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1/*
2 i2c-dev.c - i2c-bus driver, char device interface
3
4 Copyright (C) 1995-97 Simon G. Vogl
5 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
21 MA 02110-1301 USA.
22*/
23
24/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
25 But I have used so much of his original code and ideas that it seems
26 only fair to recognize him as co-author -- Frodo */
27
28/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
29
30#include <linux/kernel.h>
31#include <linux/module.h>
32#include <linux/device.h>
33#include <linux/notifier.h>
34#include <linux/fs.h>
35#include <linux/slab.h>
36#include <linux/init.h>
37#include <linux/list.h>
38#include <linux/i2c.h>
39#include <linux/i2c-dev.h>
40#include <linux/jiffies.h>
41#include <linux/uaccess.h>
42
43/*
44 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
45 * slave (i2c_client) with which messages will be exchanged. It's coupled
46 * with a character special file which is accessed by user mode drivers.
47 *
48 * The list of i2c_dev structures is parallel to the i2c_adapter lists
49 * maintained by the driver model, and is updated using bus notifications.
50 */
51struct i2c_dev {
52 struct list_head list;
53 struct i2c_adapter *adap;
54 struct device *dev;
55};
56
57#define I2C_MINORS 256
58static LIST_HEAD(i2c_dev_list);
59static DEFINE_SPINLOCK(i2c_dev_list_lock);
60
61static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
62{
63 struct i2c_dev *i2c_dev;
64
65 spin_lock(&i2c_dev_list_lock);
66 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
67 if (i2c_dev->adap->nr == index)
68 goto found;
69 }
70 i2c_dev = NULL;
71found:
72 spin_unlock(&i2c_dev_list_lock);
73 return i2c_dev;
74}
75
76static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
77{
78 struct i2c_dev *i2c_dev;
79
80 if (adap->nr >= I2C_MINORS) {
81 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
82 adap->nr);
83 return ERR_PTR(-ENODEV);
84 }
85
86 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
87 if (!i2c_dev)
88 return ERR_PTR(-ENOMEM);
89 i2c_dev->adap = adap;
90
91 spin_lock(&i2c_dev_list_lock);
92 list_add_tail(&i2c_dev->list, &i2c_dev_list);
93 spin_unlock(&i2c_dev_list_lock);
94 return i2c_dev;
95}
96
97static void return_i2c_dev(struct i2c_dev *i2c_dev)
98{
99 spin_lock(&i2c_dev_list_lock);
100 list_del(&i2c_dev->list);
101 spin_unlock(&i2c_dev_list_lock);
102 kfree(i2c_dev);
103}
104
105static ssize_t name_show(struct device *dev,
106 struct device_attribute *attr, char *buf)
107{
108 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
109
110 if (!i2c_dev)
111 return -ENODEV;
112 return sprintf(buf, "%s\n", i2c_dev->adap->name);
113}
114static DEVICE_ATTR_RO(name);
115
116static struct attribute *i2c_attrs[] = {
117 &dev_attr_name.attr,
118 NULL,
119};
120ATTRIBUTE_GROUPS(i2c);
121
122/* ------------------------------------------------------------------------- */
123
124/*
125 * After opening an instance of this character special file, a file
126 * descriptor starts out associated only with an i2c_adapter (and bus).
127 *
128 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
129 * traffic to any devices on the bus used by that adapter. That's because
130 * the i2c_msg vectors embed all the addressing information they need, and
131 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
132 * don't support that interface.
133 *
134 * To use read()/write() system calls on that file descriptor, or to use
135 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
136 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
137 * (never registered) i2c_client so it holds the addressing information
138 * needed by those system calls and by this SMBus interface.
