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., 51 Franklin Street, Fifth Floor, Boston,
  21     MA 02110-1301 USA.
  22 */
  23
  24 /* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
  25    But I have used so much of his original code and ideas that it seems
  26    only fair to recognize him as co-author -- Frodo */
  27
  28 /* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/device.h>
  33 #include <linux/notifier.h>
  34 #include <linux/fs.h>
  35 #include <linux/slab.h>
  36 #include <linux/init.h>
  37 #include <linux/list.h>
  38 #include <linux/i2c.h>
  39 #include <linux/i2c-dev.h>
  40 #include <linux/jiffies.h>
  41 #include <linux/uaccess.h>
  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 bus notifications.
  50  */
  51 struct i2c_dev {
  52         struct list_head list;
  53         struct i2c_adapter *adap;
  54         struct device *dev;
  55 };
  56
  57 #define I2C_MINORS      256
  58 static LIST_HEAD(i2c_dev_list);
  59 static DEFINE_SPINLOCK(i2c_dev_list_lock);
  60
  61 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  62 {
  63         struct i2c_dev *i2c_dev;
  64
  65         spin_lock(&i2c_dev_list_lock);
  66         list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
  67                 if (i2c_dev->adap->nr == index)
  68                         goto found;
  69         }
  70         i2c_dev = NULL;
  71 found:
  72         spin_unlock(&i2c_dev_list_lock);
  73         return i2c_dev;
  74 }
  75
  76 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  77 {
  78         struct i2c_dev *i2c_dev;
  79
  80         if (adap->nr >= I2C_MINORS) {
  81                 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
  82                        adap->nr);
  83                 return ERR_PTR(-ENODEV);
  84         }
  85
  86         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  87         if (!i2c_dev)
  88                 return ERR_PTR(-ENOMEM);
  89         i2c_dev->adap = adap;
  90
  91         spin_lock(&i2c_dev_list_lock);
  92         list_add_tail(&i2c_dev->list, &i2c_dev_list);
  93         spin_unlock(&i2c_dev_list_lock);
  94         return i2c_dev;
  95 }
  96
  97 static void return_i2c_dev(struct i2c_dev *i2c_dev)
  98 {
  99         spin_lock(&i2c_dev_list_lock);
 100         list_del(&i2c_dev->list);
 101         spin_unlock(&i2c_dev_list_lock);
 102         kfree(i2c_dev);
 103 }
 104
 105 static ssize_t name_show(struct device *dev,
 106                          struct device_attribute *attr, char *buf)
 107 {
 108         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
 109
 110         if (!i2c_dev)
 111                 return -ENODEV;
 112         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 113 }
 114 static DEVICE_ATTR_RO(name);
 115
 116 static struct attribute *i2c_attrs[] = {
 117         &dev_attr_name.attr,
 118         NULL,
 119 };
 120 ATTRIBUTE_GROUPS(i2c);
 121
 122 /* ------------------------------------------------------------------------- */
 123
 124 /*
 125  * After opening an instance of this character special file, a file
 126  * descriptor starts out associated only with an i2c_adapter (and bus).
 127  *
 128  * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
 129  * traffic to any devices on the bus used by that adapter.  That's because
 130  * the i2c_msg vectors embed all the addressing information they need, and
 131  * are submitted directly to an i2c_adapter.  However, SMBus-only adapters
 132  * don't support that interface.
 133  *
 134  * To use read()/write() system calls on that file descriptor, or to use
 135  * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
 136  * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl.  That configures an anonymous
 137  * (never registered) i2c_client so it holds the addressing information
 138  * needed by those system calls and by this SMBus interface.
