Loading...
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/device.h>
26#include <linux/fs.h>
27#include <linux/i2c-dev.h>
28#include <linux/i2c.h>
29#include <linux/init.h>
30#include <linux/jiffies.h>
31#include <linux/kernel.h>
32#include <linux/list.h>
33#include <linux/module.h>
34#include <linux/notifier.h>
35#include <linux/slab.h>
36#include <linux/uaccess.h>
37
38/*
39 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
40 * slave (i2c_client) with which messages will be exchanged. It's coupled
41 * with a character special file which is accessed by user mode drivers.
42 *
43 * The list of i2c_dev structures is parallel to the i2c_adapter lists
44 * maintained by the driver model, and is updated using bus notifications.
45 */
46struct i2c_dev {
47 struct list_head list;
48 struct i2c_adapter *adap;
49 struct device *dev;
50};
51
52#define I2C_MINORS 256
53static LIST_HEAD(i2c_dev_list);
54static DEFINE_SPINLOCK(i2c_dev_list_lock);
55
56static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
57{
58 struct i2c_dev *i2c_dev;
59
60 spin_lock(&i2c_dev_list_lock);
61 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
62 if (i2c_dev->adap->nr == index)
63 goto found;
64 }
65 i2c_dev = NULL;
66found:
67 spin_unlock(&i2c_dev_list_lock);
68 return i2c_dev;
69}
70
71static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
72{
73 struct i2c_dev *i2c_dev;
74
75 if (adap->nr >= I2C_MINORS) {
76 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
77 adap->nr);
78 return ERR_PTR(-ENODEV);
79 }
80
81 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
82 if (!i2c_dev)
83 return ERR_PTR(-ENOMEM);
84 i2c_dev->adap = adap;
85
86 spin_lock(&i2c_dev_list_lock);
87 list_add_tail(&i2c_dev->list, &i2c_dev_list);
88 spin_unlock(&i2c_dev_list_lock);
89 return i2c_dev;
90}
91
92static void return_i2c_dev(struct i2c_dev *i2c_dev)
93{
94 spin_lock(&i2c_dev_list_lock);
95 list_del(&i2c_dev->list);
96 spin_unlock(&i2c_dev_list_lock);
97 kfree(i2c_dev);
98}
99
100static ssize_t name_show(struct device *dev,
101 struct device_attribute *attr, char *buf)
102{
103 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
104
105 if (!i2c_dev)
106 return -ENODEV;
107 return sprintf(buf, "%s\n", i2c_dev->adap->name);
108}
109static DEVICE_ATTR_RO(name);
110
111static struct attribute *i2c_attrs[] = {
112 &dev_attr_name.attr,
113 NULL,
114};
115ATTRIBUTE_GROUPS(i2c);
116
117/* ------------------------------------------------------------------------- */
118
119/*
120 * After opening an instance of this character special file, a file
121 * descriptor starts out associated only with an i2c_adapter (and bus).
122 *
123 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
124 * traffic to any devices on the bus used by that adapter. That's because
125 * the i2c_msg vectors embed all the addressing information they need, and
126 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
127 * don't support that interface.
128 *
129 * To use read()/write() system calls on that file descriptor, or to use
130 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
131 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
132 * (never registered) i2c_client so it holds the addressing information
133 * needed by those system calls and by this SMBus interface.
