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 14 static 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 */ 38 int 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; 97 err_mem: 98 kfree(mt); 99 return -ENOMEM; 100 } 101 EXPORT_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 */ 110 void 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 } 118 EXPORT_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 */ 134 bool 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 } 161 EXPORT_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 */ 174 void 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 } 182 EXPORT_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 */ 195 void 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 } 256 EXPORT_SYMBOL(input_mt_report_pointer_emulation); 257 258 static 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 */ 276 void 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 } 285 EXPORT_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 */ 295 void 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 } 313 EXPORT_SYMBOL(input_mt_sync_frame); 314 315 static 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 } 344 345 static 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 } 359 360 static 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 } 382 383 static 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 */ 437 int 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 } 458 EXPORT_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 */ 472 int 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 } 492 EXPORT_SYMBOL(input_mt_get_slot_by_key); 493