 139  */
 140
 141 static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
 142                 loff_t *offset)
 143 {
 144         char *tmp;
 145         int ret;
 146
 147         struct i2c_client *client = file->private_data;
 148
 149         if (count > 8192)
 150                 count = 8192;
 151
 152         tmp = kmalloc(count, GFP_KERNEL);
 153         if (tmp == NULL)
 154                 return -ENOMEM;
 155
 156         pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
 157                 iminor(file_inode(file)), count);
 158
 159         ret = i2c_master_recv(client, tmp, count);
 160         if (ret >= 0)
 161                 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
 162         kfree(tmp);
 163         return ret;
 164 }
 165
 166 static ssize_t i2cdev_write(struct file *file, const char __user *buf,
 167                 size_t count, loff_t *offset)
 168 {
 169         int ret;
 170         char *tmp;
 171         struct i2c_client *client = file->private_data;
 172
 173         if (count > 8192)
 174                 count = 8192;
 175
 176         tmp = memdup_user(buf, count);
 177         if (IS_ERR(tmp))
 178                 return PTR_ERR(tmp);
 179
 180         pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
 181                 iminor(file_inode(file)), count);
 182
 183         ret = i2c_master_send(client, tmp, count);
 184         kfree(tmp);
 185         return ret;
 186 }
 187
 188 static int i2cdev_check(struct device *dev, void *addrp)
 189 {
 190         struct i2c_client *client = i2c_verify_client(dev);
 191
 192         if (!client || client->addr != *(unsigned int *)addrp)
 193                 return 0;
 194
 195         return dev->driver ? -EBUSY : 0;
 196 }
 197
 198 /* walk up mux tree */
 199 static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
 200 {
 201         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 202         int result;
 203
 204         result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
 205         if (!result && parent)
 206                 result = i2cdev_check_mux_parents(parent, addr);
 207
 208         return result;
 209 }
 210
 211 /* recurse down mux tree */
 212 static int i2cdev_check_mux_children(struct device *dev, void *addrp)
 213 {
 214         int result;
 215
 216         if (dev->type == &i2c_adapter_type)
 217                 result = device_for_each_child(dev, addrp,
 218                                                 i2cdev_check_mux_children);
 219         else
 220                 result = i2cdev_check(dev, addrp);
 221
 222         return result;
 223 }
 224
 225 /* This address checking function differs from the one in i2c-core
 226    in that it considers an address with a registered device, but no
 227    driver bound to it, as NOT busy. */
 228 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 229 {
 230         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 231         int result = 0;
 232
 233         if (parent)
 234                 result = i2cdev_check_mux_parents(parent, addr);
 235
 236         if (!result)
 237                 result = device_for_each_child(&adapter->dev, &addr,
 238                                                 i2cdev_check_mux_children);
 239
 240         return result;
 241 }
 242
 243 static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
 244                 unsigned long arg)
 245 {
 246         struct i2c_rdwr_ioctl_data rdwr_arg;
 247         struct i2c_msg *rdwr_pa;
 248         u8 __user **data_ptrs;
 249         int i, res;
 250
 251         if (copy_from_user(&rdwr_arg,
 252                            (struct i2c_rdwr_ioctl_data __user *)arg,
 253                            sizeof(rdwr_arg)))
 254                 return -EFAULT;
 255
 256         /* Put an arbitrary limit on the number of messages that can
 257          * be sent at once */
 258         if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 259                 return -EINVAL;
 260
 261         rdwr_pa = memdup_user(rdwr_arg.msgs,
 262                               rdwr_arg.nmsgs * sizeof(struct i2c_msg));
 263         if (IS_ERR(rdwr_pa))
 264                 return PTR_ERR(rdwr_pa);
 265
 266         data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 267         if (data_ptrs == NULL) {
 268                 kfree(rdwr_pa);
 269                 return -ENOMEM;
 270         }
 271
 272         res = 0;
 273         for (i = 0; i < rdwr_arg.nmsgs; i++) {
 274                 /* Limit the size of the message to a sane amount */
 275                 if (rdwr_pa[i].len > 8192) {
 276                         res = -EINVAL;
 277                         break;
 278                 }
 279
 280                 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 281                 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
 282                 if (IS_ERR(rdwr_pa[i].buf)) {
 283                         res = PTR_ERR(rdwr_pa[i].buf);
 284                         break;
 285                 }
 286
 287                 /*
 288                  * If the message length is received from the slave (similar
 289                  * to SMBus block read), we must ensure that the buffer will
 290                  * be large enough to cope with a message length of
 291                  * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
 292                  * drivers allow. The first byte in the buffer must be
 293                  * pre-filled with the number of extra bytes, which must be
 294                  * at least one to hold the message length, but can be
 295                  * greater (for example to account for a checksum byte at
 296                  * the end of the message.)
