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/cdev.h> 26 #include <linux/device.h> 27 #include <linux/fs.h> 28 #include <linux/i2c-dev.h> 29 #include <linux/i2c.h> 30 #include <linux/init.h> 31 #include <linux/jiffies.h> 32 #include <linux/kernel.h> 33 #include <linux/list.h> 34 #include <linux/module.h> 35 #include <linux/notifier.h> 36 #include <linux/slab.h> 37 #include <linux/uaccess.h> 38 #include <linux/compat.h> 39 40 /* 41 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a 42 * slave (i2c_client) with which messages will be exchanged. It's coupled 43 * with a character special file which is accessed by user mode drivers. 44 * 45 * The list of i2c_dev structures is parallel to the i2c_adapter lists 46 * maintained by the driver model, and is updated using bus notifications. 47 */ 48 struct i2c_dev { 49 struct list_head list; 50 struct i2c_adapter *adap; 51 struct device *dev; 52 struct cdev cdev; 53 }; 54 55 #define I2C_MINORS MINORMASK 56 static LIST_HEAD(i2c_dev_list); 57 static DEFINE_SPINLOCK(i2c_dev_list_lock); 58 59 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index) 60 { 61 struct i2c_dev *i2c_dev; 62 63 spin_lock(&i2c_dev_list_lock); 64 list_for_each_entry(i2c_dev, &i2c_dev_list, list) { 65 if (i2c_dev->adap->nr == index) 66 goto found; 67 } 68 i2c_dev = NULL; 69 found: 70 spin_unlock(&i2c_dev_list_lock); 71 return i2c_dev; 72 } 73 74 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap) 75 { 76 struct i2c_dev *i2c_dev; 77 78 if (adap->nr >= I2C_MINORS) { 79 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n", 80 adap->nr); 81 return ERR_PTR(-ENODEV); 82 } 83 84 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL); 85 if (!i2c_dev) 86 return ERR_PTR(-ENOMEM); 87 i2c_dev->adap = adap; 88 89 spin_lock(&i2c_dev_list_lock); 90 list_add_tail(&i2c_dev->list, &i2c_dev_list); 91 spin_unlock(&i2c_dev_list_lock); 92 return i2c_dev; 93 } 94 95 static void put_i2c_dev(struct i2c_dev *i2c_dev) 96 { 97 spin_lock(&i2c_dev_list_lock); 98 list_del(&i2c_dev->list); 99 spin_unlock(&i2c_dev_list_lock); 100 kfree(i2c_dev); 101 } 102 103 static ssize_t name_show(struct device *dev, 104 struct device_attribute *attr, char *buf) 105 { 106 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt)); 107 108 if (!i2c_dev) 109 return -ENODEV; 110 return sprintf(buf, "%s\n", i2c_dev->adap->name); 111 } 112 static DEVICE_ATTR_RO(name); 113 114 static struct attribute *i2c_attrs[] = { 115 &dev_attr_name.attr, 116 NULL, 117 }; 118 ATTRIBUTE_GROUPS(i2c); 119 120 /* ------------------------------------------------------------------------- */ 121 122 /* 123 * After opening an instance of this character special file, a file 124 * descriptor starts out associated only with an i2c_adapter (and bus). 125 * 126 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg 127 * traffic to any devices on the bus used by that adapter. That's because 128 * the i2c_msg vectors embed all the addressing information they need, and 129 * are submitted directly to an i2c_adapter. However, SMBus-only adapters 130 * don't support that interface. 131 * 132 * To use read()/write() system calls on that file descriptor, or to use 133 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue 134 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous 135 * (never registered) i2c_client so it holds the addressing information 136 * needed by those system calls and by this SMBus interface. 137 */ 138 139 static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count, 140 loff_t *offset) 141 { 142 char *tmp; 143 int ret; 144 145 struct i2c_client *client = file->private_data; 146 147 if (count > 8192) 148 count = 8192; 149 150 tmp = kmalloc(count, GFP_KERNEL); 151 if (tmp == NULL) 152 return -ENOMEM; 153 154 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n", 155 iminor(file_inode(file)), count); 156 157 ret = i2c_master_recv(client, tmp, count); 158 if (ret >= 0) 159 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret; 160 kfree(tmp); 161 return ret; 162 } 163 164 static ssize_t i2cdev_write(struct file *file, const char __user *buf, 165 size_t