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 'unused' */ 92 for (i = 0; i < num_slots; i++) 93 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -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 void input_mt_report_slot_state(struct input_dev *dev, 133 unsigned int tool_type, bool active) 134 { 135 struct input_mt *mt = dev->mt; 136 struct input_mt_slot *slot; 137 int id; 138 139 if (!mt) 140 return; 141 142 slot = &mt->slots[mt->slot]; 143 slot->frame = mt->frame; 144 145 if (!active) { 146 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1); 147 return; 148 } 149 150 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID); 151 if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type) 152 id = input_mt_new_trkid(mt); 153 154 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id); 155 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type); 156 } 157 EXPORT_SYMBOL(input_mt_report_slot_state); 158 159 /** 160 * input_mt_report_finger_count() - report contact count 161 * @dev: input device with allocated MT slots 162 * @count: the number of contacts 163 * 164 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP, 165 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP. 166 * 167 * The input core ensures only the KEY events already setup for 168 * this device will produce output. 169 */ 170 void input_mt_report_finger_count(struct input_dev *dev, int count) 171 { 172 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1); 173 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2); 174 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3); 175 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4); 176 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5); 177 } 178 EXPORT_SYMBOL(input_mt_report_finger_count); 179 180 /** 181 * input_mt_report_pointer_emulation() - common pointer emulation 182 * @dev: input device with allocated MT slots 183 * @use_count: report number of active contacts as finger count 184 * 185 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and 186 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true. 187 * 188 * The input core ensures only the KEY and ABS axes already setup for 189 * this device will produce output. 190 */ 191 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count) 192 { 193 struct input_mt *mt = dev->mt; 194 struct input_mt_slot *oldest; 195 int oldid, count, i; 196 197 if (!mt) 198 return; 199 200 oldest = NULL; 201 oldid = mt->trkid; 202 count = 0; 203 204 for (i = 0; i < mt->num_slots; ++i) { 205 struct input_mt_slot *ps = &mt->slots[i]; 206 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID); 207 208 if (id < 0) 209 continue; 210 if ((id - oldid) & TRKID_SGN) { 211 oldest = ps; 212 oldid = id; 213 } 214 count++; 215 } 216 217 input_event(dev, EV_KEY, BTN_TOUCH, count > 0); 218 if (use_count) 219 input_mt_report_finger_count(dev, count); 220 221 if (oldest) { 222 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X); 223 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y); 224 225 input_event(dev, EV_ABS, ABS_X, x); 226 input_event(dev, EV_ABS, ABS_Y, y); 227 228 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) { 229 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE); 230 input_event(dev, EV_ABS, ABS_PRESSURE, p); 231 } 232 } else { 233 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) 234 input_event(dev, EV_ABS, ABS_PRESSURE, 0); 235 } 236 } 237 EXPORT_SYMBOL(input_mt_report_pointer_emulation); 238 239 static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt) 240 { 241 int i; 242 243 for (i = 0; i < mt->num_slots; i++) { 244 if (!input_mt_is_used(mt, &mt->slots[i])) { 245 input_mt_slot(dev, i); 246 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1); 247 } 248 } 249 } 250 251 /** 252 * input_mt_drop_unused() - Inactivate slots not seen in this frame 253 * @dev: input device with allocated MT slots 254 * 255 * Lift all slots not seen since the last call to this function. 256 */ 257 void input_mt_drop_unused(struct input_dev *dev) 258 { 259 struct input_mt *mt = dev->mt; 260 261 if (mt) { 262 __input_mt_drop_unused(dev, mt); 263 mt->frame++; 264 } 265 } 266 EXPORT_SYMBOL(input_mt_drop_unused); 267 268 /** 269 * input_mt_sync_frame() - synchronize mt frame 270 * @dev: input device with allocated MT slots 271 * 272 * Close the frame and prepare the internal state for a new one. 273 * Depending on the flags, marks unused slots as inactive and performs 274 * pointer emulation. 