 297                  */
 298                 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
 299                         if (!(rdwr_pa[i].flags & I2C_M_RD) ||
 300                             rdwr_pa[i].buf[0] < 1 ||
 301                             rdwr_pa[i].len < rdwr_pa[i].buf[0] +
 302                                              I2C_SMBUS_BLOCK_MAX) {
 303                                 res = -EINVAL;
 304                                 break;
 305                         }
 306
 307                         rdwr_pa[i].len = rdwr_pa[i].buf[0];
 308                 }
 309         }
 310         if (res < 0) {
 311                 int j;
 312                 for (j = 0; j < i; ++j)
 313                         kfree(rdwr_pa[j].buf);
 314                 kfree(data_ptrs);
 315                 kfree(rdwr_pa);
 316                 return res;
 317         }
 318
 319         res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
 320         while (i-- > 0) {
 321                 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 322                         if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
 323                                          rdwr_pa[i].len))
 324                                 res = -EFAULT;
 325                 }
 326                 kfree(rdwr_pa[i].buf);
 327         }
 328         kfree(data_ptrs);
 329         kfree(rdwr_pa);
 330         return res;
 331 }
 332
 333 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
 334                 unsigned long arg)
 335 {
 336         struct i2c_smbus_ioctl_data data_arg;
 337         union i2c_smbus_data temp;
 338         int datasize, res;
 339
 340         if (copy_from_user(&data_arg,
 341                            (struct i2c_smbus_ioctl_data __user *) arg,
 342                            sizeof(struct i2c_smbus_ioctl_data)))
 343                 return -EFAULT;
 344         if ((data_arg.size != I2C_SMBUS_BYTE) &&
 345             (data_arg.size != I2C_SMBUS_QUICK) &&
 346             (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 347             (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 348             (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 349             (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 350             (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
 351             (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 352             (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 353                 dev_dbg(&client->adapter->dev,
 354                         "size out of range (%x) in ioctl I2C_SMBUS.\n",
 355                         data_arg.size);
 356                 return -EINVAL;
 357         }
 358         /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 359            so the check is valid if size==I2C_SMBUS_QUICK too. */
 360         if ((data_arg.read_write != I2C_SMBUS_READ) &&
 361             (data_arg.read_write != I2C_SMBUS_WRITE)) {
 362                 dev_dbg(&client->adapter->dev,
 363                         "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 364                         data_arg.read_write);
 365                 return -EINVAL;
 366         }
 367
 368         /* Note that command values are always valid! */
 369
 370         if ((data_arg.size == I2C_SMBUS_QUICK) ||
 371             ((data_arg.size == I2C_SMBUS_BYTE) &&
 372             (data_arg.read_write == I2C_SMBUS_WRITE)))
 373                 /* These are special: we do not use data */
 374                 return i2c_smbus_xfer(client->adapter, client->addr,
 375                                       client->flags, data_arg.read_write,
 376                                       data_arg.command, data_arg.size, NULL);
 377
 378         if (data_arg.data == NULL) {
 379                 dev_dbg(&client->adapter->dev,
 380                         "data is NULL pointer in ioctl I2C_SMBUS.\n");
 381                 return -EINVAL;
 382         }
 383
 384         if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 385             (data_arg.size == I2C_SMBUS_BYTE))
 386                 datasize = sizeof(data_arg.data->byte);
 387         else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 388                  (data_arg.size == I2C_SMBUS_PROC_CALL))
 389                 datasize = sizeof(data_arg.data->word);
 390         else /* size == smbus block, i2c block, or block proc. call */
 391                 datasize = sizeof(data_arg.data->block);
 392
 393         if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 394             (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 395             (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
 396             (data_arg.read_write == I2C_SMBUS_WRITE)) {
 397                 if (copy_from_user(&temp, data_arg.data, datasize))
 398                         return -EFAULT;
 399         }
 400         if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
 401                 /* Convert old I2C block commands to the new
 402                    convention. This preserves binary compatibility. */
 403                 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
 404                 if (data_arg.read_write == I2C_SMBUS_READ)
 405                         temp.block[0] = I2C_SMBUS_BLOCK_MAX;
 406         }
 407         res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 408               data_arg.read_write, data_arg.command, data_arg.size, &temp);
 409         if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 410                      (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 411                      (data_arg.read_write == I2C_SMBUS_READ))) {
 412                 if (copy_to_user(data_arg.data, &temp, datasize))
 413                         return -EFAULT;
 414         }
 415         return res;
 416 }
 417
 418 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 419 {
 420         struct i2c_client *client = file->private_data;
 421         unsigned long funcs;
 422
 423         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 424                 cmd, arg);
 425
 426         switch (cmd) {
 427         case I2C_SLAVE:
 428         case I2C_SLAVE_FORCE:
 429                 /* NOTE:  devices set up to work with "new style" drivers
 430                  * can't use I2C_SLAVE, even when the device node is not
 431                  * bound to a driver.  Only I2C_SLAVE_FORCE will work.
