1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 i2c-dev.c - i2c-bus driver, char device interface 4 5 Copyright (C) 1995-97 Simon G. Vogl 6 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl> 7 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com> 8 9*/ 10 11/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module. 12 But I have used so much of his original code and ideas that it seems 13 only fair to recognize him as co-author -- Frodo */ 14 15/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */ 16 17#include <linux/cdev.h> 18#include <linux/compat.h> 19#include <linux/device.h> 20#include <linux/fs.h> 21#include <linux/i2c-dev.h> 22#include <linux/i2c.h> 23#include <linux/init.h> 24#include <linux/jiffies.h> 25#include <linux/kernel.h> 26#include <linux/list.h> 27#include <linux/module.h> 28#include <linux/notifier.h> 29#include <linux/slab.h> 30#include <linux/uaccess.h> 31 32/* 33 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a 34 * slave (i2c_client) with which messages will be exchanged. It's coupled 35 * with a character special file which is accessed by user mode drivers. 36 * 37 * The list of i2c_dev structures is parallel to the i2c_adapter lists 38 * maintained by the driver model, and is updated using bus notifications. 39 */ 40struct i2c_dev { 41 struct list_head list; 42 struct i2c_adapter *adap; 43 struct device dev; 44 struct cdev cdev; 45}; 46 47#define I2C_MINORS (MINORMASK + 1) 48static LIST_HEAD(i2c_dev_list); 49static DEFINE_SPINLOCK(i2c_dev_list_lock); 50 51static struct i2c_dev *i2c_dev_get_by_minor(unsigned index) 52{ 53 struct i2c_dev *i2c_dev; 54 55 spin_lock(&i2c_dev_list_lock); 56 list_for_each_entry(i2c_dev, &i2c_dev_list, list) { 57 if (i2c_dev->adap->nr == index) 58 goto found; 59 } 60 i2c_dev = NULL; 61found: 62 spin_unlock(&i2c_dev_list_lock); 63 return i2c_dev; 64} 65 66static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap) 67{ 68 struct i2c_dev *i2c_dev; 69 70 if (adap->nr >= I2C_MINORS) { 71 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n", 72 adap->nr); 73 return ERR_PTR(-ENODEV); 74 } 75 76 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL); 77 if (!i2c_dev) 78 return ERR_PTR(-ENOMEM); 79 i2c_dev->adap = adap; 80 81 spin_lock(&i2c_dev_list_lock); 82 list_add_tail(&i2c_dev->list, &i2c_dev_list); 83 spin_unlock(&i2c_dev_list_lock); 84 return i2c_dev; 85} 86 87static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev) 88{ 89 spin_lock(&i2c_dev_list_lock); 90 list_del(&i2c_dev->list); 91 spin_unlock(&i2c_dev_list_lock); 92 if (del_cdev) 93 cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev); 94 put_device(&i2c_dev->dev); 95} 96 97static ssize_t name_show(struct device *dev, 98 struct device_attribute *attr, char *buf) 99{ 100 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt)); 101 102 if (!i2c_dev) 103 return -ENODEV; 104 return sprintf(buf, "%s\n", i2c_dev->adap->name); 105} 106static DEVICE_ATTR_RO(name); 107 108static struct attribute *i2c_attrs[] = { 109 &dev_attr_name.attr, 110 NULL, 111}; 112ATTRIBUTE_GROUPS(i2c); 113 114/* ------------------------------------------------------------------------- */ 115 116/* 117 * After opening an instance of this character special file, a file 118 * descriptor starts out associated only with an i2c_adapter (and bus). 119 * 120 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg 121 * traffic to any devices on the bus used by that adapter. That's because 122 * the i2c_msg vectors embed all the addressing information they need, and 123 * are submitted directly to an i2c_adapter. However, SMBus-only adapters 124 * don't support that interface. 