git.oblomov.eu Git - linux-2.6/blob - drivers/input/joydev.c

   1 /*
   2  * Joystick device driver for the input driver suite.
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  * Copyright (c) 1999 Colin Van Dyke
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <asm/io.h>
  14 #include <asm/system.h>
  15 #include <linux/delay.h>
  16 #include <linux/errno.h>
  17 #include <linux/joystick.h>
  18 #include <linux/input.h>
  19 #include <linux/kernel.h>
  20 #include <linux/major.h>
  21 #include <linux/slab.h>
  22 #include <linux/mm.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/module.h>
  25 #include <linux/poll.h>
  26 #include <linux/init.h>
  27 #include <linux/device.h>
  28
  29 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  30 MODULE_DESCRIPTION("Joystick device interfaces");
  31 MODULE_SUPPORTED_DEVICE("input/js");
  32 MODULE_LICENSE("GPL");
  33
  34 #define JOYDEV_MINOR_BASE       0
  35 #define JOYDEV_MINORS           16
  36 #define JOYDEV_BUFFER_SIZE      64
  37
  38 struct joydev {
  39         int exist;
  40         int open;
  41         int minor;
  42         char name[16];
  43         struct input_handle handle;
  44         wait_queue_head_t wait;
  45         struct list_head client_list;
  46         spinlock_t client_lock; /* protects client_list */
  47         struct mutex mutex;
  48         struct device dev;
  49
  50         struct js_corr corr[ABS_MAX + 1];
  51         struct JS_DATA_SAVE_TYPE glue;
  52         int nabs;
  53         int nkey;
  54         __u16 keymap[KEY_MAX - BTN_MISC + 1];
  55         __u16 keypam[KEY_MAX - BTN_MISC + 1];
  56         __u8 absmap[ABS_MAX + 1];
  57         __u8 abspam[ABS_MAX + 1];
  58         __s16 abs[ABS_MAX + 1];
  59 };
  60
  61 struct joydev_client {
  62         struct js_event buffer[JOYDEV_BUFFER_SIZE];
  63         int head;
  64         int tail;
  65         int startup;
  66         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  67         struct fasync_struct *fasync;
  68         struct joydev *joydev;
  69         struct list_head node;
  70 };
  71
  72 static struct joydev *joydev_table[JOYDEV_MINORS];
  73 static DEFINE_MUTEX(joydev_table_mutex);
  74
  75 static int joydev_correct(int value, struct js_corr *corr)
  76 {
  77         switch (corr->type) {
  78
  79         case JS_CORR_NONE:
  80                 break;
  81
  82         case JS_CORR_BROKEN:
  83                 value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
  84                         ((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
  85                         ((corr->coef[2] * (value - corr->coef[0])) >> 14);
  86                 break;
  87
  88         default:
  89                 return 0;
  90         }
  91
  92         return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
  93 }
  94
  95 static void joydev_pass_event(struct joydev_client *client,
  96                               struct js_event *event)
  97 {
  98         struct joydev *joydev = client->joydev;
  99
 100         /*
 101          * IRQs already disabled, just acquire the lock
 102          */
 103         spin_lock(&client->buffer_lock);
 104
 105         client->buffer[client->head] = *event;
 106
 107         if (client->startup == joydev->nabs + joydev->nkey) {
 108                 client->head++;
 109                 client->head &= JOYDEV_BUFFER_SIZE - 1;
 110                 if (client->tail == client->head)
 111                         client->startup = 0;
 112         }
 113
 114         spin_unlock(&client->buffer_lock);
 115
 116         kill_fasync(&client->fasync, SIGIO, POLL_IN);
 117 }
 118
 119 static void joydev_event(struct input_handle *handle,
 120                          unsigned int type, unsigned int code, int value)
 121 {
 122         struct joydev *joydev = handle->private;
 123         struct joydev_client *client;
 124         struct js_event event;
 125
 126         switch (type) {
 127
 128         case EV_KEY:
 129                 if (code < BTN_MISC || value == 2)
 130                         return;
 131                 event.type = JS_EVENT_BUTTON;
 132                 event.number = joydev->keymap[code - BTN_MISC];
 133                 event.value = value;
 134                 break;
 135
 136         case EV_ABS:
 137                 event.type = JS_EVENT_AXIS;
 138                 event.number = joydev->absmap[code];
 139                 event.value = joydev_correct(value,
 140                                         &joydev->corr[event.number]);
 141                 if (event.value == joydev->abs[event.number])
 142                         return;
 143                 joydev->abs[event.number] = event.value;
 144                 break;
 145
 146         default:
 147                 return;
 148         }
 149
 150         event.time = jiffies_to_msecs(jiffies);
 151
 152         list_for_each_entry_rcu(client, &joydev->client_list, node)
