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->absbit[BIT_WORD(dst)] |= BIT_MASK(dst);
  22         }
  23 }
  24
  25 /**
  26  * input_mt_init_slots() - initialize MT input slots
  27  * @dev: input device supporting MT events and finger tracking
  28  * @num_slots: number of slots used by the device
  29  * @flags: mt tasks to handle in core
  30  *
  31  * This function allocates all necessary memory for MT slot handling
  32  * in the input device, prepares the ABS_MT_SLOT and
  33  * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
  34  * Depending on the flags set, it also performs pointer emulation and
  35  * frame synchronization.
  36  *
  37  * May be called repeatedly. Returns -EINVAL if attempting to
  38  * reinitialize with a different number of slots.
  39  */
  40 int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
  41                         unsigned int flags)
  42 {
  43         struct input_mt *mt = dev->mt;
  44         int i;
  45
  46         if (!num_slots)
  47                 return 0;
  48         if (mt)
  49                 return mt->num_slots != num_slots ? -EINVAL : 0;
  50
  51         mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
  52         if (!mt)
  53                 goto err_mem;
  54
  55         mt->num_slots = num_slots;
  56         mt->flags = flags;
  57         input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
  58         input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
  59
  60         if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
  61                 __set_bit(EV_KEY, dev->evbit);
  62                 __set_bit(BTN_TOUCH, dev->keybit);
  63
  64                 copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
  65                 copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
  66                 copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
  67         }
  68         if (flags & INPUT_MT_POINTER) {
  69                 __set_bit(BTN_TOOL_FINGER, dev->keybit);
  70                 __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
  71                 if (num_slots >= 3)
  72                         __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
  73                 if (num_slots >= 4)
  74                         __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
  75                 if (num_slots >= 5)
  76                         __set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
  77                 __set_bit(INPUT_PROP_POINTER, dev->propbit);
  78         }
  79         if (flags & INPUT_MT_DIRECT)
  80                 __set_bit(INPUT_PROP_DIRECT, dev->propbit);
  81         if (flags & INPUT_MT_TRACK) {
  82                 unsigned int n2 = num_slots * num_slots;
  83                 mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
  84                 if (!mt->red)
  85                         goto err_mem;
  86         }
  87
  88         /* Mark slots as 'unused' */
  89         for (i = 0; i < num_slots; i++)
  90                 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
  91
  92         dev->mt = mt;
  93         return 0;
  94 err_mem:
  95         kfree(mt);
  96         return -ENOMEM;
  97 }
  98 EXPORT_SYMBOL(input_mt_init_slots);
  99
 100 /**
 101  * input_mt_destroy_slots() - frees the MT slots of the input device
 102  * @dev: input device with allocated MT slots
 103  *
 104  * This function is only needed in error path as the input core will
 105  * automatically free the MT slots when the device is destroyed.
 106  */
 107 void input_mt_destroy_slots(struct input_dev *dev)
 108 {
 109         if (dev->mt) {
 110                 kfree(dev->mt->red);
 111                 kfree(dev->mt);
 112         }
 113         dev->mt = NULL;
 114 }
 115 EXPORT_SYMBOL(input_mt_destroy_slots);
 116
 117 /**
 118  * input_mt_report_slot_state() - report contact state
 119  * @dev: input device with allocated MT slots
 120  * @tool_type: the tool type to use in this slot
 121  * @active: true if contact is active, false otherwise
 122  *
 123  * Reports a contact via ABS_MT_TRACKING_ID, and optionally
 124  * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
 125  * inactive, or if the tool type is changed, a new tracking id is
 126  * assigned to the slot. The tool type is only reported if the
 127  * corresponding absbit field is set.
 128  */
 129 void input_mt_report_slot_state(struct input_dev *dev,
 130                                 unsigned int tool_type, bool active)
 131 {
 132         struct input_mt *mt = dev->mt;
 133         struct input_mt_slot *slot;
 134         int id;
 135
 136         if (!mt)
 137                 return;
 138
 139         slot = &mt->slots[mt->slot];
 140         slot->frame = mt->frame;
 141
 142         if (!active) {
 143                 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
 144                 return;
 145         }
 146
 147         id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
 148         if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
 149                 id = input_mt_new_trkid(mt);
 150
 151         input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
 152         input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
 153 }
 154 EXPORT_SYMBOL(input_mt_report_slot_state);
 155
 156 /**
 157  * input_mt_report_finger_count() - report contact count
 158  * @dev: input device with allocated MT slots
 159  * @count: the number of contacts
 160  *
 161  * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
 162  * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
 163  *
 164  * The input core ensures only the KEY events already setup for
 165  * this device will produce output.
