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/kernel.h>
27 #include <linux/module.h>
28 #include <linux/device.h>
29 #include <linux/notifier.h>
30 #include <linux/fs.h>
31 #include <linux/slab.h>
32 #include <linux/init.h>
33 #include <linux/list.h>
34 #include <linux/i2c.h>
35 #include <linux/i2c-dev.h>
36 #include <linux/jiffies.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 */
47 struct 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
55 static LIST_HEAD(i2c_dev_list);
56 static DEFINE_SPINLOCK(i2c_dev_list_lock);
57
i2c_dev_get_by_minor(unsigned index)58 static 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;
68 found:
69 spin_unlock(&i2c_dev_list_lock);
70 return i2c_dev;
71 }
72
get_free_i2c_dev(struct i2c_adapter * adap)73 static 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
put_i2c_dev(struct i2c_dev * i2c_dev,bool del_cdev)94 static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev)
95 {
96 spin_lock(&i2c_dev_list_lock);
97 list_del(&i2c_dev->list);
98 spin_unlock(&i2c_dev_list_lock);
99 if (del_cdev)
100 cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev);
101 put_device(&i2c_dev->dev);
102 }
103
name_show(struct device * dev,struct device_attribute * attr,char * buf)104 static ssize_t name_show(struct device *dev,
105 struct device_attribute *attr, char *buf)
106 {
107 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
108
109 if (!i2c_dev)
110 return -ENODEV;
111 return sprintf(buf, "%s\n", i2c_dev->adap->name);
112 }
113 static DEVICE_ATTR_RO(name);
114
115 static struct attribute *i2c_attrs[] = {
116 &dev_attr_name.attr,
117 NULL,
118 };
119 ATTRIBUTE_GROUPS(i2c);
120
121 /* ------------------------------------------------------------------------- */
122
123 /*
124 * After opening an instance of this character special file, a file
125 * descriptor starts out associated only with an i2c_adapter (and bus).
126 *
127 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
128 * traffic to any devices on the bus used by that adapter. That's because
129 * the i2c_msg vectors embed all the addressing information they need, and
130 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
131 * don't support that interface.
132 *
133 * To use read()/write() system calls on that file descriptor, or to use
134 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
135 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
136 * (never registered) i2c_client so it holds the addressing information
137 * needed by those system calls and by this SMBus interface.
138 */
139
i2cdev_read(struct file * file,char __user * buf,size_t count,loff_t * offset)140 static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
141 loff_t *offset)
142 {
143 char *tmp;
144 int ret;
145
146 struct i2c_client *client = file->private_data;
147
148 if (count > 8192)
149 count = 8192;
150
151 tmp = kzalloc(count, GFP_KERNEL);
152 if (tmp == NULL)
153 return -ENOMEM;
154
155 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
156 iminor(file_inode(file)), count);
157
158 ret = i2c_master_recv(client, tmp, count);
159 if (ret >= 0)
160 if (copy_to_user(buf, tmp, ret))
161 ret = -EFAULT;
162 kfree(tmp);
163 return ret;
164 }
165
i2cdev_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)166 static 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
i2cdev_check(struct device * dev,void * addrp)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 */
i2cdev_check_mux_parents(struct i2c_adapter * adapter,int addr)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 */
i2cdev_check_mux_children(struct device * dev,void * addrp)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. */
i2cdev_check_addr(struct i2c_adapter * adapter,unsigned int addr)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
i2cdev_ioctl_rdwr(struct i2c_client * client,unsigned long arg)243 static noinline int i2cdev_ioctl_rdwr(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_RDWR_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 i++;
304 res = -EINVAL;
305 break;
306 }
307
308 rdwr_pa[i].len = rdwr_pa[i].buf[0];
309 }
310 }
311 if (res < 0) {
312 int j;
313 for (j = 0; j < i; ++j)
314 kfree(rdwr_pa[j].buf);
315 kfree(data_ptrs);
316 kfree(rdwr_pa);
317 return res;
318 }
319
320 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
321 while (i-- > 0) {
322 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
323 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
324 rdwr_pa[i].len))
325 res = -EFAULT;
326 }
327 kfree(rdwr_pa[i].buf);
328 }
329 kfree(data_ptrs);
330 kfree(rdwr_pa);
331 return res;
332 }
333
i2cdev_ioctl_smbus(struct i2c_client * client,unsigned long arg)334 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
335 unsigned long arg)
336 {
337 struct i2c_smbus_ioctl_data data_arg;
338 union i2c_smbus_data temp = {};
339 int datasize, res;
340
341 if (copy_from_user(&data_arg,
342 (struct i2c_smbus_ioctl_data __user *) arg,
343 sizeof(struct i2c_smbus_ioctl_data)))
344 return -EFAULT;
345 if ((data_arg.size != I2C_SMBUS_BYTE) &&
346 (data_arg.size != I2C_SMBUS_QUICK) &&
347 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
348 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
349 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
350 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