275 */ 276 void input_mt_sync_frame(struct input_dev *dev) 277 { 278 struct input_mt *mt = dev->mt; 279 bool use_count = false; 280 281 if (!mt) 282 return; 283 284 if (mt->flags & INPUT_MT_DROP_UNUSED) 285 __input_mt_drop_unused(dev, mt); 286 287 if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT)) 288 use_count = true; 289 290 input_mt_report_pointer_emulation(dev, use_count); 291 292 mt->frame++; 293 } 294 EXPORT_SYMBOL(input_mt_sync_frame); 295 296 static int adjust_dual(int *begin, int step, int *end, int eq, int mu) 297 { 298 int f, *p, s, c; 299 300 if (begin == end) 301 return 0; 302 303 f = *begin; 304 p = begin + step; 305 s = p == end ? f + 1 : *p; 306 307 for (; p != end; p += step) 308 if (*p < f) 309 s = f, f = *p; 310 else if (*p < s) 311 s = *p; 312 313 c = (f + s + 1) / 2; 314 if (c == 0 || (c > mu && (!eq || mu > 0))) 315 return 0; 316 /* Improve convergence for positive matrices by penalizing overcovers */ 317 if (s < 0 && mu <= 0) 318 c *= 2; 319 320 for (p = begin; p != end; p += step) 321 *p -= c; 322 323 return (c < s && s <= 0) || (f >= 0 && f < c); 324 } 325 326 static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu) 327 { 328 int i, k, sum; 329 330 for (k = 0; k < nrc; k++) { 331 for (i = 0; i < nr; i++) 332 adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu); 333 sum = 0; 334 for (i = 0; i < nrc; i += nr) 335 sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu); 336 if (!sum) 337 break; 338 } 339 } 340 341 static int input_mt_set_matrix(struct input_mt *mt, 342 const struct input_mt_pos *pos, int num_pos, 343 int mu) 344 { 345 const struct input_mt_pos *p; 346 struct input_mt_slot *s; 347 int *w = mt->red; 348 int x, y; 349 350 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 351 if (!input_mt_is_active(s)) 352 continue; 353 x = input_mt_get_value(s, ABS_MT_POSITION_X); 354 y = input_mt_get_value(s, ABS_MT_POSITION_Y); 355 for (p = pos; p != pos + num_pos; p++) { 356 int dx = x - p->x, dy = y - p->y; 357 *w++ = dx * dx + dy * dy - mu; 358 } 359 } 360 361 return w - mt->red; 362 } 363 364 static void input_mt_set_slots(struct input_mt *mt, 365 int *slots, int num_pos) 366 { 367 struct input_mt_slot *s; 368 int *w = mt->red, *p; 369 370 for (p = slots; p != slots + num_pos; p++) 371 *p = -1; 372 373 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 374 if (!input_mt_is_active(s)) 375 continue; 376 for (p = slots; p != slots + num_pos; p++) 377 if (*w++ < 0) 378 *p = s - mt->slots; 379 } 380 381 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { 382 if (input_mt_is_active(s)) 383 continue; 384 for (p = slots; p != slots + num_pos; p++) 385 if (*p < 0) { 386 *p = s - mt->slots; 387 break; 388 } 389 } 390 } 391 392 /** 393 * input_mt_assign_slots() - perform a best-match assignment 394 * @dev: input device with allocated MT slots 395 * @slots: the slot assignment to be filled 396 * @pos: the position array to match 397 * @num_pos: number of positions 398 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite) 399 * 400 * Performs a best match against the current contacts and returns 401 * the slot assignment list. New contacts are assigned to unused 402 * slots. 403 * 404 * The assignments are balanced so that all coordinate displacements are 405 * below the euclidian distance dmax. If no such assignment can be found, 406 * some contacts are assigned to unused slots. 407 * 408 * Returns zero on success, or negative error in case of failure. 409 */ 410 int input_mt_assign_slots(struct input_dev *dev, int *slots, 411 const struct input_mt_pos *pos, int num_pos, 412 int dmax) 413 { 414 struct input_mt *mt = dev->mt; 415 int mu = 2 * dmax * dmax; 416 int nrc; 417 418 if (!mt || !mt->red) 419 return -ENXIO; 420 if (num_pos > mt->num_slots) 421 return -EINVAL; 422 if (num_pos < 1) 423 return 0; 424 425 nrc = input_mt_set_matrix(mt, pos, num_pos, mu); 426 find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu); 427 input_mt_set_slots(mt, slots, num_pos); 428 429 return 0; 430 } 431 EXPORT_SYMBOL(input_mt_assign_slots); 432 433 /** 434 * input_mt_get_slot_by_key() - return slot matching key 435 * @dev: input device with allocated MT slots 436 * @key: the key of the sought slot 437 * 438 * Returns the slot of the given key, if it exists, otherwise 439 * set the key on the first unused slot and return. 440 * 441 * If no available slot can be found, -1 is returned. 442 */ 443 int input_mt_get_slot_by_key(struct input_dev *dev, int key) 444 { 445 struct input_mt *mt = dev->mt; 446 struct input_mt_slot *s; 447 448 if (!mt) 449 return -1; 450 451 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 452 if (input_mt_is_active(s) && s->key == key) 453 return s - mt->slots; 454 455 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) 456 if (!input_mt_is_active(s)) { 457 s->key = key; 458 return s - mt->slots; 459 } 460 461 return -1; 462 } 463 EXPORT_SYMBOL(input_mt_get_slot_by_key); 464