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); 536