351 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
352 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
353 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
354 dev_dbg(&client->adapter->dev,
355 "size out of range (%x) in ioctl I2C_SMBUS.\n",
356 data_arg.size);
357 return -EINVAL;
358 }
359 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
360 so the check is valid if size==I2C_SMBUS_QUICK too. */
361 if ((data_arg.read_write != I2C_SMBUS_READ) &&
362 (data_arg.read_write != I2C_SMBUS_WRITE)) {
363 dev_dbg(&client->adapter->dev,
364 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
365 data_arg.read_write);
366 return -EINVAL;
367 }
368
369 /* Note that command values are always valid! */
370
371 if ((data_arg.size == I2C_SMBUS_QUICK) ||
372 ((data_arg.size == I2C_SMBUS_BYTE) &&
373 (data_arg.read_write == I2C_SMBUS_WRITE)))
374 /* These are special: we do not use data */
375 return i2c_smbus_xfer(client->adapter, client->addr,
376 client->flags, data_arg.read_write,
377 data_arg.command, data_arg.size, NULL);
378
379 if (data_arg.data == NULL) {
380 dev_dbg(&client->adapter->dev,
381 "data is NULL pointer in ioctl I2C_SMBUS.\n");
382 return -EINVAL;
383 }
384
385 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
386 (data_arg.size == I2C_SMBUS_BYTE))
387 datasize = sizeof(data_arg.data->byte);
388 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
389 (data_arg.size == I2C_SMBUS_PROC_CALL))
390 datasize = sizeof(data_arg.data->word);
391 else /* size == smbus block, i2c block, or block proc. call */
392 datasize = sizeof(data_arg.data->block);
393
394 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
395 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
396 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
397 (data_arg.read_write == I2C_SMBUS_WRITE)) {
398 if (copy_from_user(&temp, data_arg.data, datasize))
399 return -EFAULT;
400 }
401 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
402 /* Convert old I2C block commands to the new
403 convention. This preserves binary compatibility. */
404 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
405 if (data_arg.read_write == I2C_SMBUS_READ)
406 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
407 }
408 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
409 data_arg.read_write, data_arg.command, data_arg.size, &temp);
410 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
411 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
412 (data_arg.read_write == I2C_SMBUS_READ))) {
413 if (copy_to_user(data_arg.data, &temp, datasize))
414 return -EFAULT;
415 }
416 return res;
417 }
418
i2cdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)419 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
420 {
421 struct i2c_client *client = file->private_data;
422 unsigned long funcs;
423
424 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
425 cmd, arg);
426
427 switch (cmd) {
428 case I2C_SLAVE:
429 case I2C_SLAVE_FORCE:
430 if ((arg > 0x3ff) ||
431 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
432 return -EINVAL;
433 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
434 return -EBUSY;
435 /* REVISIT: address could become busy later */
436 client->addr = arg;
437 return 0;
438 case I2C_TENBIT:
439 if (arg)
440 client->flags |= I2C_M_TEN;
441 else
442 client->flags &= ~I2C_M_TEN;
443 return 0;
444 case I2C_PEC:
445 /*
446 * Setting the PEC flag here won't affect kernel drivers,
447 * which will be using the i2c_client node registered with
448 * the driver model core. Likewise, when that client has
449 * the PEC flag already set, the i2c-dev driver won't see
450 * (or use) this setting.
451 */
452 if (arg)
453 client->flags |= I2C_CLIENT_PEC;
454 else
455 client->flags &= ~I2C_CLIENT_PEC;
456 return 0;
457 case I2C_FUNCS:
458 funcs = i2c_get_functionality(client->adapter);
459 return put_user(funcs, (unsigned long __user *)arg);
460
461 case I2C_RDWR:
462 return i2cdev_ioctl_rdwr(client, arg);
463
464 case I2C_SMBUS:
465 return i2cdev_ioctl_smbus(client, arg);
466
467 case I2C_RETRIES:
468 if (arg > INT_MAX)
469 return -EINVAL;
470
471 client->adapter->retries = arg;
472 break;
473 case I2C_TIMEOUT:
474 if (arg > INT_MAX)
475 return -EINVAL;
476
477 /* For historical reasons, user-space sets the timeout
478 * value in units of 10 ms.
479 */
480 client->adapter->timeout = msecs_to_jiffies(arg * 10);
481 break;
482 default:
483 /* NOTE: returning a fault code here could cause trouble
484 * in buggy userspace code. Some old kernel bugs returned
485 * zero in this case, and userspace code might accidentally
486 * have depended on that bug.
487 */
488 return -ENOTTY;
489 }
490 return 0;
491 }
492
i2cdev_open(struct inode * inode,struct file * file)493 static int i2cdev_open(struct inode *inode, struct file *file)
494 {
495 unsigned int minor = iminor(inode);
496 struct i2c_client *client;
497 struct i2c_adapter *adap;
498
499 adap = i2c_get_adapter(minor);
500 if (!adap)
501 return -ENODEV;
502
503 /* This creates an anonymous i2c_client, which may later be
504 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
505 *
506 * This client is ** NEVER REGISTERED ** with the driver model
507 * or I2C core code!! It just holds private copies of addressing
508 * information and maybe a PEC flag.
