drivers/media/IR/lirc_dev.c

   1 /*
   2  * LIRC base driver
   3  *
   4  * by Artur Lipowski <alipowski@interia.pl>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/errno.h>
  26 #include <linux/ioctl.h>
  27 #include <linux/fs.h>
  28 #include <linux/poll.h>
  29 #include <linux/completion.h>
  30 #include <linux/errno.h>
  31 #include <linux/mutex.h>
  32 #include <linux/wait.h>
  33 #include <linux/unistd.h>
  34 #include <linux/kthread.h>
  35 #include <linux/bitops.h>
  36 #include <linux/device.h>
  37 #include <linux/cdev.h>
  38
  39 #include <media/lirc.h>
  40 #include <media/lirc_dev.h>
  41
  42 static int debug;
  43
  44 #define IRCTL_DEV_NAME  "BaseRemoteCtl"
  45 #define NOPLUG          -1
  46 #define LOGHEAD         "lirc_dev (%s[%d]): "
  47
  48 static dev_t lirc_base_dev;
  49
  50 struct irctl {
  51         struct lirc_driver d;
  52         int attached;
  53         int open;
  54
  55         struct mutex irctl_lock;
  56         struct lirc_buffer *buf;
  57         unsigned int chunk_size;
  58
  59         struct task_struct *task;
  60         long jiffies_to_wait;
  61 };
  62
  63 static DEFINE_MUTEX(lirc_dev_lock);
  64
  65 static struct irctl *irctls[MAX_IRCTL_DEVICES];
  66 static struct cdev cdevs[MAX_IRCTL_DEVICES];
  67
  68 /* Only used for sysfs but defined to void otherwise */
  69 static struct class *lirc_class;
  70
  71 /*  helper function
  72  *  initializes the irctl structure
  73  */
  74 static void lirc_irctl_init(struct irctl *ir)
  75 {
  76         mutex_init(&ir->irctl_lock);
  77         ir->d.minor = NOPLUG;
  78 }
  79
  80 static void lirc_irctl_cleanup(struct irctl *ir)
  81 {
  82         dev_dbg(ir->d.dev, LOGHEAD "cleaning up\n", ir->d.name, ir->d.minor);
  83
  84         device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
  85
  86         if (ir->buf != ir->d.rbuf) {
  87                 lirc_buffer_free(ir->buf);
  88                 kfree(ir->buf);
  89         }
  90         ir->buf = NULL;
  91 }
  92
  93 /*  helper function
  94  *  reads key codes from driver and puts them into buffer
  95  *  returns 0 on success
  96  */
  97 static int lirc_add_to_buf(struct irctl *ir)
  98 {
  99         if (ir->d.add_to_buf) {
 100                 int res = -ENODATA;
 101                 int got_data = 0;
 102
 103                 /*
 104                  * service the device as long as it is returning
 105                  * data and we have space
 106                  */
 107 get_data:
 108                 res = ir->d.add_to_buf(ir->d.data, ir->buf);
 109                 if (res == 0) {
 110                         got_data++;
 111                         goto get_data;
 112                 }
 113
 114                 if (res == -ENODEV)
 115                         kthread_stop(ir->task);
 116
 117                 return got_data ? 0 : res;
 118         }
 119
 120         return 0;
 121 }
 122
 123 /* main function of the polling thread
 124  */
 125 static int lirc_thread(void *irctl)
 126 {
 127         struct irctl *ir = irctl;
 128
 129         dev_dbg(ir->d.dev, LOGHEAD "poll thread started\n",
 130                 ir->d.name, ir->d.minor);
 131
 132         do {
 133                 if (ir->open) {
 134                         if (ir->jiffies_to_wait) {
 135                                 set_current_state(TASK_INTERRUPTIBLE);
 136                                 schedule_timeout(ir->jiffies_to_wait);
 137                         }
 138                         if (kthread_should_stop())
 139                                 break;
 140                         if (!lirc_add_to_buf(ir))
 141                                 wake_up_interruptible(&ir->buf->wait_poll);
 142                 } else {
 143                         set_current_state(TASK_INTERRUPTIBLE);
 144                         schedule();
 145                 }
