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_TRACK) {
  83                 unsigned int n2 = num_slots * num_slots;
  84                 mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
  85                 if (!mt->red)
  86                         goto err_mem;
  87         }
  88
  89         /* Mark slots as 'unused' */
  90         for (i = 0; i < num_slots; i++)
  91                 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
  92
  93         dev->mt = mt;
  94         return 0;
  95 err_mem:
  96         kfree(mt);
  97         return -ENOMEM;
  98 }
  99 EXPORT_SYMBOL(input_mt_init_slots);
 100
 101 /**
 102  * input_mt_destroy_slots() - frees the MT slots of the input device
 103  * @dev: input device with allocated MT slots
 104  *
 105  * This function is only needed in error path as the input core will
 106  * automatically free the MT slots when the device is destroyed.
 107  */
 108 void input_mt_destroy_slots(struct input_dev *dev)
 109 {
 110         if (dev->mt) {
 111                 kfree(dev->mt->red);
 112                 kfree(dev->mt);
 113         }
 114         dev->mt = NULL;
 115 }
 116 EXPORT_SYMBOL(input_mt_destroy_slots);
 117
 118 /**
 119  * input_mt_report_slot_state() - report contact state
 120  * @dev: input device with allocated MT slots
 121  * @tool_type: the tool type to use in this slot
 122  * @active: true if contact is active, false otherwise
 123  *
 124  * Reports a contact via ABS_MT_TRACKING_ID, and optionally
 125  * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
 126  * inactive, or if the tool type is changed, a new tracking id is
 127  * assigned to the slot. The tool type is only reported if the
 128  * corresponding absbit field is set.
 129  */
 130 void input_mt_report_slot_state(struct input_dev *dev,
 131                                 unsigned int tool_type, bool active)
 132 {
 133         struct input_mt *mt = dev->mt;
 134         struct input_mt_slot *slot;
 135         int id;
 136
 137         if (!mt)
 138                 return;
 139
 140         slot = &mt->slots[mt->slot];
 141         slot->frame = mt->frame;
 142
 143         if (!active) {
 144                 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
 145                 return;
 146         }
 147
 148         id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
 149         if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
 150                 id = input_mt_new_trkid(mt);
 151
 152         input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
 153         input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
 154 }
 155 EXPORT_SYMBOL(input_mt_report_slot_state);
 156
 157 /**
 158  * input_mt_report_finger_count() - report contact count
 159  * @dev: input device with allocated MT slots
 160  * @count: the number of contacts
 161  *
 162  * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
 163  * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
 164  *
 165  * The input core ensures only the KEY events already setup for
 166  * this device will produce output.
 167  */
 168 void input_mt_report_finger_count(struct input_dev *dev, int count)
 169 {
 170         input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
 171         input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
 172         input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
 173         input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
 174         input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
 175 }
 176 EXPORT_SYMBOL(input_mt_report_finger_count);
 177
 178 /**
 179  * input_mt_report_pointer_emulation() - common pointer emulation
 180  * @dev: input device with allocated MT slots
 181  * @use_count: report number of active contacts as finger count
 182  *
 183  * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
 184  * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
 185  *
 186  * The input core ensures only the KEY and ABS axes already setup for
 187  * this device will produce output.
 188  */
 189 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
 190 {
 191         struct input_mt *mt = dev->mt;
 192         struct input_mt_slot *oldest;
 193         int oldid, count, i;
 194
 195         if (!mt)
 196                 return;
 197
 198         oldest = NULL;
 199         oldid = mt->trkid;
 200         count = 0;
 201
 202         for (i = 0; i < mt->num_slots; ++i) {
 203                 struct input_mt_slot *ps = &mt->slots[i];
 204                 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
 205
 206                 if (id < 0)
 207                         continue;
 208                 if ((id - oldid) & TRKID_SGN) {
 209                         oldest = ps;
 210                         oldid = id;
 211                 }
 212                 count++;
 213         }
 214
 215         input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
 216         if (use_count)
 217                 input_mt_report_finger_count(dev, count);
 218
 219         if (oldest) {
 220                 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
 221                 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
 222
 223                 input_event(dev, EV_ABS, ABS_X, x);
 224                 input_event(dev, EV_ABS, ABS_Y, y);
 225
 226                 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
 227                         int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
 228                         input_event(dev, EV_ABS, ABS_PRESSURE, p);
 229                 }
 230         } else {
 231                 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
 232                         input_event(dev, EV_ABS, ABS_PRESSURE, 0);
 233         }
 234 }
 235 EXPORT_SYMBOL(input_mt_report_pointer_emulation);
 236
 237 /**
 238  * input_mt_sync_frame() - synchronize mt frame
 239  * @dev: input device with allocated MT slots
 240  *
 241  * Close the frame and prepare the internal state for a new one.
 242  * Depending on the flags, marks unused slots as inactive and performs
 243  * pointer emulation.