134 */
135
136static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
137 loff_t *offset)
138{
139 char *tmp;
140 int ret;
141
142 struct i2c_client *client = file->private_data;
143
144 if (count > 8192)
145 count = 8192;
146
147 tmp = kmalloc(count, GFP_KERNEL);
148 if (tmp == NULL)
149 return -ENOMEM;
150
151 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
152 iminor(file_inode(file)), count);
153
154 ret = i2c_master_recv(client, tmp, count);
155 if (ret >= 0)
156 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
157 kfree(tmp);
158 return ret;
159}
160
161static ssize_t i2cdev_write(struct file *file, const char __user *buf,
162 size_t count, loff_t *offset)
163{
164 int ret;
165 char *tmp;
166 struct i2c_client *client = file->private_data;
167
168 if (count > 8192)
169 count = 8192;
170
171 tmp = memdup_user(buf, count);
172 if (IS_ERR(tmp))
173 return PTR_ERR(tmp);
174
175 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
176 iminor(file_inode(file)), count);
177
178 ret = i2c_master_send(client, tmp, count);
179 kfree(tmp);
180 return ret;
181}
182
183static int i2cdev_check(struct device *dev, void *addrp)
184{
185 struct i2c_client *client = i2c_verify_client(dev);
186
187 if (!client || client->addr != *(unsigned int *)addrp)
188 return 0;
189
190 return dev->driver ? -EBUSY : 0;
191}
192
193/* walk up mux tree */
194static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
195{
196 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
197 int result;
198
199 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
200 if (!result && parent)
201 result = i2cdev_check_mux_parents(parent, addr);
202
203 return result;
204}
205
206/* recurse down mux tree */
207static int i2cdev_check_mux_children(struct device *dev, void *addrp)
208{
209 int result;
210
211 if (dev->type == &i2c_adapter_type)
212 result = device_for_each_child(dev, addrp,
213 i2cdev_check_mux_children);
214 else
215 result = i2cdev_check(dev, addrp);
216
217 return result;
218}
219
220/* This address checking function differs from the one in i2c-core
221 in that it considers an address with a registered device, but no
222 driver bound to it, as NOT busy. */
223static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
224{
225 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
226 int result = 0;
227
228 if (parent)
229 result = i2cdev_check_mux_parents(parent, addr);
230
231 if (!result)
232 result = device_for_each_child(&adapter->dev, &addr,
233 i2cdev_check_mux_children);
234
235 return result;
236}
237
238static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
239 unsigned long arg)
240{
241 struct i2c_rdwr_ioctl_data rdwr_arg;
242 struct i2c_msg *rdwr_pa;
243 u8 __user **data_ptrs;
244 int i, res;
245
246 if (copy_from_user(&rdwr_arg,
247 (struct i2c_rdwr_ioctl_data __user *)arg,
248 sizeof(rdwr_arg)))
249 return -EFAULT;
250
251 /* Put an arbitrary limit on the number of messages that can
252 * be sent at once */
253 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
254 return -EINVAL;
255
256 rdwr_pa = memdup_user(rdwr_arg.msgs,
257 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
258 if (IS_ERR(rdwr_pa))
259 return PTR_ERR(rdwr_pa);
260
261 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
262 if (data_ptrs == NULL) {
263 kfree(rdwr_pa);
264 return -ENOMEM;
265 }
266
267 res = 0;
268 for (i = 0; i < rdwr_arg.nmsgs; i++) {
269 /* Limit the size of the message to a sane amount */
270 if (rdwr_pa[i].len > 8192) {
271 res = -EINVAL;
272 break;
273 }
274
275 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
276 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
277 if (IS_ERR(rdwr_pa[i].buf)) {
278 res = PTR_ERR(rdwr_pa[i].buf);
279 break;
280 }
281
282 /*
283 * If the message length is received from the slave (similar
284 * to SMBus block read), we must ensure that the buffer will
285 * be large enough to cope with a message length of
286 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
287 * drivers allow. The first byte in the buffer must be
288 * pre-filled with the number of extra bytes, which must be
289 * at least one to hold the message length, but can be
290 * greater (for example to account for a checksum byte at
291 * the end of the message.)
