drivers/i2c/i2c-dev.c

   1 /*
   2     i2c-dev.c - i2c-bus driver, char device interface
   3
   4     Copyright (C) 1995-97 Simon G. Vogl
   5     Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
   6     Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 /* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
  24    But I have used so much of his original code and ideas that it seems
  25    only fair to recognize him as co-author -- Frodo */
  26
  27 /* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
  28
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/fs.h>
  32 #include <linux/slab.h>
  33 #include <linux/init.h>
  34 #include <linux/list.h>
  35 #include <linux/i2c.h>
  36 #include <linux/i2c-dev.h>
  37 #include <linux/smp_lock.h>
  38 #include <linux/jiffies.h>
  39 #include <asm/uaccess.h>
  40
  41 static struct i2c_driver i2cdev_driver;
  42
  43 /*
  44  * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
  45  * slave (i2c_client) with which messages will be exchanged.  It's coupled
  46  * with a character special file which is accessed by user mode drivers.
  47  *
  48  * The list of i2c_dev structures is parallel to the i2c_adapter lists
  49  * maintained by the driver model, and is updated using notifications
  50  * delivered to the i2cdev_driver.
  51  */
  52 struct i2c_dev {
  53         struct list_head list;
  54         struct i2c_adapter *adap;
  55         struct device *dev;
  56 };
  57
  58 #define I2C_MINORS      256
  59 static LIST_HEAD(i2c_dev_list);
  60 static DEFINE_SPINLOCK(i2c_dev_list_lock);
  61
  62 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  63 {
  64         struct i2c_dev *i2c_dev;
  65
  66         spin_lock(&i2c_dev_list_lock);
  67         list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
  68                 if (i2c_dev->adap->nr == index)
  69                         goto found;
  70         }
  71         i2c_dev = NULL;
  72 found:
  73         spin_unlock(&i2c_dev_list_lock);
  74         return i2c_dev;
  75 }
  76
  77 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  78 {
  79         struct i2c_dev *i2c_dev;
  80
  81         if (adap->nr >= I2C_MINORS) {
  82                 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
  83                        adap->nr);
  84                 return ERR_PTR(-ENODEV);
  85         }
  86
  87         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  88         if (!i2c_dev)
  89                 return ERR_PTR(-ENOMEM);
  90         i2c_dev->adap = adap;
  91
  92         spin_lock(&i2c_dev_list_lock);
  93         list_add_tail(&i2c_dev->list, &i2c_dev_list);
  94         spin_unlock(&i2c_dev_list_lock);
  95         return i2c_dev;
  96 }
  97
  98 static void return_i2c_dev(struct i2c_dev *i2c_dev)
  99 {
 100         spin_lock(&i2c_dev_list_lock);
 101         list_del(&i2c_dev->list);
 102         spin_unlock(&i2c_dev_list_lock);
 103         kfree(i2c_dev);
 104 }
 105
 106 static ssize_t show_adapter_name(struct device *dev,
 107                                  struct device_attribute *attr, char *buf)
 108 {
 109         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
 110
 111         if (!i2c_dev)
 112                 return -ENODEV;
 113         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 114 }
 115 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 116
 117 /* ------------------------------------------------------------------------- */
 118
 119 /*
 120  * After opening an instance of this character special file, a file
 121  * descriptor starts out associated only with an i2c_adapter (and bus).
 122  *
 123  * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
 124  * traffic to any devices on the bus used by that adapter.  That's because
 125  * the i2c_msg vectors embed all the addressing information they need, and
 126  * are submitted directly to an i2c_adapter.  However, SMBus-only adapters
 127  * don't support that interface.
 128  *
 129  * To use read()/write() system calls on that file descriptor, or to use
 130  * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
 131  * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl.  That configures an anonymous
 132  * (never registered) i2c_client so it holds the addressing information
 133  * needed by those system calls and by this SMBus interface.
