulation.
278 */
279void input_mt_sync_frame(struct input_dev *dev)
280{
281 struct input_mt *mt = dev->mt;
282 bool use_count = false;
283
284 if (!mt)
285 return;
286
287 if (mt->flags & INPUT_MT_DROP_UNUSED)
288 __input_mt_drop_unused(dev, mt);
289
290 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
291 use_count = true;
292
293 input_mt_report_pointer_emulation(dev, use_count);
294
295 mt->frame++;
296}
297EXPORT_SYMBOL(input_mt_sync_frame);
298
299static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
300{
301 int f, *p, s, c;
302
303 if (begin == end)
304 return 0;
305
306 f = *begin;
307 p = begin + step;
308 s = p == end ? f + 1 : *p;
309
310 for (; p != end; p += step)
311 if (*p < f)
312 s = f, f = *p;
313 else if (*p < s)
314 s = *p;
315
316 c = (f + s + 1) / 2;
317 if (c == 0 || (c > mu && (!eq || mu > 0)))
318 return 0;
319 /* Improve convergence for positive matrices by penalizing overcovers */
320 if (s < 0 && mu <= 0)
321 c *= 2;
322
323 for (p = begin; p != end; p += step)
324 *p -= c;
325
326 return (c < s && s <= 0) || (f >= 0 && f < c);
327}
328
329static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
330{
331 int i, k, sum;
332
333 for (k = 0; k < nrc; k++) {
334 for (i = 0; i < nr; i++)
335 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
336 sum = 0;
337 for (i = 0; i < nrc; i += nr)
338 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
339 if (!sum)
340 break;
341 }
342}
343
344static int input_mt_set_matrix(struct input_mt *mt,
345 const struct input_mt_pos *pos, int num_pos,
346 int mu)
347{
348 const struct input_mt_pos *p;
349 struct input_mt_slot *s;
350 int *w = mt->red;
351 int x, y;
352
353 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
354 if (!input_mt_is_active(s))
355 continue;
356 x = input_mt_get_value(s, ABS_MT_POSITION_X);
357 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
358 for (p = pos; p != pos + num_pos; p++) {
359 int dx = x - p->x, dy = y - p->y;
360 *w++ = dx * dx + dy * dy - mu;
361 }
362 }
363
364 return w - mt->red;
365}
366
367static void input_mt_set_slots(struct input_mt *mt,
368 int *slots, int num_pos)
369{
370 struct input_mt_slot *s;
371 int *w = mt->red, j;
372
373 for (j = 0; j != num_pos; j++)
374 slots[j] = -1;
375
376 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
377 if (!input_mt_is_active(s))
378 continue;
379
380 for (j = 0; j != num_pos; j++) {
381 if (w[j] < 0) {
382 slots[j] = s - mt->slots;
383 break;
384 }
385 }
386
387 w += num_pos;
388 }
389
390 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
391 if (input_mt_is_active(s))
392 continue;
393
394 for (j = 0; j != num_pos; j++) {
395 if (slots[j] < 0) {
396 slots[j] = s - mt->slots;
397 break;
398 }
399 }
400 }
401}
402
403/**
404 * input_mt_assign_slots() - perform a best-match assignment
405 * @dev: input device with allocated MT slots
406 * @slots: the slot assignment to be filled
407 * @pos: the position array to match
408 * @num_pos: number of positions
409 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
410 *
411 * Performs a best match against the current contacts and returns
412 * the slot assignment list. New contacts are assigned to unused
413 * slots.
414 *
415 * The assignments are balanced so that all coordinate displacements are
416 * below the euclidian distance dmax. If no such assignment can be found,
417 * some contacts are assigned to unused slots.
418 *
419 * Returns zero on success, or negative error in case of failure.
420 */
421int input_mt_assign_slots(struct input_dev *dev, int *slots,
422 const struct input_mt_pos *pos, int num_pos,
423 int dmax)
424{
425 struct input_mt *mt = dev->mt;
426 int mu = 2 * dmax * dmax;
427 int nrc;
428
429 if (!mt || !mt->red)
430 return -ENXIO;
431 if (num_pos > mt->num_slots)
432 return -EINVAL;
433 if (num_pos < 1)
434 return 0;
435
436 nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
437 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
438 input_mt_set_slots(mt, slots, num_pos);
439
440 return 0;
441}
442EXPORT_SYMBOL(input_mt_assign_slots);
443
444/**
445 * input_mt_get_slot_by_key() - return slot matching key
446 * @dev: input device with allocated MT slots
447 * @key: the key of the sought slot
448 *
449 * Returns the slot of the given key, if it exists, otherwise
450 * set the key on the first unused slot and return.