 146         } while (!kthread_should_stop());
 147
 148         dev_dbg(ir->d.dev, LOGHEAD "poll thread ended\n",
 149                 ir->d.name, ir->d.minor);
 150
 151         return 0;
 152 }
 153
 154
 155 static struct file_operations lirc_dev_fops = {
 156         .owner          = THIS_MODULE,
 157         .read           = lirc_dev_fop_read,
 158         .write          = lirc_dev_fop_write,
 159         .poll           = lirc_dev_fop_poll,
 160         .unlocked_ioctl = lirc_dev_fop_ioctl,
 161 #ifdef CONFIG_COMPAT
 162         .compat_ioctl   = lirc_dev_fop_ioctl,
 163 #endif
 164         .open           = lirc_dev_fop_open,
 165         .release        = lirc_dev_fop_close,
 166 };
 167
 168 static int lirc_cdev_add(struct irctl *ir)
 169 {
 170         int retval;
 171         struct lirc_driver *d = &ir->d;
 172         struct cdev *cdev = &cdevs[d->minor];
 173
 174         if (d->fops) {
 175                 cdev_init(cdev, d->fops);
 176                 cdev->owner = d->owner;
 177         } else {
 178                 cdev_init(cdev, &lirc_dev_fops);
 179                 cdev->owner = THIS_MODULE;
 180         }
 181         kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
 182
 183         retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
 184         if (retval)
 185                 kobject_put(&cdev->kobj);
 186
 187         return retval;
 188 }
 189
 190 int lirc_register_driver(struct lirc_driver *d)
 191 {
 192         struct irctl *ir;
 193         int minor;
 194         int bytes_in_key;
 195         unsigned int chunk_size;
 196         unsigned int buffer_size;
 197         int err;
 198
 199         if (!d) {
 200                 printk(KERN_ERR "lirc_dev: lirc_register_driver: "
 201                        "driver pointer must be not NULL!\n");
 202                 err = -EBADRQC;
 203                 goto out;
 204         }
 205
 206         if (!d->dev) {
 207                 printk(KERN_ERR "%s: dev pointer not filled in!\n", __func__);
 208                 err = -EINVAL;
 209                 goto out;
 210         }
 211
 212         if (MAX_IRCTL_DEVICES <= d->minor) {
 213                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 214                         "\"minor\" must be between 0 and %d (%d)!\n",
 215                         MAX_IRCTL_DEVICES-1, d->minor);
 216                 err = -EBADRQC;
 217                 goto out;
 218         }
 219
 220         if (1 > d->code_length || (BUFLEN * 8) < d->code_length) {
 221                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 222                         "code length in bits for minor (%d) "
 223                         "must be less than %d!\n",
 224                         d->minor, BUFLEN * 8);
 225                 err = -EBADRQC;
 226                 goto out;
 227         }
 228
 229         dev_dbg(d->dev, "lirc_dev: lirc_register_driver: sample_rate: %d\n",
 230                 d->sample_rate);
 231         if (d->sample_rate) {
 232                 if (2 > d->sample_rate || HZ < d->sample_rate) {
 233                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 234                                 "sample_rate must be between 2 and %d!\n", HZ);
 235                         err = -EBADRQC;
 236                         goto out;
 237                 }
 238                 if (!d->add_to_buf) {
 239                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 240                                 "add_to_buf cannot be NULL when "
 241                                 "sample_rate is set\n");
 242                         err = -EBADRQC;
 243                         goto out;
 244                 }
 245         } else if (!(d->fops && d->fops->read) && !d->rbuf) {
 246                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 247                         "fops->read and rbuf cannot all be NULL!\n");
