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
  19 /* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
  20    But I have used so much of his original code and ideas that it seems
  21    only fair to recognize him as co-author -- Frodo */
  22
  23 /* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/device.h>
  28 #include <linux/notifier.h>
  29 #include <linux/fs.h>
  30 #include <linux/slab.h>
  31 #include <linux/init.h>
  32 #include <linux/list.h>
  33 #include <linux/i2c.h>
  34 #include <linux/i2c-dev.h>
  35 #include <linux/jiffies.h>
  36 #include <linux/uaccess.h>
  37
  38 /*
  39  * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
  40  * slave (i2c_client) with which messages will be exchanged.  It's coupled
  41  * with a character special file which is accessed by user mode drivers.
  42  *
  43  * The list of i2c_dev structures is parallel to the i2c_adapter lists
  44  * maintained by the driver model, and is updated using bus notifications.
  45  */
  46 struct i2c_dev {
  47         struct list_head list;
  48         struct i2c_adapter *adap;
  49         struct device *dev;
  50 };
  51
  52 #define I2C_MINORS      256
  53 static LIST_HEAD(i2c_dev_list);
  54 static DEFINE_SPINLOCK(i2c_dev_list_lock);
  55
  56 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  57 {
  58         struct i2c_dev *i2c_dev;
  59
  60         spin_lock(&i2c_dev_list_lock);
  61         list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
  62                 if (i2c_dev->adap->nr == index)
  63                         goto found;
  64         }
  65         i2c_dev = NULL;
  66 found:
  67         spin_unlock(&i2c_dev_list_lock);
  68         return i2c_dev;
  69 }
  70
  71 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  72 {
  73         struct i2c_dev *i2c_dev;
  74
  75         if (adap->nr >= I2C_MINORS) {
  76                 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
  77                        adap->nr);
  78                 return ERR_PTR(-ENODEV);
  79         }
  80
  81         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  82         if (!i2c_dev)
  83                 return ERR_PTR(-ENOMEM);
  84         i2c_dev->adap = adap;
  85
  86         spin_lock(&i2c_dev_list_lock);
  87         list_add_tail(&i2c_dev->list, &i2c_dev_list);
  88         spin_unlock(&i2c_dev_list_lock);
  89         return i2c_dev;
  90 }
  91
  92 static void return_i2c_dev(struct i2c_dev *i2c_dev)
  93 {
  94         spin_lock(&i2c_dev_list_lock);
  95         list_del(&i2c_dev->list);
  96         spin_unlock(&i2c_dev_list_lock);
  97         kfree(i2c_dev);
  98 }
  99
 100 static ssize_t name_show(struct device *dev,
 101                          struct device_attribute *attr, char *buf)
 102 {
 103         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
 104
 105         if (!i2c_dev)
 106                 return -ENODEV;
 107         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 108 }
 109 static DEVICE_ATTR_RO(name);
 110
 111 static struct attribute *i2c_attrs[] = {
 112         &dev_attr_name.attr,
 113         NULL,
 114 };
 115 ATTRIBUTE_GROUPS(i2c);
 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 = 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_inode(file)), 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,
 162                 size_t count, loff_t *offset)
 163 {
 164         int ret;
 165         char *tmp;
 166         struct i2c_client *client = file->private_data;
 167
 168         if (count > 8192)
 169                 count = 8192;
 170
 171         tmp = memdup_user(buf, count);
 172         if (IS_ERR(tmp))
 173                 return PTR_ERR(tmp);
 174
 175         pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
 176                 iminor(file_inode(file)), count);
 177
 178         ret = i2c_master_send(client, tmp, count);
 179         kfree(tmp);
 180         return ret;
 181 }
 182
 183 static int i2cdev_check(struct device *dev, void *addrp)
 184 {
 185         struct i2c_client *client = i2c_verify_client(dev);
 186