125 * 126 * To use read()/write() system calls on that file descriptor, or to use 127 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue 128 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous 129 * (never registered) i2c_client so it holds the addressing information 130 * needed by those system calls and by this SMBus interface. 131 */ 132 133static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count, 134 loff_t *offset) 135{ 136 char *tmp; 137 int ret; 138 139 struct i2c_client *client = file->private_data; 140 141 if (count > 8192) 142 count = 8192; 143 144 tmp = kzalloc(count, GFP_KERNEL); 145 if (tmp == NULL) 146 return -ENOMEM; 147 148 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n", 149 iminor(file_inode(file)), count); 150 151 ret = i2c_master_recv(client, tmp, count); 152 if (ret >= 0) 153 if (copy_to_user(buf, tmp, ret)) 154 ret = -EFAULT; 155 kfree(tmp); 156 return ret; 157} 158 159static ssize_t i2cdev_write(struct file *file, const char __user *buf, 160 size_t count, loff_t *offset) 161{ 162 int ret; 163 char *tmp; 164 struct i2c_client *client = file->private_data; 165 166 if (count > 8192) 167 count = 8192; 168 169 tmp = memdup_user(buf, count); 170 if (IS_ERR(tmp)) 171 return PTR_ERR(tmp); 172 173 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n", 174 iminor(file_inode(file)), count); 175 176 ret = i2c_master_send(client, tmp, count); 177 kfree(tmp); 178 return ret; 179} 180 181static int i2cdev_check(struct device *dev, void *addrp) 182{ 183 struct i2c_client *client = i2c_verify_client(dev); 184 185 if (!client || client->addr != *(unsigned int *)addrp) 186 return 0; 187 188 return dev->driver ? -EBUSY : 0; 189} 190 191/* walk up mux tree */ 192static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr) 193{ 194 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 195 int result; 196 197 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check); 198 if (!result && parent) 199 result = i2cdev_check_mux_parents(parent, addr); 200 201 return result; 202} 203 204/* recurse down mux tree */ 205static int i2cdev_check_mux_children(struct device *dev, void *addrp) 206{ 207 int result; 208 209 if (dev->type == &i2c_adapter_type) 210 result = device_for_each_child(dev, addrp, 211 i2cdev_check_mux_children); 212 else 213 result = i2cdev_check(dev, addrp); 214 215 return result; 216} 217 218/* This address checking function differs from the one in i2c-core 219 in that it considers an address with a registered device, but no 220 driver bound to it, as NOT busy. */ 221static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr) 222{ 223 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 224 int result = 0; 225 226 if (parent) 227 result = i2cdev_check_mux_parents(parent, addr); 228 229 if (!result) 230 result = device_for_each_child(&adapter->dev, &addr, 231 i2cdev_check_mux_children); 232 233 return result; 234} 235 236static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, 237 unsigned nmsgs, struct i2c_msg *msgs) 238{ 239 u8 __user **data_ptrs; 240 int i, res; 241 242 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL); 243 if (data_ptrs == NULL) { 244 kfree(msgs); 245 return -ENOMEM; 246 } 247 248 res = 0; 249 for (i = 0; i < nmsgs; i++) { 250 /* Limit the size of the message to a sane amount */ 251 if (msgs[i].len > 8192) { 252 res = -EINVAL; 253 break; 254 } 255 256 data_ptrs[i] = (u8 __user *)msgs[i].buf; 257 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len); 258 if (IS_ERR(msgs[i].buf)) { 