 134  */
 135
 136 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 137                             loff_t *offset)
 138 {
 139         char *tmp;
 140         int ret;
 141
 142         struct i2c_client *client = (struct i2c_client *)file->private_data;
 143
 144         if (count > 8192)
 145                 count = 8192;
 146
 147         tmp = kmalloc(count,GFP_KERNEL);
 148         if (tmp==NULL)
 149                 return -ENOMEM;
 150
 151         pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
 152                 iminor(file->f_path.dentry->d_inode), count);
 153
 154         ret = i2c_master_recv(client,tmp,count);
 155         if (ret >= 0)
 156                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 157         kfree(tmp);
 158         return ret;
 159 }
 160
 161 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 162                              loff_t *offset)
 163 {
 164         int ret;
 165         char *tmp;
 166         struct i2c_client *client = (struct i2c_client *)file->private_data;
 167
 168         if (count > 8192)
 169                 count = 8192;
 170
 171         tmp = kmalloc(count,GFP_KERNEL);
 172         if (tmp==NULL)
 173                 return -ENOMEM;
 174         if (copy_from_user(tmp,buf,count)) {
 175                 kfree(tmp);
 176                 return -EFAULT;
 177         }
 178
 179         pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
 180                 iminor(file->f_path.dentry->d_inode), count);
 181
 182         ret = i2c_master_send(client,tmp,count);
 183         kfree(tmp);
 184         return ret;
 185 }
 186
 187 static int i2cdev_check(struct device *dev, void *addrp)
 188 {
 189         struct i2c_client *client = i2c_verify_client(dev);
 190
 191         if (!client || client->addr != *(unsigned int *)addrp)
 192                 return 0;
 193
 194         return dev->driver ? -EBUSY : 0;
 195 }
 196
 197 /* This address checking function differs from the one in i2c-core
 198    in that it considers an address with a registered device, but no
 199    driver bound to it, as NOT busy. */
 200 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 201 {
 202         return device_for_each_child(&adapter->dev, &addr, i2cdev_check);
 203 }
 204
 205 static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
 206                 unsigned long arg)
 207 {
 208         struct i2c_rdwr_ioctl_data rdwr_arg;
 209         struct i2c_msg *rdwr_pa;
 210         u8 __user **data_ptrs;
 211         int i, res;
 212
 213         if (copy_from_user(&rdwr_arg,
 214                            (struct i2c_rdwr_ioctl_data __user *)arg,
 215                            sizeof(rdwr_arg)))
 216                 return -EFAULT;
 217
 218         /* Put an arbitrary limit on the number of messages that can
 219          * be sent at once */
 220         if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 221                 return -EINVAL;
 222
 223         rdwr_pa = (struct i2c_msg *)
 224                 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 225                 GFP_KERNEL);
 226         if (!rdwr_pa)
 227                 return -ENOMEM;
 228
 229         if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 230                            rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 231                 kfree(rdwr_pa);
 232                 return -EFAULT;
 233         }
 234
 235         data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 236         if (data_ptrs == NULL) {
 237                 kfree(rdwr_pa);
 238                 return -ENOMEM;
 239         }
 240
 241         res = 0;
 242         for (i = 0; i < rdwr_arg.nmsgs; i++) {
 243                 /* Limit the size of the message to a sane amount;
 244                  * and don't let length change either. */
 245                 if ((rdwr_pa[i].len > 8192) ||
 246                     (rdwr_pa[i].flags & I2C_M_RECV_LEN)) {
 247                         res = -EINVAL;
 248                         break;
 249                 }
 250                 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 251                 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 252                 if (rdwr_pa[i].buf == NULL) {
 253                         res = -ENOMEM;
 254                         break;
 255                 }
 256                 if (copy_from_user(rdwr_pa[i].buf, data_ptrs[i],
 257                                    rdwr_pa[i].len)) {
 258                                 ++i; /* Needs to be kfreed too */
 259                                 res = -EFAULT;
 260                         break;
 261                 }
 262         }
 263         if (res < 0) {
 264                 int j;
 265                 for (j = 0; j < i; ++j)
 266                         kfree(rdwr_pa[j].buf);
 267                 kfree(data_ptrs);
 268                 kfree(rdwr_pa);
 269                 return res;
 270         }
 271
 272         res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
 273         while (i-- > 0) {
 274                 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 275                         if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
 276                                          rdwr_pa[i].len))