 187         if (!client || client->addr != *(unsigned int *)addrp)
 188                 return 0;
 189
 190         return dev->driver ? -EBUSY : 0;
 191 }
 192
 193 /* walk up mux tree */
 194 static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
 195 {
 196         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 197         int result;
 198
 199         result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
 200         if (!result && parent)
 201                 result = i2cdev_check_mux_parents(parent, addr);
 202
 203         return result;
 204 }
 205
 206 /* recurse down mux tree */
 207 static int i2cdev_check_mux_children(struct device *dev, void *addrp)
 208 {
 209         int result;
 210
 211         if (dev->type == &i2c_adapter_type)
 212                 result = device_for_each_child(dev, addrp,
 213                                                 i2cdev_check_mux_children);
 214         else
 215                 result = i2cdev_check(dev, addrp);
 216
 217         return result;
 218 }
 219
 220 /* This address checking function differs from the one in i2c-core
 221    in that it considers an address with a registered device, but no
 222    driver bound to it, as NOT busy. */
 223 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 224 {
 225         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 226         int result = 0;
 227
 228         if (parent)
 229                 result = i2cdev_check_mux_parents(parent, addr);
 230
 231         if (!result)
 232                 result = device_for_each_child(&adapter->dev, &addr,
 233                                                 i2cdev_check_mux_children);
 234
 235         return result;
 236 }
 237
 238 static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
 239                 unsigned long arg)
 240 {
 241         struct i2c_rdwr_ioctl_data rdwr_arg;
 242         struct i2c_msg *rdwr_pa;
 243         u8 __user **data_ptrs;
 244         int i, res;
 245
 246         if (copy_from_user(&rdwr_arg,
 247                            (struct i2c_rdwr_ioctl_data __user *)arg,
 248                            sizeof(rdwr_arg)))
 249                 return -EFAULT;
 250
 251         /* Put an arbitrary limit on the number of messages that can
 252          * be sent at once */
 253         if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 254                 return -EINVAL;
 255
 256         rdwr_pa = memdup_user(rdwr_arg.msgs,
 257                               rdwr_arg.nmsgs * sizeof(struct i2c_msg));
 258         if (IS_ERR(rdwr_pa))
 259                 return PTR_ERR(rdwr_pa);
 260
 261         data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 262         if (data_ptrs == NULL) {
 263                 kfree(rdwr_pa);
 264                 return -ENOMEM;
 265         }
 266
 267         res = 0;
 268         for (i = 0; i < rdwr_arg.nmsgs; i++) {
 269                 /* Limit the size of the message to a sane amount */
 270                 if (rdwr_pa[i].len > 8192) {
 271                         res = -EINVAL;
 272                         break;
 273                 }
 274
 275                 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 276                 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
 277                 if (IS_ERR(rdwr_pa[i].buf)) {
 278                         res = PTR_ERR(rdwr_pa[i].buf);
 279                         break;
 280                 }
 281
 282                 /*
 283                  * If the message length is received from the slave (similar
 284                  * to SMBus block read), we must ensure that the buffer will
 285                  * be large enough to cope with a message length of
 286                  * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
 287                  * drivers allow. The first byte in the buffer must be
 288                  * pre-filled with the number of extra bytes, which must be
 289                  * at least one to hold the message length, but can be
 290                  * greater (for example to account for a checksum byte at
 291                  * the end of the message.)