139 */
140
141static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
142 loff_t *offset)
143{
144 char *tmp;
145 int ret;
146
147 struct i2c_client *client = file->private_data;
148
149 if (count > 8192)
150 count = 8192;
151
152 tmp = kmalloc(count, GFP_KERNEL);
153 if (tmp == NULL)
154 return -ENOMEM;
155
156 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
157 iminor(file_inode(file)), count);
158
159 ret = i2c_master_recv(client, tmp, count);
160 if (ret >= 0)
161 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
162 kfree(tmp);
163 return ret;
164}
165
166static ssize_t i2cdev_write(struct file *file, const char __user *buf,
167 size_t count, loff_t *offset)
168{
169 int ret;
170 char *tmp;
171 struct i2c_client *client = file->private_data;
172
173 if (count > 8192)
174 count = 8192;
175
176 tmp = memdup_user(buf, count);
177 if (IS_ERR(tmp))
178 return PTR_ERR(tmp);
179
180 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
181 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 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. */
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_rdrw(struct i2c_client *client,
244 unsigned long arg)
245{
246 struct i2c_rdwr_ioctl_data rdwr_arg;
247 struct i2c_msg *rdwr_pa;
248 u8 __user **data_ptrs;
249 int i, res;
250
251 if (copy_from_user(&rdwr_arg,
252 (struct i2c_rdwr_ioctl_data __user *)arg,
253 sizeof(rdwr_arg)))
254 return -EFAULT;
255
256 /* Put an arbitrary limit on the number of messages that can
257 * be sent at once */
258 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
259 return -EINVAL;
260
261 rdwr_pa = memdup_user(rdwr_arg.msgs,
262 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
263 if (IS_ERR(rdwr_pa))
264 return PTR_ERR(rdwr_pa);
265
266 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
267 if (data_ptrs == NULL) {
268 kfree(rdwr_pa);
269 return -ENOMEM;
270 }
271
272 res = 0;
273 for (i = 0; i < rdwr_arg.nmsgs; i++) {
274 /* Limit the size of the message to a sane amount */
275 if (rdwr_pa[i].len > 8192) {
276 res = -EINVAL;
277 break;
278 }
279
280 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
281 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
282 if (IS_ERR(rdwr_pa[i].buf)) {
283 res = PTR_ERR(rdwr_pa[i].buf);
284 break;
285 }
286
287 /*
288 * If the message length is received from the slave (similar
289 * to SMBus block read), we must ensure that the buffer will
290 * be large enough to cope with a message length of
291 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
292 * drivers allow. The first byte in the buffer must be
293 * pre-filled with the number of extra bytes, which must be
294 * at least one to hold the message length, but can be
295 * greater (for example to account for a checksum byte at
296 * the end of the message.)
297 */
298 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
299 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
300 rdwr_pa[i].buf[0] < 1 ||
301 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
302 I2C_SMBUS_BLOCK_MAX) {
303 res = -EINVAL;
304 break;
305 }
306
307 rdwr_pa[i].len = rdwr_pa[i].buf[0];
308 }
309 }
310 if (res < 0) {
311 int j;
312 for (j = 0; j < i; ++j)
313 kfree(rdwr_pa[j].buf);
314 kfree(data_ptrs);
315 kfree(rdwr_pa);
316 return res;
317 }
318
319 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
320 while (i-- > 0) {
321 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
322 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
323 rdwr_pa[i].len))
324 res = -EFAULT;
325 }
326 kfree(rdwr_pa[i].buf);
327 }
328 kfree(data_ptrs);
329 kfree(rdwr_pa);
330 return res;
331}
332
333static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
334 unsigned long arg)
335{
336 struct i2c_smbus_ioctl_data data_arg;
337 union i2c_smbus_data temp;
338 int datasize, res;
339
340 if (copy_from_user(&data_arg,
341 (struct i2c_smbus_ioctl_data __user *) arg,
342 sizeof(struct i2c_smbus_ioctl_data)))
343 return -EFAULT;
344 if ((data_arg.size != I2C_SMBUS_BYTE) &&
345 (data_arg.size != I2C_SMBUS_QUICK) &&
346 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
347 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
348 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
349 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
350 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
351 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
352 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
353 dev_dbg(&client->adapter->dev,
354 "size out of range (%x) in ioctl I2C_SMBUS.\n",
355 data_arg.size);
356 return -EINVAL;
357 }
358 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
359 so the check is valid if size==I2C_SMBUS_QUICK too. */
360 if ((data_arg.read_write != I2C_SMBUS_READ) &&
361 (data_arg.read_write != I2C_SMBUS_WRITE)) {
362 dev_dbg(&client->adapter->dev,
