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(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 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 == NULL) { 255 kfree(msgs); 256 return -ENOMEM; 257 } 258 259 res = 0; 260 for (i = 0; i < nmsgs; i++) { 261 /* Limit the size of the message to a sane amount */ 262 if (msgs[i].len > 8192) { 263 res = -EINVAL; 264 break; 265 } 266 267 data_ptrs[i] = (u8 __user *)msgs[i].buf; 268 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len); 269 if (IS_ERR(msgs[i].buf)) { 270 res = PTR_ERR(msgs[i].buf); 271 break; 272 } 273 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */ 274 msgs[i].flags |= I2C_M_DMA_SAFE; 275 276 /* 277 * If the message length is received from the slave (similar 278 * to SMBus block read), we must ensure that the buffer will 279 * be large enough to cope with a message length of 280 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus 281 * drivers allow. The first byte in the buffer must be 282 * pre-filled with the number of extra bytes, which must be 283 * at least one to hold the message length, but can be 284 * greater (for example to account for a checksum byte at 285 * the end of the message.) 286 */ 287 if (msgs[i].flags & I2C_M_RECV_LEN) { 288 if (!(msgs[i].flags & I2C_M_RD) || 289 msgs[i].len < 1 || msgs[i].buf[0] < 1 || 290 msgs[i].len < msgs[i].buf[0] + 291 I2C_SMBUS_BLOCK_MAX) { 292 i++; 293 res = -EINVAL; 294 break; 295 } 296 297 msgs[i].len = msgs[i].buf[0]; 298 } 299 } 300 if (res < 0) { 301 int j; 302 for (j = 0; j < i; ++j) 303 kfree(msgs[j].buf); 304 kfree(data_ptrs); 305 kfree(msgs); 306 return res; 307 } 308 309 res = i2c_transfer(client->adapter, msgs, nmsgs); 310 while (i-- > 0) { 311 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) { 312 if (copy_to_user(data_ptrs[i], msgs[i].buf, 313 msgs[i].len)) 314 res = -EFAULT; 315 } 316 kfree(msgs[i].buf); 317 } 318 kfree(data_ptrs); 319 kfree(msgs); 320 return res; 321 } 322 323 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, 324 u8 read_write, u8 command, u32 size, 325 union i2c_smbus_data __user *data) 326 { 327 union i2c_smbus_data temp = {}; 328 int datasize, res; 329 330 if ((size != I2C_SMBUS_BYTE) && 331 (size != I2C_SMBUS_QUICK) && 332 (size != I2C_SMBUS_BYTE_DATA) && 333 (size != I2C_SMBUS_WORD_DATA) && 334 (size != I2C_SMBUS_PROC_CALL) && 335 (size != I2C_SMBUS_BLOCK_DATA) && 336 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) && 337 (size != I2C_SMBUS_I2C_BLOCK_DATA) && 338 (size != I2C_SMBUS_BLOCK_PROC_CALL)) { 339 dev_dbg(&client->adapter->dev, 340 "size out of range (%x) in ioctl I2C_SMBUS.\n", 341 size); 342 return -EINVAL; 343 } 344 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 345 so the check is valid if size==I2C_SMBUS_QUICK too. */ 346 if ((read_write != I2C_SMBUS_READ) && 347 (read_write != I2C_SMBUS_WRITE)) { 348 dev_dbg(&client->adapter->dev, 349 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 350 read_write); 351 return -EINVAL; 352 } 353 354 /* Note that command values are always valid! */ 355 356 if ((size == I2C_SMBUS_QUICK) || 357 ((size == I2C_SMBUS_BYTE) && 358 (read_write == I2C_SMBUS_WRITE))) 359 /* These are special: we do not use data */ 360 return i2c_smbus_xfer(client->adapter, client->addr, 361 client->flags, read_write, 362 command, size, NULL); 363 364 if (data == NULL) { 365 dev_dbg(&client->adapter->dev, 366 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 