drivers/input/input-mt.c

   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);