363 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
364 data_arg.read_write);
365 return -EINVAL;
366 }
367
368 /* Note that command values are always valid! */
369
370 if ((data_arg.size == I2C_SMBUS_QUICK) ||
371 ((data_arg.size == I2C_SMBUS_BYTE) &&
372 (data_arg.read_write == I2C_SMBUS_WRITE)))
373 /* These are special: we do not use data */
374 return i2c_smbus_xfer(client->adapter, client->addr,
375 client->flags, data_arg.read_write,
376 data_arg.command, data_arg.size, NULL);
377
378 if (data_arg.data == NULL) {
379 dev_dbg(&client->adapter->dev,
380 "data is NULL pointer in ioctl I2C_SMBUS.\n");
381 return -EINVAL;
382 }
383
384 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
385 (data_arg.size == I2C_SMBUS_BYTE))
386 datasize = sizeof(data_arg.data->byte);
387 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
388 (data_arg.size == I2C_SMBUS_PROC_CALL))
389 datasize = sizeof(data_arg.data->word);
390 else /* size == smbus block, i2c block, or block proc. call */
391 datasize = sizeof(data_arg.data->block);
392
393 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
394 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
395 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
396 (data_arg.read_write == I2C_SMBUS_WRITE)) {
397 if (copy_from_user(&temp, data_arg.data, datasize))
398 return -EFAULT;
399 }
400 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
401 /* Convert old I2C block commands to the new
402 convention. This preserves binary compatibility. */
403 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
404 if (data_arg.read_write == I2C_SMBUS_READ)
405 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
406 }
407 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
408 data_arg.read_write, data_arg.command, data_arg.size, &temp);
409 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
410 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
411 (data_arg.read_write == I2C_SMBUS_READ))) {
412 if (copy_to_user(data_arg.data, &temp, datasize))
413 return -EFAULT;
414 }
415 return res;
416}
417
418static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
419{
420 struct i2c_client *client = file->private_data;
421 unsigned long funcs;
422
423 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
424 cmd, arg);
425
426 switch (cmd) {
427 case I2C_SLAVE:
428 case I2C_SLAVE_FORCE:
429 /* NOTE: devices set up to work with "new style" drivers
430 * can't use I2C_SLAVE, even when the device node is not
431 * bound to a driver. Only I2C_SLAVE_FORCE will work.
432 *
433 * Setting the PEC flag here won't affect kernel drivers,
434 * which will be using the i2c_client node registered with
435 * the driver model core. Likewise, when that client has
436 * the PEC flag already set, the i2c-dev driver won't see
437 * (or use) this setting.
438 */
439 if ((arg > 0x3ff) ||
440 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
441 return -EINVAL;
442 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
443 return -EBUSY;
444 /* REVISIT: address could become busy later */
445 client->addr = arg;
446 return 0;
447 case I2C_TENBIT:
448 if (arg)
449 client->flags |= I2C_M_TEN;
450 else
451 client->flags &= ~I2C_M_TEN;
452 return 0;
453 case I2C_PEC:
454 if (arg)
455 client->flags |= I2C_CLIENT_PEC;
456 else
457 client->flags &= ~I2C_CLIENT_PEC;
458 return 0;
459 case I2C_FUNCS:
460 funcs = i2c_get_functionality(client->adapter);
461 return put_user(funcs, (unsigned long __user *)arg);
462
463 case I2C_RDWR:
464 return i2cdev_ioctl_rdrw(client, arg);
465
466 case I2C_SMBUS:
467 return i2cdev_ioctl_smbus(client, arg);
468
469 case I2C_RETRIES:
470 client->adapter->retries = arg;
471 break;
472 case I2C_TIMEOUT:
473 /* For historical reasons, user-space sets the timeout
474 * value in units of 10 ms.
475 */
476 client->adapter->timeout = msecs_to_jiffies(arg * 10);
477 break;
478 default:
479 /* NOTE: returning a fault code here could cause trouble
480 * in buggy userspace code. Some old kernel bugs returned
481 * zero in this case, and userspace code might accidentally
482 * have depended on that bug.
483 */
484 return -ENOTTY;
485 }
486 return 0;
487}
488
489static int i2cdev_open(struct inode *inode, struct file *file)
490{
491 unsigned int minor = iminor(inode);
492 struct i2c_client *client;
493 struct i2c_adapter *adap;
494 struct i2c_dev *i2c_dev;
495
496 i2c_dev = i2c_dev_get_by_minor(minor);
497 if (!i2c_dev)
498 return -ENODEV;
499
500 adap = i2c_get_adapter(i2c_dev->adap->nr);
501 if (!adap)
502 return -ENODEV;
503
504 /* This creates an anonymous i2c_client, which may later be
505 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
506 *
507 * This client is ** NEVER REGISTERED ** with the driver model
508 * or I2C core code!! It just holds private copies of addressing
509 * information and maybe a PEC flag.
