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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19#include <linux/cdev.h> 20#include <linux/compat.h> 21#include <linux/device.h> 22#include <linux/fs.h> 23#include <linux/i2c-dev.h> 24#include <linux/i2c.h> 25#include <linux/init.h> 26#include <linux/jiffies.h> 27#include <linux/kernel.h> 28#include <linux/list.h> 29#include <linux/module.h> 30#include <linux/notifier.h> 31#include <linux/slab.h> 32#include <linux/uaccess.h> 33 34/* 35 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a 36 * slave (i2c_client) with which messages will be exchanged. It's coupled 37 * with a character special file which is accessed by user mode drivers. 38 * 39 * The list of i2c_dev structures is parallel to the i2c_adapter lists 40 * maintained by the driver model, and is updated using bus notifications. 41 */ 42struct i2c_dev { 43 struct list_head list; 44 struct i2c_adapter *adap; 45 struct device dev; 46 struct cdev cdev; 47}; 48 49#define I2C_MINORS (MINORMASK + 1) 50static LIST_HEAD(i2c_dev_list); 51static DEFINE_SPINLOCK(i2c_dev_list_lock); 52 53static struct i2c_dev *i2c_dev_get_by_minor(unsigned index) 54{ 55 struct i2c_dev *i2c_dev; 56 57 spin_lock(&i2c_dev_list_lock); 58 list_for_each_entry(i2c_dev, &i2c_dev_list, list) { 59 if (i2c_dev->adap->nr == index) 60 goto found; 61 } 62 i2c_dev = NULL; 63found: 64 spin_unlock(&i2c_dev_list_lock); 65 return i2c_dev; 66} 67 68static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap) 69{ 70 struct i2c_dev *i2c_dev; 71 72 if (adap->nr >= I2C_MINORS) { 73 pr_err("Out of device minors (%d)\n", adap->nr); 74 return ERR_PTR(-ENODEV); 75 } 76 77 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL); 78 if (!i2c_dev) 79 return ERR_PTR(-ENOMEM); 80 i2c_dev->adap = adap; 81 82 spin_lock(&i2c_dev_list_lock); 83 list_add_tail(&i2c_dev->list, &i2c_dev_list); 84 spin_unlock(&i2c_dev_list_lock); 85 return i2c_dev; 86} 87 88static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev) 89{ 90 spin_lock(&i2c_dev_list_lock); 91 list_del(&i2c_dev->list); 92 spin_unlock(&i2c_dev_list_lock); 93 if (del_cdev) 94 cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev); 95 put_device(&i2c_dev->dev); 96} 97 98static ssize_t name_show(struct device *dev, 99 struct device_attribute *attr, char *buf) 100{ 101 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt)); 102 103 if (!i2c_dev) 104 return -ENODEV; 105 return sysfs_emit(buf, "%s\n", i2c_dev->adap->name); 106} 107static DEVICE_ATTR_RO(name); 108 109static struct attribute *i2c_attrs[] = { 110 &dev_attr_name.attr, 111 NULL, 112}; 113ATTRIBUTE_GROUPS(i2c); 114 115/* ------------------------------------------------------------------------- */ 116 117/* 118 * After opening an instance of this character special file, a file 119 * descriptor starts out associated only with an i2c_adapter (and bus). 120 * 121 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg 122 * traffic to any devices on the bus used by that adapter. That's because 123 * the i2c_msg vectors embed all the addressing information they need, and 124 * are submitted directly to an i2c_adapter. However, SMBus-only adapters 125 * don't support that interface. 126 * 127 * To use read()/write() system calls on that file descriptor, or to use 128 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue 129 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous 130 * (never registered) i2c_client so it holds the addressing information 131 * needed by those system calls and by this SMBus interface. 