292 */
293 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
294 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
295 rdwr_pa[i].buf[0] < 1 ||
296 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
297 I2C_SMBUS_BLOCK_MAX) {
298 res = -EINVAL;
299 break;
300 }
301
302 rdwr_pa[i].len = rdwr_pa[i].buf[0];
303 }
304 }
305 if (res < 0) {
306 int j;
307 for (j = 0; j < i; ++j)
308 kfree(rdwr_pa[j].buf);
309 kfree(data_ptrs);
310 kfree(rdwr_pa);
311 return res;
312 }
313
314 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
315 while (i-- > 0) {
316 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
317 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
318 rdwr_pa[i].len))
319 res = -EFAULT;
320 }
321 kfree(rdwr_pa[i].buf);
322 }
323 kfree(data_ptrs);
324 kfree(rdwr_pa);
325 return res;
326}
327
328static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
329 unsigned long arg)
330{
331 struct i2c_smbus_ioctl_data data_arg;
332 union i2c_smbus_data temp;
333 int datasize, res;
334
335 if (copy_from_user(&data_arg,
336 (struct i2c_smbus_ioctl_data __user *) arg,
337 sizeof(struct i2c_smbus_ioctl_data)))
338 return -EFAULT;
339 if ((data_arg.size != I2C_SMBUS_BYTE) &&
340 (data_arg.size != I2C_SMBUS_QUICK) &&
341 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
342 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
343 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
344 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
345 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
346 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
347 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
348 dev_dbg(&client->adapter->dev,
349 "size out of range (%x) in ioctl I2C_SMBUS.\n",
350 data_arg.size);
351 return -EINVAL;
352 }
353 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
354 so the check is valid if size==I2C_SMBUS_QUICK too. */
355 if ((data_arg.read_write != I2C_SMBUS_READ) &&
356 (data_arg.read_write != I2C_SMBUS_WRITE)) {
357 dev_dbg(&client->adapter->dev,
358 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
359 data_arg.read_write);
360 return -EINVAL;
361 }
362
363 /* Note that command values are always valid! */
364
365 if ((data_arg.size == I2C_SMBUS_QUICK) ||
366 ((data_arg.size == I2C_SMBUS_BYTE) &&
367 (data_arg.read_write == I2C_SMBUS_WRITE)))
368 /* These are special: we do not use data */
369 return i2c_smbus_xfer(client->adapter, client->addr,
370 client->flags, data_arg.read_write,
371 data_arg.command, data_arg.size, NULL);
372
373 if (data_arg.data == NULL) {
374 dev_dbg(&client->adapter->dev,
375 "data is NULL pointer in ioctl I2C_SMBUS.\n");
376 return -EINVAL;
377 }
378
379 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
380 (data_arg.size == I2C_SMBUS_BYTE))
381 datasize = sizeof(data_arg.data->byte);
382 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
383 (data_arg.size == I2C_SMBUS_PROC_CALL))
384 datasize = sizeof(data_arg.data->word);
385 else /* size == smbus block, i2c block, or block proc. call */
386 datasize = sizeof(data_arg.data->block);
387
388 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
389 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
390 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
391 (data_arg.read_write == I2C_SMBUS_WRITE)) {
392 if (copy_from_user(&temp, data_arg.data, datasize))
393 return -EFAULT;
394 }
395 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
396 /* Convert old I2C block commands to the new
397 convention. This preserves binary compatibility. */
398 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
399 if (data_arg.read_write == I2C_SMBUS_READ)
400 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
401 }
402 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
403 data_arg.read_write, data_arg.command, data_arg.size, &temp);
404 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
405 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
406 (data_arg.read_write == I2C_SMBUS_READ))) {
407 if (copy_to_user(data_arg.data, &temp, datasize))
408 return -EFAULT;
409 }
410 return res;
411}
412
413static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
414{
415 struct i2c_client *client = file->private_data;
416 unsigned long funcs;
417
418 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
419 cmd, arg);
420
421 switch (cmd) {
422 case I2C_SLAVE:
423 case I2C_SLAVE_FORCE:
424 if ((arg > 0x3ff) ||
425 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
426 return -EINVAL;
427 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
428 return -EBUSY;
429 /* REVISIT: address could become busy later */
430 client->addr = arg;
431 return 0;
432 case I2C_TENBIT:
433 if (arg)
434 client->flags |= I2C_M_TEN;
435 else
436 client->flags &= ~I2C_M_TEN;
437 return 0;
438 case I2C_PEC:
439 /*
440 * Setting the PEC flag here won't affect kernel drivers,
441 * which will be using the i2c_client node registered with
442 * the driver model core. Likewise, when that client has
443 * the PEC flag already set, the i2c-dev driver won't see
444 * (or use) this setting.
