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