132 */ 133 134static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count, 135 loff_t *offset) 136{ 137 char *tmp; 138 int ret; 139 140 struct i2c_client *client = file->private_data; 141 142 if (count > 8192) 143 count = 8192; 144 145 tmp = kzalloc(count, GFP_KERNEL); 146 if (tmp == NULL) 147 return -ENOMEM; 148 149 pr_debug("i2c-%d reading %zu bytes.\n", 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-%d writing %zu bytes.\n", iminor(file_inode(file)), count); 174 175 ret = i2c_master_send(client, tmp, count); 176 kfree(tmp); 177 return ret; 178} 179 180static int i2cdev_check(struct device *dev, void *addrp) 181{ 182 struct i2c_client *client = i2c_verify_client(dev); 183 184 if (!client || client->addr != *(unsigned int *)addrp) 185 return 0; 186 187 return dev->driver ? -EBUSY : 0; 188} 189 190/* walk up mux tree */ 191static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr) 192{ 193 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 194 int result; 195 196 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check); 197 if (!result && parent) 198 result = i2cdev_check_mux_parents(parent, addr); 199 200 return result; 201} 202 203/* recurse down mux tree */ 204static int i2cdev_check_mux_children(struct device *dev, void *addrp) 205{ 206 int result; 207 208 if (dev->type == &i2c_adapter_type) 209 result = device_for_each_child(dev, addrp, 210 i2cdev_check_mux_children); 211 else 212 result = i2cdev_check(dev, addrp); 213 214 return result; 215} 216 217/* This address checking function differs from the one in i2c-core 218 in that it considers an address with a registered device, but no 219 driver bound to it, as NOT busy. */ 220static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr) 221{ 222 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 223 int result = 0; 224 225 if (parent) 226 result = i2cdev_check_mux_parents(parent, addr); 227 228 if (!result) 229 result = device_for_each_child(&adapter->dev, &addr, 230 i2cdev_check_mux_children); 231 232 return result; 233} 234 235static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, 236 unsigned nmsgs, struct i2c_msg *msgs) 237{ 238 u8 __user **data_ptrs; 239 int i, res; 240 241 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL); 242 if (data_ptrs == NULL) { 243 kfree(msgs); 244 return -ENOMEM; 245 } 246 247 res = 0; 248 for (i = 0; i < nmsgs; i++) { 249 /* Limit the size of the message to a sane amount */ 250 if (msgs[i].len > 8192) { 251 res = -EINVAL; 252 break; 253 } 254 255 data_ptrs[i] = (u8 __user *)msgs[i].buf; 256 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len); 257 if (IS_ERR(msgs[i].buf)) { 258 res = PTR_ERR(msgs[i].buf); 259 break; 260 } 261 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */ 262 msgs[i].flags |= I2C_M_DMA_SAFE; 263 264 /* 265 * If the message length is received from the slave (similar 266 * to SMBus block read), we must ensure that the buffer will 267 * be large enough to cope with a message length of 268 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus 269 * drivers allow. The first byte in the buffer must be 270 * pre-filled with the number of extra bytes, which must be 271 * at least one to hold the message length, but can be 272 * greater (for example to account for a checksum byte at 273 * the end of the message.) 274 */ 275 if (msgs[i].flags & I2C_M_RECV_LEN) { 276 if (!