367 return -EINVAL; 368 } 369 370 if ((size == I2C_SMBUS_BYTE_DATA) || 371 (size == I2C_SMBUS_BYTE)) 372 datasize = sizeof(data->byte); 373 else if ((size == I2C_SMBUS_WORD_DATA) || 374 (size == I2C_SMBUS_PROC_CALL)) 375 datasize = sizeof(data->word); 376 else /* size == smbus block, i2c block, or block proc. call */ 377 datasize = sizeof(data->block); 378 379 if ((size == I2C_SMBUS_PROC_CALL) || 380 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 381 (size == I2C_SMBUS_I2C_BLOCK_DATA) || 382 (read_write == I2C_SMBUS_WRITE)) { 383 if (copy_from_user(&temp, data, datasize)) 384 return -EFAULT; 385 } 386 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) { 387 /* Convert old I2C block commands to the new 388 convention. This preserves binary compatibility. */ 389 size = I2C_SMBUS_I2C_BLOCK_DATA; 390 if (read_write == I2C_SMBUS_READ) 391 temp.block[0] = I2C_SMBUS_BLOCK_MAX; 392 } 393 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 394 read_write, command, size, &temp); 395 if (!res && ((size == I2C_SMBUS_PROC_CALL) || 396 (size == I2C_SMBUS_BLOCK_PROC_CALL) || 397 (read_write == I2C_SMBUS_READ))) { 398 if (copy_to_user(data, &temp, datasize)) 399 return -EFAULT; 400 } 401 return res; 402 } 403 404 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 405 { 406 struct i2c_client *client = file->private_data; 407 unsigned long funcs; 408 409 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", 410 cmd, arg); 411 412 switch (cmd) { 413 case I2C_SLAVE: 414 case I2C_SLAVE_FORCE: 415 if ((arg > 0x3ff) || 416 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 417 return -EINVAL; 418 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg)) 419 return -EBUSY; 420 /* REVISIT: address could become busy later */ 421 client->addr = arg; 422 return 0; 423 case I2C_TENBIT: 424 if (arg) 425 client->flags |= I2C_M_TEN; 426 else 427 client->flags &= ~I2C_M_TEN; 428 return 0; 429 case I2C_PEC: 430 /* 431 * Setting the PEC flag here won't affect kernel drivers, 432 * which will be using the i2c_client node registered with 433 * the driver model core. Likewise, when that client has 434 * the PEC flag already set, the i2c-dev driver won't see 435 * (or use) this setting. 436 */ 437 if (arg) 438 client->flags |= I2C_CLIENT_PEC; 439 else 440 client->flags &= ~I2C_CLIENT_PEC; 441 return 0; 442 case I2C_FUNCS: 443 funcs = i2c_get_functionality(client->adapter); 444 return put_user(funcs, (unsigned long __user *)arg); 445 446 case I2C_RDWR: { 447 struct i2c_rdwr_ioctl_data rdwr_arg; 448 struct i2c_msg *rdwr_pa; 449 450 if (copy_from_user(&rdwr_arg, 451 (struct i2c_rdwr_ioctl_data __user *)arg, 452 sizeof(rdwr_arg))) 453 return -EFAULT; 454 455 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 456 return -EINVAL; 457 458 /* 459 * Put an arbitrary limit on the number of messages that can 460 * be sent at once 461 */ 462 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 463 return -EINVAL; 464 465 rdwr_pa = memdup_array_user(rdwr_arg.msgs, 466 rdwr_arg.nmsgs, sizeof(struct i2c_msg)); 467 if (IS_ERR(rdwr_pa)) 468 return PTR_ERR(rdwr_pa); 469 470 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 471 } 472 473 case I2C_SMBUS: { 474 struct i2c_smbus_ioctl_data data_arg; 475 if (copy_from_user(&data_arg, 476 (struct i2c_smbus_ioctl_data __user *) arg, 477 sizeof(struct i2c_smbus_ioctl_data))) 478 return -EFAULT; 479 return i2cdev_ioctl_smbus(client, data_arg.read_write, 