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