 277                                 res = -EFAULT;
 278                 }
 279                 kfree(rdwr_pa[i].buf);
 280         }
 281         kfree(data_ptrs);
 282         kfree(rdwr_pa);
 283         return res;
 284 }
 285
 286 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
 287                 unsigned long arg)
 288 {
 289         struct i2c_smbus_ioctl_data data_arg;
 290         union i2c_smbus_data temp;
 291         int datasize, res;
 292
 293         if (copy_from_user(&data_arg,
 294                            (struct i2c_smbus_ioctl_data __user *) arg,
 295                            sizeof(struct i2c_smbus_ioctl_data)))
 296                 return -EFAULT;
 297         if ((data_arg.size != I2C_SMBUS_BYTE) &&
 298             (data_arg.size != I2C_SMBUS_QUICK) &&
 299             (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 300             (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 301             (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 302             (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 303             (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
 304             (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 305             (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 306                 dev_dbg(&client->adapter->dev,
 307                         "size out of range (%x) in ioctl I2C_SMBUS.\n",
 308                         data_arg.size);
 309                 return -EINVAL;
 310         }
 311         /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 312            so the check is valid if size==I2C_SMBUS_QUICK too. */
 313         if ((data_arg.read_write != I2C_SMBUS_READ) &&
 314             (data_arg.read_write != I2C_SMBUS_WRITE)) {
 315                 dev_dbg(&client->adapter->dev,
 316                         "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 317                         data_arg.read_write);
 318                 return -EINVAL;
 319         }
 320
 321         /* Note that command values are always valid! */
 322
 323         if ((data_arg.size == I2C_SMBUS_QUICK) ||
 324             ((data_arg.size == I2C_SMBUS_BYTE) &&
 325             (data_arg.read_write == I2C_SMBUS_WRITE)))
 326                 /* These are special: we do not use data */
 327                 return i2c_smbus_xfer(client->adapter, client->addr,
 328                                       client->flags, data_arg.read_write,
 329                                       data_arg.command, data_arg.size, NULL);
 330
 331         if (data_arg.data == NULL) {
 332                 dev_dbg(&client->adapter->dev,
 333                         "data is NULL pointer in ioctl I2C_SMBUS.\n");
 334                 return -EINVAL;
 335         }
 336
 337         if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 338             (data_arg.size == I2C_SMBUS_BYTE))
 339                 datasize = sizeof(data_arg.data->byte);
 340         else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 341                  (data_arg.size == I2C_SMBUS_PROC_CALL))
 342                 datasize = sizeof(data_arg.data->word);
 343         else /* size == smbus block, i2c block, or block proc. call */
 344                 datasize = sizeof(data_arg.data->block);
 345
 346         if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 347             (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 348             (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
 349             (data_arg.read_write == I2C_SMBUS_WRITE)) {
 350                 if (copy_from_user(&temp, data_arg.data, datasize))
 351                         return -EFAULT;
 352         }
 353         if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
 354                 /* Convert old I2C block commands to the new
 355                    convention. This preserves binary compatibility. */
 356                 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
 357                 if (data_arg.read_write == I2C_SMBUS_READ)
 358                         temp.block[0] = I2C_SMBUS_BLOCK_MAX;
 359         }
 360         res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 361               data_arg.read_write, data_arg.command, data_arg.size, &temp);
 362         if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 363                      (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 364                      (data_arg.read_write == I2C_SMBUS_READ))) {
 365                 if (copy_to_user(data_arg.data, &temp, datasize))
 366                         return -EFAULT;
 367         }
 368         return res;
 369 }
 370
 371 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 372 {
 373         struct i2c_client *client = (struct i2c_client *)file->private_data;
 374         unsigned long funcs;
 375
 376         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 377                 cmd, arg);
 378
 379         switch ( cmd ) {
 380         case I2C_SLAVE:
 381         case I2C_SLAVE_FORCE:
 382                 /* NOTE:  devices set up to work with "new style" drivers
 383                  * can't use I2C_SLAVE, even when the device node is not
 384                  * bound to a driver.  Only I2C_SLAVE_FORCE will work.