451 *
452 * If no available slot can be found, -1 is returned.
453 * Note that for this function to work properly, input_mt_sync_frame() has
454 * to be called at each frame.
455 */
456int input_mt_get_slot_by_key(struct input_dev *dev, int key)
457{
458 struct input_mt *mt = dev->mt;
459 struct input_mt_slot *s;
460
461 if (!mt)
462 return -1;
463
464 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
465 if (input_mt_is_active(s) && s->key == key)
466 return s - mt->slots;
467
468 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
469 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) {
470 s->key = key;
471 return s - mt->slots;
472 }
473
474 return -1;
475}
476EXPORT_SYMBOL(input_mt_get_slot_by_key);
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 /* Arbitrary limit for avoiding too large memory allocation. */
50 if (num_slots > 1024)
51 return -EINVAL;
52
53 mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
54 if (!mt)
55 goto err_mem;
56
57 mt->num_slots = num_slots;
58 mt->flags = flags;
59 input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
60 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
61
62 if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
63 __set_bit(EV_KEY, dev->evbit);
64 __set_bit(BTN_TOUCH, dev->keybit);
65
66 copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
67 copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
68 copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
69 }
70 if (flags & INPUT_MT_POINTER) {
71 __set_bit(BTN_TOOL_FINGER, dev->keybit);
72 __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
73 if (num_slots >= 3)
74 __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
75 if (num_slots >= 4)
76 __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
77 if (num_slots >= 5)
78 __set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
79 __set_bit(INPUT_PROP_POINTER, dev->propbit);
80 }
81 if (flags & INPUT_MT_DIRECT)
82 __set_bit(INPUT_PROP_DIRECT, dev->propbit);
83 if (flags & INPUT_MT_SEMI_MT)
84 __set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
85 if (flags & INPUT_MT_TRACK) {
86 unsigned int n2 = num_slots * num_slots;
87 mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
88 if (!mt->red)
89 goto err_mem;
90 }
91
92 /* Mark slots as 'inactive' */
93 for (i = 0; i < num_slots; i++)
94 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
95
96 /* Mark slots as 'unused' */
97 mt->frame = 1;
98
99 dev->mt = mt;
100 return 0;
101err_mem:
102 kfree(mt);
103 return -ENOMEM;
104}
105EXPORT_SYMBOL(input_mt_init_slots);
106
107/**
108 * input_mt_destroy_slots() - frees the MT slots of the input device
109 * @dev: input device with allocated MT slots
110 *
111 * This function is only needed in error path as the input core will
112 * automatically free the MT slots when the device is destroyed.
113 */
114void input_mt_destroy_slots(struct input_dev *dev)
115{
116 if (dev->mt) {
117 kfree(dev->mt->red);
118 kfree(dev->mt);
119 }
120 dev->mt = NULL;
121}
122EXPORT_SYMBOL(input_mt_destroy_slots);
123
124/**
125 * input_mt_report_slot_state() - report contact state
126 * @dev: input device with allocated MT slots
127 * @tool_type: the tool type to use in this slot
128 * @active: true if contact is active, false otherwise
129 *
130 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
131 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
132 * inactive, or if the tool type is changed, a new tracking id is
133 * assigned to the slot. The tool type is only reported if the
134 * corresponding absbit field is set.
135 *
136 * Returns true if contact is active.
137 */
138bool input_mt_report_slot_state(struct input_dev *dev,
139 unsigned int tool_type, bool active)
140{
141 struct input_mt *mt = dev->mt;
142 struct input_mt_slot *slot;
143 int id;
144
145 if (!mt)
146 return false;
147
148 slot = &mt->slots[mt->slot];
149 slot->frame = mt->frame;
150
151 if (!active) {
152 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
153 return false;
154 }
155
156 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
157 if (id < 0)
158 id = input_mt_new_trkid(mt);
159
160 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
161 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
162
163 return true;
164}
165EXPORT_SYMBOL(input_mt_report_slot_state);
166
167/**
168 * input_mt_report_finger_count() - report contact count
169 * @dev: input device with allocated MT slots
170 * @count: the number of contacts
171 *
172 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
173 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
174 *
175 * The input core ensures only the KEY events already setup for
176 * this device will produce output.
177 */
178void input_mt_report_finger_count(struct input_dev *dev, int count)
179{
180 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
181 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
182 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
183 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
184 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
185}
186EXPORT_SYMBOL(input_mt_report_finger_count);
187
188/**
189 * input_mt_report_pointer_emulation() - common pointer emulation
190 * @dev: input device with allocated MT slots
191 * @use_count: report number of active contacts as finger count
192 *
193 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
194 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
195 *
196 * The input core ensures only the KEY and ABS axes already setup for
197 * this device will produce output.