count, loff_t *offset) 166 { 167 int ret; 168 char *tmp; 169 struct i2c_client *client = file->private_data; 170 171 if (count > 8192) 172 count = 8192; 173 174 tmp = memdup_user(buf, count); 175 if (IS_ERR(tmp)) 176 return PTR_ERR(tmp); 177 178 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n", 179 iminor(file_inode(file)), count); 180 181 ret = i2c_master_send(client, tmp, count); 182 kfree(tmp); 183 return ret; 184 } 185 186 static int i2cdev_check(struct device *dev, void *addrp) 187 { 188 struct i2c_client *client = i2c_verify_client(dev); 189 190 if (!client || client->addr != *(unsigned int *)addrp) 191 return 0; 192 193 return dev->driver ? -EBUSY : 0; 194 } 195 196 /* walk up mux tree */ 197 static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr) 198 { 199 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 200 int result; 201 202 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check); 203 if (!result && parent) 204 result = i2cdev_check_mux_parents(parent, addr); 205 206 return result; 207 } 208 209 /* recurse down mux tree */ 210 static int i2cdev_check_mux_children(struct device *dev, void *addrp) 211 { 212 int result; 213 214 if (dev->type == &i2c_adapter_type) 215 result = device_for_each_child(dev, addrp, 216 i2cdev_check_mux_children); 217 else 218 result = i2cdev_check(dev, addrp); 219 220 return result; 221 } 222 223 /* This address checking function differs from the one in i2c-core 224 in that it considers an address with a registered device, but no 225 driver bound to it, as NOT busy. */ 226 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr) 227 { 228 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 229 int result = 0; 230 231 if (parent) 232 result = i2cdev_check_mux_parents(parent, addr); 233 234 if (!result) 235 result = device_for_each_child(&adapter->dev, &addr, 236 i2cdev_check_mux_children); 237 238 return result; 239 } 240 241 static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, 242 unsigned nmsgs, struct i2c_msg *msgs) 243 { 244 u8 __user **data_ptrs; 245 int i, res; 246 247 data_ptrs = kmalloc(nmsgs * sizeof(u8 __user *), GFP_KERNEL); 248 if (data_ptrs == NULL) { 249 kfree(msgs); 250 return -ENOMEM; 251 } 252 253 res = 0; 254 for (i = 0; i < nmsgs; i++) { 255 /* Limit the size of the message to a sane amount */ 256 if (msgs[i].len > 8192) { 257 res = -EINVAL; 258 break; 259 } 260 261 data_ptrs[i] = (u8 __user *)msgs[i].buf; 262 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len); 263 if (IS_ERR(msgs[i].buf)) { 264 res = PTR_ERR(msgs[i].buf); 265 break; 266 } 267 268 /* 269 * If the message length is received from the slave (similar 270 * to SMBus block read), we must ensure that the buffer will 271 * be large enough to cope with a message length of 272 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus 273 * drivers allow. The first byte in the buffer must be 274 * pre-filled with the number of extra bytes, which must be 275 * at least one to hold the message length, but can be 276 * greater (for example to account for a checksum byte at 277 * the end of the message.) 278 */ 279 if (msgs[i].flags & I2C_M_RECV_LEN) { 280 if (!(msgs[i].flags & I2C_M_RD) || 281 msgs[i].buf[0] < 1 || 282 msgs[i].len < msgs[i].buf[0] + 283 I2C_SMBUS_BLOCK_MAX) { 284 res = -EINVAL; 285 break; 286 } 287 288 msgs[i].len = msgs[i].buf[0]; 289 } 290 } 291 if (res < 0) { 292 int j; 293 for (j = 0; j < i; ++j) 294 kfree(msgs[j].buf); 295 kfree(data_ptrs); 296 kfree(msgs); 297 return res; 298 } 299 300 res = i2c_transfer(client->adapter, msgs, nmsgs); 301 while (i-- > 0) { 302 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) { 303 if (copy_to_user(data_ptrs[i], msgs[i].buf, 304 msgs[i].len)) 305 res = -EFAULT; 306 } 307 kfree(msgs[i].buf); 308 } 309 kfree(data_ptrs); 310 kfree(msgs); 311 return res; 312 } 313 314 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, 315 u8 read_write, u8 command, u32 size, 316 union i2c_smbus_data __user *data) 317 { 318 union i2c_smbus_data temp = {}; 319 int datasize, res; 320 321 if ((size != I2C_SMBUS_BYTE) && 322 (size != I2C_SMBUS_QUICK) && 323 (size != I2C_SMBUS_BYTE_DATA) && 324 (size != I2C_SMBUS_WORD_DATA) && 325 (size != I2C_SMBUS_PROC_CALL) && 326 (size != I2C_SMBUS_BLOCK_DATA) && 327 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) && 328 (size != I2C_SMBUS_I2C_BLOCK_DATA) && 329 (size != I2C_SMBUS_BLOCK_PROC_CALL)) { 330 dev_dbg(&client->adapter->dev, 331 "size out of range (%x) in ioctl I2C_SMBUS.