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/mutex.h>
  31 #include <linux/wait.h>
  32 #include <linux/unistd.h>
  33 #include <linux/kthread.h>
  34 #include <linux/bitops.h>
  35 #include <linux/device.h>
  36 #include <linux/cdev.h>
  37
  38 #include <media/lirc.h>
  39 #include <media/lirc_dev.h>
  40
  41 static int debug;
  42
  43 #define IRCTL_DEV_NAME  "BaseRemoteCtl"
  44 #define NOPLUG          -1
  45 #define LOGHEAD         "lirc_dev (%s[%d]): "
  46
  47 static dev_t lirc_base_dev;
  48
  49 struct irctl {
  50         struct lirc_driver d;
  51         int attached;
  52         int open;
  53
  54         struct mutex irctl_lock;
  55         struct lirc_buffer *buf;
  56         unsigned int chunk_size;
  57
  58         struct task_struct *task;
  59         long jiffies_to_wait;
  60 };
  61
  62 static DEFINE_MUTEX(lirc_dev_lock);
  63
  64 static struct irctl *irctls[MAX_IRCTL_DEVICES];
  65 static struct cdev cdevs[MAX_IRCTL_DEVICES];
  66
  67 /* Only used for sysfs but defined to void otherwise */
  68 static struct class *lirc_class;
  69
  70 /*  helper function
  71  *  initializes the irctl structure
  72  */
  73 static void lirc_irctl_init(struct irctl *ir)
  74 {
  75         mutex_init(&ir->irctl_lock);
  76         ir->d.minor = NOPLUG;
  77 }
  78
  79 static void lirc_irctl_cleanup(struct irctl *ir)
  80 {
  81         dev_dbg(ir->d.dev, LOGHEAD "cleaning up\n", ir->d.name, ir->d.minor);
  82
  83         device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
  84
  85         if (ir->buf != ir->d.rbuf) {
  86                 lirc_buffer_free(ir->buf);
  87                 kfree(ir->buf);
  88         }
  89         ir->buf = NULL;
  90 }
  91
  92 /*  helper function
  93  *  reads key codes from driver and puts them into buffer
  94  *  returns 0 on success
  95  */
  96 static int lirc_add_to_buf(struct irctl *ir)
  97 {
  98         if (ir->d.add_to_buf) {
  99                 int res = -ENODATA;
 100                 int got_data = 0;
 101
 102                 /*
 103                  * service the device as long as it is returning
 104                  * data and we have space
 105                  */
 106 get_data:
 107                 res = ir->d.add_to_buf(ir->d.data, ir->buf);
 108                 if (res == 0) {
 109                         got_data++;
 110                         goto get_data;
 111                 }
 112
 113                 if (res == -ENODEV)
 114                         kthread_stop(ir->task);
 115
 116                 return got_data ? 0 : res;
 117         }
 118
 119         return 0;
 120 }
 121
 122 /* main function of the polling thread
 123  */
 124 static int lirc_thread(void *irctl)
 125 {
 126         struct irctl *ir = irctl;
 127
 128         dev_dbg(ir->d.dev, LOGHEAD "poll thread started\n",
 129                 ir->d.name, ir->d.minor);
 130
 131         do {
 132                 if (ir->open) {
 133                         if (ir->jiffies_to_wait) {
 134                                 set_current_state(TASK_INTERRUPTIBLE);
 135                                 schedule_timeout(ir->jiffies_to_wait);
 136                         }
 137                         if (kthread_should_stop())
 138                                 break;
 139                         if (!lirc_add_to_buf(ir))
 140                                 wake_up_interruptible(&ir->buf->wait_poll);
 141                 } else {
 142                         set_current_state(TASK_INTERRUPTIBLE);
 143                         schedule();
 144                 }
 145         } while (!kthread_should_stop());
 146
 147         dev_dbg(ir->d.dev, LOGHEAD "poll thread ended\n",
 148                 ir->d.name, ir->d.minor);
 149
 150         return 0;
 151 }
 152
 153
 154 static struct file_operations lirc_dev_fops = {
 155         .owner          = THIS_MODULE,
