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 */ 42 struct 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) 50 static LIST_HEAD(i2c_dev_list); 51 static DEFINE_SPINLOCK(i2c_dev_list_lock); 52 53 static 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; 63 found: 64 spin_unlock(&i2c_dev_list_lock); 65 return i2c_dev; 66 } 67 68 static 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_obj(*i2c_dev); 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 88 static 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 98 static 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 } 107 static DEVICE_ATTR_RO(name); 108 109 static struct attribute *i2c_attrs[] = { 110 &dev_attr_name.attr, 111 NULL, 112 }; 113 ATTRIBUTE_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 */ 133 134 static 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 /* Adapter must support I2C transfers */ 143 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 144 return -EOPNOTSUPP; 145 146 if (count > 8192) 147 count = 8192; 148 149 tmp = kzalloc(count, GFP_KERNEL); 150 if (tmp == NULL) 151 return -ENOMEM; 152 153 pr_debug("i2c-%d reading %zu bytes.\n", iminor(file_inode(file)), count); 154 155 ret = i2c_master_recv(client, tmp, count); 156 if (ret >= 0) 157 if (copy_to_user(buf, tmp, ret)) 158 ret = -EFAULT; 159 kfree(tmp); 160 return ret; 161 } 162 163 static ssize_t i2cdev_write(struct file *file, const char __user *buf, 164 size_t count, loff_t *offset) 165 { 166 int ret; 167 char *tmp; 168 struct i2c_client *client = file->private_data; 169 170 /* Adapter must support I2C transfers */ 171 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 172 return -EOPNOTSUPP; 173 174 if (count > 8192) 175 count = 8192; 176 177 tmp = memdup_user(buf, count); 178 if (IS_ERR(tmp)) 179 return PTR_ERR(tmp); 180 181 pr_debug("i2c-%d writing %zu bytes.\n", iminor(file_inode(file)), count); 182 183 ret = i2c_master_send(client, tmp, count); 184 kfree(tmp); 185 return ret; 186 } 187 188 static int i2cdev_check(struct device *dev, void *addrp) 189 { 190 struct i2c_client *client = i2c_verify_client(dev); 191 192 if (!client || client->addr != *(unsigned int *)addrp) 193 return 0; 194 195 return dev->driver ? -EBUSY : 0; 196 } 197 198 /* walk up mux tree */ 199 static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr) 200 { 201 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 202 int result; 203 204 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check); 205 if (!result && parent) 206 result = i2cdev_check_mux_parents(parent, addr); 207 208 return result; 209 } 210 211 /* recurse down mux tree */ 212 static int i2cdev_check_mux_children(struct device *dev, void *addrp) 213 { 214 int result; 215 216 if (dev->type == &i2c_adapter_type) 217 result = device_for_each_child(dev, addrp, 218 i2cdev_check_mux_children); 219 else 220 result = i2cdev_check(dev, addrp); 221 222 return result; 223 } 224 225 /* This address checking function differs from the one in i2c-core 226 in that it considers an address with a registered device, but no 227 driver bound to it, as NOT busy. */ 228 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr) 229 { 230 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 231 int result = 0; 232 233 if (parent) 234 result = i2cdev_check_mux_parents(parent, addr); 235 236 if (!result) 237 result = device_for_each_child(&adapter->dev, &addr, 238 i2cdev_check_mux_children); 239 240 return result; 241 } 242 243 static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, 244 unsigned nmsgs, struct i2c_msg *msgs) 245 { 246 u8 __user **data_ptrs; 247 int i, res; 248 249 /* Adapter must support I2C transfers */ 250 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 