\n", 332 size); 333 return -EINVAL; 334 } 335 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 336 so the check is valid if size==I2C_SMBUS_QUICK too. */ 337 if ((read_write != I2C_SMBUS_READ) && 338 (read_write != I2C_SMBUS_WRITE)) { 339 dev_dbg(&client->adapter->dev, 340 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 341 read_write); 342 return -EINVAL; 343 } 344 345 /* Note that command values are always valid! */ 346 347 if ((size == I2C_SMBUS_QUICK) || 348 ((size == I2C_SMBUS_BYTE) && 349 (read_write == I2C_SMBUS_WRITE))) 350 /* These are special: we do not use data */ 351 return i2c_smbus_xfer(client->adapter, client->addr, 352 client->flags, read_write, 353 command, size, NULL); 354 355 if (data == NULL) { 356 dev_dbg(&client->adapter->dev, 357 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 358 return -EINVAL; 359 } 360 361 if ((size == I2C_SMBUS_BYTE_DATA) || 362 (size == I2C_SMBUS_BYTE)) 363 datasize = sizeof(data->byte); 364 else if ((size == I2C_SMBUS_WORD_DATA) || 365 (size == I2C_SMBUS_PROC_CALL)) 366 datasize = sizeof(data->word); 367 else /* size == smbus block, i2c block, or block proc. call */ 368 datasize = sizeof(data->block); 369 370 if ((size == I2C_SMBUS_PROC_CALL) || 371 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 372 (size == I2C_SMBUS_I2C_BLOCK_DATA) || 373 (read_write == I2C_SMBUS_WRITE)) { 374 if (copy_from_user(&temp, data, datasize)) 375 return -EFAULT; 376 } 377 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) { 378 /* Convert old I2C block commands to the new 379 convention. This preserves binary compatibility. */ 380 size = I2C_SMBUS_I2C_BLOCK_DATA; 381 if (read_write == I2C_SMBUS_READ) 382 temp.block[0] = I2C_SMBUS_BLOCK_MAX; 383 } 384 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 385 read_write, command, size, &temp); 386 if (!res && ((size == I2C_SMBUS_PROC_CALL) || 387 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 388 (read_write == I2C_SMBUS_READ))) { 389 if (copy_to_user(data, &temp, datasize)) 390 return -EFAULT; 391 } 392 return res; 393 } 394 395 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 396 { 397 struct i2c_client *client = file->private_data; 398 unsigned long funcs; 399 400 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", 401 cmd, arg); 402 403 switch (cmd) { 404 case I2C_SLAVE: 405 case I2C_SLAVE_FORCE: 406 if ((arg > 0x3ff) || 407 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 408 return -EINVAL; 409 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg)) 410 return -EBUSY; 411 /* REVISIT: address could become busy later */ 412 client->addr = arg; 413 return 0; 414 case I2C_TENBIT: 415 if (arg) 416 client->flags |= I2C_M_TEN; 417 else 418 client->flags &= ~I2C_M_TEN; 419 return 0; 420 case I2C_PEC: 421 /* 422 * Setting the PEC flag here won't affect kernel drivers, 423 * which will be using the i2c_client node registered with 424 * the driver model core. Likewise, when that client has 425 * the PEC flag already set, the i2c-dev driver won't see 426 * (or use) this setting. 427 */ 428 if (arg) 429 client->flags |= I2C_CLIENT_PEC; 430 else 431 client->flags &= ~I2C_CLIENT_PEC; 432 return 0; 433 case I2C_FUNCS: 434 funcs = i2c_get_functionality(client->adapter); 435 return put_user(funcs, (unsigned long __user *)arg); 436 437 case I2C_RDWR: { 438 struct i2c_rdwr_ioctl_data rdwr_arg; 439 struct i2c_msg *rdwr_pa; 440 441 if (copy_from_user(&rdwr_arg, 442 (struct i2c_rdwr_ioctl_data __user *)arg, 443 sizeof(rdwr_arg))) 444 return -EFAULT; 445 446 /* Put an arbitrary limit on the number of messages that can 447 * be sent at once */ 448 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 449 return -EINVAL; 450 451 rdwr_pa = memdup_user(rdwr_arg.msgs, 452 