198 */
199void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
200{
201 struct input_mt *mt = dev->mt;
202 struct input_mt_slot *oldest;
203 int oldid, count, i;
204
205 if (!mt)
206 return;
207
208 oldest = NULL;
209 oldid = mt->trkid;
210 count = 0;
211
212 for (i = 0; i < mt->num_slots; ++i) {
213 struct input_mt_slot *ps = &mt->slots[i];
214 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
215
216 if (id < 0)
217 continue;
218 if ((id - oldid) & TRKID_SGN) {
219 oldest = ps;
220 oldid = id;
221 }
222 count++;
223 }
224
225 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
226
227 if (use_count) {
228 if (count == 0 &&
229 !test_bit(ABS_MT_DISTANCE, dev->absbit) &&
230 test_bit(ABS_DISTANCE, dev->absbit) &&
231 input_abs_get_val(dev, ABS_DISTANCE) != 0) {
232 /*
233 * Force reporting BTN_TOOL_FINGER for devices that
234 * only report general hover (and not per-contact
235 * distance) when contact is in proximity but not
236 * on the surface.
237 */
238 count = 1;
239 }
240
241 input_mt_report_finger_count(dev, count);
242 }
243
244 if (oldest) {
245 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
246 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
247
248 input_event(dev, EV_ABS, ABS_X, x);
249 input_event(dev, EV_ABS, ABS_Y, y);
250
251 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
252 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
253 input_event(dev, EV_ABS, ABS_PRESSURE, p);
254 }
255 } else {
256 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
257 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
258 }
259}
260EXPORT_SYMBOL(input_mt_report_pointer_emulation);
261
262static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
263{
264 int i;
265
266 lockdep_assert_held(&dev->event_lock);
267
268 for (i = 0; i < mt->num_slots; i++) {
269 if (input_mt_is_active(&mt->slots[i]) &&
270 !input_mt_is_used(mt, &mt->slots[i])) {
271 input_handle_event(dev, EV_ABS, ABS_MT_SLOT, i);
272 input_handle_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
273 }
274 }
275}
276
277/**
278 * input_mt_drop_unused() - Inactivate slots not seen in this frame
279 * @dev: input device with allocated MT slots
280 *
281 * Lift all slots not seen since the last call to this function.
282 */
283void input_mt_drop_unused(struct input_dev *dev)
284{
285 struct input_mt *mt = dev->mt;
286
287 if (mt) {
288 unsigned long flags;
289
290 spin_lock_irqsave(&dev->event_lock, flags);
291
292 __input_mt_drop_unused(dev, mt);
293 mt->frame++;
294
295 spin_unlock_irqrestore(&dev->event_lock, flags);
296 }
297}
298EXPORT_SYMBOL(input_mt_drop_unused);
299
300/**
301 * input_mt_release_slots() - Deactivate all slots
302 * @dev: input device with allocated MT slots
303 *
304 * Lift all active slots.
305 */
306void input_mt_release_slots(struct input_dev *dev)
307{
308 struct input_mt *mt = dev->mt;
309
310 lockdep_assert_held(&dev->event_lock);
311
312 if (mt) {
313 /* This will effectively mark all slots unused. */
314 mt->frame++;
315
316 __input_mt_drop_unused(dev, mt);
317
318 if (test_bit(ABS_PRESSURE, dev->absbit))
319 input_handle_event(dev, EV_ABS, ABS_PRESSURE, 0);
320
321 mt->frame++;
322 }
323}
324
325/**
326 * input_mt_sync_frame() - synchronize mt frame
327 * @dev: input device with allocated MT slots
328 *
329 * Close the frame and prepare the internal state for a new one.
330 * Depending on the flags, marks unused slots as inactive and performs
331 * pointer emulation.