251 return -EOPNOTSUPP; 252 253 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL); 254 if (!data_ptrs) 255 return -ENOMEM; 256 257 res = 0; 258 for (i = 0; i < nmsgs; i++) { 259 /* Limit the size of the message to a sane amount */ 260 if (msgs[i].len > 8192) { 261 res = -EINVAL; 262 break; 263 } 264 265 data_ptrs[i] = (u8 __user *)msgs[i].buf; 266 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len); 267 if (IS_ERR(msgs[i].buf)) { 268 res = PTR_ERR(msgs[i].buf); 269 break; 270 } 271 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */ 272 msgs[i].flags |= I2C_M_DMA_SAFE; 273 274 /* 275 * If the message length is received from the slave (similar 276 * to SMBus block read), we must ensure that the buffer will 277 * be large enough to cope with a message length of 278 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus 279 * drivers allow. The first byte in the buffer must be 280 * pre-filled with the number of extra bytes, which must be 281 * at least one to hold the message length, but can be 282 * greater (for example to account for a checksum byte at 283 * the end of the message.) 284 */ 285 if (msgs[i].flags & I2C_M_RECV_LEN) { 286 if (!(msgs[i].flags & I2C_M_RD) || 287 msgs[i].len < 1 || msgs[i].buf[0] < 1 || 288 msgs[i].len < msgs[i].buf[0] + 289 I2C_SMBUS_BLOCK_MAX) { 290 i++; 291 res = -EINVAL; 292 break; 293 } 294 295 msgs[i].len = msgs[i].buf[0]; 296 } 297 } 298 if (res < 0) { 299 int j; 300 for (j = 0; j < i; ++j) 301 kfree(msgs[j].buf); 302 kfree(data_ptrs); 303 return res; 304 } 305 306 res = i2c_transfer(client->adapter, msgs, nmsgs); 307 while (i-- > 0) { 308 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) { 309 if (copy_to_user(data_ptrs[i], msgs[i].buf, 310 msgs[i].len)) 311 res = -EFAULT; 312 } 313 kfree(msgs[i].buf); 314 } 315 kfree(data_ptrs); 316 return res; 317 } 318 319 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, 320 u8 read_write, u8 command, u32 size, 321 union i2c_smbus_data __user *data) 322 { 323 union i2c_smbus_data temp = {}; 324 int datasize, res; 325 326 if ((size != I2C_SMBUS_BYTE) && 327 (size != I2C_SMBUS_QUICK) && 328 (size != I2C_SMBUS_BYTE_DATA) && 329 (size != I2C_SMBUS_WORD_DATA) && 330 (size != I2C_SMBUS_PROC_CALL) && 331 (size != I2C_SMBUS_BLOCK_DATA) && 332 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) && 333 (size != I2C_SMBUS_I2C_BLOCK_DATA) && 334 (size != I2C_SMBUS_BLOCK_PROC_CALL)) { 335 dev_dbg(&client->adapter->dev, 336 "size out of range (%x) in ioctl I2C_SMBUS.\n", 337 size); 338 return -EINVAL; 339 } 340 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 341 so the check is valid if size==I2C_SMBUS_QUICK too. */ 342 if ((read_write != I2C_SMBUS_READ) && 343 (read_write != I2C_SMBUS_WRITE)) { 344 dev_dbg(&client->adapter->dev, 345 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 346 read_write); 347 return -EINVAL; 348 } 349 350 /* Note that command values are always valid! */ 351 352 if ((size == I2C_SMBUS_QUICK) || 353 ((size == I2C_SMBUS_BYTE) && 354 (read_write == I2C_SMBUS_WRITE))) 355 /* These are special: we do not use data */ 356 return i2c_smbus_xfer(client->adapter, client->addr, 357 client->flags, read_write, 358 command, size, NULL); 359 360 if (data == NULL) { 361 dev_dbg(&client->adapter->dev, 362 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 363 return -EINVAL; 364 } 365 366 if ((size == I2C_SMBUS_BYTE_DATA) || 367 (size == I2C_SMBUS_BYTE)) 368 datasize = sizeof(data->byte); 369 else if ((size == I2C_SMBUS_WORD_DATA) || 370 (size == I2C_SMBUS_PROC_CALL)) 371 datasize = sizeof(data->word); 372 else /* size == smbus block, i2c block, or block proc. call */ 373 datasize = sizeof(data->block); 374 375 if ((size == I2C_SMBUS_PROC_CALL) || 376 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 377 (size == I2C_SMBUS_I2C_BLOCK_DATA) || 378 (read_write == I2C_SMBUS_WRITE)) { 379 if (copy_from_user(&temp, data, datasize)) 380 return -EFAULT; 381 } 382 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) { 383 /* Convert old I2C block commands to the new 384 convention. This preserves binary compatibility. */ 385 size = I2C_SMBUS_I2C_BLOCK_DATA; 386 if (read_write == I2C_SMBUS_READ) 387 temp.block[0] = I2C_SMBUS_BLOCK_MAX; 388 } 389 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 390 read_write, command, size, &temp); 391 if (!res && ((size == I2C_SMBUS_PROC_CALL) || 392 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 393 (read_write == I2C_SMBUS_READ))) { 394 if (copy_to_user(data, &temp, datasize)) 395 return -EFAULT; 396 } 397 return res; 398 } 399 400 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 401 { 402 struct i2c_client *client = file->private_data; 403 unsigned long funcs; 404 405 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", 406 cmd, arg); 407 408 switch (cmd) { 409 case I2C_SLAVE: 410 case I2C_SLAVE_FORCE: 411 if ((arg > 0x3ff) || 412 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 413 return -EINVAL; 414 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg)) 415 return -EBUSY; 416 /* REVISIT: address could become busy later */ 417 client->addr = arg; 418 return 0; 419 case I2C_TENBIT: 420 if (arg) 421 client->flags |= I2C_M_TEN; 422 else 423 client->flags &= ~I2C_M_TEN; 424 return 0; 425 case I2C_PEC: 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) 434 client->flags |= I2C_CLIENT_PEC; 435 else 436 client->flags &= ~I2C_CLIENT_PEC; 437 return 0; 438 case I2C_FUNCS: 439 funcs = i2c_get_functionality(client->adapter); 440 return put_user(funcs, (unsigned long __user *)arg); 441 442 case I2C_RDWR: { 443 struct i2c_rdwr_ioctl_data rdwr_arg; 444 struct i2c_msg *rdwr_pa; 445 int res; 446 447 if (copy_from_user(&rdwr_arg, 448 (struct i2c_rdwr_ioctl_data __user *)arg, 449 sizeof(rdwr_arg))) 450 return -EFAULT; 451 452 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 453 return -EINVAL; 454 455 /* 456 * Put an arbitrary limit on the number of messages that can 457 * be sent at once 458 */ 459 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 460 return -EINVAL; 461 462 rdwr_pa = memdup_array_user(rdwr_arg.msgs, 463 rdwr_arg.nmsgs, sizeof(struct i2c_msg)); 464 if (IS_ERR(rdwr_pa)) 465 return PTR_ERR(rdwr_pa); 466 467 res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 468 kfree(rdwr_pa); 469 return res; 470 } 471 472 case I2C_SMBUS: { 473 struct i2c_smbus_ioctl_data data_arg; 474 if (copy_from_user(&data_arg, 475 (struct i2c_smbus_ioctl_data __user *) arg, 476 sizeof(struct i2c_smbus_ioctl_data))) 477 return -EFAULT; 478 return i2cdev_ioctl_smbus(client, data_arg.read_write, 479 data_arg.command, 480 data_arg.size, 481 data_arg.data); 482 } 483 case I2C_RETRIES: 484 if (arg > INT_MAX) 485 return -EINVAL; 486 487 client->adapter->retries = arg; 488 break; 489 case I2C_TIMEOUT: 490 if (arg > INT_MAX) 491 return -EINVAL; 492 493 /* For historical reasons, user-space sets the timeout 494 * value in units of 10 ms. 495 */ 496 client->adapter->timeout = msecs_to_jiffies(arg * 10); 497 break; 498 default: 499 /* NOTE: returning a fault code here could cause trouble 500 * in buggy userspace code. Some old kernel bugs returned 501 * zero in this case, and userspace code might accidentally 502 * have depended on that bug. 503 */ 504 return -ENOTTY; 505 } 506 return 0; 507 } 508 509 #ifdef CONFIG_COMPAT 510 511 struct i2c_smbus_ioctl_data32 { 512 u8 read_write; 513 u8 command; 514 u32 size; 515 compat_caddr_t