445 */
446 if (arg)
447 client->flags |= I2C_CLIENT_PEC;
448 else
449 client->flags &= ~I2C_CLIENT_PEC;
450 return 0;
451 case I2C_FUNCS:
452 funcs = i2c_get_functionality(client->adapter);
453 return put_user(funcs, (unsigned long __user *)arg);
454
455 case I2C_RDWR:
456 return i2cdev_ioctl_rdwr(client, arg);
457
458 case I2C_SMBUS:
459 return i2cdev_ioctl_smbus(client, arg);
460
461 case I2C_RETRIES:
462 client->adapter->retries = arg;
463 break;
464 case I2C_TIMEOUT:
465 /* For historical reasons, user-space sets the timeout
466 * value in units of 10 ms.
467 */
468 client->adapter->timeout = msecs_to_jiffies(arg * 10);
469 break;
470 default:
471 /* NOTE: returning a fault code here could cause trouble
472 * in buggy userspace code. Some old kernel bugs returned
473 * zero in this case, and userspace code might accidentally
474 * have depended on that bug.
475 */
476 return -ENOTTY;
477 }
478 return 0;
479}
480
481static int i2cdev_open(struct inode *inode, struct file *file)
482{
483 unsigned int minor = iminor(inode);
484 struct i2c_client *client;
485 struct i2c_adapter *adap;
486 struct i2c_dev *i2c_dev;
487
488 i2c_dev = i2c_dev_get_by_minor(minor);
489 if (!i2c_dev)
490 return -ENODEV;
491
492 adap = i2c_get_adapter(i2c_dev->adap->nr);
493 if (!adap)
494 return -ENODEV;
495
496 /* This creates an anonymous i2c_client, which may later be
497 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
498 *
499 * This client is ** NEVER REGISTERED ** with the driver model
500 * or I2C core code!! It just holds private copies of addressing
501 * information and maybe a PEC flag.
502 */
503 client = kzalloc(sizeof(*client), GFP_KERNEL);
504 if (!client) {
505 i2c_put_adapter(adap);
506 return -ENOMEM;
507 }
508 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
509
510 client->adapter = adap;
511 file->private_data = client;
512
513 return 0;
514}
515
516static int i2cdev_release(struct inode *inode, struct file *file)
517{
518 struct i2c_client *client = file->private_data;
519
520 i2c_put_adapter(client->adapter);
521 kfree(client);
522 file->private_data = NULL;
523
524 return 0;
525}
526
527static const struct file_operations i2cdev_fops = {
528 .owner = THIS_MODULE,
529 .llseek = no_llseek,
530 .read = i2cdev_read,
531 .write = i2cdev_write,
532 .unlocked_ioctl = i2cdev_ioctl,
533 .open = i2cdev_open,
534 .release = i2cdev_release,
535};
536
537/* ------------------------------------------------------------------------- */
538
539static struct class *i2c_dev_class;
540
541static int i2cdev_attach_adapter(struct device *dev, void *dummy)
542{
543 struct i2c_adapter *adap;
544 struct i2c_dev *i2c_dev;
545 int res;
546
547 if (dev->type != &i2c_adapter_type)
548 return 0;
549 adap = to_i2c_adapter(dev);
550
551 i2c_dev = get_free_i2c_dev(adap);
552 if (IS_ERR(i2c_dev))
553 return PTR_ERR(i2c_dev);
554
555 /* register this i2c device with the driver core */
556 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
557 MKDEV(I2C_MAJOR, adap->nr), NULL,
558 "i2c-%d", adap->nr);
559 if (IS_ERR(i2c_dev->dev)) {
560 res = PTR_ERR(i2c_dev->dev);
561 goto error;
562 }
563
564 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
565 adap->name, adap->nr);
566 return 0;
567error:
568 return_i2c_dev(i2c_dev);
569 return res;
570}
571