480 data_arg.command, 481 data_arg.size, 482 data_arg.data); 483 } 484 case I2C_RETRIES: 485 if (arg > INT_MAX) 486 return -EINVAL; 487 488 client->adapter->retries = arg; 489 break; 490 case I2C_TIMEOUT: 491 if (arg > INT_MAX) 492 return -EINVAL; 493 494 /* For historical reasons, user-space sets the timeout 495 * value in units of 10 ms. 496 */ 497 client->adapter->timeout = msecs_to_jiffies(arg * 10); 498 break; 499 default: 500 /* NOTE: returning a fault code here could cause trouble 501 * in buggy userspace code. Some old kernel bugs returned 502 * zero in this case, and userspace code might accidentally 503 * have depended on that bug. 504 */ 505 return -ENOTTY; 506 } 507 return 0; 508 } 509 510 #ifdef CONFIG_COMPAT 511 512 struct i2c_smbus_ioctl_data32 { 513 u8 read_write; 514 u8 command; 515 u32 size; 516 compat_caddr_t data; /* union i2c_smbus_data *data */ 517 }; 518 519 struct i2c_msg32 { 520 u16 addr; 521 u16 flags; 522 u16 len; 523 compat_caddr_t buf; 524 }; 525 526 struct i2c_rdwr_ioctl_data32 { 527 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */ 528 u32 nmsgs; 529 }; 530 531 static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 532 { 533 struct i2c_client *client = file->private_data; 534 unsigned long funcs; 535 switch (cmd) { 536 case I2C_FUNCS: 537 funcs = i2c_get_functionality(client->adapter); 538 return put_user(funcs, (compat_ulong_t __user *)arg); 539 case I2C_RDWR: { 540 struct i2c_rdwr_ioctl_data32 rdwr_arg; 541 struct i2c_msg32 __user *p; 542 struct i2c_msg *rdwr_pa; 543 int i; 544 545 if (copy_from_user(&rdwr_arg, 546 (struct i2c_rdwr_ioctl_data32 __user *)arg, 547 sizeof(rdwr_arg))) 548 return -EFAULT; 549 550 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) 551 return -EINVAL; 552 553 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) 554 return -EINVAL; 555 556 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg), 557 GFP_KERNEL); 558 if (!rdwr_pa) 559 return -ENOMEM; 560 561 p = compat_ptr(rdwr_arg.msgs); 562 for (i = 0; i < rdwr_arg.nmsgs; i++) { 563 struct i2c_msg32 umsg; 564 if (copy_from_user(&umsg, p + i, sizeof(umsg))) { 565 kfree(rdwr_pa); 566 return -EFAULT; 567 } 568 rdwr_pa[i] = (struct i2c_msg) { 569 .addr = umsg.addr, 570 .flags = umsg.flags, 571 .len = umsg.len, 572 .buf = (__force __u8 *)compat_ptr(umsg.buf), 573 }; 574 } 575 576 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa); 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(sizeof(*client), GFP_KERNEL); 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 .llseek = no_llseek, 641 .read = i2cdev_read, 642 .write = i2cdev_write, 643 .unlocked_ioctl = i2cdev_ioctl, 644 .compat_ioctl = compat_i2cdev_ioctl, 645 .open = i2cdev_open, 646 .release = i2cdev_release, 647 }; 648 649 /* ------------------------------------------------------------------------- */ 650 651 static const struct class i2c_dev_class = { 652 .name = "i2c-dev", 653 .dev_groups = i2c_groups, 654 }; 655 656 static void i2cdev_dev_release(struct device *dev) 657 { 658 struct i2c_dev *i2c_dev; 659 660 i2c_dev = container_of(dev, struct i2c_dev, dev); 661 kfree(i2c_dev); 662 } 663 664 static int i2cdev_attach_adapter(struct device *dev) 665 { 666 struct i2c_adapter *adap; 667 struct i2c_dev *i2c_dev; 668 int res; 669 670 if (dev->type != &i2c_adapter_type) 671 return NOTIFY_DONE; 672 adap = to_i2c_adapter(dev); 673 674 i2c_dev = get_free_i2c_dev(adap); 675 