 248                 err = -EBADRQC;
 249                 goto out;
 250         } else if (!d->rbuf) {
 251                 if (!(d->fops && d->fops->read && d->fops->poll &&
 252                       d->fops->unlocked_ioctl)) {
 253                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 254                                 "neither read, poll nor unlocked_ioctl can be NULL!\n");
 255                         err = -EBADRQC;
 256                         goto out;
 257                 }
 258         }
 259
 260         mutex_lock(&lirc_dev_lock);
 261
 262         minor = d->minor;
 263
 264         if (minor < 0) {
 265                 /* find first free slot for driver */
 266                 for (minor = 0; minor < MAX_IRCTL_DEVICES; minor++)
 267                         if (!irctls[minor])
 268                                 break;
 269                 if (MAX_IRCTL_DEVICES == minor) {
 270                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 271                                 "no free slots for drivers!\n");
 272                         err = -ENOMEM;
 273                         goto out_lock;
 274                 }
 275         } else if (irctls[minor]) {
 276                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 277                         "minor (%d) just registered!\n", minor);
 278                 err = -EBUSY;
 279                 goto out_lock;
 280         }
 281
 282         ir = kzalloc(sizeof(struct irctl), GFP_KERNEL);
 283         if (!ir) {
 284                 err = -ENOMEM;
 285                 goto out_lock;
 286         }
 287         lirc_irctl_init(ir);
 288         irctls[minor] = ir;
 289         d->minor = minor;
 290
 291         if (d->sample_rate) {
 292                 ir->jiffies_to_wait = HZ / d->sample_rate;
 293         } else {
 294                 /* it means - wait for external event in task queue */
 295                 ir->jiffies_to_wait = 0;
 296         }
 297
 298         /* some safety check 8-) */
 299         d->name[sizeof(d->name)-1] = '\0';
 300
 301         bytes_in_key = BITS_TO_LONGS(d->code_length) +
 302                         (d->code_length % 8 ? 1 : 0);
 303         buffer_size = d->buffer_size ? d->buffer_size : BUFLEN / bytes_in_key;
 304         chunk_size  = d->chunk_size  ? d->chunk_size  : bytes_in_key;
 305
 306         if (d->rbuf) {
 307                 ir->buf = d->rbuf;
 308         } else {
 309                 ir->buf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
 310                 if (!ir->buf) {
 311                         err = -ENOMEM;
 312                         goto out_lock;
 313                 }
 314                 err = lirc_buffer_init(ir->buf, chunk_size, buffer_size);
 315                 if (err) {
 316                         kfree(ir->buf);
 317                         goto out_lock;
 318                 }
 319         }
 320         ir->chunk_size = ir->buf->chunk_size;
 321
 322         if (d->features == 0)
 323                 d->features = LIRC_CAN_REC_LIRCCODE;
 324
 325         ir->d = *d;
 326
 327         device_create(lirc_class, ir->d.dev,
 328                       MKDEV(MAJOR(lirc_base_dev), ir->d.minor), NULL,
 329                       "lirc%u", ir->d.minor);
 330
 331         if (d->sample_rate) {
 332                 /* try to fire up polling thread */
 333                 ir->task = kthread_run(lirc_thread, (void *)ir, "lirc_dev");
 334                 if (IS_ERR(ir->task)) {
 335                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 336                                 "cannot run poll thread for minor = %d\n",
 337                                 d->minor);
 338                         err = -ECHILD;
 339                         goto out_sysfs;
 340                 }
