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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 i2c-dev.c - i2c-bus driver, char device interface4 5 Copyright (C) 1995-97 Simon G. Vogl6 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 seems13 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 ": " fmt18 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 a36 * slave (i2c_client) with which messages will be exchanged. It's coupled37 * 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 lists40 * 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 file119 * descriptor starts out associated only with an i2c_adapter (and bus).120 *121 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg122 * traffic to any devices on the bus used by that adapter. That's because123 * the i2c_msg vectors embed all the addressing information they need, and124 * are submitted directly to an i2c_adapter. However, SMBus-only adapters125 * don't support that interface.126 *127 * To use read()/write() system calls on that file descriptor, or to use128 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue129 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous130 * (never registered) i2c_client so it holds the addressing information131 * 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 /* 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 163static 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 188static 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 */199static 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 */212static 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 else220 result = i2cdev_check(dev, addrp);221 222 return result;223}224 225/* This address checking function differs from the one in i2c-core226 in that it considers an address with a registered device, but no227 driver bound to it, as NOT busy. */228static 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 243static 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 (similar278 * to SMBus block read), we must ensure that the buffer will279 * be large enough to cope with a message length of280 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus281 * drivers allow. The first byte in the buffer must be282 * pre-filled with the number of extra bytes, which must be283 * at least one to hold the message length, but can be284 * greater (for example to account for a checksum byte at285 * 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 323static 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 new388 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 404static 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 else427 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 with433 * the driver model core. Likewise, when that client has434 * the PEC flag already set, the i2c-dev driver won't see435 * (or use) this setting.436 */437 if (arg)438 client->flags |= I2C_CLIENT_PEC;439 else440 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 can460 * be sent at once461 */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 timeout495 * 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 trouble501 * in buggy userspace code. Some old kernel bugs returned502 * zero in this case, and userspace code might accidentally503 * have depended on that bug.504 */505 return -ENOTTY;506 }507 return 0;508}509 510#ifdef CONFIG_COMPAT511 512struct 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 519struct i2c_msg32 {520 u16 addr;521 u16 flags;522 u16 len;523 compat_caddr_t buf;524};525 526struct i2c_rdwr_ioctl_data32 {527 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */528 u32 nmsgs;529};530 531static 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#else594#define compat_i2cdev_ioctl NULL595#endif596 597static 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 be608 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.609 *610 * This client is ** NEVER REGISTERED ** with the driver model611 * or I2C core code!! It just holds private copies of addressing612 * 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 627static 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 638static 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 650static const struct class i2c_dev_class = {651 .name = "i2c-dev",652 .dev_groups = i2c_groups,653};654 655static 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 663static 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 697err_put_i2c_dev:698 put_i2c_dev(i2c_dev, false);699 return NOTIFY_DONE;700}701 702static 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 721static 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 736static struct notifier_block i2cdev_notifier = {737 .notifier_call = i2cdev_notifier_call,738};739 740/* ------------------------------------------------------------------------- */741 742static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy)743{744 i2cdev_attach_adapter(dev);745 return 0;746}747 748static 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 keeping756 */757 758static 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 782out_unreg_class:783 class_unregister(&i2c_dev_class);784out_unreg_chrdev:785 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);786out:787 pr_err("Driver Initialisation failed\n");788 return res;789}790 791static 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 799MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");800MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");801MODULE_DESCRIPTION("I2C /dev entries driver");802MODULE_LICENSE("GPL");803 804module_init(i2c_dev_init);805module_exit(i2c_dev_exit);806