 153                 joydev_pass_event(client, &event);
 154
 155         wake_up_interruptible(&joydev->wait);
 156 }
 157
 158 static int joydev_fasync(int fd, struct file *file, int on)
 159 {
 160         int retval;
 161         struct joydev_client *client = file->private_data;
 162
 163         retval = fasync_helper(fd, file, on, &client->fasync);
 164
 165         return retval < 0 ? retval : 0;
 166 }
 167
 168 static void joydev_free(struct device *dev)
 169 {
 170         struct joydev *joydev = container_of(dev, struct joydev, dev);
 171
 172         kfree(joydev);
 173 }
 174
 175 static void joydev_attach_client(struct joydev *joydev,
 176                                  struct joydev_client *client)
 177 {
 178         spin_lock(&joydev->client_lock);
 179         list_add_tail_rcu(&client->node, &joydev->client_list);
 180         spin_unlock(&joydev->client_lock);
 181         /*
 182          * We don't use synchronize_rcu() here because read-side
 183          * critical section is protected by a spinlock (dev->event_lock)
 184          * instead of rcu_read_lock().
 185          */
 186         synchronize_sched();
 187 }
 188
 189 static void joydev_detach_client(struct joydev *joydev,
 190                                  struct joydev_client *client)
 191 {
 192         spin_lock(&joydev->client_lock);
 193         list_del_rcu(&client->node);
 194         spin_unlock(&joydev->client_lock);
 195         synchronize_sched();
 196 }
 197
 198 static int joydev_open_device(struct joydev *joydev)
 199 {
 200         int retval;
 201
 202         retval = mutex_lock_interruptible(&joydev->mutex);
 203         if (retval)
 204                 return retval;
 205
 206         if (!joydev->exist)
 207                 retval = -ENODEV;
 208         else if (!joydev->open++) {
 209                 retval = input_open_device(&joydev->handle);
 210                 if (retval)
 211                         joydev->open--;
 212         }
 213
 214         mutex_unlock(&joydev->mutex);
 215         return retval;
 216 }
 217
 218 static void joydev_close_device(struct joydev *joydev)
 219 {
 220         mutex_lock(&joydev->mutex);
 221
 222         if (joydev->exist && !--joydev->open)
 223                 input_close_device(&joydev->handle);
 224
 225         mutex_unlock(&joydev->mutex);
 226 }
 227
 228 /*
 229  * Wake up users waiting for IO so they can disconnect from
 230  * dead device.
 231  */
 232 static void joydev_hangup(struct joydev *joydev)
 233 {
 234         struct joydev_client *client;
 235
 236         spin_lock(&joydev->client_lock);
 237         list_for_each_entry(client, &joydev->client_list, node)
 238                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 239         spin_unlock(&joydev->client_lock);
 240
 241         wake_up_interruptible(&joydev->wait);
 242 }
 243
 244 static int joydev_release(struct inode *inode, struct file *file)
 245 {
 246         struct joydev_client *client = file->private_data;
 247         struct joydev *joydev = client->joydev;
 248
 249         joydev_fasync(-1, file, 0);
 250         joydev_detach_client(joydev, client);
 251         kfree(client);
 252
 253         joydev_close_device(joydev);
 254         put_device(&joydev->dev);
 255
 256         return 0;
 257 }
 258
 259 static int joydev_open(struct inode *inode, struct file *file)
 260 {
 261         struct joydev_client *client;
 262         struct joydev *joydev;
 263         int i = iminor(inode) - JOYDEV_MINOR_BASE;
 264         int error;
 265
 266         if (i >= JOYDEV_MINORS)
 267                 return -ENODEV;
 268
 269         error = mutex_lock_interruptible(&joydev_table_mutex);
 270         if (error)
 271                 return error;
 272         joydev = joydev_table[i];
 273         if (joydev)
 274                 get_device(&joydev->dev);
 275         mutex_unlock(&joydev_table_mutex);
 276
 277         if (!joydev)
 278                 return -ENODEV;
 279
 280         client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
 281         if (!client) {
 282                 error = -ENOMEM;
 283                 goto err_put_joydev;
 284         }
 285
 286         spin_lock_init(&client->buffer_lock);
 287         client->joydev = joydev;
 288         joydev_attach_client(joydev, client);
 289
 290         error = joydev_open_device(joydev);
 291         if (error)
 292                 goto err_free_client;
 293
 294         file->private_data = client;
 295         return 0;
 296
 297  err_free_client:
 298         joydev_detach_client(joydev, client);
 299         kfree(client);
 300  err_put_joydev:
 301         put_device(&joydev->dev);
 302         return error;
 303 }
 304
 305 static int joydev_generate_startup_event(struct joydev_client *client,
 306                                          struct input_dev *input,
 307                                          struct js_event *event)
 308 {
 309         struct joydev *joydev = client->joydev;