 156         .read           = lirc_dev_fop_read,
 157         .write          = lirc_dev_fop_write,
 158         .poll           = lirc_dev_fop_poll,
 159         .unlocked_ioctl = lirc_dev_fop_ioctl,
 160 #ifdef CONFIG_COMPAT
 161         .compat_ioctl   = lirc_dev_fop_ioctl,
 162 #endif
 163         .open           = lirc_dev_fop_open,
 164         .release        = lirc_dev_fop_close,
 165         .llseek         = noop_llseek,
 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         nonseekable_open(inode, file);
 477
 478         return retval;
 479 }
 480 EXPORT_SYMBOL(lirc_dev_fop_open);
 481
 482 int lirc_dev_fop_close(struct inode *inode, struct file *file)
 483 {
 484         struct irctl *ir = irctls[iminor(inode)];
 485         struct cdev *cdev = &cdevs[iminor(inode)];
 486
 487         if (!ir) {
 488                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 489                 return -EINVAL;
 490         }
 491
 492         dev_dbg(ir->d.dev, LOGHEAD "close called\n", ir->d.name, ir->d.minor);
 493
 494         WARN_ON(mutex_lock_killable(&lirc_dev_lock));
 495
 496         ir->open--;
 497         if (ir->attached) {
 498                 ir->d.set_use_dec(ir->d.data);
 499                 module_put(cdev->owner);
 500         } else {
 501                 lirc_irctl_cleanup(ir);
 502                 cdev_del(cdev);
 503                 irctls[ir->d.minor] = NULL;
 504                 kfree(ir);
 505         }
 506
 507         mutex_unlock(&lirc_dev_lock);
 508
 509         return 0;
 510 }
 511 EXPORT_SYMBOL(lirc_dev_fop_close);
 512
 513 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait)
 514 {
 515         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 516         unsigned int ret;
 517
 518         if (!ir) {
 519                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 520                 return POLLERR;
 521         }
 522
 523         dev_dbg(ir->d.dev, LOGHEAD "poll called\n", ir->d.name, ir->d.minor);
 524
 525         if (!ir->attached) {
 526                 mutex_unlock(&ir->irctl_lock);
 527                 return POLLERR;
 528         }
 529
 530         poll_wait(file, &ir->buf->wait_poll, wait);
 531
 532         if (ir->buf)
 533                 if (lirc_buffer_empty(ir->buf))
 534                         ret = 0;
 535                 else
 536                         ret = POLLIN | POLLRDNORM;
 537         else
 538                 ret = POLLERR;
 539
 540         dev_dbg(ir->d.dev, LOGHEAD "poll result = %d\n",
 541                 ir->d.name, ir->d.minor, ret);
 542
 543         return ret;
 544 }
 545 EXPORT_SYMBOL(lirc_dev_fop_poll);
 546
 547 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 548 {
 549         __u32 mode;
 550         int result = 0;
 551         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 552
 553         if (!ir) {
 554                 printk(KERN_ERR "lirc_dev: %s: no irctl found!\n", __func__);
 555                 return -ENODEV;
 556         }
 557
 558         dev_dbg(ir->d.dev, LOGHEAD "ioctl called (0x%x)\n",
 559                 ir->d.name, ir->d.minor, cmd);
 560
 561         if (ir->d.minor == NOPLUG || !ir->attached) {
 562                 dev_dbg(ir->d.dev, LOGHEAD "ioctl result = -ENODEV\n",
 563                         ir->d.name, ir->d.minor);
 564                 return -ENODEV;
 565         }
 566
 567         mutex_lock(&ir->irctl_lock);
 568
 569         switch (cmd) {
 570         case LIRC_GET_FEATURES:
 571                 result = put_user(ir->d.features, (__u32 *)arg);
 572                 break;
 573         case LIRC_GET_REC_MODE:
 574                 if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
 575                         result = -ENOSYS;
 576                         break;
 577                 }
 578