 432                  *
 433                  * Setting the PEC flag here won't affect kernel drivers,
 434                  * which will be using the i2c_client node registered with
 435                  * the driver model core.  Likewise, when that client has
 436                  * the PEC flag already set, the i2c-dev driver won't see
 437                  * (or use) this setting.
 438                  */
 439                 if ((arg > 0x3ff) ||
 440                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 441                         return -EINVAL;
 442                 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
 443                         return -EBUSY;
 444                 /* REVISIT: address could become busy later */
 445                 client->addr = arg;
 446                 return 0;
 447         case I2C_TENBIT:
 448                 if (arg)
 449                         client->flags |= I2C_M_TEN;
 450                 else
 451                         client->flags &= ~I2C_M_TEN;
 452                 return 0;
 453         case I2C_PEC:
 454                 if (arg)
 455                         client->flags |= I2C_CLIENT_PEC;
 456                 else
 457                         client->flags &= ~I2C_CLIENT_PEC;
 458                 return 0;
 459         case I2C_FUNCS:
 460                 funcs = i2c_get_functionality(client->adapter);
 461                 return put_user(funcs, (unsigned long __user *)arg);
 462
 463         case I2C_RDWR:
 464                 return i2cdev_ioctl_rdrw(client, arg);
 465
 466         case I2C_SMBUS:
 467                 return i2cdev_ioctl_smbus(client, arg);
 468
 469         case I2C_RETRIES:
 470                 client->adapter->retries = arg;
 471                 break;
 472         case I2C_TIMEOUT:
 473                 /* For historical reasons, user-space sets the timeout
 474                  * value in units of 10 ms.
 475                  */
 476                 client->adapter->timeout = msecs_to_jiffies(arg * 10);
 477                 break;
 478         default:
 479                 /* NOTE:  returning a fault code here could cause trouble
 480                  * in buggy userspace code.  Some old kernel bugs returned
 481                  * zero in this case, and userspace code might accidentally
 482                  * have depended on that bug.
 483                  */
 484                 return -ENOTTY;
 485         }
 486         return 0;
 487 }
 488
 489 static int i2cdev_open(struct inode *inode, struct file *file)
 490 {
 491         unsigned int minor = iminor(inode);
 492         struct i2c_client *client;
 493         struct i2c_adapter *adap;
 494         struct i2c_dev *i2c_dev;
 495
 496         i2c_dev = i2c_dev_get_by_minor(minor);
 497         if (!i2c_dev)
 498                 return -ENODEV;
 499
 500         adap = i2c_get_adapter(i2c_dev->adap->nr);
 501         if (!adap)
 502                 return -ENODEV;
 503
 504         /* This creates an anonymous i2c_client, which may later be
 505          * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
 506          *
 507          * This client is ** NEVER REGISTERED ** with the driver model
 508          * or I2C core code!!  It just holds private copies of addressing
 509          * information and maybe a PEC flag.