 310         int have_event;
 311
 312         spin_lock_irq(&client->buffer_lock);
 313
 314         have_event = client->startup < joydev->nabs + joydev->nkey;
 315
 316         if (have_event) {
 317
 318                 event->time = jiffies_to_msecs(jiffies);
 319                 if (client->startup < joydev->nkey) {
 320                         event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
 321                         event->number = client->startup;
 322                         event->value = !!test_bit(joydev->keypam[event->number],
 323                                                   input->key);
 324                 } else {
 325                         event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
 326                         event->number = client->startup - joydev->nkey;
 327                         event->value = joydev->abs[event->number];
 328                 }
 329                 client->startup++;
 330         }
 331
 332         spin_unlock_irq(&client->buffer_lock);
 333
 334         return have_event;
 335 }
 336
 337 static int joydev_fetch_next_event(struct joydev_client *client,
 338                                    struct js_event *event)
 339 {
 340         int have_event;
 341
 342         spin_lock_irq(&client->buffer_lock);
 343
 344         have_event = client->head != client->tail;
 345         if (have_event) {
 346                 *event = client->buffer[client->tail++];
 347                 client->tail &= JOYDEV_BUFFER_SIZE - 1;
 348         }
 349
 350         spin_unlock_irq(&client->buffer_lock);
 351
 352         return have_event;
 353 }
 354
 355 /*
 356  * Old joystick interface
 357  */
 358 static ssize_t joydev_0x_read(struct joydev_client *client,
 359                               struct input_dev *input,
 360                               char __user *buf)
 361 {
 362         struct joydev *joydev = client->joydev;
 363         struct JS_DATA_TYPE data;
 364         int i;
 365
 366         spin_lock_irq(&input->event_lock);
 367
 368         /*
 369          * Get device state
 370          */
 371         for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
 372                 data.buttons |=
 373                         test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
 374         data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
 375         data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
 376
 377         /*
 378          * Reset reader's event queue
 379          */
 380         spin_lock(&client->buffer_lock);
 381         client->startup = 0;
 382         client->tail = client->head;
 383         spin_unlock(&client->buffer_lock);
 384
 385         spin_unlock_irq(&input->event_lock);
 386
 387         if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
 388                 return -EFAULT;
 389
 390         return sizeof(struct JS_DATA_TYPE);
 391 }
 392
 393 static inline int joydev_data_pending(struct joydev_client *client)
 394 {
 395         struct joydev *joydev = client->joydev;
 396
 397         return client->startup < joydev->nabs + joydev->nkey ||
 398                 client->head != client->tail;
 399 }
 400
 401 static ssize_t joydev_read(struct file *file, char __user *buf,
 402                            size_t count, loff_t *ppos)
 403 {
 404         struct joydev_client *client = file->private_data;
 405         struct joydev *joydev = client->joydev;
 406         struct input_dev *input = joydev->handle.dev;
 407         struct js_event event;
 408         int retval;
 409
 410         if (!joydev->exist)
 411                 return -ENODEV;
 412
 413         if (count < sizeof(struct js_event))
 414                 return -EINVAL;
 415
 416         if (count == sizeof(struct JS_DATA_TYPE))
 417                 return joydev_0x_read(client, input, buf);
 418
 419         if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
 420                 return -EAGAIN;
 421
 422         retval = wait_event_interruptible(joydev->wait,
 423                         !joydev->exist || joydev_data_pending(client));
 424         if (retval)
 425                 return retval;
 426
 427         if (!joydev->exist)
 428                 return -ENODEV;
 429
 430         while (retval + sizeof(struct js_event) <= count &&
 431                joydev_generate_startup_event(client, input, &event)) {
 432
 433                 if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
 434                         return -EFAULT;
 435
 436                 retval += sizeof(struct js_event);
 437         }
 438
 439         while (retval + sizeof(struct js_event) <= count &&
 440                joydev_fetch_next_event(client, &event)) {
 441
 442                 if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
 443                         return -EFAULT;
 444
 445                 retval += sizeof(struct js_event);
 446         }
 447
 448         return retval;