572static int i2cdev_detach_adapter(struct device *dev, void *dummy)
573{
574 struct i2c_adapter *adap;
575 struct i2c_dev *i2c_dev;
576
577 if (dev->type != &i2c_adapter_type)
578 return 0;
579 adap = to_i2c_adapter(dev);
580
581 i2c_dev = i2c_dev_get_by_minor(adap->nr);
582 if (!i2c_dev) /* attach_adapter must have failed */
583 return 0;
584
585 return_i2c_dev(i2c_dev);
586 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
587
588 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
589 return 0;
590}
591
592static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
593 void *data)
594{
595 struct device *dev = data;
596
597 switch (action) {
598 case BUS_NOTIFY_ADD_DEVICE:
599 return i2cdev_attach_adapter(dev, NULL);
600 case BUS_NOTIFY_DEL_DEVICE:
601 return i2cdev_detach_adapter(dev, NULL);
602 }
603
604 return 0;
605}
606
607static struct notifier_block i2cdev_notifier = {
608 .notifier_call = i2cdev_notifier_call,
609};
610
611/* ------------------------------------------------------------------------- */
612
613/*
614 * module load/unload record keeping
615 */
616
617static int __init i2c_dev_init(void)
618{
619 int res;
620
621 printk(KERN_INFO "i2c /dev entries driver\n");
622
623 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
624 if (res)
625 goto out;
626
627 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
628 if (IS_ERR(i2c_dev_class)) {
629 res = PTR_ERR(i2c_dev_class);
630 goto out_unreg_chrdev;
631 }
632 i2c_dev_class->dev_groups = i2c_groups;
633
634 /* Keep track of adapters which will be added or removed later */
635 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
636 if (res)
637 goto out_unreg_class;
638
639 /* Bind to already existing adapters right away */
640 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
641
642 return 0;
643
644out_unreg_class:
645 class_destroy(i2c_dev_class);
646out_unreg_chrdev:
647 unregister_chrdev(I2C_MAJOR, "i2c");
648out:
649 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
650 return res;
651}
652
653static void __exit i2c_dev_exit(void)
654{
655 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
656 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
657 class_destroy(i2c_dev_class);
658 unregister_chrdev(I2C_MAJOR, "i2c");
659}
660
661MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
662 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
663MODULE_DESCRIPTION("I2C /dev entries driver");
664MODULE_LICENSE("GPL");
665
666module_init(i2c_dev_init);
667module_exit(i2c_dev_exit);
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#include <linux/cdev.h>
18#include <linux/compat.h>
19#include <linux/device.h>
20#include <linux/fs.h>
21#include <linux/i2c-dev.h>
22#include <linux/i2c.h>
23#include <linux/init.h>
24#include <linux/jiffies.h>
25#include <linux/kernel.h>
26#include <linux/list.h>
27#include <linux/module.h>
28#include <linux/notifier.h>
29#include <linux/slab.h>
30#include <linux/uaccess.h>
31
32/*
33 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
34 * slave (i2c_client) with which messages will be exchanged. It's coupled
35 * with a character special file which is accessed by user mode drivers.
36 *
37 * The list of i2c_dev structures is parallel to the i2c_adapter lists
38 * maintained by the driver model, and is updated using bus notifications.
