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 17 static 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 */ 41 int 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(struct_size(mt, slots, num_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; 100 err_mem: 101 kfree(mt); 102 return -ENOMEM; 103 } 104 EXPORT_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 */ 113 void 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 } 121 EXPORT_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 * 135 * Returns true if contact is active. 136 */ 137 bool input_mt_report_slot_state(struct input_dev *dev, 138 unsigned int tool_type, bool active) 139 { 140 struct input_mt *mt = dev->mt; 141 struct input_mt_slot *slot; 142 int id; 143 144 if (!mt) 145 return false; 146 147 slot = &mt->slots[mt->slot]; 148 slot->frame = mt->frame; 149 150 if (!active) { 151 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1); 152 return false; 153 } 154 155 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID); 156 if (id < 0) 157 id = input_mt_new_trkid(mt); 158 159 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id); 160 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type); 161 162 return true; 163 } 164 EXPORT_SYMBOL(input_mt_report_slot_state); 165 166 /** 167 * input_mt_report_finger_count() - report contact count 168 * @dev: input device with allocated MT slots 169 * @count: the number of contacts 170 * 171 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP, 172 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP. 173 * 174 * The input core ensures only the KEY events already setup for 175 * this device will produce output. 176 */ 177 void input_mt_report_finger_count(struct input_dev *dev, int count) 178 { 179 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1); 180 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2); 181 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3); 182 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4); 183 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5); 184 } 185 EXPORT_SYMBOL(input_mt_report_finger_count); 186 187 /** 188 * input_mt_report_pointer_emulation() - common pointer emulation 189 * @dev: input device with allocated MT slots 190 * @use_count: report number of active contacts as finger count 191 * 192 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and 193 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true. 194 * 195 * The input core ensures only the KEY and ABS axes already setup for 196 * this device will produce output. 197 */ 198 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count) 199 { 200 struct input_mt *mt = dev->mt; 201 struct input_mt_slot *oldest; 202 int oldid, count, i; 203 204 if (!mt) 205 return; 206 207 oldest = NULL; 208 oldid = mt->trkid; 209 count = 0; 210 211 for (i = 0; i < mt->num_slots; ++i) { 212 struct input_mt_slot *ps = &mt->slots[i]; 213 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID); 214 215 if (id < 0) 216 continue; 217 if ((id - oldid) & TRKID_SGN) { 218 oldest = ps; 219 oldid = id; 220 } 221 count++; 222 } 223 224 input_event(dev, EV_KEY, BTN_TOUCH, count > 0); 225 226 if (use_count) { 227 if (count == 0 && 228 !test_bit(ABS_MT_DISTANCE, dev->absbit) && 229 test_bit(ABS_DISTANCE, dev->absbit) && 230 input_abs_get_val(dev, ABS_DISTANCE) != 0) { 231 /* 232 * Force reporting BTN_TOOL_FINGER for devices that 233 * only report general hover (and not per-contact 234 * distance) when contact is in proximity but not 235 * on the surface. 236 */ 237 count = 1; 238 } 239 240 input_mt_report_finger_count(dev, count); 241 } 242 243 if (oldest) { 244 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X); 245 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y); 246 247 input_event(dev, EV_ABS, ABS_X, x); 248 input_event(dev, EV_ABS, ABS_Y, y); 249 250 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) { 251 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE); 252 input_event(dev, EV_ABS, ABS_PRESSURE, p); 253 } 254 } else { 255 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) 256 input_event(dev, EV_ABS, ABS_PRESSURE, 0); 257 } 258 } 259 EXPORT_SYMBOL(input_mt_report_pointer_emulation); 260 261 static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt) 262 { 263 int i; 264 265 for (i = 0; i < mt->num_slots; i++) { 266 if (!input_mt_is_used(mt, &mt->slots[i])) { 267 input_mt_slot(dev, i); 268 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1); 269 } 270 } 271 } 272 273 /** 274 * input_mt_drop_unused() - Inactivate slots not seen in this frame 275 * @dev: input device with allocated MT slots 276 * 277 * Lift all slots not seen since the last call to this function. 278 */ 279 void input_mt_drop_unused(struct input_dev *dev) 280 { 281 struct input_mt *mt = dev->mt; 282 283 if (mt) { 284 __input_mt_drop_unused(dev, mt); 285 mt->frame++; 286 } 287 } 288 EXPORT_SYMBOL(input_mt_drop_unused); 289 290 /** 291 * input_mt_sync_frame() - synchronize mt frame 292 * @dev: input device with allocated MT slots 293 * 294 * Close the frame and prepare the internal state for a new one. 295 * Depending on the flags, marks unused slots as inactive and performs 296 * pointer emulation. 