 385                  *
 386                  * Setting the PEC flag here won't affect kernel drivers,
 387                  * which will be using the i2c_client node registered with
 388                  * the driver model core.  Likewise, when that client has
 389                  * the PEC flag already set, the i2c-dev driver won't see
 390                  * (or use) this setting.
 391                  */
 392                 if ((arg > 0x3ff) ||
 393                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 394                         return -EINVAL;
 395                 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
 396                         return -EBUSY;
 397                 /* REVISIT: address could become busy later */
 398                 client->addr = arg;
 399                 return 0;
 400         case I2C_TENBIT:
 401                 if (arg)
 402                         client->flags |= I2C_M_TEN;
 403                 else
 404                         client->flags &= ~I2C_M_TEN;
 405                 return 0;
 406         case I2C_PEC:
 407                 if (arg)
 408                         client->flags |= I2C_CLIENT_PEC;
 409                 else
 410                         client->flags &= ~I2C_CLIENT_PEC;
 411                 return 0;
 412         case I2C_FUNCS:
 413                 funcs = i2c_get_functionality(client->adapter);
 414                 return put_user(funcs, (unsigned long __user *)arg);
 415
 416         case I2C_RDWR:
 417                 return i2cdev_ioctl_rdrw(client, arg);
 418
 419         case I2C_SMBUS:
 420                 return i2cdev_ioctl_smbus(client, arg);
 421
 422         case I2C_RETRIES:
 423                 client->adapter->retries = arg;
 424                 break;
 425         case I2C_TIMEOUT:
 426                 /* For historical reasons, user-space sets the timeout
 427                  * value in units of 10 ms.
 428                  */
 429                 client->adapter->timeout = msecs_to_jiffies(arg * 10);
 430                 break;
 431         default:
 432                 /* NOTE:  returning a fault code here could cause trouble
 433                  * in buggy userspace code.  Some old kernel bugs returned
 434                  * zero in this case, and userspace code might accidentally
 435                  * have depended on that bug.
 436                  */
 437                 return -ENOTTY;
 438         }
 439         return 0;
 440 }
 441
 442 static int i2cdev_open(struct inode *inode, struct file *file)
 443 {
 444         unsigned int minor = iminor(inode);
 445         struct i2c_client *client;
 446         struct i2c_adapter *adap;
 447         struct i2c_dev *i2c_dev;
 448         int ret = 0;
 449
 450         lock_kernel();
 451         i2c_dev = i2c_dev_get_by_minor(minor);
 452         if (!i2c_dev) {
 453                 ret = -ENODEV;
 454                 goto out;
 455         }
 456
 457         adap = i2c_get_adapter(i2c_dev->adap->nr);
 458         if (!adap) {
 459                 ret = -ENODEV;
 460                 goto out;
 461         }
 462
 463         /* This creates an anonymous i2c_client, which may later be
 464          * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
 465          *
 466          * This client is ** NEVER REGISTERED ** with the driver model
 467          * or I2C core code!!  It just holds private copies of addressing
 468          * information and maybe a PEC flag.