259 res = PTR_ERR(msgs[i].buf); 260 break; 261 } 262 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */ 263 msgs[i].flags |= I2C_M_DMA_SAFE; 264 265 /* 266 * If the message length is received from the slave (similar 267 * to SMBus block read), we must ensure that the buffer will 268 * be large enough to cope with a message length of 269 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus 270 * drivers allow. The first byte in the buffer must be 271 * pre-filled with the number of extra bytes, which must be 272 * at least one to hold the message length, but can be 273 * greater (for example to account for a checksum byte at 274 * the end of the message.) 275 */ 276 if (msgs[i].flags & I2C_M_RECV_LEN) { 277 if (!(msgs[i].flags & I2C_M_RD) || 278 msgs[i].len < 1 || msgs[i].buf[0] < 1 || 279 msgs[i].len < msgs[i].buf[0] + 280 I2C_SMBUS_BLOCK_MAX) { 281 i++; 282 res = -EINVAL; 283 break; 284 } 285 286 msgs[i].len = msgs[i].buf[0]; 287 } 288 } 289 if (res < 0) { 290 int j; 291 for (j = 0; j < i; ++j) 292 kfree(msgs[j].buf); 293 kfree(data_ptrs); 294 kfree(msgs); 295 return res; 296 } 297 298 res = i2c_transfer(client->adapter, msgs, nmsgs); 299 while (i-- > 0) { 300 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) { 301 if (copy_to_user(data_ptrs[i], msgs[i].buf, 302 msgs[i].len)) 303 res = -EFAULT; 304 } 305 kfree(msgs[i].buf); 306 } 307 kfree(data_ptrs); 308 kfree(msgs); 309 return res; 310} 311 312static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, 313 u8 read_write, u8 command, u32 size, 314 union i2c_smbus_data __user *data) 315{ 316 union i2c_smbus_data temp = {}; 317 int datasize, res; 318 319 if ((size != I2C_SMBUS_BYTE) && 320 (size != I2C_SMBUS_QUICK) && 321 (size != I2C_SMBUS_BYTE_DATA) && 322 (size != I2C_SMBUS_WORD_DATA) && 323 (size != I2C_SMBUS_PROC_CALL) && 324 (size != I2C_SMBUS_BLOCK_DATA) && 325 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) && 326 (size != I2C_SMBUS_I2C_BLOCK_DATA) && 327 (size != I2C_SMBUS_BLOCK_PROC_CALL)) { 328 dev_dbg(&client->adapter->dev, 329 "size out of range (%x) in ioctl I2C_SMBUS.\n", 330 size); 331 return -EINVAL; 332 } 333 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 334 so the check is valid if size==I2C_SMBUS_QUICK too. */ 335 if ((read_write != I2C_SMBUS_READ) && 336 (read_write != I2C_SMBUS_WRITE)) { 337 dev_dbg(&client->adapter->dev, 338 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 339 read_write); 340 return -EINVAL; 341 } 342 343 /* Note that command values are always valid! */ 344 345 if ((size == I2C_SMBUS_QUICK) || 346 ((size == I2C_SMBUS_BYTE) && 347 (read_write == I2C_SMBUS_WRITE))) 348 /* These are special: we do not use data */ 349 return i2c_smbus_xfer(client->adapter, client->addr, 350 client->flags, read_write, 351 command, size, NULL); 352 353 if (data == NULL) { 354 dev_dbg(&client->adapter->dev, 355 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 356 return -EINVAL; 357 } 358 359 if ((size == I2C_SMBUS_BYTE_DATA) || 360 (size == I2C_SMBUS_BYTE)) 361 datasize = sizeof(data->byte); 362 else if ((size == I2C_SMBUS_WORD_DATA) || 363 (size == I2C_SMBUS_PROC_CALL)) 364 datasize = sizeof(data->word); 365 else /* size == smbus block, i2c block, or block proc. call */ 366 datasize = sizeof(data->block); 367 368 if ((size == I2C_SMBUS_PROC_CALL) || 369 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 370 (size == I2C_SMBUS_I2C_BLOCK_DATA) || 371 (read_write == I2C_SMBUS_WRITE)) { 372 if (copy_from_user(&temp, data, datasize)) 373 return -EFAULT; 374 } 375 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) { 