(msgs[i].flags & I2C_M_RD) || 277 msgs[i].len < 1 || msgs[i].buf[0] < 1 || 278 msgs[i].len < msgs[i].buf[0] + 279 I2C_SMBUS_BLOCK_MAX) { 280 i++; 281 res = -EINVAL; 282 break; 283 } 284 285 msgs[i].len = msgs[i].buf[0]; 286 } 287 } 288 if (res < 0) { 289 int j; 290 for (j = 0; j < i; ++j) 291 kfree(msgs[j].buf); 292 kfree(data_ptrs); 293 kfree(msgs); 294 return res; 295 } 296 297 res = i2c_transfer(client->adapter, msgs, nmsgs); 298 while (i-- > 0) { 299 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) { 300 if (copy_to_user(data_ptrs[i], msgs[i].buf, 301 msgs[i].len)) 302 res = -EFAULT; 303 } 304 kfree(msgs[i].buf); 305 } 306 kfree(data_ptrs); 307 kfree(msgs); 308 return res; 309} 310 311static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, 312 u8 read_write, u8 command, u32 size, 313 union i2c_smbus_data __user *data) 314{ 315 union i2c_smbus_data temp = {}; 316 int datasize, res; 317 318 if ((size != I2C_SMBUS_BYTE) && 319 (size != I2C_SMBUS_QUICK) && 320 (size != I2C_SMBUS_BYTE_DATA) && 321 (size != I2C_SMBUS_WORD_DATA) && 322 (size != I2C_SMBUS_PROC_CALL) && 323 (size != I2C_SMBUS_BLOCK_DATA) && 324 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) && 325 (size != I2C_SMBUS_I2C_BLOCK_DATA) && 326 (size != I2C_SMBUS_BLOCK_PROC_CALL)) { 327 dev_dbg(&client->adapter->dev, 328 "size out of range (%x) in ioctl I2C_SMBUS.\n", 329 size); 330 return -EINVAL; 331 } 332 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 333 so the check is valid if size==I2C_SMBUS_QUICK too. */ 334 if ((read_write != I2C_SMBUS_READ) && 335 (read_write != I2C_SMBUS_WRITE)) { 336 dev_dbg(&client->adapter->dev, 337 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 338 read_write); 339 return -EINVAL; 340 } 341 342 /* Note that command values are always valid! */ 343 344 if ((size == I2C_SMBUS_QUICK) || 345 ((size == I2C_SMBUS_BYTE) && 346 (read_write == I2C_SMBUS_WRITE))) 347 /* These are special: we do not use data */ 348 return i2c_smbus_xfer(client->adapter, client->addr, 349 client->flags, read_write, 350 command, size, NULL); 351 352 if (data == NULL) { 353 dev_dbg(&client->adapter->dev, 354 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 355 return -EINVAL; 356 } 357 358 if ((size == I2C_SMBUS_BYTE_DATA) || 359 (size == I2C_SMBUS_BYTE)) 360 datasize = sizeof(data->byte); 361 else if ((size == I2C_SMBUS_WORD_DATA) || 362 (size == I2C_SMBUS_PROC_CALL)) 363 datasize = sizeof(data->word); 364 else /* size == smbus block, i2c block, or block proc. call */ 365 datasize = sizeof(data->block); 366 367 if ((size == I2C_SMBUS_PROC_CALL) || 368 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 369 (size == I2C_SMBUS_I2C_BLOCK_DATA) || 370 (read_write == I2C_SMBUS_WRITE)) { 371 if (copy_from_user(&temp, data, datasize)) 372 return -EFAULT; 373 } 374 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) { 375 /* Convert old I2C block commands to the new 376 convention. This preserves binary compatibility. */ 377 size = I2C_SMBUS_I2C_BLOCK_DATA; 378 if (read_write == I2C_SMBUS_READ) 379 temp.block[0] = I2C_SMBUS_BLOCK_MAX; 380 } 381 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 382 read_write, command, size, &temp); 383 if (!res && ((size == I2C_SMBUS_PROC_CALL) || 384 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 385 (read_write == I2C_SMBUS_READ))) { 386 if (copy_to_user(data, &temp, datasize)) 387 return -EFAULT; 388 } 389 return res; 390} 391 392static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 