510 */
511 client = kzalloc(sizeof(*client), GFP_KERNEL);
512 if (!client) {
513 i2c_put_adapter(adap);
514 return -ENOMEM;
515 }
516 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
517
518 client->adapter = adap;
519 file->private_data = client;
520
521 return 0;
522}
523
524static int i2cdev_release(struct inode *inode, struct file *file)
525{
526 struct i2c_client *client = file->private_data;
527
528 i2c_put_adapter(client->adapter);
529 kfree(client);
530 file->private_data = NULL;
531
532 return 0;
533}
534
535static const struct file_operations i2cdev_fops = {
536 .owner = THIS_MODULE,
537 .llseek = no_llseek,
538 .read = i2cdev_read,
539 .write = i2cdev_write,
540 .unlocked_ioctl = i2cdev_ioctl,
541 .open = i2cdev_open,
542 .release = i2cdev_release,
543};
544
545/* ------------------------------------------------------------------------- */
546
547static struct class *i2c_dev_class;
548
549static int i2cdev_attach_adapter(struct device *dev, void *dummy)
550{
551 struct i2c_adapter *adap;
552 struct i2c_dev *i2c_dev;
553 int res;
554
555 if (dev->type != &i2c_adapter_type)
556 return 0;
557 adap = to_i2c_adapter(dev);
558
559 i2c_dev = get_free_i2c_dev(adap);
560 if (IS_ERR(i2c_dev))
561 return PTR_ERR(i2c_dev);
562
563 /* register this i2c device with the driver core */
564 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
565 MKDEV(I2C_MAJOR, adap->nr), NULL,
566 "i2c-%d", adap->nr);
567 if (IS_ERR(i2c_dev->dev)) {
568 res = PTR_ERR(i2c_dev->dev);
569 goto error;
570 }
571
572 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
573 adap->name, adap->nr);
574 return 0;
575error:
576 return_i2c_dev(i2c_dev);
577 return res;
578}
579
580static int i2cdev_detach_adapter(struct device *dev, void *dummy)
581{
582 struct i2c_adapter *adap;
583 struct i2c_dev *i2c_dev;
584
585 if (dev->type != &i2c_adapter_type)
586 return 0;
587 adap = to_i2c_adapter(dev);
588
589 i2c_dev = i2c_dev_get_by_minor(adap->nr);
590 if (!i2c_dev) /* attach_adapter must have failed */
591 return 0;
592
593 return_i2c_dev(i2c_dev);
594 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
595
596 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
597 return 0;
598}
599
600static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
601 void *data)
602{
603 struct device *dev = data;
604
605 switch (action) {
606 case BUS_NOTIFY_ADD_DEVICE:
607 return i2cdev_attach_adapter(dev, NULL);
608 case BUS_NOTIFY_DEL_DEVICE:
609 return i2cdev_detach_adapter(dev, NULL);
610 }
611
612 return 0;
613}
614
615static struct notifier_block i2cdev_notifier = {
616 .notifier_call = i2cdev_notifier_call,
617};
618
619/* ------------------------------------------------------------------------- */
620
621/*
622 * module load/unload record keeping
623 */
624
625static int __init i2c_dev_init(void)
626{
627 int res;
628
629 printk(KERN_INFO "i2c /dev entries driver\n");
630
631 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
632 if (res)
633 goto out;
634
635 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
636 if (IS_ERR(i2c_dev_class)) {
637 res = PTR_ERR(i2c_dev_class);
638 goto out_unreg_chrdev;
639 }
640 i2c_dev_class->dev_groups = i2c_groups;
641
642 /* Keep track of adapters which will be added or removed later */
643 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
644 if (res)
645 goto out_unreg_class;
646
647 /* Bind to already existing adapters right away */
648 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
649
650 return 0;
651
652out_unreg_class:
653 class_destroy(i2c_dev_class);
654out_unreg_chrdev:
655 unregister_chrdev(I2C_MAJOR, "i2c");
656out:
657 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
658 return res;
659}
660
661static void __exit i2c_dev_exit(void)
662{
663 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
664 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
665 class_destroy(i2c_dev_class);
666 unregister_chrdev(I2C_MAJOR, "i2c");
667}
668
669MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
670 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
671MODULE_DESCRIPTION("I2C /dev entries driver");
672MODULE_LICENSE("GPL");
673
674module_init(i2c_dev_init);
675module_exit(i2c_dev_exit);
1/*
2 i2c-dev.c - i2c-bus driver, char device interface
3
4 Copyright (C) 1995-97 Simon G. Vogl
5 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17*/
18
19/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
20 But I have used so much of his original code and ideas that it seems
21 only fair to recognize him as co-author -- Frodo */
22
23/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
24
25#include <linux/cdev.h>
26#include <linux/device.h>
27#include <linux/fs.h>
28#include <linux/i2c-dev.h>
29#include <linux/i2c.h>
30#include <linux/init.h>
31#include <linux/jiffies.h>
32#include <linux/kernel.h>
33#include <linux/list.h>
34#include <linux/module.h>
35#include <linux/notifier.h>
36#include <linux/slab.h>
37#include <linux/uaccess.h>
38
39/*
40 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
41 * slave (i2c_client) with which messages will be exchanged. It's coupled
42 * with a character special file which is accessed by user mode drivers.