 449 }
 450
 451 /* No kernel lock - fine */
 452 static unsigned int joydev_poll(struct file *file, poll_table *wait)
 453 {
 454         struct joydev_client *client = file->private_data;
 455         struct joydev *joydev = client->joydev;
 456
 457         poll_wait(file, &joydev->wait, wait);
 458         return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
 459                 (joydev->exist ?  0 : (POLLHUP | POLLERR));
 460 }
 461
 462 static int joydev_ioctl_common(struct joydev *joydev,
 463                                 unsigned int cmd, void __user *argp)
 464 {
 465         struct input_dev *dev = joydev->handle.dev;
 466         int i, j;
 467
 468         switch (cmd) {
 469
 470         case JS_SET_CAL:
 471                 return copy_from_user(&joydev->glue.JS_CORR, argp,
 472                                 sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
 473
 474         case JS_GET_CAL:
 475                 return copy_to_user(argp, &joydev->glue.JS_CORR,
 476                                 sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
 477
 478         case JS_SET_TIMEOUT:
 479                 return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
 480
 481         case JS_GET_TIMEOUT:
 482                 return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
 483
 484         case JSIOCGVERSION:
 485                 return put_user(JS_VERSION, (__u32 __user *) argp);
 486
 487         case JSIOCGAXES:
 488                 return put_user(joydev->nabs, (__u8 __user *) argp);
 489
 490         case JSIOCGBUTTONS:
 491                 return put_user(joydev->nkey, (__u8 __user *) argp);
 492
 493         case JSIOCSCORR:
 494                 if (copy_from_user(joydev->corr, argp,
 495                               sizeof(joydev->corr[0]) * joydev->nabs))
 496                     return -EFAULT;
 497
 498                 for (i = 0; i < joydev->nabs; i++) {
 499                         j = joydev->abspam[i];
 500                         joydev->abs[i] = joydev_correct(dev->abs[j],
 501                                                         &joydev->corr[i]);
 502                 }
 503                 return 0;
 504
 505         case JSIOCGCORR:
 506                 return copy_to_user(argp, joydev->corr,
 507                         sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
 508
 509         case JSIOCSAXMAP:
 510                 if (copy_from_user(joydev->abspam, argp,
 511                                    sizeof(__u8) * (ABS_MAX + 1)))
 512                         return -EFAULT;
 513
 514                 for (i = 0; i < joydev->nabs; i++) {
 515                         if (joydev->abspam[i] > ABS_MAX)
 516                                 return -EINVAL;
 517                         joydev->absmap[joydev->abspam[i]] = i;
 518                 }
 519                 return 0;
 520
 521         case JSIOCGAXMAP:
 522                 return copy_to_user(argp, joydev->abspam,
 523                         sizeof(__u8) * (ABS_MAX + 1)) ? -EFAULT : 0;
 524
 525         case JSIOCSBTNMAP:
 526                 if (copy_from_user(joydev->keypam, argp,
 527                                    sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)))
 528                         return -EFAULT;
 529
 530                 for (i = 0; i < joydev->nkey; i++) {
 531                         if (joydev->keypam[i] > KEY_MAX ||
 532                             joydev->keypam[i] < BTN_MISC)
 533                                 return -EINVAL;
 534                         joydev->keymap[joydev->keypam[i] - BTN_MISC] = i;
 535                 }
 536
 537                 return 0;
 538
 539         case JSIOCGBTNMAP:
 540                 return copy_to_user(argp, joydev->keypam,
 541                         sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)) ? -EFAULT : 0;
 542
 543         default:
 544                 if ((cmd & ~IOCSIZE_MASK) == JSIOCGNAME(0)) {
 545                         int len;
 546                         if (!dev->name)
 547                                 return 0;
 548                         len = strlen(dev->name) + 1;
 549                         if (len > _IOC_SIZE(cmd))
 550                                 len = _IOC_SIZE(cmd);
 551                         if (copy_to_user(argp, dev->name, len))
 552                                 return -EFAULT;
 553                         return len;
 554                 }
 555         }
 556         return -EINVAL;
 557 }
 558
 559 #ifdef CONFIG_COMPAT
 560 static long joydev_compat_ioctl(struct file *file,
 561                                 unsigned int cmd, unsigned long arg)
 562 {
 563         struct joydev_client *client = file->private_data;
 564         struct joydev *joydev = client->joydev;
 565         void __user *argp = (void __user *)arg;
 566         s32 tmp32;
 567         struct JS_DATA_SAVE_TYPE_32 ds32;
 568         int retval;