 292                  */
 293                 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
 294                         if (!(rdwr_pa[i].flags & I2C_M_RD) ||
 295                             rdwr_pa[i].buf[0] < 1 ||
 296                             rdwr_pa[i].len < rdwr_pa[i].buf[0] +
 297                                              I2C_SMBUS_BLOCK_MAX) {
 298                                 res = -EINVAL;
 299                                 break;
 300                         }
 301
 302                         rdwr_pa[i].len = rdwr_pa[i].buf[0];
 303                 }
 304         }
 305         if (res < 0) {
 306                 int j;
 307                 for (j = 0; j < i; ++j)
 308                         kfree(rdwr_pa[j].buf);
 309                 kfree(data_ptrs);
 310                 kfree(rdwr_pa);
 311                 return res;
 312         }
 313
 314         res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
 315         while (i-- > 0) {
 316                 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 317                         if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
 318                                          rdwr_pa[i].len))
 319                                 res = -EFAULT;
 320                 }
 321                 kfree(rdwr_pa[i].buf);
 322         }
 323         kfree(data_ptrs);
 324         kfree(rdwr_pa);
 325         return res;
 326 }
 327
 328 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
 329                 unsigned long arg)
 330 {
 331         struct i2c_smbus_ioctl_data data_arg;
 332         union i2c_smbus_data temp;
 333         int datasize, res;
 334
 335         if (copy_from_user(&data_arg,
 336                            (struct i2c_smbus_ioctl_data __user *) arg,
 337                            sizeof(struct i2c_smbus_ioctl_data)))
 338                 return -EFAULT;
 339         if ((data_arg.size != I2C_SMBUS_BYTE) &&
 340             (data_arg.size != I2C_SMBUS_QUICK) &&
 341             (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 342             (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 343             (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 344             (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 345             (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
 346             (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 347             (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 348                 dev_dbg(&client->adapter->dev,
 349                         "size out of range (%x) in ioctl I2C_SMBUS.\n",
 350                         data_arg.size);
 351                 return -EINVAL;
 352         }
 353         /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 354            so the check is valid if size==I2C_SMBUS_QUICK too. */
 355         if ((data_arg.read_write != I2C_SMBUS_READ) &&
 356             (data_arg.read_write != I2C_SMBUS_WRITE)) {
 357                 dev_dbg(&client->adapter->dev,
 358                         "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 359                         data_arg.read_write);
 360                 return -EINVAL;
 361         }
 362
 363         /* Note that command values are always valid! */
 364
 365         if ((data_arg.size == I2C_SMBUS_QUICK) ||
 366             ((data_arg.size == I2C_SMBUS_BYTE) &&
 367             (data_arg.read_write == I2C_SMBUS_WRITE)))
 368                 /* These are special: we do not use data */
 369                 return i2c_smbus_xfer(client->adapter, client->addr,
 370                                       client->flags, data_arg.read_write,
 371                                       data_arg.command, data_arg.size, NULL);
 372
 373         if (data_arg.data == NULL) {
 374                 dev_dbg(&client->adapter->dev,
 375                         "data is NULL pointer in ioctl I2C_SMBUS.\n");
 376                 return -EINVAL;
 377         }
 378
 379         if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 380             (data_arg.size == I2C_SMBUS_BYTE))
 381                 datasize = sizeof(data_arg.data->byte);
 382         else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 383                  (data_arg.size == I2C_SMBUS_PROC_CALL))
 384                 datasize = sizeof(data_arg.data->word);
 385         else /* size == smbus block, i2c block, or block proc. call */
 386                 datasize = sizeof(data_arg.data->block);
 387
 388         if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 389             (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 390             (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
 391             (data_arg.read_write == I2C_SMBUS_WRITE)) {
 392                 if (copy_from_user(&temp, data_arg.data, datasize))
 393                         return -EFAULT;
 394         }
 395         if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
 396                 /* Convert old I2C block commands to the new
 397                    convention. This preserves binary compatibility. */
 398                 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
 399                 if (data_arg.read_write == I2C_SMBUS_READ)
 400                         temp.block[0] = I2C_SMBUS_BLOCK_MAX;
 401         }
 402         res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 403               data_arg.read_write, data_arg.command, data_arg.size, &temp);
 404         if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 405                      (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 406                      (data_arg.read_write == I2C_SMBUS_READ))) {
 407                 if (copy_to_user(data_arg.data, &temp, datasize))
 408                         return -EFAULT;
 409         }
 410         return res;
 411 }
 412
 413 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 414 {
 415         struct i2c_client *client = file->private_data;
 416         unsigned long funcs;
 417
 418         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 419                 cmd, arg);
 420
 421         switch (cmd) {
 422         case I2C_SLAVE:
 423         case I2C_SLAVE_FORCE:
 424                 /* NOTE:  devices set up to work with "new style" drivers
 425                  * can't use I2C_SLAVE, even when the device node is not
 426                  * bound to a driver.  Only I2C_SLAVE_FORCE will work.