if (IS_ERR(i2c_dev)) 676 return NOTIFY_DONE; 677 678 cdev_init(&i2c_dev->cdev, &i2cdev_fops); 679 i2c_dev->cdev.owner = THIS_MODULE; 680 681 device_initialize(&i2c_dev->dev); 682 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr); 683 i2c_dev->dev.class = &i2c_dev_class; 684 i2c_dev->dev.parent = &adap->dev; 685 i2c_dev->dev.release = i2cdev_dev_release; 686 687 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr); 688 if (res) 689 goto err_put_i2c_dev; 690 691 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev); 692 if (res) 693 goto err_put_i2c_dev; 694 695 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr); 696 return NOTIFY_OK; 697 698 err_put_i2c_dev: 699 put_i2c_dev(i2c_dev, false); 700 return NOTIFY_DONE; 701 } 702 703 static int i2cdev_detach_adapter(struct device *dev) 704 { 705 struct i2c_adapter *adap; 706 struct i2c_dev *i2c_dev; 707 708 if (dev->type != &i2c_adapter_type) 709 return NOTIFY_DONE; 710 adap = to_i2c_adapter(dev); 711 712 i2c_dev = i2c_dev_get_by_minor(adap->nr); 713 if (!i2c_dev) /* attach_adapter must have failed */ 714 return NOTIFY_DONE; 715 716 put_i2c_dev(i2c_dev, true); 717 718 pr_debug("adapter [%s] unregistered\n", adap->name); 719 return NOTIFY_OK; 720 } 721 722 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action, 723 void *data) 724 { 725 struct device *dev = data; 726 727 switch (action) { 728 case BUS_NOTIFY_ADD_DEVICE: 729 return i2cdev_attach_adapter(dev); 730 case BUS_NOTIFY_DEL_DEVICE: 731 return i2cdev_detach_adapter(dev); 732 } 733 734 return NOTIFY_DONE; 735 } 736 737 static struct notifier_block i2cdev_notifier = { 738 .notifier_call = i2cdev_notifier_call, 739 }; 740 741 /* ------------------------------------------------------------------------- */ 742 743 static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy) 744 { 745 i2cdev_attach_adapter(dev); 746 return 0; 747 } 748 749 static int __exit i2c_dev_detach_adapter(struct device *dev, void *dummy) 750 { 751 i2cdev_detach_adapter(dev); 752 return 0; 753 } 754 755 /* 756 * module load/unload record keeping 757 */ 758 759 static int __init i2c_dev_init(void) 760 { 761 int res; 762 763 pr_info("i2c /dev entries driver\n"); 764 765 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c"); 766 if (res) 767 goto out; 768 769 res = class_register(&i2c_dev_class); 770 if (res) 771 goto out_unreg_chrdev; 772 773 /* Keep track of adapters which will be added or removed later */ 774 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier); 775 if (res) 776 goto out_unreg_class; 777 778 /* Bind to already existing adapters right away */ 779 i2c_for_each_dev(NULL, i2c_dev_attach_adapter); 780 781 return 0; 782 783 out_unreg_class: 784 class_unregister(&i2c_dev_class); 785 out_unreg_chrdev: 786 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 787 out: 788 pr_err("Driver Initialisation failed\n"); 789 return res; 790 } 791 792 static void __exit i2c_dev_exit(void) 793 { 794 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier); 795 i2c_for_each_dev(NULL, i2c_dev_detach_adapter); 796 class_unregister(&i2c_dev_class); 797 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); 798 } 799 800 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 801 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 802 MODULE_DESCRIPTION("I2C /dev entries driver"); 803 MODULE_LICENSE("GPL"); 804 805 module_init(i2c_dev_init); 806 module_exit(i2c_dev_exit); 807