 569
 570         retval = mutex_lock_interruptible(&joydev->mutex);
 571         if (retval)
 572                 return retval;
 573
 574         if (!joydev->exist) {
 575                 retval = -ENODEV;
 576                 goto out;
 577         }
 578
 579         switch (cmd) {
 580
 581         case JS_SET_TIMELIMIT:
 582                 retval = get_user(tmp32, (s32 __user *) arg);
 583                 if (retval == 0)
 584                         joydev->glue.JS_TIMELIMIT = tmp32;
 585                 break;
 586
 587         case JS_GET_TIMELIMIT:
 588                 tmp32 = joydev->glue.JS_TIMELIMIT;
 589                 retval = put_user(tmp32, (s32 __user *) arg);
 590                 break;
 591
 592         case JS_SET_ALL:
 593                 retval = copy_from_user(&ds32, argp,
 594                                         sizeof(ds32)) ? -EFAULT : 0;
 595                 if (retval == 0) {
 596                         joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
 597                         joydev->glue.BUSY          = ds32.BUSY;
 598                         joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
 599                         joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
 600                         joydev->glue.JS_SAVE       = ds32.JS_SAVE;
 601                         joydev->glue.JS_CORR       = ds32.JS_CORR;
 602                 }
 603                 break;
 604
 605         case JS_GET_ALL:
 606                 ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
 607                 ds32.BUSY          = joydev->glue.BUSY;
 608                 ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
 609                 ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
 610                 ds32.JS_SAVE       = joydev->glue.JS_SAVE;
 611                 ds32.JS_CORR       = joydev->glue.JS_CORR;
 612
 613                 retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
 614                 break;
 615
 616         default:
 617                 retval = joydev_ioctl_common(joydev, cmd, argp);
 618                 break;
 619         }
 620
 621  out:
 622         mutex_unlock(&joydev->mutex);
 623         return retval;
 624 }
 625 #endif /* CONFIG_COMPAT */
 626
 627 static long joydev_ioctl(struct file *file,
 628                          unsigned int cmd, unsigned long arg)
 629 {
 630         struct joydev_client *client = file->private_data;
 631         struct joydev *joydev = client->joydev;
 632         void __user *argp = (void __user *)arg;
 633         int retval;
 634
 635         retval = mutex_lock_interruptible(&joydev->mutex);
 636         if (retval)
 637                 return retval;
 638
 639         if (!joydev->exist) {
 640                 retval = -ENODEV;
 641                 goto out;
 642         }
 643
 644         switch (cmd) {
 645
 646         case JS_SET_TIMELIMIT:
 647                 retval = get_user(joydev->glue.JS_TIMELIMIT,
 648                                   (long __user *) arg);
 649                 break;
 650
 651         case JS_GET_TIMELIMIT:
 652                 retval = put_user(joydev->glue.JS_TIMELIMIT,
 653                                   (long __user *) arg);
 654                 break;
 655
 656         case JS_SET_ALL:
 657                 retval = copy_from_user(&joydev->glue, argp,
 658                                         sizeof(joydev->glue)) ? -EFAULT: 0;
 659                 break;
 660
 661         case JS_GET_ALL:
 662                 retval = copy_to_user(argp, &joydev->glue,
 663                                       sizeof(joydev->glue)) ? -EFAULT : 0;
 664                 break;
 665
 666         default:
 667                 retval = joydev_ioctl_common(joydev, cmd, argp);
 668                 break;
 669         }
 670  out:
 671         mutex_unlock(&joydev->mutex);
 672         return retval;
 673 }
 674
 675 static const struct file_operations joydev_fops = {
 676         .owner          = THIS_MODULE,
 677         .read           = joydev_read,
 678         .poll           = joydev_poll,
 679         .open           = joydev_open,
 680         .release        = joydev_release,
 681         .unlocked_ioctl = joydev_ioctl,
 682 #ifdef CONFIG_COMPAT
 683         .compat_ioctl   = joydev_compat_ioctl,
 684 #endif
 685         .fasync         = joydev_fasync,
 686 };
 687
 688 static int joydev_install_chrdev(struct joydev *joydev)
 689 {
 690         joydev_table[joydev->minor] = joydev;
 691         return 0;
 692 }
 693
 694 static void joydev_remove_chrdev(struct joydev *joydev)
 695 {
 696         mutex_lock(&joydev_table_mutex);
 697         joydev_table[joydev->minor] = NULL;
 698         mutex_unlock(&joydev_table_mutex);
 699 }
 700
 701 /*
 702  * Mark device non-existant. This disables writes, ioctls and
 703  * prevents new users from opening the device. Already posted
 704  * blocking reads will stay, however new ones will fail.