 166  */
 167 void input_mt_report_finger_count(struct input_dev *dev, int count)
 168 {
 169         input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
 170         input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
 171         input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
 172         input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
 173         input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
 174 }
 175 EXPORT_SYMBOL(input_mt_report_finger_count);
 176
 177 /**
 178  * input_mt_report_pointer_emulation() - common pointer emulation
 179  * @dev: input device with allocated MT slots
 180  * @use_count: report number of active contacts as finger count
 181  *
 182  * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
 183  * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
 184  *
 185  * The input core ensures only the KEY and ABS axes already setup for
 186  * this device will produce output.
 187  */
 188 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
 189 {
 190         struct input_mt *mt = dev->mt;
 191         struct input_mt_slot *oldest;
 192         int oldid, count, i;
 193
 194         if (!mt)
 195                 return;
 196
 197         oldest = 0;
 198         oldid = mt->trkid;
 199         count = 0;
 200
 201         for (i = 0; i < mt->num_slots; ++i) {
 202                 struct input_mt_slot *ps = &mt->slots[i];
 203                 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
 204
 205                 if (id < 0)
 206                         continue;
 207                 if ((id - oldid) & TRKID_SGN) {
 208                         oldest = ps;
 209                         oldid = id;
 210                 }
 211                 count++;
 212         }
 213
 214         input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
 215         if (use_count)
 216                 input_mt_report_finger_count(dev, count);
 217
 218         if (oldest) {
 219                 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
 220                 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
 221
 222                 input_event(dev, EV_ABS, ABS_X, x);
 223                 input_event(dev, EV_ABS, ABS_Y, y);
 224
 225                 if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
 226                         int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
 227                         input_event(dev, EV_ABS, ABS_PRESSURE, p);
 228                 }
 229         } else {
 230                 if (test_bit(ABS_MT_PRESSURE, dev->absbit))
 231                         input_event(dev, EV_ABS, ABS_PRESSURE, 0);
 232         }
 233 }
 234 EXPORT_SYMBOL(input_mt_report_pointer_emulation);
 235
 236 /**
 237  * input_mt_sync_frame() - synchronize mt frame
 238  * @dev: input device with allocated MT slots
 239  *
 240  * Close the frame and prepare the internal state for a new one.
 241  * Depending on the flags, marks unused slots as inactive and performs
 242  * pointer emulation.
 243  */
 244 void input_mt_sync_frame(struct input_dev *dev)
 245 {
 246         struct input_mt *mt = dev->mt;
 247         struct input_mt_slot *s;
 248
 249         if (!mt)
 250                 return;
 251
 252         if (mt->flags & INPUT_MT_DROP_UNUSED) {
 253                 for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 254                         if (s->frame == mt->frame)
 255                                 continue;
 256                         input_mt_slot(dev, s - mt->slots);
 257                         input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
 258                 }
 259         }
 260
 261         input_mt_report_pointer_emulation(dev, (mt->flags & INPUT_MT_POINTER));
 262
 263         mt->frame++;
 264 }
 265 EXPORT_SYMBOL(input_mt_sync_frame);
 266
 267 static int adjust_dual(int *begin, int step, int *end, int eq)
 268 {
 269         int f, *p, s, c;
 270
 271         if (begin == end)
 272                 return 0;
 273
 274         f = *begin;
 275         p = begin + step;
 276         s = p == end ? f + 1 : *p;
 277
 278         for (; p != end; p += step)
 279                 if (*p < f)
 280                         s = f, f = *p;
 281                 else if (*p < s)
 282                         s = *p;
 283
 284         c = (f + s + 1) / 2;
 285         if (c == 0 || (c > 0 && !eq))
 286                 return 0;
 287         if (s < 0)
 288                 c *= 2;
 289
 290         for (p = begin; p != end; p += step)
 291                 *p -= c;
 292
 293         return (c < s && s <= 0) || (f >= 0 && f < c);
 294 }
 295
 296 static void find_reduced_matrix(int *w, int nr, int nc, int nrc)