 427                  *
 428                  * Setting the PEC flag here won't affect kernel drivers,
 429                  * which will be using the i2c_client node registered with
 430                  * the driver model core.  Likewise, when that client has
 431                  * the PEC flag already set, the i2c-dev driver won't see
 432                  * (or use) this setting.
 433                  */
 434                 if ((arg > 0x3ff) ||
 435                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 436                         return -EINVAL;
 437                 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
 438                         return -EBUSY;
 439                 /* REVISIT: address could become busy later */
 440                 client->addr = arg;
 441                 return 0;
 442         case I2C_TENBIT:
 443                 if (arg)
 444                         client->flags |= I2C_M_TEN;
 445                 else
 446                         client->flags &= ~I2C_M_TEN;
 447                 return 0;
 448         case I2C_PEC:
 449                 if (arg)
 450                         client->flags |= I2C_CLIENT_PEC;
 451                 else
 452                         client->flags &= ~I2C_CLIENT_PEC;
 453                 return 0;
 454         case I2C_FUNCS:
 455                 funcs = i2c_get_functionality(client->adapter);
 456                 return put_user(funcs, (unsigned long __user *)arg);
 457
 458         case I2C_RDWR:
 459                 return i2cdev_ioctl_rdrw(client, arg);
 460
 461         case I2C_SMBUS:
 462                 return i2cdev_ioctl_smbus(client, arg);
 463
 464         case I2C_RETRIES:
 465                 client->adapter->retries = arg;
 466                 break;
 467         case I2C_TIMEOUT:
 468                 /* For historical reasons, user-space sets the timeout
 469                  * value in units of 10 ms.
 470                  */
 471                 client->adapter->timeout = msecs_to_jiffies(arg * 10);
 472                 break;
 473         default:
 474                 /* NOTE:  returning a fault code here could cause trouble
 475                  * in buggy userspace code.  Some old kernel bugs returned
 476                  * zero in this case, and userspace code might accidentally
 477                  * have depended on that bug.
 478                  */
 479                 return -ENOTTY;
 480         }
 481         return 0;
 482 }
 483
 484 static int i2cdev_open(struct inode *inode, struct file *file)
 485 {
 486         unsigned int minor = iminor(inode);
 487         struct i2c_client *client;
 488         struct i2c_adapter *adap;
 489         struct i2c_dev *i2c_dev;
 490
 491         i2c_dev = i2c_dev_get_by_minor(minor);
 492         if (!i2c_dev)
 493                 return -ENODEV;
 494
 495         adap = i2c_get_adapter(i2c_dev->adap->nr);
 496         if (!adap)
 497                 return -ENODEV;
 498
 499         /* This creates an anonymous i2c_client, which may later be
 500          * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
 501          *
 502          * This client is ** NEVER REGISTERED ** with the driver model
 503          * or I2C core code!!  It just holds private copies of addressing
 504          * information and maybe a PEC flag.