 510          */
 511         client = kzalloc(sizeof(*client), GFP_KERNEL);
 512         if (!client) {
 513                 i2c_put_adapter(adap);
 514                 return -ENOMEM;
 515         }
 516         snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 517
 518         client->adapter = adap;
 519         file->private_data = client;
 520
 521         return 0;
 522 }
 523
 524 static int i2cdev_release(struct inode *inode, struct file *file)
 525 {
 526         struct i2c_client *client = file->private_data;
 527
 528         i2c_put_adapter(client->adapter);
 529         kfree(client);
 530         file->private_data = NULL;
 531
 532         return 0;
 533 }
 534
 535 static const struct file_operations i2cdev_fops = {
 536         .owner          = THIS_MODULE,
 537         .llseek         = no_llseek,
 538         .read           = i2cdev_read,
 539         .write          = i2cdev_write,
 540         .unlocked_ioctl = i2cdev_ioctl,
 541         .open           = i2cdev_open,
 542         .release        = i2cdev_release,
 543 };
 544
 545 /* ------------------------------------------------------------------------- */
 546
 547 static struct class *i2c_dev_class;
 548
 549 static int i2cdev_attach_adapter(struct device *dev, void *dummy)
 550 {
 551         struct i2c_adapter *adap;
 552         struct i2c_dev *i2c_dev;
 553         int res;
 554
 555         if (dev->type != &i2c_adapter_type)
 556                 return 0;
 557         adap = to_i2c_adapter(dev);
 558
 559         i2c_dev = get_free_i2c_dev(adap);
 560         if (IS_ERR(i2c_dev))
 561                 return PTR_ERR(i2c_dev);
 562
 563         /* register this i2c device with the driver core */
 564         i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
 565                                      MKDEV(I2C_MAJOR, adap->nr), NULL,
 566                                      "i2c-%d", adap->nr);
 567         if (IS_ERR(i2c_dev->dev)) {
 568                 res = PTR_ERR(i2c_dev->dev);
 569                 goto error;
 570         }
 571
 572         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 573                  adap->name, adap->nr);
 574         return 0;
 575 error:
 576         return_i2c_dev(i2c_dev);
 577         return res;
 578 }
 579
 580 static int i2cdev_detach_adapter(struct device *dev, void *dummy)
 581 {
 582         struct i2c_adapter *adap;
 583         struct i2c_dev *i2c_dev;
 584
 585         if (dev->type != &i2c_adapter_type)
 586                 return 0;
 587         adap = to_i2c_adapter(dev);
 588
 589         i2c_dev = i2c_dev_get_by_minor(adap->nr);
 590         if (!i2c_dev) /* attach_adapter must have failed */
 591                 return 0;
 592
 593         return_i2c_dev(i2c_dev);
 594         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 595
 596         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 597         return 0;
 598 }
 599
 600 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
 601                          void *data)
 602 {
 603         struct device *dev = data;
 604
 605         switch (action) {
 606         case BUS_NOTIFY_ADD_DEVICE:
 607                 return i2cdev_attach_adapter(dev, NULL);
 608         case BUS_NOTIFY_DEL_DEVICE:
 609                 return i2cdev_detach_adapter(dev, NULL);
 610         }
 611
 612         return 0;
 613 }
 614
 615 static struct notifier_block i2cdev_notifier = {
 616         .notifier_call = i2cdev_notifier_call,
 617 };
 618
 619 /* ------------------------------------------------------------------------- */
 620
 621 /*
 622  * module load/unload record keeping
 623  */
 624
 625 static int __init i2c_dev_init(void)
 626 {
 627         int res;
 628
 629         printk(KERN_INFO "i2c /dev entries driver\n");
 630
 631         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 632         if (res)
 633                 goto out;
 634
 635         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
 636         if (IS_ERR(i2c_dev_class)) {
 637                 res = PTR_ERR(i2c_dev_class);
 638                 goto out_unreg_chrdev;
 639         }
 640         i2c_dev_class->dev_groups = i2c_groups;
 641
 642         /* Keep track of adapters which will be added or removed later */
 643         res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
 644         if (res)
 645                 goto out_unreg_class;
 646
 647         /* Bind to already existing adapters right away */
 648         i2c_for_each_dev(NULL, i2cdev_attach_adapter);
 649
 650         return 0;
 651
 652 out_unreg_class:
 653         class_destroy(i2c_dev_class);
 654 out_unreg_chrdev:
 655         unregister_chrdev(I2C_MAJOR, "i2c");
 656 out:
 657         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 658         return res;
 659 }
 660
 661 static void __exit i2c_dev_exit(void)
 662 {
 663         bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
 664         i2c_for_each_dev(NULL, i2cdev_detach_adapter);
 665         class_destroy(i2c_dev_class);
 666         unregister_chrdev(I2C_MAJOR, "i2c");
 667 }
 668
 669 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 670                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 671 MODULE_DESCRIPTION("I2C /dev entries driver");
 672 MODULE_LICENSE("GPL");
 673
 674 module_init(i2c_dev_init);
 675 module_exit(i2c_dev_exit);