 705  */
 706 static void joydev_mark_dead(struct joydev *joydev)
 707 {
 708         mutex_lock(&joydev->mutex);
 709         joydev->exist = 0;
 710         mutex_unlock(&joydev->mutex);
 711 }
 712
 713 static void joydev_cleanup(struct joydev *joydev)
 714 {
 715         struct input_handle *handle = &joydev->handle;
 716
 717         joydev_mark_dead(joydev);
 718         joydev_hangup(joydev);
 719         joydev_remove_chrdev(joydev);
 720
 721         /* joydev is marked dead so noone else accesses joydev->open */
 722         if (joydev->open)
 723                 input_close_device(handle);
 724 }
 725
 726 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
 727                           const struct input_device_id *id)
 728 {
 729         struct joydev *joydev;
 730         int i, j, t, minor;
 731         int error;
 732
 733         for (minor = 0; minor < JOYDEV_MINORS; minor++)
 734                 if (!joydev_table[minor])
 735                         break;
 736
 737         if (minor == JOYDEV_MINORS) {
 738                 printk(KERN_ERR "joydev: no more free joydev devices\n");
 739                 return -ENFILE;
 740         }
 741
 742         joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
 743         if (!joydev)
 744                 return -ENOMEM;
 745
 746         INIT_LIST_HEAD(&joydev->client_list);
 747         spin_lock_init(&joydev->client_lock);
 748         mutex_init(&joydev->mutex);
 749         init_waitqueue_head(&joydev->wait);
 750
 751         snprintf(joydev->name, sizeof(joydev->name), "js%d", minor);
 752         joydev->exist = 1;
 753         joydev->minor = minor;
 754
 755         joydev->exist = 1;
 756         joydev->handle.dev = dev;
 757         joydev->handle.name = joydev->name;
 758         joydev->handle.handler = handler;
 759         joydev->handle.private = joydev;
 760
 761         for (i = 0; i < ABS_MAX + 1; i++)
 762                 if (test_bit(i, dev->absbit)) {
 763                         joydev->absmap[i] = joydev->nabs;
 764                         joydev->abspam[joydev->nabs] = i;
 765                         joydev->nabs++;
 766                 }
 767
 768         for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
 769                 if (test_bit(i + BTN_MISC, dev->keybit)) {
 770                         joydev->keymap[i] = joydev->nkey;
 771                         joydev->keypam[joydev->nkey] = i + BTN_MISC;
 772                         joydev->nkey++;
 773                 }
 774
 775         for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
 776                 if (test_bit(i + BTN_MISC, dev->keybit)) {
 777                         joydev->keymap[i] = joydev->nkey;
 778                         joydev->keypam[joydev->nkey] = i + BTN_MISC;
 779                         joydev->nkey++;
 780                 }
 781
 782         for (i = 0; i < joydev->nabs; i++) {
 783                 j = joydev->abspam[i];
 784                 if (dev->absmax[j] == dev->absmin[j]) {
 785                         joydev->corr[i].type = JS_CORR_NONE;
 786                         joydev->abs[i] = dev->abs[j];
 787                         continue;
 788                 }
 789                 joydev->corr[i].type = JS_CORR_BROKEN;
 790                 joydev->corr[i].prec = dev->absfuzz[j];
 791                 joydev->corr[i].coef[0] =
 792                         (dev->absmax[j] + dev->absmin[j]) / 2 - dev->absflat[j];
 793                 joydev->corr[i].coef[1] =
 794                         (dev->absmax[j] + dev->absmin[j]) / 2 + dev->absflat[j];
 795
 796                 t = (dev->absmax[j] - dev->absmin[j]) / 2 - 2 * dev->absflat[j];
 797                 if (t) {
 798                         joydev->corr[i].coef[2] = (1 << 29) / t;
