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 if (use_count) 222 input_mt_report_finger_count(dev, count); 223 224 if (oldest) { 225 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X); 226 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y); 227 228 input_event(dev, EV_ABS, ABS_X, x); 229 input_event(dev, EV_ABS, ABS_Y, y); 230 231 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) { 232 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE); 233 input_event(dev, EV_ABS, ABS_PRESSURE, p); 234 } 235 } else { 236 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) 237 input_event(dev, EV_ABS, ABS_PRESSURE, 0); 238 } 239 } 240 EXPORT_SYMBOL(input_mt_report_pointer_emulation); 241 242 static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt) 243 { 244 int i; 245 246 for (i = 0; i < mt->num_slots; i++) { 247 if (!input_mt_is_used(mt, &mt->slots[i])) { 248 input_mt_slot(dev, i); 249 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1); 250 } 251 } 252 } 253 254 /** 255 * input_mt_drop_unused() - Inactivate slots not seen in this frame 256 * @dev: input device with allocated MT slots 257 * 258 * Lift all slots not seen since the last call to this function. 259 */ 260 void input_mt_drop_unused(struct input_dev *dev) 261 { 262 struct input_mt *mt = dev->mt; 263 264 if (mt) { 265 __input_mt_drop_unused(dev, mt); 266 mt->frame++; 267 } 268 } 269 EXPORT_SYMBOL(input_mt_drop_unused); 270 271 /** 272 * input_mt_sync_frame() - synchronize mt frame 273 * @dev: input device with allocated MT slots 274 * 275 * Close the frame and prepare the internal state for a new one. 276 * Depending on the flags, marks unused slots as inactive and performs 277 * pointer emulation. 278 */ 279 void input_mt_sync_frame(struct input_dev *dev) 280 { 281 struct input_mt *mt = dev->mt; 282 bool use_count = false; 283 284 if (!mt) 285 return; 286 287 if (mt->flags & INPUT_MT_DROP_UNUSED) 288 __input_mt_drop_unused(dev, mt); 289 290 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT)) 291 use_count = true; 292 293 input_mt_report_pointer_emulation(dev, use_count); 294 295 mt->frame++; 296 } 297 EXPORT_SYMBOL(input_mt_sync_frame); 298 299 static int adjust_dual(int *begin, int step, int *end, int eq, int mu) 300 { 301 int f, *p, s, c; 302 303 if (begin == end) 304 return 0; 305 306 f = *begin; 307 p = begin + step; 308 s = p == end ? f + 1 : *p; 309 310 for (; p != end; p += step) 311 if (*p < f) 312 s = f, f = *p; 313 else if (*p < s) 314 s = *p; 315 316 c = (f + s + 1) / 2; 317 if (c == 0 || (c > mu && (!eq || mu > 0))) 318 return 0; 319 /* Improve convergence for positive matrices by penalizing overcovers */ 320 if (s < 0 && mu <= 0) 321 c *= 2; 322 323 for (p = begin; p != end; p += step) 324 *p -= c; 325 326 return (c < s && s <= 0) || (f >= 0 && f < c); 327 } 328 329 static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu) 330 { 331 int i, k, sum; 332 333 for (k = 0; k < nrc; k++) { 334 for (i = 0; i < nr; i++) 335 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu); 336 sum = 0; 337 for (i = 0; i < nrc; i += nr) 338 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu); 339 if (!sum) 340 break; 341 } 342 } 343 344 static int input_mt_set_matrix(struct input_mt *mt, 345 const struct input_mt_pos *pos, int num_pos, 346 int mu) 347 { 348 const struct input_mt_pos *p; 349 struct input_mt_slot *s; 350 int *w = mt->red; 351 int x, y; 352 353 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 354 if (!input_mt_is_active(s)) 355 continue; 356 x = input_mt_get_value(s, ABS_MT_POSITION_X); 357 y = input_mt_get_value(s, ABS_MT_POSITION_Y); 358 for (p = pos; p != pos + num_pos; p++) { 359 int dx = x - p->x, dy = y - p->y; 360 *w++ = dx * dx + dy * dy - mu; 361 } 362 } 363 364 return w - mt->red; 365 } 366 367 static void input_mt_set_slots(struct input_mt *mt, 368 int *slots, int num_pos) 369 { 370 struct input_mt_slot *s; 371 int *w = mt->red, j; 372 373 for (j = 0; j != num_pos; j++) 374 slots[j] = -1; 375 376 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 377 if (!input_mt_is_active(s)) 378 continue; 379 380 for (j = 0; j != num_pos; j++) { 381 if (w[j] < 0) { 382 slots[j] = s - mt->slots; 383 break; 384 } 385 } 386 387 w += num_pos; 388 } 389 390 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 391 if (input_mt_is_active(s)) 392 continue; 393 394 for (j = 0; j != num_pos; j++) { 395 if (slots[j] < 0) { 396 slots[j] = s - mt->slots; 397 break; 398 } 399 } 400 } 401 } 402 403 /** 404 * input_mt_assign_slots() - perform a best-match assignment 405 * @dev: input device with allocated MT slots 406 * @slots: the slot assignment to be filled 407 * @pos: the position array to match 408 * @num_pos: number of positions 409 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite) 410 * 411 * Performs a best match against the current contacts and returns 412 * the slot assignment list. New contacts are assigned to unused 413 * slots. 414 * 415 * The assignments are balanced so that all coordinate displacements are 416 * below the euclidian distance dmax. If no such assignment can be found, 417 * some contacts are assigned to unused slots. 418 * 419 * Returns zero on success, or negative error in case of failure. 420 */ 421 int input_mt_assign_slots(struct input_dev *dev, int *slots, 422 const struct input_mt_pos *pos, int num_pos, 423 int dmax) 424 { 425 struct input_mt *mt = dev->mt; 426 int mu = 2 * dmax * dmax; 427 int nrc; 428 429 if (!mt || !mt->red) 430 return -ENXIO; 431 if (num_pos > mt->num_slots) 432 return -EINVAL; 433 if (num_pos < 1) 434 return 0; 435 436 nrc = input_mt_set_matrix(mt, pos, num_pos, mu); 437 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu); 438 input_mt_set_slots(mt, slots, num_pos); 439 440 return 0; 441 } 442 EXPORT_SYMBOL(input_mt_assign_slots); 443 444 /** 445 * input_mt_get_slot_by_key() - return slot matching key 446 * @dev: input device with allocated MT slots 447 * @key: the key of the sought slot 448 * 449 * Returns the slot of the given key, if it exists, otherwise 450 * set the key on the first unused slot and return. 451 * 452 * If no available slot can be found, -1 is returned. 453 * Note that for this function to work properly, input_mt_sync_frame() has 454 * to be called at each frame. 455 */ 456 int input_mt_get_slot_by_key(struct input_dev *dev, int key) 457 { 458 struct input_mt *mt = dev->mt; 459 struct input_mt_slot *s; 460 461 if (!mt) 462 return -1; 463 464 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 465 if (input_mt_is_active(s) && s->key == key) 466 return s - mt->slots; 467 468 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 469 if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) { 470 s->key = key; 471 return s - mt->slots; 472 } 473 474 return -1; 475 } 476 EXPORT_SYMBOL(input_mt_get_slot_by_key); 477