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 '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);