 341         }
 342
 343         err = lirc_cdev_add(ir);
 344         if (err)
 345                 goto out_sysfs;
 346
 347         ir->attached = 1;
 348         mutex_unlock(&lirc_dev_lock);
 349
 350         dev_info(ir->d.dev, "lirc_dev: driver %s registered at minor = %d\n",
 351                  ir->d.name, ir->d.minor);
 352         return minor;
 353
 354 out_sysfs:
 355         device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
 356 out_lock:
 357         mutex_unlock(&lirc_dev_lock);
 358 out:
 359         return err;
 360 }
 361 EXPORT_SYMBOL(lirc_register_driver);
 362
 363 int lirc_unregister_driver(int minor)
 364 {
 365         struct irctl *ir;
 366         struct cdev *cdev;
 367
 368         if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
 369                 printk(KERN_ERR "lirc_dev: %s: minor (%d) must be between "
 370                        "0 and %d!\n", __func__, minor, MAX_IRCTL_DEVICES-1);
 371                 return -EBADRQC;
 372         }
 373
 374         ir = irctls[minor];
 375         if (!ir) {
 376                 printk(KERN_ERR "lirc_dev: %s: failed to get irctl struct "
 377                        "for minor %d!\n", __func__, minor);
 378                 return -ENOENT;
 379         }
 380
 381         cdev = &cdevs[minor];
 382
 383         mutex_lock(&lirc_dev_lock);
 384
 385         if (ir->d.minor != minor) {
 386                 printk(KERN_ERR "lirc_dev: %s: minor (%d) device not "
 387                        "registered!\n", __func__, minor);
 388                 mutex_unlock(&lirc_dev_lock);
 389                 return -ENOENT;
 390         }
 391
 392         /* end up polling thread */
 393         if (ir->task)
 394                 kthread_stop(ir->task);
 395
 396         dev_dbg(ir->d.dev, "lirc_dev: driver %s unregistered from minor = %d\n",
 397                 ir->d.name, ir->d.minor);
 398
 399         ir->attached = 0;
 400         if (ir->open) {
 401                 dev_dbg(ir->d.dev, LOGHEAD "releasing opened driver\n",
 402                         ir->d.name, ir->d.minor);
 403                 wake_up_interruptible(&ir->buf->wait_poll);
 404                 mutex_lock(&ir->irctl_lock);
 405                 ir->d.set_use_dec(ir->d.data);
 406                 module_put(cdev->owner);
 407                 mutex_unlock(&ir->irctl_lock);
 408         } else {
 409                 lirc_irctl_cleanup(ir);
 410                 cdev_del(cdev);
 411                 kfree(ir);
 412                 irctls[minor] = NULL;
 413         }
 414
 415         mutex_unlock(&lirc_dev_lock);
 416
 417         return 0;
 418 }
 419 EXPORT_SYMBOL(lirc_unregister_driver);
 420
 421 int lirc_dev_fop_open(struct inode *inode, struct file *file)
 422 {
 423         struct irctl *ir;
 424         struct cdev *cdev;
 425         int retval = 0;
 426
 427         if (iminor(inode) >= MAX_IRCTL_DEVICES) {
 428                 printk(KERN_WARNING "lirc_dev [%d]: open result = -ENODEV\n",
 429                        iminor(inode));
 430                 return -ENODEV;
 431         }
 432
 433         if (mutex_lock_interruptible(&lirc_dev_lock))
 434                 return -ERESTARTSYS;
 435
 436         ir = irctls[iminor(inode)];
 437         if (!ir) {
 438                 retval = -ENODEV;
 439                 goto error;
 440         }
 441
 442         dev_dbg(ir->d.dev, LOGHEAD "open called\n", ir->d.name, ir->d.minor);
 443
 444         if (ir->d.minor == NOPLUG) {
 445                 retval = -ENODEV;
 446                 goto error;
 447         }
 448
 449         if (ir->open) {
 450                 retval = -EBUSY;
 451                 goto error;
 452         }
 453
 454         cdev = &cdevs[iminor(inode)];
 455         if (try_module_get(cdev->owner)) {
 456                 ir->open++;
 457                 retval = ir->d.set_use_inc(ir->d.data);
 458
