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 15 static 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 */ 39 int 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; 101 err_mem: 102 kfree(mt); 103 return -ENOMEM; 104 } 105 EXPORT_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 */ 114 void 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 } 122 EXPORT_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 */ 138 bool 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 } 165 EXPORT_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 */ 178 void 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 } 186 EXPORT_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 */ 199 void 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 } 260 EXPORT_SYMBOL(input_mt_report_pointer_emulation); 261 262 static 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 */ 283 void input_mt_drop_unused(struct input_dev *dev) 284 { 285 struct input_mt *mt = dev->mt; 286 287 if (mt) { 288 guard(spinlock_irqsave)(&dev->event_lock); 289 290 __input_mt_drop_unused(dev, mt); 291 mt->frame++; 292 } 293 } 294 EXPORT_SYMBOL(input_mt_drop_unused); 295 296 /** 297 * input_mt_release_slots() - Deactivate all slots 298 * @dev: input device with allocated MT slots 299 * 300 * Lift all active slots. 301 */ 302 void input_mt_release_slots(struct input_dev *dev) 303 { 304 struct input_mt *mt = dev->mt; 305 306 lockdep_assert_held(&dev->event_lock); 307 308 if (mt) { 309 /* This will effectively mark all slots unused. */ 310 mt->frame++; 311 312 __input_mt_drop_unused(dev, mt); 313 314 if (test_bit(ABS_PRESSURE, dev->absbit)) 315 input_handle_event(dev, EV_ABS, ABS_PRESSURE, 0); 316 317 mt->frame++; 318 } 319 } 320 321 /** 322 * input_mt_sync_frame() - synchronize mt frame 323 * @dev: input device with allocated MT slots 324 * 325 * Close the frame and prepare the internal state for a new one. 326 * Depending on the flags, marks unused slots as inactive and performs 327 * pointer emulation. 328 */ 329 void input_mt_sync_frame(struct input_dev *dev) 330 { 331 struct input_mt *mt = dev->mt; 332 bool use_count = false; 333 334 if (!mt) 335 return; 336 337 if (mt->flags & INPUT_MT_DROP_UNUSED) { 338 guard(spinlock_irqsave)(&dev->event_lock); 339 __input_mt_drop_unused(dev, mt); 340 } 341 342 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT)) 343 use_count = true; 344 345 input_mt_report_pointer_emulation(dev, use_count); 346 347 mt->frame++; 348 } 349 EXPORT_SYMBOL(input_mt_sync_frame); 350 351 static int adjust_dual(int *begin, int step, int *end, int eq, int mu) 352 { 353 int f, *p, s, c; 354 355 if (begin == end) 356 return 0; 357 358 f = *begin; 359 p = begin + step; 360 s = p == end ? f + 1 : *p; 361 362 for (; p != end; p += step) { 363 if (*p < f) { 364 s = f; 365 f = *p; 366 } else if (*p < s) { 367 s = *p; 368 } 369 } 370 371 c = (f + s + 1) / 2; 372 if (c == 0 || (c > mu && (!eq || mu > 0))) 373 return 0; 374 /* Improve convergence for positive matrices by penalizing overcovers */ 375 if (s < 0 && mu <= 0) 376 c *= 2; 377 378 for (p = begin; p != end; p += step) 379 *p -= c; 380 381 return (c < s && s <= 0) || (f >= 0 && f < c); 382 } 383 384 static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu) 385 { 386 int i, k, sum; 387 388 for (k = 0; k < nrc; k++) { 389 for (i = 0; i < nr; i++) 390 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu); 391 sum = 0; 392 for (i = 0; i < nrc; i += nr) 393 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu); 394 if (!sum) 395 break; 396 } 397 } 398 399 static int input_mt_set_matrix(struct input_mt *mt, 400 const struct input_mt_pos *pos, int num_pos, 401 int mu) 402 { 403 const struct input_mt_pos *p; 404 struct input_mt_slot *s; 405 int *w = mt->red; 406 int x, y; 407 408 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 409 if (!input_mt_is_active(s)) 410 continue; 411 x = input_mt_get_value(s, ABS_MT_POSITION_X); 412 y = input_mt_get_value(s, ABS_MT_POSITION_Y); 413 for (p = pos; p != pos + num_pos; p++) { 414 int dx = x - p->x, dy = y - p->y; 415 *w++ = dx * dx + dy * dy - mu; 416 } 417 } 418 419 return w - mt->red; 420 } 421 422 static void input_mt_set_slots(struct input_mt *mt, 423 int *slots, int num_pos) 424 { 425 struct input_mt_slot *s; 426 int *w = mt->red, j; 427 428 for (j = 0; j != num_pos; j++) 429 slots[j] = -1; 430 431 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 432 if (!input_mt_is_active(s)) 433 continue; 434 435 for (j = 0; j != num_pos; j++) { 436 if (w[j] < 0) { 437 slots[j] = s - mt->slots; 438 break; 439 } 440 } 441 442 w += num_pos; 443 } 444 445 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 446 if (input_mt_is_active(s)) 447 continue; 448 449 for (j = 0; j != num_pos; j++) { 450 if (slots[j] < 0) { 451 slots[j] = s - mt->slots; 452 break; 453 } 454 } 455 } 456 } 457 458 /** 459 * input_mt_assign_slots() - perform a best-match assignment 460 * @dev: input device with allocated MT slots 461 * @slots: the slot assignment to be filled 462 * @pos: the position array to match 463 * @num_pos: number of positions 464 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite) 465 * 466 * Performs a best match against the current contacts and returns 467 * the slot assignment list. New contacts are assigned to unused 468 * slots. 469 * 470 * The assignments are balanced so that all coordinate displacements are 471 * below the euclidian distance dmax. If no such assignment can be found, 472 * some contacts are assigned to unused slots. 473 * 474 * Returns zero on success, or negative error in case of failure. 475 */ 476 int input_mt_assign_slots(struct input_dev *dev, int *slots, 477 const struct input_mt_pos *pos, int num_pos, 478 int dmax) 479 { 480 struct input_mt *mt = dev->mt; 481 int mu = 2 * dmax * dmax; 482 int nrc; 483 484 if (!mt || !mt->red) 485 return -ENXIO; 486 if (num_pos > mt->num_slots) 487 return -EINVAL; 488 if (num_pos < 1) 489 return 0; 490 491 nrc = input_mt_set_matrix(mt, pos, num_pos, mu); 492 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu); 493 input_mt_set_slots(mt, slots, num_pos); 494 495 return 0; 496 } 497 EXPORT_SYMBOL(input_mt_assign_slots); 498 499 /** 500 * input_mt_get_slot_by_key() - return slot matching key 501 * @dev: input device with allocated MT slots 502 * @key: the key of the sought slot 503 * 504 * Returns the slot of the given key, if it exists, otherwise 505 * set the key on the first unused slot and return. 506 * 507 * If no available slot can be found, -1 is returned. 508 * Note that for this function to work properly, input_mt_sync_frame() has 509 * to be called at each frame. 510 */ 511 int input_mt_get_slot_by_key(struct input_dev *dev, int key) 512 { 513 struct input_mt *mt = dev->mt; 514 struct input_mt_slot *s; 515 516 if (!mt) 517 return -1; 518 519 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 520 if (input_mt_is_active(s) && s->key == key) 521 return s - mt->slots; 522 523 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 524 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) { 525 s->key = key; 526 return s - mt->slots; 527 } 528 529 return -1; 530 } 531 EXPORT_SYMBOL(input_mt_get_slot_by_key); 532