 579                 result = put_user(LIRC_REC2MODE
 580                                   (ir->d.features & LIRC_CAN_REC_MASK),
 581                                   (__u32 *)arg);
 582                 break;
 583         case LIRC_SET_REC_MODE:
 584                 if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
 585                         result = -ENOSYS;
 586                         break;
 587                 }
 588
 589                 result = get_user(mode, (__u32 *)arg);
 590                 if (!result && !(LIRC_MODE2REC(mode) & ir->d.features))
 591                         result = -EINVAL;
 592                 /*
 593                  * FIXME: We should actually set the mode somehow but
 594                  * for now, lirc_serial doesn't support mode changing either
 595                  */
 596                 break;
 597         case LIRC_GET_LENGTH:
 598                 result = put_user(ir->d.code_length, (__u32 *)arg);
 599                 break;
 600         case LIRC_GET_MIN_TIMEOUT:
 601                 if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
 602                     ir->d.min_timeout == 0) {
 603                         result = -ENOSYS;
 604                         break;
 605                 }
 606
 607                 result = put_user(ir->d.min_timeout, (__u32 *)arg);
 608                 break;
 609         case LIRC_GET_MAX_TIMEOUT:
 610                 if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
 611                     ir->d.max_timeout == 0) {
 612                         result = -ENOSYS;
 613                         break;
 614                 }
 615
 616                 result = put_user(ir->d.max_timeout, (__u32 *)arg);
 617                 break;
 618         default:
 619                 result = -EINVAL;
 620         }
 621
 622         dev_dbg(ir->d.dev, LOGHEAD "ioctl result = %d\n",
 623                 ir->d.name, ir->d.minor, result);
 624
 625         mutex_unlock(&ir->irctl_lock);
 626
 627         return result;
 628 }
 629 EXPORT_SYMBOL(lirc_dev_fop_ioctl);
 630
 631 ssize_t lirc_dev_fop_read(struct file *file,
 632                           char *buffer,
 633                           size_t length,
 634                           loff_t *ppos)
 635 {
 636         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 637         unsigned char *buf;
 638         int ret = 0, written = 0;
 639         DECLARE_WAITQUEUE(wait, current);
 640
 641         if (!ir) {
 642                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 643                 return -ENODEV;
 644         }
 645
 646         dev_dbg(ir->d.dev, LOGHEAD "read called\n", ir->d.name, ir->d.minor);
 647
 648         buf = kzalloc(ir->chunk_size, GFP_KERNEL);
 649         if (!buf)
 650                 return -ENOMEM;
 651
 652         if (mutex_lock_interruptible(&ir->irctl_lock))
 653                 return -ERESTARTSYS;
 654         if (!ir->attached) {
 655                 mutex_unlock(&ir->irctl_lock);
 656                 return -ENODEV;
 657         }
 658
 659         if (length % ir->chunk_size) {
 660                 dev_dbg(ir->d.dev, LOGHEAD "read result = -EINVAL\n",
 661                         ir->d.name, ir->d.minor);
 662                 mutex_unlock(&ir->irctl_lock);
 663                 return -EINVAL;
 664         }
 665
 666         /*
 667          * we add ourselves to the task queue before buffer check
 668          * to avoid losing scan code (in case when queue is awaken somewhere
 669          * between while condition checking and scheduling)
 670          */
 671         add_wait_queue(&ir->buf->wait_poll, &wait);
 672         set_current_state(TASK_INTERRUPTIBLE);
 673
 674         /*
 675          * while we didn't provide 'length' bytes, device is opened in blocking
 676          * mode and 'copy_to_user' is happy, wait for data.