 459                 if (retval) {
 460                         module_put(cdev->owner);
 461                         ir->open--;
 462                 } else {
 463                         lirc_buffer_clear(ir->buf);
 464                 }
 465                 if (ir->task)
 466                         wake_up_process(ir->task);
 467         }
 468
 469 error:
 470         if (ir)
 471                 dev_dbg(ir->d.dev, LOGHEAD "open result = %d\n",
 472                         ir->d.name, ir->d.minor, retval);
 473
 474         mutex_unlock(&lirc_dev_lock);
 475
 476         return retval;
 477 }
 478 EXPORT_SYMBOL(lirc_dev_fop_open);
 479
 480 int lirc_dev_fop_close(struct inode *inode, struct file *file)
 481 {
 482         struct irctl *ir = irctls[iminor(inode)];
 483         struct cdev *cdev = &cdevs[iminor(inode)];
 484
 485         if (!ir) {
 486                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 487                 return -EINVAL;
 488         }
 489
 490         dev_dbg(ir->d.dev, LOGHEAD "close called\n", ir->d.name, ir->d.minor);
 491
 492         WARN_ON(mutex_lock_killable(&lirc_dev_lock));
 493
 494         ir->open--;
 495         if (ir->attached) {
 496                 ir->d.set_use_dec(ir->d.data);
 497                 module_put(cdev->owner);
 498         } else {
 499                 lirc_irctl_cleanup(ir);
 500                 cdev_del(cdev);
 501                 irctls[ir->d.minor] = NULL;
 502                 kfree(ir);
 503         }
 504
 505         mutex_unlock(&lirc_dev_lock);
 506
 507         return 0;
 508 }
 509 EXPORT_SYMBOL(lirc_dev_fop_close);
 510
 511 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait)
 512 {
 513         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 514         unsigned int ret;
 515
 516         if (!ir) {
 517                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 518                 return POLLERR;
 519         }
 520
 521         dev_dbg(ir->d.dev, LOGHEAD "poll called\n", ir->d.name, ir->d.minor);
 522
 523         if (!ir->attached) {
 524                 mutex_unlock(&ir->irctl_lock);
 525                 return POLLERR;
 526         }
 527
 528         poll_wait(file, &ir->buf->wait_poll, wait);
 529
 530         if (ir->buf)
 531                 if (lirc_buffer_empty(ir->buf))
 532                         ret = 0;
 533                 else
 534                         ret = POLLIN | POLLRDNORM;
 535         else
 536                 ret = POLLERR;
 537
 538         dev_dbg(ir->d.dev, LOGHEAD "poll result = %d\n",
 539                 ir->d.name, ir->d.minor, ret);
 540
 541         return ret;
 542 }
 543 EXPORT_SYMBOL(lirc_dev_fop_poll);
 544
 545 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 546 {
 547         __u32 mode;
 548         int result = 0;
 549         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 550
 551         if (!ir) {
 552                 printk(KERN_ERR "lirc_dev: %s: no irctl found!\n", __func__);
 553                 return -ENODEV;
 554         }
 555
 556         dev_dbg(ir->d.dev, LOGHEAD "ioctl called (0x%x)\n",
 557                 ir->d.name, ir->d.minor, cmd);
 558
 559         if (ir->d.minor == NOPLUG || !ir->attached) {
 560                 dev_dbg(ir->d.dev, LOGHEAD "ioctl result = -ENODEV\n",
 561                         ir->d.name, ir->d.minor);
 562                 return -ENODEV;
 563         }
 564
 565         mutex_lock(&ir->irctl_lock);
 566
 567         switch (cmd) {
 568         case LIRC_GET_FEATURES:
 569                 result = put_user(ir->d.features, (__u32 *)arg);
 570                 break;
 571         case LIRC_GET_REC_MODE:
 572                 if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
 573                         result = -ENOSYS;
 574                         break;
 575                 }
 576