 244  */
 245 void input_mt_sync_frame(struct input_dev *dev)
 246 {
 247         struct input_mt *mt = dev->mt;
 248         struct input_mt_slot *s;
 249
 250         if (!mt)
 251                 return;
 252
 253         if (mt->flags & INPUT_MT_DROP_UNUSED) {
 254                 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 255                         if (input_mt_is_used(mt, s))
 256                                 continue;
 257                         input_mt_slot(dev, s - mt->slots);
 258                         input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
 259                 }
 260         }
 261
 262         input_mt_report_pointer_emulation(dev, (mt->flags & INPUT_MT_POINTER));
 263
 264         mt->frame++;
 265 }
 266 EXPORT_SYMBOL(input_mt_sync_frame);
 267
 268 static int adjust_dual(int *begin, int step, int *end, int eq)
 269 {
 270         int f, *p, s, c;
 271
 272         if (begin == end)
 273                 return 0;
 274
 275         f = *begin;
 276         p = begin + step;
 277         s = p == end ? f + 1 : *p;
 278
 279         for (; p != end; p += step)
 280                 if (*p < f)
 281                         s = f, f = *p;
 282                 else if (*p < s)
 283                         s = *p;
 284
 285         c = (f + s + 1) / 2;
 286         if (c == 0 || (c > 0 && !eq))
 287                 return 0;
 288         if (s < 0)
 289                 c *= 2;
 290
 291         for (p = begin; p != end; p += step)
 292                 *p -= c;
 293
 294         return (c < s && s <= 0) || (f >= 0 && f < c);
 295 }
 296
 297 static void find_reduced_matrix(int *w, int nr, int nc, int nrc)
 298 {
 299         int i, k, sum;
 300
 301         for (k = 0; k < nrc; k++) {
 302                 for (i = 0; i < nr; i++)
 303                         adjust_dual(w + i, nr, w + i + nrc, nr <= nc);
 304                 sum = 0;
 305                 for (i = 0; i < nrc; i += nr)
 306                         sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr);
 307                 if (!sum)
 308                         break;
 309         }
 310 }
 311
 312 static int input_mt_set_matrix(struct input_mt *mt,
 313                                const struct input_mt_pos *pos, int num_pos)
 314 {
 315         const struct input_mt_pos *p;
 316         struct input_mt_slot *s;
 317         int *w = mt->red;
 318         int x, y;
 319
 320         for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 321                 if (!input_mt_is_active(s))
 322                         continue;
 323                 x = input_mt_get_value(s, ABS_MT_POSITION_X);
 324                 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
 325                 for (p = pos; p != pos + num_pos; p++) {
 326                         int dx = x - p->x, dy = y - p->y;
 327                         *w++ = dx * dx + dy * dy;
 328                 }
 329         }
 330
 331         return w - mt->red;
 332 }
 333
 334 static void input_mt_set_slots(struct input_mt *mt,
 335                                int *slots, int num_pos)
 336 {
 337         struct input_mt_slot *s;
 338         int *w = mt->red, *p;
 339
 340         for (p = slots; p != slots + num_pos; p++)
 341                 *p = -1;
 342
 343         for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 344                 if (!input_mt_is_active(s))
 345                         continue;
 346                 for (p = slots; p != slots + num_pos; p++)
 347                         if (*w++ < 0)
 348                                 *p = s - mt->slots;
 349         }
 350
 351         for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 352                 if (input_mt_is_active(s))
 353                         continue;
 354                 for (p = slots; p != slots + num_pos; p++)
 355                         if (*p < 0) {
 356                                 *p = s - mt->slots;
 357                                 break;
 358                         }
 359         }
 360 }
 361
 362 /**
 363  * input_mt_assign_slots() - perform a best-match assignment
 364  * @dev: input device with allocated MT slots
 365  * @slots: the slot assignment to be filled
 366  * @pos: the position array to match
 367  * @num_pos: number of positions
 368  *
 369  * Performs a best match against the current contacts and returns
 370  * the slot assignment list. New contacts are assigned to unused
 371  * slots.
 372  *
 373  * Returns zero on success, or negative error in case of failure.
 374  */
 375 int input_mt_assign_slots(struct input_dev *dev, int *slots,
 376                           const struct input_mt_pos *pos, int num_pos)
 377 {
 378         struct input_mt *mt = dev->mt;
 379         int nrc;
 380
 381         if (!mt || !mt->red)
 382                 return -ENXIO;
 383         if (num_pos > mt->num_slots)
 384                 return -EINVAL;
 385         if (num_pos < 1)
 386                 return 0;
 387
 388         nrc = input_mt_set_matrix(mt, pos, num_pos);
 389         find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc);
 390         input_mt_set_slots(mt, slots, num_pos);
 391
 392         return 0;
 393 }
 394 EXPORT_SYMBOL(input_mt_assign_slots);
 395
 396 /**
 397  * input_mt_get_slot_by_key() - return slot matching key
 398  * @dev: input device with allocated MT slots
 399  * @key: the key of the sought slot
 400  *
 401  * Returns the slot of the given key, if it exists, otherwise
 402  * set the key on the first unused slot and return.
 403  *
 404  * If no available slot can be found, -1 is returned.
 405  */
 406 int input_mt_get_slot_by_key(struct input_dev *dev, int key)
 407 {
 408         struct input_mt *mt = dev->mt;
 409         struct input_mt_slot *s;
 410
 411         if (!mt)
 412                 return -1;
 413
 414         for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
 415                 if (input_mt_is_active(s) && s->key == key)
 416                         return s - mt->slots;
 417
 418         for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
 419                 if (!input_mt_is_active(s)) {
 420                         s->key = key;
 421                         return s - mt->slots;
 422                 }
 423
 424         return -1;
 425 }
 426 EXPORT_SYMBOL(input_mt_get_slot_by_key);