data; /* union i2c_smbus_data *data */ 516 }; 517 518 struct i2c_msg32 { 519 u16 addr; 520 u16 flags; 521 u16 len; 522 compat_caddr_t buf; 523 }; 524 525 struct i2c_rdwr_ioctl_data32 { 526 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */ 527 u32 nmsgs; 528 }; 529 530 static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 531 { 532 struct i2c_client *client = file->private_data; 533 unsigned long funcs; 534 switch (cmd) { 535 case I2C_FUNCS: 536 funcs = i2c_get_functionality(client->adapter); 537 return put_user(funcs, (compat_ulong_t __user *)arg); 538 case I2C_RDWR: { 539 struct i2c_rdwr_ioctl_data32 rdwr_arg; 540 struct i2c_msg32 __user *p; 541 struct i2c_msg *rdwr_pa; 542 int i, res; 543 544 if (copy_from_user(&rdwr_arg, 545 (struct i2c_rdwr_ioctl_data32 __user *)arg, 546 sizeof(rdwr_arg))) 547 return -EFAULT; 548 549 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 550 return -EINVAL; 551 552 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 553 return -EINVAL; 554 555 rdwr_pa = kmalloc_objs(struct i2c_msg, rdwr_arg.nmsgs); 556 if (!rdwr_pa) 557 return -ENOMEM; 558 559 p = compat_ptr(rdwr_arg.msgs); 560 for (i = 0; i < rdwr_arg.nmsgs; i++) { 561 struct i2c_msg32 umsg; 562 if (copy_from_user(&umsg, p + i, sizeof(umsg))) { 563 kfree(rdwr_pa); 564 return -EFAULT; 565 } 566 rdwr_pa[i] = (struct i2c_msg) { 567 .addr = umsg.addr, 568 .flags = umsg.flags, 569 .len = umsg.len, 570 .buf = (__force __u8 *)compat_ptr(umsg.buf), 571 }; 572 } 573 574 res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 575 kfree(rdwr_pa); 576 return res; 577 } 578 case I2C_SMBUS: { 579 struct i2c_smbus_ioctl_data32 data32; 580 if (copy_from_user(&data32, 581 (void __user *) arg, 582 sizeof(data32))) 583 return -EFAULT; 584 return i2cdev_ioctl_smbus(client, data32.read_write, 585 data32.command, 586 data32.size, 587 compat_ptr(data32.data)); 588 } 589 default: 590 return i2cdev_ioctl(file, cmd, arg); 591 } 592 } 593 #else 594 #define compat_i2cdev_ioctl NULL 595 #endif 596 597 static int i2cdev_open(struct inode *inode, struct file *file) 598 { 599 unsigned int minor = iminor(inode); 600 struct i2c_client *client; 601 struct i2c_adapter *adap; 602 603 adap = i2c_get_adapter(minor); 604 if (!adap) 605 return -ENODEV; 606 607 /* This creates an anonymous i2c_client, which may later be 608 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE. 609 * 610 * This client is ** NEVER REGISTERED ** with the driver model 611 * or I2C core code!! It just holds private copies of addressing 612 * information and maybe a PEC flag. 613 */ 614 client = kzalloc_obj(*client); 615 if (!client) { 616 i2c_put_adapter(adap); 617 return -ENOMEM; 618 } 619 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr); 620 621 client->adapter = adap; 622 file->private_data = client; 623 624 return 0; 625 } 626 627 static int i2cdev_release(struct inode *inode, struct file *file) 628 { 629 struct i2c_client *client = file->private_data; 630 631 i2c_put_adapter(client->adapter); 632 kfree(client); 633 file->private_data = NULL; 634 635 return 0; 636 } 637 638 static const struct file_operations i2cdev_fops = { 639 .owner = THIS_MODULE, 640 .read = i2cdev_read, 641 .write = i2cdev_write, 642 .unlocked_ioctl = i2cdev_ioctl, 643 .compat_ioctl = compat_i2cdev_ioctl, 644 .open = i2cdev_open, 645 .release = i2cdev_release, 646 }; 647 648 /* ------------------------------------------------------------------------- */ 649 650 static const struct class i2c_dev_class = { 651 .name = "i2c-dev", 652 .dev_groups = i2c_groups, 653 }; 654 655 static void i2cdev_dev_release(struct device *dev) 656 { 657 struct i2c_dev *i2c_dev; 658 659 i2c_dev = container_of(dev, struct i2c_dev, dev); 660 kfree(i2c_dev); 