 577                 result = put_user(LIRC_REC2MODE
 578                                   (ir->d.features & LIRC_CAN_REC_MASK),
 579                                   (__u32 *)arg);
 580                 break;
 581         case LIRC_SET_REC_MODE:
 582                 if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
 583                         result = -ENOSYS;
 584                         break;
 585                 }
 586
 587                 result = get_user(mode, (__u32 *)arg);
 588                 if (!result && !(LIRC_MODE2REC(mode) & ir->d.features))
 589                         result = -EINVAL;
 590                 /*
 591                  * FIXME: We should actually set the mode somehow but
 592                  * for now, lirc_serial doesn't support mode changing either
 593                  */
 594                 break;
 595         case LIRC_GET_LENGTH:
 596                 result = put_user(ir->d.code_length, (__u32 *)arg);
 597                 break;
 598         case LIRC_GET_MIN_TIMEOUT:
 599                 if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
 600                     ir->d.min_timeout == 0) {
 601                         result = -ENOSYS;
 602                         break;
 603                 }
 604
 605                 result = put_user(ir->d.min_timeout, (__u32 *)arg);
 606                 break;
 607         case LIRC_GET_MAX_TIMEOUT:
 608                 if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
 609                     ir->d.max_timeout == 0) {
 610                         result = -ENOSYS;
 611                         break;
 612                 }
 613
 614                 result = put_user(ir->d.max_timeout, (__u32 *)arg);
 615                 break;
 616         default:
 617                 result = -EINVAL;
 618         }
 619
 620         dev_dbg(ir->d.dev, LOGHEAD "ioctl result = %d\n",
 621                 ir->d.name, ir->d.minor, result);
 622
 623         mutex_unlock(&ir->irctl_lock);
 624
 625         return result;
 626 }
 627 EXPORT_SYMBOL(lirc_dev_fop_ioctl);
 628
 629 ssize_t lirc_dev_fop_read(struct file *file,
 630                           char *buffer,
 631                           size_t length,
 632                           loff_t *ppos)
 633 {
 634         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 635         unsigned char *buf;
 636         int ret = 0, written = 0;
 637         DECLARE_WAITQUEUE(wait, current);
 638
 639         if (!ir) {
 640                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 641                 return -ENODEV;
 642         }
 643
 644         dev_dbg(ir->d.dev, LOGHEAD "read called\n", ir->d.name, ir->d.minor);
 645
 646         buf = kzalloc(ir->chunk_size, GFP_KERNEL);
 647         if (!buf)
 648                 return -ENOMEM;
 649
 650         if (mutex_lock_interruptible(&ir->irctl_lock))
 651                 return -ERESTARTSYS;
 652         if (!ir->attached) {
 653                 mutex_unlock(&ir->irctl_lock);
 654                 return -ENODEV;
 655         }
 656
 657         if (length % ir->chunk_size) {
 658                 dev_dbg(ir->d.dev, LOGHEAD "read result = -EINVAL\n",
 659                         ir->d.name, ir->d.minor);
 660                 mutex_unlock(&ir->irctl_lock);
 661                 return -EINVAL;
 662         }
 663
 664         /*
 665          * we add ourselves to the task queue before buffer check
 666          * to avoid losing scan code (in case when queue is awaken somewhere
 667          * between while condition checking and scheduling)
 668          */
 669         add_wait_queue(&ir->buf->wait_poll, &wait);
 670         set_current_state(TASK_INTERRUPTIBLE);
 671
 672         /*
 673          * while we didn't provide 'length' bytes, device is opened in blocking
 674          * mode and 'copy_to_user' is happy, wait for data.