43 *
44 * The list of i2c_dev structures is parallel to the i2c_adapter lists
45 * maintained by the driver model, and is updated using bus notifications.
46 */
47struct i2c_dev {
48 struct list_head list;
49 struct i2c_adapter *adap;
50 struct device *dev;
51 struct cdev cdev;
52};
53
54#define I2C_MINORS MINORMASK
55static LIST_HEAD(i2c_dev_list);
56static DEFINE_SPINLOCK(i2c_dev_list_lock);
57
58static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
59{
60 struct i2c_dev *i2c_dev;
61
62 spin_lock(&i2c_dev_list_lock);
63 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
64 if (i2c_dev->adap->nr == index)
65 goto found;
66 }
67 i2c_dev = NULL;
68found:
69 spin_unlock(&i2c_dev_list_lock);
70 return i2c_dev;
71}
72
73static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
74{
75 struct i2c_dev *i2c_dev;
76
77 if (adap->nr >= I2C_MINORS) {
78 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
79 adap->nr);
80 return ERR_PTR(-ENODEV);
81 }
82
83 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
84 if (!i2c_dev)
85 return ERR_PTR(-ENOMEM);
86 i2c_dev->adap = adap;
87
88 spin_lock(&i2c_dev_list_lock);
89 list_add_tail(&i2c_dev->list, &i2c_dev_list);
90 spin_unlock(&i2c_dev_list_lock);
91 return i2c_dev;
92}
93
94static void put_i2c_dev(struct i2c_dev *i2c_dev)
95{
96 spin_lock(&i2c_dev_list_lock);
97 list_del(&i2c_dev->list);
98 spin_unlock(&i2c_dev_list_lock);
99 kfree(i2c_dev);
100}
101
102static ssize_t name_show(struct device *dev,
103 struct device_attribute *attr, char *buf)
104{
105 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
106
107 if (!i2c_dev)
108 return -ENODEV;
109 return sprintf(buf, "%s\n", i2c_dev->adap->name);
110}
111static DEVICE_ATTR_RO(name);
112
113static struct attribute *i2c_attrs[] = {
114 &dev_attr_name.attr,
115 NULL,
116};
117ATTRIBUTE_GROUPS(i2c);
118
119/* ------------------------------------------------------------------------- */
120
121/*
122 * After opening an instance of this character special file, a file
123 * descriptor starts out associated only with an i2c_adapter (and bus).
124 *
125 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
126 * traffic to any devices on the bus used by that adapter. That's because
127 * the i2c_msg vectors embed all the addressing information they need, and
128 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
129 * don't support that interface.
130 *
131 * To use read()/write() system calls on that file descriptor, or to use
132 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
133 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
134 * (never registered) i2c_client so it holds the addressing information
135 * needed by those system calls and by this SMBus interface.
136 */
137
138static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
139 loff_t *offset)
140{
141 char *tmp;
142 int ret;
143
144 struct i2c_client *client = file->private_data;
145
146 if (count > 8192)
147 count = 8192;
148
149 tmp = kmalloc(count, GFP_KERNEL);
150 if (tmp == NULL)
151 return -ENOMEM;
152
153 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
154 iminor(file_inode(file)), count);
155
156 ret = i2c_master_recv(client, tmp, count);
157 if (ret >= 0)
158 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
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 if (count > 8192)
171 count = 8192;
172
173 tmp = memdup_user(buf, count);
174 if (IS_ERR(tmp))
175 return PTR_ERR(tmp);
176
177 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
178 iminor(file_inode(file)), count);
179
180 ret = i2c_master_send(client, tmp, count);
181 kfree(tmp);
182 return ret;
183}
184
185static int i2cdev_check(struct device *dev, void *addrp)
186{
187 struct i2c_client *client = i2c_verify_client(dev);
188
189 if (!client || client->addr != *(unsigned int *)addrp)
190 return 0;
191
192 return dev->driver ? -EBUSY : 0;
193}
194
195/* walk up mux tree */
196static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
197{
198 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
199 int result;
200
201 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
202 if (!result && parent)
203 result = i2cdev_check_mux_parents(parent, addr);
204
205 return result;
206}
207
208/* recurse down mux tree */
209static int i2cdev_check_mux_children(struct device *dev, void *addrp)
210{
211 int result;
212
213 if (dev->type == &i2c_adapter_type)
214 result = device_for_each_child(dev, addrp,
215 i2cdev_check_mux_children);