332 */
333void input_mt_sync_frame(struct input_dev *dev)
334{
335 struct input_mt *mt = dev->mt;
336 bool use_count = false;
337
338 if (!mt)
339 return;
340
341 if (mt->flags & INPUT_MT_DROP_UNUSED) {
342 unsigned long flags;
343
344 spin_lock_irqsave(&dev->event_lock, flags);
345 __input_mt_drop_unused(dev, mt);
346 spin_unlock_irqrestore(&dev->event_lock, flags);
347 }
348
349 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
350 use_count = true;
351
352 input_mt_report_pointer_emulation(dev, use_count);
353
354 mt->frame++;
355}
356EXPORT_SYMBOL(input_mt_sync_frame);
357
358static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
359{
360 int f, *p, s, c;
361
362 if (begin == end)
363 return 0;
364
365 f = *begin;
366 p = begin + step;
367 s = p == end ? f + 1 : *p;
368
369 for (; p != end; p += step) {
370 if (*p < f) {
371 s = f;
372 f = *p;
373 } else if (*p < s) {
374 s = *p;
375 }
376 }
377
378 c = (f + s + 1) / 2;
379 if (c == 0 || (c > mu && (!eq || mu > 0)))
380 return 0;
381 /* Improve convergence for positive matrices by penalizing overcovers */
382 if (s < 0 && mu <= 0)
383 c *= 2;
384
385 for (p = begin; p != end; p += step)
386 *p -= c;
387
388 return (c < s && s <= 0) || (f >= 0 && f < c);
389}
390
391static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
392{
393 int i, k, sum;
394
395 for (k = 0; k < nrc; k++) {
396 for (i = 0; i < nr; i++)
397 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
398 sum = 0;
399 for (i = 0; i < nrc; i += nr)
400 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
401 if (!sum)
402 break;
403 }
404}
405
406static int input_mt_set_matrix(struct input_mt *mt,
407 const struct input_mt_pos *pos, int num_pos,
408 int mu)
409{
410 const struct input_mt_pos *p;
411 struct input_mt_slot *s;
412 int *w = mt->red;
413 int x, y;
414
415 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
416 if (!input_mt_is_active(s))
417 continue;
418 x = input_mt_get_value(s, ABS_MT_POSITION_X);
419 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
420 for (p = pos; p != pos + num_pos; p++) {
421 int dx = x - p->x, dy = y - p->y;
422 *w++ = dx * dx + dy * dy - mu;
423 }
424 }
425
426 return w - mt->red;
427}
428
429static void input_mt_set_slots(struct input_mt *mt,
430 int *slots, int num_pos)
431{
432 struct input_mt_slot *s;
433 int *w = mt->red, j;
434
435 for (j = 0; j != num_pos; j++)
436 slots[j] = -1;
437
438 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
439 if (!input_mt_is_active(s))
440 continue;
441
442 for (j = 0; j != num_pos; j++) {
443 if (w[j] < 0) {
444 slots[j] = s - mt->slots;
445 break;
446 }
447 }
448
449 w += num_pos;
450 }
451
452 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
453 if (input_mt_is_active(s))
454 continue;
455
456 for (j = 0; j != num_pos; j++) {
457 if (slots[j] < 0) {
458 slots[j] = s - mt->slots;
459 break;
460 }
461 }
462 }
463}
464
465/**
466 * input_mt_assign_slots() - perform a best-match assignment
467 * @dev: input device with allocated MT slots
468 * @slots: the slot assignment to be filled
469 * @pos: the position array to match
470 * @num_pos: number of positions
471 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
472 *
473 * Performs a best match against the current contacts and returns
474 * the slot assignment list. New contacts are assigned to unused
475 * slots.
476 *
477 * The assignments are balanced so that all coordinate displacements are
478 * below the euclidian distance dmax. If no such assignment can be found,
479 * some contacts are assigned to unused slots.
480 *
481 * Returns zero on success, or negative error in case of failure.
482 */
483int input_mt_assign_slots(struct input_dev *dev, int *slots,
484 const struct input_mt_pos *pos, int num_pos,
485 int dmax)
486{
487 struct input_mt *mt = dev->mt;
488 int mu = 2 * dmax * dmax;
489 int nrc;
490
491 if (!mt || !mt->red)
492 return -ENXIO;
493 if (num_pos > mt->num_slots)
494 return -EINVAL;
495 if (num_pos < 1)
496 return 0;
497
498 nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
499 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
500 input_mt_set_slots(mt, slots, num_pos);
501
502 return 0;
503}
504EXPORT_SYMBOL(input_mt_assign_slots);
505
506/**
507 * input_mt_get_slot_by_key() - return slot matching key
508 * @dev: input device with allocated MT slots
509 * @key: the key of the sought slot
510 *
511 * Returns the slot of the given key, if it exists, otherwise
512 * set the key on the first unused slot and return.
513 *
514 * If no available slot can be found, -1 is returned.
515 * Note that for this function to work properly, input_mt_sync_frame() has
516 * to be called at each frame.
517 */
518int input_mt_get_slot_by_key(struct input_dev *dev, int key)
519{
520 struct input_mt *mt = dev->mt;
521 struct input_mt_slot *s;
522
523 if (!mt)
524 return -1;
525
526 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
527 if (input_mt_is_active(s) && s->key == key)
528 return s - mt->slots;
529
530 for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
531 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) {
532 s->key = key;
533 return s - mt->slots;
534 }
535
536 return -1;
537}
538EXPORT_SYMBOL(input_mt_get_slot_by_key);