 469          */
 470         client = kzalloc(sizeof(*client), GFP_KERNEL);
 471         if (!client) {
 472                 i2c_put_adapter(adap);
 473                 ret = -ENOMEM;
 474                 goto out;
 475         }
 476         snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 477         client->driver = &i2cdev_driver;
 478
 479         client->adapter = adap;
 480         file->private_data = client;
 481
 482 out:
 483         unlock_kernel();
 484         return ret;
 485 }
 486
 487 static int i2cdev_release(struct inode *inode, struct file *file)
 488 {
 489         struct i2c_client *client = file->private_data;
 490
 491         i2c_put_adapter(client->adapter);
 492         kfree(client);
 493         file->private_data = NULL;
 494
 495         return 0;
 496 }
 497
 498 static const struct file_operations i2cdev_fops = {
 499         .owner          = THIS_MODULE,
 500         .llseek         = no_llseek,
 501         .read           = i2cdev_read,
 502         .write          = i2cdev_write,
 503         .unlocked_ioctl = i2cdev_ioctl,
 504         .open           = i2cdev_open,
 505         .release        = i2cdev_release,
 506 };
 507
 508 /* ------------------------------------------------------------------------- */
 509
 510 /*
 511  * The legacy "i2cdev_driver" is used primarily to get notifications when
 512  * I2C adapters are added or removed, so that each one gets an i2c_dev
 513  * and is thus made available to userspace driver code.
 514  */
 515
 516 static struct class *i2c_dev_class;
 517
 518 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 519 {
 520         struct i2c_dev *i2c_dev;
 521         int res;
 522
 523         i2c_dev = get_free_i2c_dev(adap);
 524         if (IS_ERR(i2c_dev))
 525                 return PTR_ERR(i2c_dev);
 526
 527         /* register this i2c device with the driver core */
 528         i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
 529                                      MKDEV(I2C_MAJOR, adap->nr), NULL,
 530                                      "i2c-%d", adap->nr);
 531         if (IS_ERR(i2c_dev->dev)) {
 532                 res = PTR_ERR(i2c_dev->dev);
 533                 goto error;
 534         }
 535         res = device_create_file(i2c_dev->dev, &dev_attr_name);
 536         if (res)
 537                 goto error_destroy;
 538
 539         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 540                  adap->name, adap->nr);
 541         return 0;
 542 error_destroy:
 543         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 544 error:
 545         return_i2c_dev(i2c_dev);
 546         return res;
 547 }
 548
 549 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 550 {
 551         struct i2c_dev *i2c_dev;
 552
 553         i2c_dev = i2c_dev_get_by_minor(adap->nr);
 554         if (!i2c_dev) /* attach_adapter must have failed */
 555                 return 0;
 556
 557         device_remove_file(i2c_dev->dev, &dev_attr_name);
 558         return_i2c_dev(i2c_dev);
 559         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 560
 561         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 562         return 0;
 563 }
 564
 565 static struct i2c_driver i2cdev_driver = {
 566         .driver = {
 567                 .name   = "dev_driver",
 568         },
 569         .attach_adapter = i2cdev_attach_adapter,
 570         .detach_adapter = i2cdev_detach_adapter,
 571 };
 572
 573 /* ------------------------------------------------------------------------- */
 574
 575 /*
 576  * module load/unload record keeping
 577  */
 578
 579 static int __init i2c_dev_init(void)
 580 {
 581         int res;
 582
 583         printk(KERN_INFO "i2c /dev entries driver\n");
 584
 585         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 586         if (res)
 587                 goto out;
 588
 589         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
 590         if (IS_ERR(i2c_dev_class)) {
 591                 res = PTR_ERR(i2c_dev_class);
 592                 goto out_unreg_chrdev;
 593         }
 594
 595         res = i2c_add_driver(&i2cdev_driver);
 596         if (res)
 597                 goto out_unreg_class;
 598
 599         return 0;
 600
 601 out_unreg_class:
 602         class_destroy(i2c_dev_class);
 603 out_unreg_chrdev:
 604         unregister_chrdev(I2C_MAJOR, "i2c");
 605 out:
 606         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 607         return res;
 608 }
 609
 610 static void __exit i2c_dev_exit(void)
 611 {
 612         i2c_del_driver(&i2cdev_driver);
 613         class_destroy(i2c_dev_class);
 614         unregister_chrdev(I2C_MAJOR,"i2c");
 615 }
 616
 617 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 618                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 619 MODULE_DESCRIPTION("I2C /dev entries driver");
 620 MODULE_LICENSE("GPL");
 621
 622 module_init(i2c_dev_init);
 623 module_exit(i2c_dev_exit);