216 else
217 result = i2cdev_check(dev, addrp);
218
219 return result;
220}
221
222/* This address checking function differs from the one in i2c-core
223 in that it considers an address with a registered device, but no
224 driver bound to it, as NOT busy. */
225static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
226{
227 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
228 int result = 0;
229
230 if (parent)
231 result = i2cdev_check_mux_parents(parent, addr);
232
233 if (!result)
234 result = device_for_each_child(&adapter->dev, &addr,
235 i2cdev_check_mux_children);
236
237 return result;
238}
239
240static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
241 unsigned long arg)
242{
243 struct i2c_rdwr_ioctl_data rdwr_arg;
244 struct i2c_msg *rdwr_pa;
245 u8 __user **data_ptrs;
246 int i, res;
247
248 if (copy_from_user(&rdwr_arg,
249 (struct i2c_rdwr_ioctl_data __user *)arg,
250 sizeof(rdwr_arg)))
251 return -EFAULT;
252
253 /* Put an arbitrary limit on the number of messages that can
254 * be sent at once */
255 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
256 return -EINVAL;
257
258 rdwr_pa = memdup_user(rdwr_arg.msgs,
259 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
260 if (IS_ERR(rdwr_pa))
261 return PTR_ERR(rdwr_pa);
262
263 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
264 if (data_ptrs == NULL) {
265 kfree(rdwr_pa);
266 return -ENOMEM;
267 }
268
269 res = 0;
270 for (i = 0; i < rdwr_arg.nmsgs; i++) {
271 /* Limit the size of the message to a sane amount */
272 if (rdwr_pa[i].len > 8192) {
273 res = -EINVAL;
274 break;
275 }
276
277 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
278 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
279 if (IS_ERR(rdwr_pa[i].buf)) {
280 res = PTR_ERR(rdwr_pa[i].buf);
281 break;
282 }
283
284 /*
285 * If the message length is received from the slave (similar
286 * to SMBus block read), we must ensure that the buffer will
287 * be large enough to cope with a message length of
288 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
289 * drivers allow. The first byte in the buffer must be
290 * pre-filled with the number of extra bytes, which must be
291 * at least one to hold the message length, but can be
292 * greater (for example to account for a checksum byte at
293 * the end of the message.)
294 */
295 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
296 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
297 rdwr_pa[i].buf[0] < 1 ||
298 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
299 I2C_SMBUS_BLOCK_MAX) {
300 res = -EINVAL;
301 break;
302 }
303
304 rdwr_pa[i].len = rdwr_pa[i].buf[0];
305 }
306 }
307 if (res < 0) {
308 int j;
309 for (j = 0; j < i; ++j)
310 kfree(rdwr_pa[j].buf);
311 kfree(data_ptrs);
312 kfree(rdwr_pa);
313 return res;
314 }
315
316 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
317 while (i-- > 0) {
318 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
319 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
320 rdwr_pa[i].len))
321 res = -EFAULT;
322 }
323 kfree(rdwr_pa[i].buf);
324 }
325 kfree(data_ptrs);
326 kfree(rdwr_pa);
327 return res;
328}
329
330static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
331 unsigned long arg)
332{
333 struct i2c_smbus_ioctl_data data_arg;
334 union i2c_smbus_data temp = {};
335 int datasize, res;
336
337 if (copy_from_user(&data_arg,
338 (struct i2c_smbus_ioctl_data __user *) arg,
339 sizeof(struct i2c_smbus_ioctl_data)))
340 return -EFAULT;
341 if ((data_arg.size != I2C_SMBUS_BYTE) &&
342 (data_arg.size != I2C_SMBUS_QUICK) &&
343 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
344 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
345 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
346 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
347 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
348 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
349 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
350 dev_dbg(&client->adapter->dev,
351 "size out of range (%x) in ioctl I2C_SMBUS.\n",
352 data_arg.size);
353 return -EINVAL;
354 }
355 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
356 so the check is valid if size==I2C_SMBUS_QUICK too. */
357 if ((data_arg.read_write != I2C_SMBUS_READ) &&
358 (data_arg.read_write != I2C_SMBUS_WRITE)) {
359 dev_dbg(&client->adapter->dev,
360 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
361 data_arg.read_write);