509 */
510 client = kzalloc(sizeof(*client), GFP_KERNEL);
511 if (!client) {
512 i2c_put_adapter(adap);
513 return -ENOMEM;
514 }
515 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
516
517 client->adapter = adap;
518 file->private_data = client;
519
520 return 0;
521 }
522
i2cdev_release(struct inode * inode,struct file * file)523 static int i2cdev_release(struct inode *inode, struct file *file)
524 {
525 struct i2c_client *client = file->private_data;
526
527 i2c_put_adapter(client->adapter);
528 kfree(client);
529 file->private_data = NULL;
530
531 return 0;
532 }
533
534 static const struct file_operations i2cdev_fops = {
535 .owner = THIS_MODULE,
536 .llseek = no_llseek,
537 .read = i2cdev_read,
538 .write = i2cdev_write,
539 .unlocked_ioctl = i2cdev_ioctl,
540 .open = i2cdev_open,
541 .release = i2cdev_release,
542 };
543
544 /* ------------------------------------------------------------------------- */
545
546 static struct class *i2c_dev_class;
547
i2cdev_dev_release(struct device * dev)548 static void i2cdev_dev_release(struct device *dev)
549 {
550 struct i2c_dev *i2c_dev;
551
552 i2c_dev = container_of(dev, struct i2c_dev, dev);
553 kfree(i2c_dev);
554 }
555
i2cdev_attach_adapter(struct device * dev,void * dummy)556 static int i2cdev_attach_adapter(struct device *dev, void *dummy)
557 {
558 struct i2c_adapter *adap;
559 struct i2c_dev *i2c_dev;
560 int res;
561
562 if (dev->type != &i2c_adapter_type)
563 return 0;
564 adap = to_i2c_adapter(dev);
565
566 i2c_dev = get_free_i2c_dev(adap);
567 if (IS_ERR(i2c_dev))
568 return PTR_ERR(i2c_dev);
569
570 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
571 i2c_dev->cdev.owner = THIS_MODULE;
572
573 device_initialize(&i2c_dev->dev);
574 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
575 i2c_dev->dev.class = i2c_dev_class;
576 i2c_dev->dev.parent = &adap->dev;
577 i2c_dev->dev.release = i2cdev_dev_release;
578 dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
579
580 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
581 if (res) {
582 put_i2c_dev(i2c_dev, false);
583 return res;
584 }
585
586 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
587 adap->name, adap->nr);
588 return 0;
589 }
590
i2cdev_detach_adapter(struct device * dev,void * dummy)591 static int i2cdev_detach_adapter(struct device *dev, void *dummy)
592 {
593 struct i2c_adapter *adap;
594 struct i2c_dev *i2c_dev;
595
596 if (dev->type != &i2c_adapter_type)
597 return 0;
598 adap = to_i2c_adapter(dev);
599
600 i2c_dev = i2c_dev_get_by_minor(adap->nr);
601 if (!i2c_dev) /* attach_adapter must have failed */
602 return 0;
603
604 put_i2c_dev(i2c_dev, true);
605
606 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
607 return 0;
608 }
609
i2cdev_notifier_call(struct notifier_block * nb,unsigned long action,void * data)610 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
611 void *data)
612 {
613 struct device *dev = data;
614
615 switch (action) {
616 case BUS_NOTIFY_ADD_DEVICE:
617 return i2cdev_attach_adapter(dev, NULL);
618 case BUS_NOTIFY_DEL_DEVICE:
619 return i2cdev_detach_adapter(dev, NULL);
620 }
621
622 return 0;
623 }
624
625 static struct notifier_block i2cdev_notifier = {
626 .notifier_call = i2cdev_notifier_call,
627 };
628
629 /* ------------------------------------------------------------------------- */
630
631 /*
632 * module load/unload record keeping
633 */
634
i2c_dev_init(void)635 static int __init i2c_dev_init(void)
636 {
637 int res;
638
639 printk(KERN_INFO "i2c /dev entries driver\n");
640
641 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
642 if (res)
643 goto out;
644
645 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
646 if (IS_ERR(i2c_dev_class)) {
647 res = PTR_ERR(i2c_dev_class);
648 goto out_unreg_chrdev;
649 }
650 i2c_dev_class->dev_groups = i2c_groups;
651
652 /* Keep track of adapters which will be added or removed later */
653 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
654 if (res)
655 goto out_unreg_class;
656
657 /* Bind to already existing adapters right away */
658 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
659
660 return 0;
661
662 out_unreg_class:
663 class_destroy(i2c_dev_class);
664 out_unreg_chrdev:
665 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
666 out:
667 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
668 return res;
669 }
670
i2c_dev_exit(void)671 static void __exit i2c_dev_exit(void)
672 {
673 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
674 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
675 class_destroy(i2c_dev_class);
676 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
677 }
678
679 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
680 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
681 MODULE_DESCRIPTION("I2C /dev entries driver");
682 MODULE_LICENSE("GPL");
683
684 module_init(i2c_dev_init);
685 module_exit(i2c_dev_exit);
686