rdwr_arg.nmsgs * sizeof(struct i2c_msg)); 453 if (IS_ERR(rdwr_pa)) 454 return PTR_ERR(rdwr_pa); 455 456 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 457 } 458 459 case I2C_SMBUS: { 460 struct i2c_smbus_ioctl_data data_arg; 461 if (copy_from_user(&data_arg, 462 (struct i2c_smbus_ioctl_data __user *) arg, 463 sizeof(struct i2c_smbus_ioctl_data))) 464 return -EFAULT; 465 return i2cdev_ioctl_smbus(client, data_arg.read_write, 466 data_arg.command, 467 data_arg.size, 468 data_arg.data); 469 } 470 case I2C_RETRIES: 471 client->adapter->retries = arg; 472 break; 473 case I2C_TIMEOUT: 474 /* For historical reasons, user-space sets the timeout 475 * value in units of 10 ms. 476 */ 477 client->adapter->timeout = msecs_to_jiffies(arg * 10); 478 break; 479 default: 480 /* NOTE: returning a fault code here could cause trouble 481 * in buggy userspace code. Some old kernel bugs returned 482 * zero in this case, and userspace code might accidentally 483 * have depended on that bug. 484 */ 485 return -ENOTTY; 486 } 487 return 0; 488 } 489 490 #ifdef CONFIG_COMPAT 491 492 struct i2c_smbus_ioctl_data32 { 493 u8 read_write; 494 u8 command; 495 u32 size; 496 compat_caddr_t data; /* union i2c_smbus_data *data */ 497 }; 498 499 struct i2c_msg32 { 500 u16 addr; 501 u16 flags; 502 u16 len; 503 compat_caddr_t buf; 504 }; 505 506 struct i2c_rdwr_ioctl_data32 { 507 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */ 508 u32 nmsgs; 509 }; 510 511 static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 512 { 513 struct i2c_client *client = file->private_data; 514 unsigned long funcs; 515 switch (cmd) { 516 case I2C_FUNCS: 517 funcs = i2c_get_functionality(client->adapter); 518 return put_user(funcs, (compat_ulong_t __user *)arg); 519 case I2C_RDWR: { 520 struct i2c_rdwr_ioctl_data32 rdwr_arg; 521 struct i2c_msg32 *p; 522 struct i2c_msg *rdwr_pa; 523 int i; 524 525 if (copy_from_user(&rdwr_arg, 526 (struct i2c_rdwr_ioctl_data32 __user *)arg, 527 sizeof(rdwr_arg))) 528 return -EFAULT; 529 530 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 531 return -EINVAL; 532 533 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg), 534 GFP_KERNEL); 535 if (!rdwr_pa) 536 return -ENOMEM; 537 538 p = compat_ptr(rdwr_arg.msgs); 539 for (i = 0; i < rdwr_arg.nmsgs; i++) { 540 struct i2c_msg32 umsg; 541 if (copy_from_user(&umsg, p + i, sizeof(umsg))) { 542 kfree(rdwr_pa); 543 return -EFAULT; 544 } 545 rdwr_pa[i] = (struct i2c_msg) { 546 .addr = umsg.addr, 547 .flags = umsg.flags, 548 .len = umsg.len, 549 .buf = compat_ptr(umsg.buf) 550 }; 551 } 552 553 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 554 } 555 case I2C_SMBUS: { 556 struct i2c_smbus_ioctl_data32 data32; 557 if (copy_from_user(&data32, 558 (void __user *) arg, 559 sizeof(data32))) 560 return -EFAULT; 561 return i2cdev_ioctl_smbus(client, data32.read_write, 562 data32.command, 563 data32.size, 564 compat_ptr(data32.data)); 565 } 566 default: 567 return i2cdev_ioctl(file, cmd, arg); 568 } 569 } 570 #else 571 #define compat_i2cdev_ioctl NULL 572 #endif 573 574 static int i2cdev_open(struct inode *inode, struct file *file) 575 { 576 unsigned int minor = iminor(inode); 577 struct i2c_client *client; 578 struct i2c_adapter *adap; 579 580 adap = i2c_get_adapter(minor); 581 if (!adap) 582 return -ENODEV; 583 584 /* This creates an anonymous i2c_client, which may later be 585 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE. 586 * 587 * This client is ** NEVER REGISTERED ** with the driver model 588 * or I2C core code!! It just holds private copies of addressing 589 * information and maybe a PEC flag. 590 */ 591 client = kzalloc(sizeof(*client), GFP_KERNEL); 592 if (!client) { 593 i2c_put_adapter(adap); 594 return -ENOMEM; 595 } 596 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr); 597 598 client->adapter = adap; 599 file->private_data = client; 600 601 return 0; 602 } 603 604 static int i2cdev_release(struct inode *inode, struct file *file) 605 { 606 struct i2c_client *client = file->private_data; 607 608 i2c_put_adapter(client->adapter); 609 kfree(client); 610 file->private_data = NULL; 611 612 return 0; 613 } 614 615 static const struct file_operations i2cdev_fops = { 616 .owner = THIS_MODULE, 617 .llseek = no_llseek, 618 .read = i2cdev_read, 619 .write = i2cdev_write, 620 .unlocked_ioctl = i2cdev_ioctl, 621 .compat_ioctl = compat_i2cdev_ioctl, 622 .open = i2cdev_open, 623 .release = i2cdev_release, 624 }; 625 626 /* ------------------------------------------------------------------------- */ 627 628 static struct class *i2c_dev_class; 629 630 static int i2cdev_attach_adapter(struct device *dev, void *dummy) 631 { 632 struct i2c_adapter *adap; 633 struct i2c_dev *i2c_dev; 634 int res; 635 636 if (dev->type != &i2c_adapter_type) 637 return 0; 638 adap = to_i2c_adapter(dev); 639 640 i2c_dev = get_free_i2c_dev(adap); 641 if (IS_ERR(i2c_dev)) 642 return PTR_ERR(i2c_dev); 643 644 cdev_init(&i2c_dev->cdev, &i2cdev_fops); 645 i2c_dev->cdev.owner = THIS_MODULE; 646 res = cdev_add(&i2c_dev->cdev, MKDEV(I2C_MAJOR, adap->nr), 1); 647 if (res) 648 goto error_cdev; 649 650 /* register this i2c device with the driver core */ 651 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev, 652 MKDEV(I2C_MAJOR, adap->nr), NULL, 653 "i2c-%d", adap->nr); 654 if (IS_ERR(i2c_dev->dev)) { 655 res = PTR_ERR(i2c_dev->dev); 656 goto error; 657 } 658 659 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n", 660 adap->name, adap->nr); 661 return 0; 662 error: 663 cdev_del(&i2c_dev->cdev); 664 error_cdev: 665 put_i2c_dev(i2c_dev); 666 return res; 667 } 668 669 static int i2cdev_detach_adapter(struct device *dev, void *dummy) 670 { 671 struct i2c_adapter *adap; 672 struct i2c_dev *i2c_dev; 673 674 if (dev->type != &i2c_adapter_type) 675 return 0; 676 adap = to_i2c_adapter(dev); 677 678 i2c_dev = i2c_dev_get_by_minor(adap->nr); 679 if (!i2c_dev) /* attach_adapter must have failed */ 680 return 0; 681 682 cdev_del(&i2c_dev->cdev); 683 put_i2c_dev(i2c_dev); 684 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr)); 685 686 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name); 687 return 0; 688 } 689 690 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action, 691 void *data) 692 { 693 struct device *dev = data; 694 695 switch (action) { 696 case BUS_NOTIFY_ADD_DEVICE: 697 return i2cdev_attach_adapter(dev, NULL); 698 case BUS_NOTIFY_DEL_DEVICE: 699 return i2cdev_detach_adapter(dev, NULL); 700 } 701 702 return 0; 703 } 704 705 static struct notifier_block i2cdev_notifier = { 706 .notifier_call = i2cdev_notifier_call, 707 }; 708 709 /* ------------------------------------------------------------------------- */ 710 711 /* 712 * module load/unload record keeping 713 */ 714 715 static int __init i2c_dev_init(void) 716 { 717 int res; 718 719 printk(KERN_INFO "i2c /dev entries driver\n"); 720 721 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c"); 722 if (res) 723 goto out; 724 725 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev"); 726 if (IS_ERR(i2c_dev_class)) { 727 res = PTR_ERR(i2c_dev_class); 728 goto out_unreg_chrdev; 729 } 730 i2c_dev_class->dev_groups = i2c_groups; 731 732 /* Keep track of adapters which will be added or removed later */ 733 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier); 734 if (res) 735 goto out_unreg_class; 736 737 /* Bind to already existing adapters right away */ 738 i2c_for_each_dev(NULL, i2cdev_attach_adapter); 739 740 return 0; 741 742 out_unreg_class: 743 class_destroy(i2c_dev_class); 744 out_unreg_chrdev: 745 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 746 out: 747 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__); 748 return res; 749 } 750 751 static void __exit i2c_dev_exit(void) 752 { 753 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier); 754 i2c_for_each_dev(NULL, i2cdev_detach_adapter); 755 class_destroy(i2c_dev_class); 756 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 757 } 758 759 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and " 760 "Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 761 MODULE_DESCRIPTION("I2C /dev entries driver"); 762 MODULE_LICENSE("GPL"); 763 764 module_init(i2c_dev_init); 765 module_exit(i2c_dev_exit); 766