362 return -EINVAL;
363 }
364
365 /* Note that command values are always valid! */
366
367 if ((data_arg.size == I2C_SMBUS_QUICK) ||
368 ((data_arg.size == I2C_SMBUS_BYTE) &&
369 (data_arg.read_write == I2C_SMBUS_WRITE)))
370 /* These are special: we do not use data */
371 return i2c_smbus_xfer(client->adapter, client->addr,
372 client->flags, data_arg.read_write,
373 data_arg.command, data_arg.size, NULL);
374
375 if (data_arg.data == NULL) {
376 dev_dbg(&client->adapter->dev,
377 "data is NULL pointer in ioctl I2C_SMBUS.\n");
378 return -EINVAL;
379 }
380
381 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
382 (data_arg.size == I2C_SMBUS_BYTE))
383 datasize = sizeof(data_arg.data->byte);
384 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
385 (data_arg.size == I2C_SMBUS_PROC_CALL))
386 datasize = sizeof(data_arg.data->word);
387 else /* size == smbus block, i2c block, or block proc. call */
388 datasize = sizeof(data_arg.data->block);
389
390 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
391 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
392 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
393 (data_arg.read_write == I2C_SMBUS_WRITE)) {
394 if (copy_from_user(&temp, data_arg.data, datasize))
395 return -EFAULT;
396 }
397 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
398 /* Convert old I2C block commands to the new
399 convention. This preserves binary compatibility. */
400 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
401 if (data_arg.read_write == I2C_SMBUS_READ)
402 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
403 }
404 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
405 data_arg.read_write, data_arg.command, data_arg.size, &temp);
406 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
407 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
408 (data_arg.read_write == I2C_SMBUS_READ))) {
409 if (copy_to_user(data_arg.data, &temp, datasize))
410 return -EFAULT;
411 }
412 return res;
413}
414
415static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
416{
417 struct i2c_client *client = file->private_data;
418 unsigned long funcs;
419
420 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
421 cmd, arg);
422
423 switch (cmd) {
424 case I2C_SLAVE:
425 case I2C_SLAVE_FORCE:
426 if ((arg > 0x3ff) ||
427 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
428 return -EINVAL;
429 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
430 return -EBUSY;
431 /* REVISIT: address could become busy later */
432 client->addr = arg;
433 return 0;
434 case I2C_TENBIT:
435 if (arg)
436 client->flags |= I2C_M_TEN;
437 else
438 client->flags &= ~I2C_M_TEN;
439 return 0;
440 case I2C_PEC:
441 /*
442 * Setting the PEC flag here won't affect kernel drivers,
443 * which will be using the i2c_client node registered with
444 * the driver model core. Likewise, when that client has
445 * the PEC flag already set, the i2c-dev driver won't see
446 * (or use) this setting.
447 */
448 if (arg)
449 client->flags |= I2C_CLIENT_PEC;
450 else
451 client->flags &= ~I2C_CLIENT_PEC;
452 return 0;
453 case I2C_FUNCS:
454 funcs = i2c_get_functionality(client->adapter);
455 return put_user(funcs, (unsigned long __user *)arg);
456
457 case I2C_RDWR:
458 return i2cdev_ioctl_rdwr(client, arg);
459
460 case I2C_SMBUS:
461 return i2cdev_ioctl_smbus(client, arg);
462
463 case I2C_RETRIES:
464 client->adapter->retries = arg;
465 break;
466 case I2C_TIMEOUT:
467 /* For historical reasons, user-space sets the timeout
468 * value in units of 10 ms.
469 */
470 client->adapter->timeout = msecs_to_jiffies(arg * 10);
471 break;
472 default:
473 /* NOTE: returning a fault code here could cause trouble
474 * in buggy userspace code. Some old kernel bugs returned
475 * zero in this case, and userspace code might accidentally
476 * have depended on that bug.
477 */
478 return -ENOTTY;
479 }
480 return 0;
481}
482
483static int i2cdev_open(struct inode *inode, struct file *file)
484{
485 unsigned int minor = iminor(inode);
486 struct i2c_client *client;
487 struct i2c_adapter *adap;
488
489 adap = i2c_get_adapter(minor);
490 if (!adap)
491 return -ENODEV;
492
493 /* This creates an anonymous i2c_client, which may later be
494 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
495 *
496 * This client is ** NEVER REGISTERED ** with the driver model
497 * or I2C core code!! It just holds private copies of addressing
498 * information and maybe a PEC flag.