 677          */
 678         while (written < length && ret == 0) {
 679                 if (lirc_buffer_empty(ir->buf)) {
 680                         /* According to the read(2) man page, 'written' can be
 681                          * returned as less than 'length', instead of blocking
 682                          * again, returning -EWOULDBLOCK, or returning
 683                          * -ERESTARTSYS */
 684                         if (written)
 685                                 break;
 686                         if (file->f_flags & O_NONBLOCK) {
 687                                 ret = -EWOULDBLOCK;
 688                                 break;
 689                         }
 690                         if (signal_pending(current)) {
 691                                 ret = -ERESTARTSYS;
 692                                 break;
 693                         }
 694
 695                         mutex_unlock(&ir->irctl_lock);
 696                         schedule();
 697                         set_current_state(TASK_INTERRUPTIBLE);
 698
 699                         if (mutex_lock_interruptible(&ir->irctl_lock)) {
 700                                 ret = -ERESTARTSYS;
 701                                 remove_wait_queue(&ir->buf->wait_poll, &wait);
 702                                 set_current_state(TASK_RUNNING);
 703                                 goto out_unlocked;
 704                         }
 705
 706                         if (!ir->attached) {
 707                                 ret = -ENODEV;
 708                                 break;
 709                         }
 710                 } else {
 711                         lirc_buffer_read(ir->buf, buf);
 712                         ret = copy_to_user((void *)buffer+written, buf,
 713                                            ir->buf->chunk_size);
 714                         written += ir->buf->chunk_size;
 715                 }
 716         }
 717
 718         remove_wait_queue(&ir->buf->wait_poll, &wait);
 719         set_current_state(TASK_RUNNING);
 720         mutex_unlock(&ir->irctl_lock);
 721
 722 out_unlocked:
 723         kfree(buf);
 724         dev_dbg(ir->d.dev, LOGHEAD "read result = %s (%d)\n",
 725                 ir->d.name, ir->d.minor, ret ? "-EFAULT" : "OK", ret);
 726
 727         return ret ? ret : written;
 728 }
 729 EXPORT_SYMBOL(lirc_dev_fop_read);
 730
 731 void *lirc_get_pdata(struct file *file)
 732 {
 733         void *data = NULL;
 734
 735         if (file && file->f_dentry && file->f_dentry->d_inode &&
 736             file->f_dentry->d_inode->i_rdev) {
 737                 struct irctl *ir;
 738                 ir = irctls[iminor(file->f_dentry->d_inode)];
 739                 data = ir->d.data;
 740         }
 741
 742         return data;
 743 }
 744 EXPORT_SYMBOL(lirc_get_pdata);
 745
 746
 747 ssize_t lirc_dev_fop_write(struct file *file, const char *buffer,
 748                            size_t length, loff_t *ppos)
 749 {
 750         struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
 751
 752         if (!ir) {
 753                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 754                 return -ENODEV;
 755         }
 756
 757         dev_dbg(ir->d.dev, LOGHEAD "write called\n", ir->d.name, ir->d.minor);
 758
 759         if (!ir->attached)
 760                 return -ENODEV;
 761
 762         return -EINVAL;
 763 }
 764 EXPORT_SYMBOL(lirc_dev_fop_write);
 765
 766
 767 static int __init lirc_dev_init(void)
 768 {
 769         int retval;
 770
 771         lirc_class = class_create(THIS_MODULE, "lirc");
 772         if (IS_ERR(lirc_class)) {
 773                 retval = PTR_ERR(lirc_class);
 774                 printk(KERN_ERR "lirc_dev: class_create failed\n");
 775                 goto error;
 776         }
 777
 778         retval = alloc_chrdev_region(&lirc_base_dev, 0, MAX_IRCTL_DEVICES,
 779                                      IRCTL_DEV_NAME);
 780         if (retval) {
 781                 class_destroy(lirc_class);
 782                 printk(KERN_ERR "lirc_dev: alloc_chrdev_region failed\n");
 783                 goto error;
 784         }
 785
 786
 787         printk(KERN_INFO "lirc_dev: IR Remote Control driver registered, "
 788                "major %d \n", MAJOR(lirc_base_dev));
 789
 790 error:
 791         return retval;
 792 }
 793
 794
 795
 796 static void __exit lirc_dev_exit(void)
 797 {
 798         class_destroy(lirc_class);
 799         unregister_chrdev_region(lirc_base_dev, MAX_IRCTL_DEVICES);
 800         printk(KERN_INFO "lirc_dev: module unloaded\n");
 801 }
 802
 803 module_init(lirc_dev_init);
 804 module_exit(lirc_dev_exit);
 805
 806 MODULE_DESCRIPTION("LIRC base driver module");
 807 MODULE_AUTHOR("Artur Lipowski");
 808 MODULE_LICENSE("GPL");
 809
 810 module_param(debug, bool, S_IRUGO | S_IWUSR);
 811 MODULE_PARM_DESC(debug, "Enable debugging messages");