661 } 662 663 static int i2cdev_attach_adapter(struct device *dev) 664 { 665 struct i2c_adapter *adap; 666 struct i2c_dev *i2c_dev; 667 int res; 668 669 if (dev->type != &i2c_adapter_type) 670 return NOTIFY_DONE; 671 adap = to_i2c_adapter(dev); 672 673 i2c_dev = get_free_i2c_dev(adap); 674 if (IS_ERR(i2c_dev)) 675 return NOTIFY_DONE; 676 677 cdev_init(&i2c_dev->cdev, &i2cdev_fops); 678 i2c_dev->cdev.owner = THIS_MODULE; 679 680 device_initialize(&i2c_dev->dev); 681 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr); 682 i2c_dev->dev.class = &i2c_dev_class; 683 i2c_dev->dev.parent = &adap->dev; 684 i2c_dev->dev.release = i2cdev_dev_release; 685 686 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr); 687 if (res) 688 goto err_put_i2c_dev; 689 690 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev); 691 if (res) 692 goto err_put_i2c_dev; 693 694 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr); 695 return NOTIFY_OK; 696 697 err_put_i2c_dev: 698 put_i2c_dev(i2c_dev, false); 699 return NOTIFY_DONE; 700 } 701 702 static int i2cdev_detach_adapter(struct device *dev) 703 { 704 struct i2c_adapter *adap; 705 struct i2c_dev *i2c_dev; 706 707 if (dev->type != &i2c_adapter_type) 708 return NOTIFY_DONE; 709 adap = to_i2c_adapter(dev); 710 711 i2c_dev = i2c_dev_get_by_minor(adap->nr); 712 if (!i2c_dev) /* attach_adapter must have failed */ 713 return NOTIFY_DONE; 714 715 put_i2c_dev(i2c_dev, true); 716 717 pr_debug("adapter [%s] unregistered\n", adap->name); 718 return NOTIFY_OK; 719 } 720 721 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action, 722 void *data) 723 { 724 struct device *dev = data; 725 726 switch (action) { 727 case BUS_NOTIFY_ADD_DEVICE: 728 return i2cdev_attach_adapter(dev); 729 case BUS_NOTIFY_DEL_DEVICE: 730 return i2cdev_detach_adapter(dev); 731 } 732 733 return NOTIFY_DONE; 734 } 735 736 static struct notifier_block i2cdev_notifier = { 737 .notifier_call = i2cdev_notifier_call, 738 }; 739 740 /* ------------------------------------------------------------------------- */ 741 742 static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy) 743 { 744 i2cdev_attach_adapter(dev); 745 return 0; 746 } 747 748 static int __exit i2c_dev_detach_adapter(struct device *dev, void *dummy) 749 { 750 i2cdev_detach_adapter(dev); 751 return 0; 752 } 753 754 /* 755 * module load/unload record keeping 756 */ 757 758 static int __init i2c_dev_init(void) 759 { 760 int res; 761 762 pr_info("i2c /dev entries driver\n"); 763 764 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c"); 765 if (res) 766 goto out; 767 768 res = class_register(&i2c_dev_class); 769 if (res) 770 goto out_unreg_chrdev; 771 772 /* Keep track of adapters which will be added or removed later */ 773 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier); 774 if (res) 775 goto out_unreg_class; 776 777 /* Bind to already existing adapters right away */ 778 i2c_for_each_dev(NULL, i2c_dev_attach_adapter); 779 780 return 0; 781 782 out_unreg_class: 783 class_unregister(&i2c_dev_class); 784 out_unreg_chrdev: 785 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 786 out: 787 pr_err("Driver Initialisation failed\n"); 788 return res; 789 } 790 791 static void __exit i2c_dev_exit(void) 792 { 793 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier); 794 i2c_for_each_dev(NULL, i2c_dev_detach_adapter); 795 class_unregister(&i2c_dev_class); 796 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 797 } 798 799 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 800 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 801 MODULE_DESCRIPTION("I2C /dev entries driver"); 802 MODULE_LICENSE("GPL"); 803 804 module_init(i2c_dev_init); 805 module_exit(i2c_dev_exit); 806