376 /* Convert old I2C block commands to the new 377 convention. This preserves binary compatibility. */ 378 size = I2C_SMBUS_I2C_BLOCK_DATA; 379 if (read_write == I2C_SMBUS_READ) 380 temp.block[0] = I2C_SMBUS_BLOCK_MAX; 381 } 382 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 383 read_write, command, size, &temp); 384 if (!res && ((size == I2C_SMBUS_PROC_CALL) || 385 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 386 (read_write == I2C_SMBUS_READ))) { 387 if (copy_to_user(data, &temp, datasize)) 388 return -EFAULT; 389 } 390 return res; 391} 392 393static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 394{ 395 struct i2c_client *client = file->private_data; 396 unsigned long funcs; 397 398 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", 399 cmd, arg); 400 401 switch (cmd) { 402 case I2C_SLAVE: 403 case I2C_SLAVE_FORCE: 404 if ((arg > 0x3ff) || 405 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 406 return -EINVAL; 407 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg)) 408 return -EBUSY; 409 /* REVISIT: address could become busy later */ 410 client->addr = arg; 411 return 0; 412 case I2C_TENBIT: 413 if (arg) 414 client->flags |= I2C_M_TEN; 415 else 416 client->flags &= ~I2C_M_TEN; 417 return 0; 418 case I2C_PEC: 419 /* 420 * Setting the PEC flag here won't affect kernel drivers, 421 * which will be using the i2c_client node registered with 422 * the driver model core. Likewise, when that client has 423 * the PEC flag already set, the i2c-dev driver won't see 424 * (or use) this setting. 425 */ 426 if (arg) 427 client->flags |= I2C_CLIENT_PEC; 428 else 429 client->flags &= ~I2C_CLIENT_PEC; 430 return 0; 431 case I2C_FUNCS: 432 funcs = i2c_get_functionality(client->adapter); 433 return put_user(funcs, (unsigned long __user *)arg); 434 435 case I2C_RDWR: { 436 struct i2c_rdwr_ioctl_data rdwr_arg; 437 struct i2c_msg *rdwr_pa; 438 439 if (copy_from_user(&rdwr_arg, 440 (struct i2c_rdwr_ioctl_data __user *)arg, 441 sizeof(rdwr_arg))) 442 return -EFAULT; 443 444 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 445 return -EINVAL; 446 447 /* 448 * Put an arbitrary limit on the number of messages that can 449 * be sent at once 450 */ 451 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 452 return -EINVAL; 453 454 rdwr_pa = memdup_user(rdwr_arg.msgs, 455 rdwr_arg.nmsgs * sizeof(struct i2c_msg)); 456 if (IS_ERR(rdwr_pa)) 457 return PTR_ERR(rdwr_pa); 458 459 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 460 } 461 462 case I2C_SMBUS: { 463 struct i2c_smbus_ioctl_data data_arg; 464 if (copy_from_user(&data_arg, 465 (struct i2c_smbus_ioctl_data __user *) arg, 466 sizeof(struct i2c_smbus_ioctl_data))) 467 return -EFAULT; 468 return i2cdev_ioctl_smbus(client, data_arg.read_write, 469 data_arg.command, 470 data_arg.size, 471 data_arg.data); 472 } 473 case I2C_RETRIES: 474 if (arg > INT_MAX) 475 return -EINVAL; 476 477 client->adapter->retries = arg; 478 break; 479 case I2C_TIMEOUT: 480 if (arg > INT_MAX) 481 return -EINVAL; 482 483 /* For historical reasons, user-space sets the timeout 484 * value in units of 10 ms. 485 */ 486 client->adapter->timeout = msecs_to_jiffies(arg * 10); 487 break; 488 default: 489 /* NOTE: returning a fault code here could cause trouble 490 * in buggy userspace code. Some old kernel bugs returned 491 * zero in this case, and userspace code might accidentally 492 * have depended on that bug. 493 */ 494 return -ENOTTY; 495 } 496 return 0; 497} 498 499#ifdef CONFIG_COMPAT 500 501struct i2c_smbus_ioctl_data32 { 502 u8 read_write; 503 u8 