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