 799                         joydev->corr[i].coef[3] = (1 << 29) / t;
 800
 801                         joydev->abs[i] = joydev_correct(dev->abs[j],
 802                                                         joydev->corr + i);
 803                 }
 804         }
 805
 806         strlcpy(joydev->dev.bus_id, joydev->name, sizeof(joydev->dev.bus_id));
 807         joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
 808         joydev->dev.class = &input_class;
 809         joydev->dev.parent = &dev->dev;
 810         joydev->dev.release = joydev_free;
 811         device_initialize(&joydev->dev);
 812
 813         error = input_register_handle(&joydev->handle);
 814         if (error)
 815                 goto err_free_joydev;
 816
 817         error = joydev_install_chrdev(joydev);
 818         if (error)
 819                 goto err_unregister_handle;
 820
 821         error = device_add(&joydev->dev);
 822         if (error)
 823                 goto err_cleanup_joydev;
 824
 825         return 0;
 826
 827  err_cleanup_joydev:
 828         joydev_cleanup(joydev);
 829  err_unregister_handle:
 830         input_unregister_handle(&joydev->handle);
 831  err_free_joydev:
 832         put_device(&joydev->dev);
 833         return error;
 834 }
 835
 836 static void joydev_disconnect(struct input_handle *handle)
 837 {
 838         struct joydev *joydev = handle->private;
 839
 840         device_del(&joydev->dev);
 841         joydev_cleanup(joydev);
 842         input_unregister_handle(handle);
 843         put_device(&joydev->dev);
 844 }
 845
 846 static const struct input_device_id joydev_blacklist[] = {
 847         {
 848                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
 849                                 INPUT_DEVICE_ID_MATCH_KEYBIT,
 850                 .evbit = { BIT(EV_KEY) },
 851                 .keybit = { [LONG(BTN_TOUCH)] = BIT(BTN_TOUCH) },
 852         },      /* Avoid itouchpads, touchscreens and tablets */
 853         { }     /* Terminating entry */
 854 };
 855
 856 static const struct input_device_id joydev_ids[] = {
 857         {
 858                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
 859                                 INPUT_DEVICE_ID_MATCH_ABSBIT,
 860                 .evbit = { BIT(EV_ABS) },
 861                 .absbit = { BIT(ABS_X) },
 862         },
 863         {
 864                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
 865                                 INPUT_DEVICE_ID_MATCH_ABSBIT,
 866                 .evbit = { BIT(EV_ABS) },
 867                 .absbit = { BIT(ABS_WHEEL) },
 868         },
 869         {
 870                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
 871                                 INPUT_DEVICE_ID_MATCH_ABSBIT,
 872                 .evbit = { BIT(EV_ABS) },
 873                 .absbit = { BIT(ABS_THROTTLE) },
 874         },
 875         { }     /* Terminating entry */
 876 };
 877
 878 MODULE_DEVICE_TABLE(input, joydev_ids);
 879
 880 static struct input_handler joydev_handler = {
 881         .event          = joydev_event,
 882         .connect        = joydev_connect,
 883         .disconnect     = joydev_disconnect,
 884         .fops           = &joydev_fops,
 885         .minor          = JOYDEV_MINOR_BASE,
 886         .name           = "joydev",
 887         .id_table       = joydev_ids,
 888         .blacklist      = joydev_blacklist,
 889 };
 890
 891 static int __init joydev_init(void)
 892 {
 893         return input_register_handler(&joydev_handler);
 894 }
 895
 896 static void __exit joydev_exit(void)
 897 {
 898         input_unregister_handler(&joydev_handler);
 899 }
 900
 901 module_init(joydev_init);
 902 module_exit(joydev_exit);