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