297 */ 298 void input_mt_sync_frame(struct input_dev *dev) 299 { 300 struct input_mt *mt = dev->mt; 301 bool use_count = false; 302 303 if (!mt) 304 return; 305 306 if (mt->flags & INPUT_MT_DROP_UNUSED) 307 __input_mt_drop_unused(dev, mt); 308 309 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT)) 310 use_count = true; 311 312 input_mt_report_pointer_emulation(dev, use_count); 313 314 mt->frame++; 315 } 316 EXPORT_SYMBOL(input_mt_sync_frame); 317 318 static int adjust_dual(int *begin, int step, int *end, int eq, int mu) 319 { 320 int f, *p, s, c; 321 322 if (begin == end) 323 return 0; 324 325 f = *begin; 326 p = begin + step; 327 s = p == end ? f + 1 : *p; 328 329 for (; p != end; p += step) 330 if (*p < f) 331 s = f, f = *p; 332 else if (*p < s) 333 s = *p; 334 335 c = (f + s + 1) / 2; 336 if (c == 0 || (c > mu && (!eq || mu > 0))) 337 return 0; 338 /* Improve convergence for positive matrices by penalizing overcovers */ 339 if (s < 0 && mu <= 0) 340 c *= 2; 341 342 for (p = begin; p != end; p += step) 343 *p -= c; 344 345 return (c < s && s <= 0) || (f >= 0 && f < c); 346 } 347 348 static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu) 349 { 350 int i, k, sum; 351 352 for (k = 0; k < nrc; k++) { 353 for (i = 0; i < nr; i++) 354 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu); 355 sum = 0; 356 for (i = 0; i < nrc; i += nr) 357 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu); 358 if (!sum) 359 break; 360 } 361 } 362 363 static int input_mt_set_matrix(struct input_mt *mt, 364 const struct input_mt_pos *pos, int num_pos, 365 int mu) 366 { 367 const struct input_mt_pos *p; 368 struct input_mt_slot *s; 369 int *w = mt->red; 370 int x, y; 371 372 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 373 if (!input_mt_is_active(s)) 374 continue; 375 x = input_mt_get_value(s, ABS_MT_POSITION_X); 376 y = input_mt_get_value(s, ABS_MT_POSITION_Y); 377 for (p = pos; p != pos + num_pos; p++) { 378 int dx = x - p->x, dy = y - p->y; 379 *w++ = dx * dx + dy * dy - mu; 380 } 381 } 382 383 return w - mt->red; 384 } 385 386 static void input_mt_set_slots(struct input_mt *mt, 387 int *slots, int num_pos) 388 { 389 struct input_mt_slot *s; 390 int *w = mt->red, j; 391 392 for (j = 0; j != num_pos; j++) 393 slots[j] = -1; 394 395 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 396 if (!input_mt_is_active(s)) 397 continue; 398 399 for (j = 0; j != num_pos; j++) { 400 if (w[j] < 0) { 401 slots[j] = s - mt->slots; 402 break; 403 } 404 } 405 406 w += num_pos; 407 } 408 409 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 410 if (input_mt_is_active(s)) 411 continue; 412 413 for (j = 0; j != num_pos; j++) { 414 if (slots[j] < 0) { 415 slots[j] = s - mt->slots; 416 break; 417 } 418 } 419 } 420 } 421 422 /** 423 * input_mt_assign_slots() - perform a best-match assignment 424 * @dev: input device with allocated MT slots 425 * @slots: the slot assignment to be filled 426 * @pos: the position array to match 427 * @num_pos: number of positions 428 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite) 429 * 430 * Performs a best match against the current contacts and returns 431 * the slot assignment list. New contacts are assigned to unused 432 * slots. 433 * 434 * The assignments are balanced so that all coordinate displacements are 435 * below the euclidian distance dmax. If no such assignment can be found, 436 * some contacts are assigned to unused slots. 437 * 438 * Returns zero on success, or negative error in case of failure. 439 */ 440 int input_mt_assign_slots(struct input_dev *dev, int *slots, 441 const struct input_mt_pos *pos, int num_pos, 442 int dmax) 443 { 444 struct input_mt *mt = dev->mt; 445 int mu = 2 * dmax * dmax; 446 int nrc; 447 448 if (!mt || !mt->red) 449 return -ENXIO; 450 if (num_pos > mt->num_slots) 451 return -EINVAL; 452 if (num_pos < 1) 453 return 0; 454 455 nrc = input_mt_set_matrix(mt, pos, num_pos, mu); 456 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu); 457 input_mt_set_slots(mt, slots, num_pos); 458 459 return 0; 460 } 461 EXPORT_SYMBOL(input_mt_assign_slots); 462 463 /** 464 * input_mt_get_slot_by_key() - return slot matching key 465 * @dev: input device with allocated MT slots 466 * @key: the key of the sought slot 467 * 468 * Returns the slot of the given key, if it exists, otherwise 469 * set the key on the first unused slot and return. 470 * 471 * If no available slot can be found, -1 is returned. 472 * Note that for this function to work properly, input_mt_sync_frame() has 473 * to be called at each frame. 474 */ 475 int input_mt_get_slot_by_key(struct input_dev *dev, int key) 476 { 477 struct input_mt *mt = dev->mt; 478 struct input_mt_slot *s; 479 480 if (!mt) 481 return -1; 482 483 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 484 if (input_mt_is_active(s) && s->key == key) 485 return s - mt->slots; 486 487 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 488 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) { 489 s->key = key; 490 return s - mt->slots; 491 } 492 493 return -1; 494 } 495 EXPORT_SYMBOL(input_mt_get_slot_by_key); 496