499 */
500 client = kzalloc(sizeof(*client), GFP_KERNEL);
501 if (!client) {
502 i2c_put_adapter(adap);
503 return -ENOMEM;
504 }
505 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
506
507 client->adapter = adap;
508 file->private_data = client;
509
510 return 0;
511}
512
513static int i2cdev_release(struct inode *inode, struct file *file)
514{
515 struct i2c_client *client = file->private_data;
516
517 i2c_put_adapter(client->adapter);
518 kfree(client);
519 file->private_data = NULL;
520
521 return 0;
522}
523
524static const struct file_operations i2cdev_fops = {
525 .owner = THIS_MODULE,
526 .llseek = no_llseek,
527 .read = i2cdev_read,
528 .write = i2cdev_write,
529 .unlocked_ioctl = i2cdev_ioctl,
530 .open = i2cdev_open,
531 .release = i2cdev_release,
532};
533
534/* ------------------------------------------------------------------------- */
535
536static struct class *i2c_dev_class;
537
538static int i2cdev_attach_adapter(struct device *dev, void *dummy)
539{
540 struct i2c_adapter *adap;
541 struct i2c_dev *i2c_dev;
542 int res;
543
544 if (dev->type != &i2c_adapter_type)
545 return 0;
546 adap = to_i2c_adapter(dev);
547
548 i2c_dev = get_free_i2c_dev(adap);
549 if (IS_ERR(i2c_dev))
550 return PTR_ERR(i2c_dev);
551
552 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
553 i2c_dev->cdev.owner = THIS_MODULE;
554 res = cdev_add(&i2c_dev->cdev, MKDEV(I2C_MAJOR, adap->nr), 1);
555 if (res)
556 goto error_cdev;
557
558 /* register this i2c device with the driver core */
559 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
560 MKDEV(I2C_MAJOR, adap->nr), NULL,
561 "i2c-%d", adap->nr);
562 if (IS_ERR(i2c_dev->dev)) {
563 res = PTR_ERR(i2c_dev->dev);
564 goto error;
565 }
566
567 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
568 adap->name, adap->nr);
569 return 0;
570error:
571 cdev_del(&i2c_dev->cdev);
572error_cdev:
573 put_i2c_dev(i2c_dev);
574 return res;
575}
576
577static int i2cdev_detach_adapter(struct device *dev, void *dummy)
578{
579 struct i2c_adapter *adap;
580 struct i2c_dev *i2c_dev;
581
582 if (dev->type != &i2c_adapter_type)
583 return 0;
584 adap = to_i2c_adapter(dev);
585
586 i2c_dev = i2c_dev_get_by_minor(adap->nr);
587 if (!i2c_dev) /* attach_adapter must have failed */
588 return 0;
589
590 cdev_del(&i2c_dev->cdev);
591 put_i2c_dev(i2c_dev);
592 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
593
594 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
595 return 0;
596}
597
598static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
599 void *data)
600{
601 struct device *dev = data;
602
603 switch (action) {
604 case BUS_NOTIFY_ADD_DEVICE:
605 return i2cdev_attach_adapter(dev, NULL);
606 case BUS_NOTIFY_DEL_DEVICE:
607 return i2cdev_detach_adapter(dev, NULL);
608 }
609
610 return 0;
611}
612
613static struct notifier_block i2cdev_notifier = {
614 .notifier_call = i2cdev_notifier_call,
615};
616
617/* ------------------------------------------------------------------------- */
618
619/*
620 * module load/unload record keeping
621 */
622
623static int __init i2c_dev_init(void)
624{
625 int res;
626
627 printk(KERN_INFO "i2c /dev entries driver\n");
628
629 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
630 if (res)
631 goto out;
632
633 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
634 if (IS_ERR(i2c_dev_class)) {
635 res = PTR_ERR(i2c_dev_class);
636 goto out_unreg_chrdev;
637 }
638 i2c_dev_class->dev_groups = i2c_groups;
639
640 /* Keep track of adapters which will be added or removed later */
641 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
642 if (res)
643 goto out_unreg_class;
644
645 /* Bind to already existing adapters right away */
646 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
647
648 return 0;
649
650out_unreg_class:
651 class_destroy(i2c_dev_class);
652out_unreg_chrdev:
653 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
654out:
655 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
656 return res;
657}
658
659static void __exit i2c_dev_exit(void)
660{
661 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
662 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
663 class_destroy(i2c_dev_class);
664 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
665}
666
667MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
668 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
669MODULE_DESCRIPTION("I2C /dev entries driver");
670MODULE_LICENSE("GPL");
671
672module_init(i2c_dev_init);
673module_exit(i2c_dev_exit);