command; 504 u32 size; 505 compat_caddr_t data; /* union i2c_smbus_data *data */ 506}; 507 508struct i2c_msg32 { 509 u16 addr; 510 u16 flags; 511 u16 len; 512 compat_caddr_t buf; 513}; 514 515struct i2c_rdwr_ioctl_data32 { 516 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */ 517 u32 nmsgs; 518}; 519 520static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 521{ 522 struct i2c_client *client = file->private_data; 523 unsigned long funcs; 524 switch (cmd) { 525 case I2C_FUNCS: 526 funcs = i2c_get_functionality(client->adapter); 527 return put_user(funcs, (compat_ulong_t __user *)arg); 528 case I2C_RDWR: { 529 struct i2c_rdwr_ioctl_data32 rdwr_arg; 530 struct i2c_msg32 *p; 531 struct i2c_msg *rdwr_pa; 532 int i; 533 534 if (copy_from_user(&rdwr_arg, 535 (struct i2c_rdwr_ioctl_data32 __user *)arg, 536 sizeof(rdwr_arg))) 537 return -EFAULT; 538 539 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 540 return -EINVAL; 541 542 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 543 return -EINVAL; 544 545 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg), 546 GFP_KERNEL); 547 if (!rdwr_pa) 548 return -ENOMEM; 549 550 p = compat_ptr(rdwr_arg.msgs); 551 for (i = 0; i < rdwr_arg.nmsgs; i++) { 552 struct i2c_msg32 umsg; 553 if (copy_from_user(&umsg, p + i, sizeof(umsg))) { 554 kfree(rdwr_pa); 555 return -EFAULT; 556 } 557 rdwr_pa[i] = (struct i2c_msg) { 558 .addr = umsg.addr, 559 .flags = umsg.flags, 560 .len = umsg.len, 561 .buf = compat_ptr(umsg.buf) 562 }; 563 } 564 565 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 566 } 567 case I2C_SMBUS: { 568 struct i2c_smbus_ioctl_data32 data32; 569 if (copy_from_user(&data32, 570 (void __user *) arg, 571 sizeof(data32))) 572 return -EFAULT; 573 return i2cdev_ioctl_smbus(client, data32.read_write, 574 data32.command, 575 data32.size, 576 compat_ptr(data32.data)); 577 } 578 default: 579 return i2cdev_ioctl(file, cmd, arg); 580 } 581} 582#else 583#define compat_i2cdev_ioctl NULL 584#endif 585 586static int i2cdev_open(struct inode *inode, struct file *file) 587{ 588 unsigned int minor = iminor(inode); 589 struct i2c_client *client; 590 struct i2c_adapter *adap; 591 592 adap = i2c_get_adapter(minor); 593 if (!adap) 594 return -ENODEV; 595 596 /* This creates an anonymous i2c_client, which may later be 597 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE. 598 * 599 * This client is ** NEVER REGISTERED ** with the driver model 600 * or I2C core code!! It just holds private copies of addressing 601 * information and maybe a PEC flag. 602 */ 603 client = kzalloc(sizeof(*client), GFP_KERNEL); 604 if (!client) { 605 i2c_put_adapter(adap); 606 return -ENOMEM; 607 } 608 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr); 609 610 client->adapter = adap; 611 file->private_data = client; 612 613 return 0; 614} 615 616static int i2cdev_release(struct inode *inode, struct file *file) 617{ 618 struct i2c_client *client = file->private_data; 619 620 i2c_put_adapter(client->adapter); 621 kfree(client); 622 file->private_data = NULL; 623 624 return 0; 625} 626 627static const struct file_operations i2cdev_fops = { 628 .owner = THIS_MODULE, 629 .llseek = no_llseek, 630 .read = i2cdev_read, 631 .write = i2cdev_write, 632 .unlocked_ioctl = i2cdev_ioctl, 633 .compat_ioctl = compat_i2cdev_ioctl, 634 .open = i2cdev_open, 635 .release = i2cdev_release, 636}; 637 638/* ------------------------------------------------------------------------- */ 639 640static struct class *i2c_dev_class; 641 642static void i2cdev_dev_release(struct device *dev) 643{ 644 struct i2c_dev *i2c_dev; 645 646 i2c_dev = container_of(dev, struct i2c_dev, dev); 647 kfree(i2c_dev); 648} 649 650static int i2cdev_attach_adapter(struct device *dev, void *dummy) 651{ 652 struct i2c_adapter *adap; 653 struct i2c_dev *i2c_dev; 654 int res; 655 656 if (dev->type != &i2c_adapter_type) 657 return 0; 658 adap = to_i2c_adapter(dev); 659 660 i2c_dev = get_free_i2c_dev(adap); 661 if (IS_ERR(i2c_dev)) 662 return PTR_ERR(i2c_dev); 663 664 cdev_init(&i2c_dev->cdev, &i2cdev_fops); 665 i2c_dev->cdev.owner = THIS_MODULE; 666 667 device_initialize(&i2c_dev->dev); 668 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr); 669 i2c_dev->dev.class = i2c_dev_class; 670 i2c_dev->dev.parent = &adap->dev; 671 i2c_dev->dev.release = i2cdev_dev_release; 672 dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr); 673 674 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev); 675 if (res) { 676 put_i2c_dev(i2c_dev, false); 677 return res; 678 } 679 680 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n", 681 adap->name, adap->nr); 682 return 0; 683} 684 685static int i2cdev_detach_adapter(struct device *dev, void *dummy) 686{ 687 struct i2c_adapter *adap; 688 struct i2c_dev *i2c_dev; 689 690 if (dev->type != &i2c_adapter_type) 691 return 0; 692 adap = to_i2c_adapter(dev); 693 694 i2c_dev = i2c_dev_get_by_minor(adap->nr); 695 if (!i2c_dev) /* attach_adapter must have failed */ 696 return 0; 697 698 put_i2c_dev(i2c_dev, true); 699 700 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name); 701 return 0; 702} 703 704static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action, 705 void *data) 706{ 707 struct device *dev = data; 708 709 switch (action) { 710 case BUS_NOTIFY_ADD_DEVICE: 711 return i2cdev_attach_adapter(dev, NULL); 712 case BUS_NOTIFY_DEL_DEVICE: 713 return i2cdev_detach_adapter(dev, NULL); 714 } 715 716 return 0; 717} 718 719static struct notifier_block i2cdev_notifier = { 720 .notifier_call = i2cdev_notifier_call, 721}; 722 723/* ------------------------------------------------------------------------- */ 724 725/* 726 * module load/unload record keeping 727 */ 728 729static int __init i2c_dev_init(void) 730{ 731 int res; 732 733 printk(KERN_INFO "i2c /dev entries driver\n"); 734 735 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c"); 736 if (res) 737 goto out; 738 739 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev"); 740 if (IS_ERR(i2c_dev_class)) { 741 res = PTR_ERR(i2c_dev_class); 742 goto out_unreg_chrdev; 743 } 744 i2c_dev_class->dev_groups = i2c_groups; 745 746 /* Keep track of adapters which will be added or removed later */ 747 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier); 748 if (res) 749 goto out_unreg_class; 750 751 /* Bind to already existing adapters right away */ 752 i2c_for_each_dev(NULL, i2cdev_attach_adapter); 753 754 return 0; 755 756out_unreg_class: 757 class_destroy(i2c_dev_class); 758out_unreg_chrdev: 759 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 760out: 761 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__); 762 return res; 763} 764 765static void __exit i2c_dev_exit(void) 766{ 767 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier); 768 i2c_for_each_dev(NULL, i2cdev_detach_adapter); 769 class_destroy(i2c_dev_class); 770 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 771} 772 773MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 774MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 775MODULE_DESCRIPTION("I2C /dev entries driver"); 776MODULE_LICENSE("GPL"); 777 778module_init(i2c_dev_init); 779module_exit(i2c_dev_exit); 780