 675          */
 676         while (written < length && ret == 0) {
 677                 if (lirc_buffer_empty(ir->buf)) {
 678                         /* According to the read(2) man page, 'written' can be
 679                          * returned as less than 'length', instead of blocking
 680                          * again, returning -EWOULDBLOCK, or returning
 681                          * -ERESTARTSYS */
 682                         if (written)
 683                                 break;
 684                         if (file->f_flags & O_NONBLOCK) {
 685                                 ret = -EWOULDBLOCK;
 686                                 break;
 687                         }
 688                         if (signal_pending(current)) {
 689                                 ret = -ERESTARTSYS;
 690                                 break;
 691                         }
 692
 693                         mutex_unlock(&ir->irctl_lock);
 694                         schedule();
 695                         set_current_state(TASK_INTERRUPTIBLE);
 696
 697                         if (mutex_lock_interruptible(&ir->irctl_lock)) {
 698                                 ret = -ERESTARTSYS;
 699                                 remove_wait_queue(&ir->buf->wait_poll, &wait);
 700                                 set_current_state(TASK_RUNNING);
 701                                 goto out_unlocked;
 702                         }
 703
 704                         if (!ir->attached) {
 705                                 ret = -ENODEV;
 706                                 break;
 707                         }
 708                 } else {
 709                         lirc_buffer_read(ir->buf, buf);
 710                         ret = copy_to_user((void *)buffer+written, buf,
 711                                            ir->buf->chunk_size);
 712                         written += ir->buf->chunk_size;
 713                 }
 714         }
 715
 716         remove_wait_queue(&ir->buf->wait_poll, &wait);
 717         set_current_state(TASK_RUNNING);
 718         mutex_unlock(&ir->irctl_lock);
 719
 720 out_unlocked:
 721         kfree(buf);
 722         dev_dbg(ir->d.dev, LOGHEAD "read result = %s (%d)\n",
 723                 ir->d.name, ir->d.minor, ret ? "-EFAULT" : "OK", ret);
 724
 725         return ret ? ret : written;
 726 }
 727 EXPORT_SYMBOL(lirc_dev_fop_read);
 728
 729 void *lirc_get_pdata(struct file *file)
 730 {
 731         void *data = NULL;
 732
 733         if (file && file->f_dentry && file->f_dentry->d_inode &&
 734             file->f_dentry->d_inode->i_rdev) {
 735                 struct irctl *ir;
 736                 ir = irctls[iminor(file->f_dentry->d_inode)];
 737                 data = ir->d.data;
 738         }
 739
 740         return data;
 741 }
 742 EXPORT_SYMBOL(lirc_get_pdata);
 743
 744
 745 ssize_t lirc_dev_fop_write(struct file *file, const char *buffer,
 746                            size_t length, loff_t *ppos)
 747 {
 748         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 749
 750         if (!ir) {
 751                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 752                 return -ENODEV;
 753         }
 754
 755         dev_dbg(ir->d.dev, LOGHEAD "write called\n", ir->d.name, ir->d.minor);
 756
 757         if (!ir->attached)
 758                 return -ENODEV;
 759
 760         return -EINVAL;
 761 }
 762 EXPORT_SYMBOL(lirc_dev_fop_write);
 763
 764
 765 static int __init lirc_dev_init(void)
 766 {
 767         int retval;
 768
 769         lirc_class = class_create(THIS_MODULE, "lirc");
 770         if (IS_ERR(lirc_class)) {
 771                 retval = PTR_ERR(lirc_class);
 772                 printk(KERN_ERR "lirc_dev: class_create failed\n");
 773                 goto error;
 774         }
 775
 776         retval = alloc_chrdev_region(&lirc_base_dev, 0, MAX_IRCTL_DEVICES,
 777                                      IRCTL_DEV_NAME);
 778         if (retval) {
 779                 class_destroy(lirc_class);
 780                 printk(KERN_ERR "lirc_dev: alloc_chrdev_region failed\n");
 781                 goto error;
 782         }
 783
 784
 785         printk(KERN_INFO "lirc_dev: IR Remote Control driver registered, "
 786                "major %d \n", MAJOR(lirc_base_dev));
 787
 788 error:
 789         return retval;
 790 }
 791
 792
 793
 794 static void __exit lirc_dev_exit(void)
 795 {
 796         class_destroy(lirc_class);
 797         unregister_chrdev_region(lirc_base_dev, MAX_IRCTL_DEVICES);
 798         printk(KERN_INFO "lirc_dev: module unloaded\n");
 799 }
 800
 801 module_init(lirc_dev_init);
 802 module_exit(lirc_dev_exit);
 803
 804 MODULE_DESCRIPTION("LIRC base driver module");
 805 MODULE_AUTHOR("Artur Lipowski");
 806 MODULE_LICENSE("GPL");
 807
 808 module_param(debug, bool, S_IRUGO | S_IWUSR);
 809 MODULE_PARM_DESC(debug, "Enable debugging messages");