 505          */
 506         client = kzalloc(sizeof(*client), GFP_KERNEL);
 507         if (!client) {
 508                 i2c_put_adapter(adap);
 509                 return -ENOMEM;
 510         }
 511         snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 512
 513         client->adapter = adap;
 514         file->private_data = client;
 515
 516         return 0;
 517 }
 518
 519 static int i2cdev_release(struct inode *inode, struct file *file)
 520 {
 521         struct i2c_client *client = file->private_data;
 522
 523         i2c_put_adapter(client->adapter);
 524         kfree(client);
 525         file->private_data = NULL;
 526
 527         return 0;
 528 }
 529
 530 static const struct file_operations i2cdev_fops = {
 531         .owner          = THIS_MODULE,
 532         .llseek         = no_llseek,
 533         .read           = i2cdev_read,
 534         .write          = i2cdev_write,
 535         .unlocked_ioctl = i2cdev_ioctl,
 536         .open           = i2cdev_open,
 537         .release        = i2cdev_release,
 538 };
 539
 540 /* ------------------------------------------------------------------------- */
 541
 542 static struct class *i2c_dev_class;
 543
 544 static int i2cdev_attach_adapter(struct device *dev, void *dummy)
 545 {
 546         struct i2c_adapter *adap;
 547         struct i2c_dev *i2c_dev;
 548         int res;
 549
 550         if (dev->type != &i2c_adapter_type)
 551                 return 0;
 552         adap = to_i2c_adapter(dev);
 553
 554         i2c_dev = get_free_i2c_dev(adap);
 555         if (IS_ERR(i2c_dev))
 556                 return PTR_ERR(i2c_dev);
 557
 558         /* register this i2c device with the driver core */
 559         i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
 560                                      MKDEV(I2C_MAJOR, adap->nr), NULL,
 561                                      "i2c-%d", adap->nr);
 562         if (IS_ERR(i2c_dev->dev)) {
 563                 res = PTR_ERR(i2c_dev->dev);
 564                 goto error;
 565         }
 566
 567         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 568                  adap->name, adap->nr);
 569         return 0;
 570 error:
 571         return_i2c_dev(i2c_dev);
 572         return res;
 573 }
 574
 575 static int i2cdev_detach_adapter(struct device *dev, void *dummy)
 576 {
 577         struct i2c_adapter *adap;
 578         struct i2c_dev *i2c_dev;
 579
 580         if (dev->type != &i2c_adapter_type)
 581                 return 0;
 582         adap = to_i2c_adapter(dev);
 583
 584         i2c_dev = i2c_dev_get_by_minor(adap->nr);
 585         if (!i2c_dev) /* attach_adapter must have failed */
 586                 return 0;
 587
 588         return_i2c_dev(i2c_dev);
 589         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 590
 591         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 592         return 0;
 593 }
 594
 595 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
 596                          void *data)
 597 {
 598         struct device *dev = data;
 599
 600         switch (action) {
 601         case BUS_NOTIFY_ADD_DEVICE:
 602                 return i2cdev_attach_adapter(dev, NULL);
 603         case BUS_NOTIFY_DEL_DEVICE:
 604                 return i2cdev_detach_adapter(dev, NULL);
 605         }
 606
 607         return 0;
 608 }
 609
 610 static struct notifier_block i2cdev_notifier = {
 611         .notifier_call = i2cdev_notifier_call,
 612 };
 613
 614 /* ------------------------------------------------------------------------- */
 615
 616 /*
 617  * module load/unload record keeping
 618  */
 619
 620 static int __init i2c_dev_init(void)
 621 {
 622         int res;
 623
 624         printk(KERN_INFO "i2c /dev entries driver\n");
 625
 626         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 627         if (res)
 628                 goto out;
 629
 630         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
 631         if (IS_ERR(i2c_dev_class)) {
 632                 res = PTR_ERR(i2c_dev_class);
 633                 goto out_unreg_chrdev;
 634         }
 635         i2c_dev_class->dev_groups = i2c_groups;
 636
 637         /* Keep track of adapters which will be added or removed later */
 638         res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
 639         if (res)
 640                 goto out_unreg_class;
 641
 642         /* Bind to already existing adapters right away */
 643         i2c_for_each_dev(NULL, i2cdev_attach_adapter);
 644
 645         return 0;
 646
 647 out_unreg_class:
 648         class_destroy(i2c_dev_class);
 649 out_unreg_chrdev:
 650         unregister_chrdev(I2C_MAJOR, "i2c");
 651 out:
 652         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 653         return res;
 654 }
 655
 656 static void __exit i2c_dev_exit(void)
 657 {
 658         bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
 659         i2c_for_each_dev(NULL, i2cdev_detach_adapter);
 660         class_destroy(i2c_dev_class);
 661         unregister_chrdev(I2C_MAJOR, "i2c");
 662 }
 663
 664 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 665                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 666 MODULE_DESCRIPTION("I2C /dev entries driver");
 667 MODULE_LICENSE("GPL");
 668
 669 module_init(i2c_dev_init);
 670 module_exit(i2c_dev_exit);