 297 {
 298         int i, k, sum;
 299
 300         for (k = 0; k < nrc; k++) {
 301                 for (i = 0; i < nr; i++)
 302                         adjust_dual(w + i, nr, w + i + nrc, nr <= nc);
 303                 sum = 0;
 304                 for (i = 0; i < nrc; i += nr)
 305                         sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr);
 306                 if (!sum)
 307                         break;
 308         }
 309 }
 310
 311 static int input_mt_set_matrix(struct input_mt *mt,
 312                                const struct input_mt_pos *pos, int num_pos)
 313 {
 314         const struct input_mt_pos *p;
 315         struct input_mt_slot *s;
 316         int *w = mt->red;
 317         int x, y;
 318
 319         for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 320                 if (!input_mt_is_active(s))
 321                         continue;
 322                 x = input_mt_get_value(s, ABS_MT_POSITION_X);
 323                 y = input_mt_get_value(s, ABS_MT_POSITION_Y);
 324                 for (p = pos; p != pos + num_pos; p++) {
 325                         int dx = x - p->x, dy = y - p->y;
 326                         *w++ = dx * dx + dy * dy;
 327                 }
 328         }
 329
 330         return w - mt->red;
 331 }
 332
 333 static void input_mt_set_slots(struct input_mt *mt,
 334                                int *slots, int num_pos)
 335 {
 336         struct input_mt_slot *s;
 337         int *w = mt->red, *p;
 338
 339         for (p = slots; p != slots + num_pos; p++)
 340                 *p = -1;
 341
 342         for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 343                 if (!input_mt_is_active(s))
 344                         continue;
 345                 for (p = slots; p != slots + num_pos; p++)
 346                         if (*w++ < 0)
 347                                 *p = s - mt->slots;
 348         }
 349
 350         for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
 351                 if (input_mt_is_active(s))
 352                         continue;
 353                 for (p = slots; p != slots + num_pos; p++)
 354                         if (*p < 0) {
 355                                 *p = s - mt->slots;
 356                                 break;
 357                         }
 358         }
 359 }
 360
 361 /**
 362  * input_mt_assign_slots() - perform a best-match assignment
 363  * @dev: input device with allocated MT slots
 364  * @slots: the slot assignment to be filled
 365  * @pos: the position array to match
 366  * @num_pos: number of positions
 367  *
 368  * Performs a best match against the current contacts and returns
 369  * the slot assignment list. New contacts are assigned to unused
 370  * slots.
 371  *
 372  * Returns zero on success, or negative error in case of failure.
 373  */
 374 int input_mt_assign_slots(struct input_dev *dev, int *slots,
 375                           const struct input_mt_pos *pos, int num_pos)
 376 {
 377         struct input_mt *mt = dev->mt;
 378         int nrc;
 379
 380         if (!mt || !mt->red)
 381                 return -ENXIO;
 382         if (num_pos > mt->num_slots)
 383                 return -EINVAL;
 384         if (num_pos < 1)
 385                 return 0;
 386
 387         nrc = input_mt_set_matrix(mt, pos, num_pos);
 388         find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc);
 389         input_mt_set_slots(mt, slots, num_pos);
 390
 391         return 0;
 392 }
 393 EXPORT_SYMBOL(input_mt_assign_slots);
 394
 395 /**
 396  * input_mt_get_slot_by_key() - return slot matching key
 397  * @dev: input device with allocated MT slots
 398  * @key: the key of the sought slot
 399  *
 400  * Returns the slot of the given key, if it exists, otherwise
 401  * set the key on the first unused slot and return.
 402  *
 403  * If no available slot can be found, -1 is returned.
 404  */
 405 int input_mt_get_slot_by_key(struct input_dev *dev, int key)
 406 {
 407         struct input_mt *mt = dev->mt;
 408         struct input_mt_slot *s;
 409
 410         if (!mt)
 411                 return -1;
 412
 413         for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
 414                 if (input_mt_is_active(s) && s->key == key)
 415                         return s - mt->slots;
 416
 417         for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
 418                 if (!input_mt_is_active(s)) {
 419                         s->key = key;
 420                         return s - mt->slots;
 421                 }
 422
 423         return -1;
 424 }
 425 EXPORT_SYMBOL(input_mt_get_slot_by_key);