393{ 394 struct i2c_client *client = file->private_data; 395 unsigned long funcs; 396 397 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", 398 cmd, arg); 399 400 switch (cmd) { 401 case I2C_SLAVE: 402 case I2C_SLAVE_FORCE: 403 if ((arg > 0x3ff) || 404 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 405 return -EINVAL; 406 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg)) 407 return -EBUSY; 408 /* REVISIT: address could become busy later */ 409 client->addr = arg; 410 return 0; 411 case I2C_TENBIT: 412 if (arg) 413 client->flags |= I2C_M_TEN; 414 else 415 client->flags &= ~I2C_M_TEN; 416 return 0; 417 case I2C_PEC: 418 /* 419 * Setting the PEC flag here won't affect kernel drivers, 420 * which will be using the i2c_client node registered with 421 * the driver model core. Likewise, when that client has 422 * the PEC flag already set, the i2c-dev driver won't see 423 * (or use) this setting. 424 */ 425 if (arg) 426 client->flags |= I2C_CLIENT_PEC; 427 else 428 client->flags &= ~I2C_CLIENT_PEC; 429 return 0; 430 case I2C_FUNCS: 431 funcs = i2c_get_functionality(client->adapter); 432 return put_user(funcs, (unsigned long __user *)arg); 433 434 case I2C_RDWR: { 435 struct i2c_rdwr_ioctl_data rdwr_arg; 436 struct i2c_msg *rdwr_pa; 437 438 if (copy_from_user(&rdwr_arg, 439 (struct i2c_rdwr_ioctl_data __user *)arg, 440 sizeof(rdwr_arg))) 441 return -EFAULT; 442 443 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 444 return -EINVAL; 445 446 /* 447 * Put an arbitrary limit on the number of messages that can 448 * be sent at once 449 */ 450 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 451 return -EINVAL; 452 453 rdwr_pa = memdup_array_user(rdwr_arg.msgs, 454 rdwr_arg.nmsgs, sizeof(struct i2c_msg)); 455 if (IS_ERR(rdwr_pa)) 456 return PTR_ERR(rdwr_pa); 457 458 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 459 } 460 461 case I2C_SMBUS: { 462 struct i2c_smbus_ioctl_data data_arg; 463 if (copy_from_user(&data_arg, 464 (struct i2c_smbus_ioctl_data __user *) arg, 465 sizeof(struct i2c_smbus_ioctl_data))) 466 return -EFAULT; 467 return i2cdev_ioctl_smbus(client, data_arg.read_write, 468 data_arg.command, 469 data_arg.size, 470 data_arg.data); 471 } 472 case I2C_RETRIES: 473 if (arg > INT_MAX) 474 return -EINVAL; 475 476 client->adapter->retries = arg; 477 break; 478 case I2C_TIMEOUT: 479 if (arg > INT_MAX) 480 return -EINVAL; 481 482 /* For historical reasons, user-space sets the timeout 483 * value in units of 10 ms. 484 */ 485 client->adapter->timeout = msecs_to_jiffies(arg * 10); 486 break; 487 default: 488 /* NOTE: returning a fault code here could cause trouble 489 * in buggy userspace code. Some old kernel bugs returned 490 * zero in this case, and userspace code might accidentally 491 * have depended on that bug. 492 */ 493 return -ENOTTY; 494 } 495 return 0; 496} 497 498#ifdef CONFIG_COMPAT 499 500struct i2c_smbus_ioctl_data32 { 501 u8 read_write; 502 u8 command; 503 u32 size; 504 compat_caddr_t data; /* union i2c_smbus_data *data */ 505}; 506 507struct i2c_msg32 { 508 u16 addr; 509 u16 flags; 510 u16 len; 511 compat_caddr_t buf; 512}; 513 514struct i2c_rdwr_ioctl_data32 { 515 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */ 516 u32 nmsgs; 517}; 518 519static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 520{ 521 struct i2c_client *client = file->private_data; 522 unsigned long funcs; 523 switch (cmd) { 524 case I2C_FUNCS: 525 funcs = i2c_get_functionality(client->adapter); 526 return put_user(funcs, (compat_ulong_t __user *)arg); 527 case I2C_RDWR: { 528 struct i2c_rdwr_ioctl_data32 rdwr_arg; 529 struct i2c_msg32 __user *p; 530 struct i2c_msg *rdwr_pa; 531 int i; 532 533 if (copy_from_user(&rdwr_arg, 534 (struct i2c_rdwr_ioctl_data32 __user *)arg, 535 sizeof(rdwr_arg))) 536 return -EFAULT; 537 538 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 539 return -EINVAL; 540 541 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 542 return -EINVAL; 543 544 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg), 545 GFP_KERNEL); 546 if (!rdwr_pa) 547 return -ENOMEM; 548 549 p = compat_ptr(rdwr_arg.msgs); 550 for (i = 0; i < rdwr_arg.nmsgs; i++) { 551 struct i2c_msg32 umsg; 552 if (copy_from_user(&umsg, p + i, sizeof(umsg))) { 553 kfree(rdwr_pa); 554 return -EFAULT; 555 } 556 rdwr_pa[i] = (struct i2c_msg) { 557 .addr = umsg.addr, 558 .flags = umsg.flags, 559 .len = umsg.len, 560 .buf = (__force __u8 *)compat_ptr(umsg.buf), 561 }; 562 } 563 564 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 565 } 566 case I2C_SMBUS: { 567 struct i2c_smbus_ioctl_data32 data32; 568 if (copy_from_user(&data32, 569 (void __user *) arg, 570 sizeof(data32))) 571 return -EFAULT; 572 return i2cdev_ioctl_smbus(client, data32.read_write, 573 data32.command, 574 data32.size, 575 compat_ptr(data32.data)); 576 } 577 default: 578 return i2cdev_ioctl(file, cmd, arg); 579 } 580} 581#else 582#define compat_i2cdev_ioctl NULL 583#endif 584 585static int i2cdev_open(struct inode *inode, struct file *file) 586{ 587 unsigned int minor = iminor(inode); 588 struct i2c_client *client; 589 struct i2c_adapter *adap; 590 591 adap = i2c_get_adapter(minor); 592 if (!adap) 593 return -ENODEV; 594 595 /* This creates an anonymous i2c_client, which may later be 596 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE. 597 * 598 * This client is ** NEVER REGISTERED ** with the driver model 599 * or I2C core code!! It just holds private copies of addressing 600 * information and maybe a PEC flag. 601 */ 602 client = kzalloc(sizeof(*client), GFP_KERNEL); 603 if (!client) { 604 i2c_put_adapter(adap); 605 return -ENOMEM; 606 } 607 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr); 608 609 client->adapter = adap; 610 file->private_data = client; 611 612 return 0; 613} 614 615static int i2cdev_release(struct inode *inode, struct file *file) 616{ 617 struct i2c_client *client = file->private_data; 618 619 i2c_put_adapter(client->adapter); 620 kfree(client); 621 file->private_data = NULL; 622 623 return 0; 624} 625 626static const struct file_operations i2cdev_fops = { 627 .owner = THIS_MODULE, 628 .llseek = no_llseek, 629 .read = i2cdev_read, 630 .write = i2cdev_write, 631 .unlocked_ioctl = i2cdev_ioctl, 632 .compat_ioctl = compat_i2cdev_ioctl, 633 .open = i2cdev_open, 634 .release = i2cdev_release, 635}; 636 637/* ------------------------------------------------------------------------- */ 638 639static const struct class i2c_dev_class = { 640 .name = "i2c-dev", 641 .dev_groups = i2c_groups, 642}; 643 644static void i2cdev_dev_release(struct device *dev) 645{ 646 struct i2c_dev *i2c_dev; 647 648 i2c_dev = container_of(dev, struct i2c_dev, dev); 649 kfree(i2c_dev); 650} 651 652static int i2cdev_attach_adapter(struct device *dev) 653{ 654 struct i2c_adapter *adap; 655 struct i2c_dev *i2c_dev; 656 int res; 657 658 if (dev->type != &i2c_adapter_type) 659 return NOTIFY_DONE; 660 adap = to_i2c_adapter(dev); 661 662 i2c_dev = get_free_i2c_dev(adap); 663 if (IS_ERR(i2c_dev)) 664 return NOTIFY_DONE; 665 666 cdev_init(&i2c_dev->cdev, &i2cdev_fops); 667 i2c_dev->cdev.owner = THIS_MODULE; 668 669 device_initialize(&i2c_dev->dev); 670 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr); 671 i2c_dev->dev.class = &i2c_dev_class; 672 i2c_dev->dev.parent = &adap->dev; 673 i2c_dev->dev.release = i2cdev_dev_release; 674 675 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr); 676 if (res) 677 goto err_put_i2c_dev; 678 679 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev); 680 if (res) 681 goto err_put_i2c_dev; 682 683 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr); 684 return NOTIFY_OK; 685 686err_put_i2c_dev: 687 put_i2c_dev(i2c_dev, false); 688 return NOTIFY_DONE; 689} 690 691static int i2cdev_detach_adapter(struct device *dev) 692{ 693 struct i2c_adapter *adap; 694 struct i2c_dev *i2c_dev; 695 696 if (dev->type != &i2c_adapter_type) 697 return NOTIFY_DONE; 698 adap = to_i2c_adapter(dev); 699 700 i2c_dev = i2c_dev_get_by_minor(adap->nr); 701 if (!i2c_dev) /* attach_adapter must have failed */ 702 return NOTIFY_DONE; 703 704 put_i2c_dev(i2c_dev, true); 705 706 pr_debug("adapter [%s] unregistered\n", adap->name); 707 return NOTIFY_OK; 708} 709 710static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action, 711 void *data) 712{ 713 struct device *dev = data; 714 715 switch (action) { 716 case BUS_NOTIFY_ADD_DEVICE: 717 return i2cdev_attach_adapter(dev); 718 case BUS_NOTIFY_DEL_DEVICE: 719 return i2cdev_detach_adapter(dev); 720 } 721 722 return NOTIFY_DONE; 723} 724 725static struct notifier_block i2cdev_notifier = { 726 .notifier_call = i2cdev_notifier_call, 727}; 728 729/* ------------------------------------------------------------------------- */ 730 731static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy) 732{ 733 i2cdev_attach_adapter(dev); 734 return 0; 735} 736 737static int __exit i2c_dev_detach_adapter(struct device *dev, void *dummy) 738{ 739 i2cdev_detach_adapter(dev); 740 return 0; 741} 742 743/* 744 * module load/unload record keeping 745 */ 746 747static int __init i2c_dev_init(void) 748{ 749 int res; 750 751 pr_info("i2c /dev entries driver\n"); 752 753 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c"); 754 if (res) 755 goto out; 756 757 res = class_register(&i2c_dev_class); 758 if (res) 759 goto out_unreg_chrdev; 760 761 /* Keep track of adapters which will be added or removed later */ 762 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier); 763 if (res) 764 goto out_unreg_class; 765 766 /* Bind to already existing adapters right away */ 767 i2c_for_each_dev(NULL, i2c_dev_attach_adapter); 768 769 return 0; 770 771out_unreg_class: 772 class_unregister(&i2c_dev_class); 773out_unreg_chrdev: 774 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 775out: 776 pr_err("Driver Initialisation failed\n"); 777 return res; 778} 779 780static void __exit i2c_dev_exit(void) 781{ 782 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier); 783 i2c_for_each_dev(NULL, i2c_dev_detach_adapter); 784 class_unregister(&i2c_dev_class); 785 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 786} 787 788MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 789MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 790MODULE_DESCRIPTION("I2C /dev entries driver"); 791MODULE_LICENSE("GPL"); 792 793module_init(i2c_dev_init); 794module_exit(i2c_dev_exit); 795