39 */
40struct i2c_dev {
41 struct list_head list;
42 struct i2c_adapter *adap;
43 struct device dev;
44 struct cdev cdev;
45};
46
47#define I2C_MINORS (MINORMASK + 1)
48static LIST_HEAD(i2c_dev_list);
49static DEFINE_SPINLOCK(i2c_dev_list_lock);
50
51static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
52{
53 struct i2c_dev *i2c_dev;
54
55 spin_lock(&i2c_dev_list_lock);
56 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
57 if (i2c_dev->adap->nr == index)
58 goto found;
59 }
60 i2c_dev = NULL;
61found:
62 spin_unlock(&i2c_dev_list_lock);
63 return i2c_dev;
64}
65
66static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
67{
68 struct i2c_dev *i2c_dev;
69
70 if (adap->nr >= I2C_MINORS) {
71 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
72 adap->nr);
73 return ERR_PTR(-ENODEV);
74 }
75
76 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
77 if (!i2c_dev)
78 return ERR_PTR(-ENOMEM);
79 i2c_dev->adap = adap;
80
81 spin_lock(&i2c_dev_list_lock);
82 list_add_tail(&i2c_dev->list, &i2c_dev_list);
83 spin_unlock(&i2c_dev_list_lock);
84 return i2c_dev;
85}
86
87static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev)
88{
89 spin_lock(&i2c_dev_list_lock);
90 list_del(&i2c_dev->list);
91 spin_unlock(&i2c_dev_list_lock);
92 if (del_cdev)
93 cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev);
94 put_device(&i2c_dev->dev);
95}
96
97static ssize_t name_show(struct device *dev,
98 struct device_attribute *attr, char *buf)
99{
100 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
101
102 if (!i2c_dev)
103 return -ENODEV;
104 return sprintf(buf, "%s\n", i2c_dev->adap->name);
105}
106static DEVICE_ATTR_RO(name);
107
108static struct attribute *i2c_attrs[] = {
109 &dev_attr_name.attr,
110 NULL,
111};
112ATTRIBUTE_GROUPS(i2c);
113
114/* ------------------------------------------------------------------------- */
115
116/*
117 * After opening an instance of this character special file, a file
118 * descriptor starts out associated only with an i2c_adapter (and bus).
119 *
120 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
121 * traffic to any devices on the bus used by that adapter. That's because
122 * the i2c_msg vectors embed all the addressing information they need, and
123 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
124 * don't support that interface.
125 *
126 * To use read()/write() system calls on that file descriptor, or to use
127 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
128 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
129 * (never registered) i2c_client so it holds the addressing information
130 * needed by those system calls and by this SMBus interface.
131 */
132
133static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
134 loff_t *offset)
135{
136 char *tmp;
137 int ret;
138
139 struct i2c_client *client = file->private_data;
140
141 if (count > 8192)
142 count = 8192;
143
144 tmp = kzalloc(count, GFP_KERNEL);
145 if (tmp == NULL)
146 return -ENOMEM;
147
148 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
149 iminor(file_inode(file)), count);
150
151 ret = i2c_master_recv(client, tmp, count);
152 if (ret >= 0)
153 if (copy_to_user(buf, tmp, ret))
154 ret = -EFAULT;
155 kfree(tmp);
156 return ret;
157}
158
159static ssize_t i2cdev_write(struct file *file, const char __user *buf,
160 size_t count, loff_t *offset)
161{
162 int ret;
163 char *tmp;
164 struct i2c_client *client = file->private_data;
165
166 if (count > 8192)
167 count = 8192;
168
169 tmp = memdup_user(buf, count);
170 if (IS_ERR(tmp))
171 return PTR_ERR(tmp);
172
173 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
174 iminor(file_inode(file)), count);
175
176 ret = i2c_master_send(client, tmp, count);
177 kfree(tmp);
178 return ret;
179}
180
181static int i2cdev_check(struct device *dev, void *addrp)
182{
183 struct i2c_client *client = i2c_verify_client(dev);
184
185 if (!client || client->addr != *(unsigned int *)addrp)
186 return 0;
187
188 return dev->driver ? -EBUSY : 0;
189}
190
191/* walk up mux tree */
192static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
193{
194 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
195 int result;
196
197 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
198 if (!result && parent)
199 result = i2cdev_check_mux_parents(parent, addr);
200
201 return result;
202}
203
204/* recurse down mux tree */
205static int i2cdev_check_mux_children(struct device *dev, void *addrp)
206{
207 int result;
208
209 if (dev->type == &i2c_adapter_type)
210 result = device_for_each_child(dev, addrp,
211 i2cdev_check_mux_children);
212 else
213 result = i2cdev_check(dev, addrp);
214
215 return result;
216}
217
218/* This address checking function differs from the one in i2c-core
219 in that it considers an address with a registered device, but no
220 driver bound to it, as NOT busy. */
221static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
222{
223 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
224 int result = 0;
225
226 if (parent)
227 result = i2cdev_check_mux_parents(parent, addr);
228
229 if (!result)
230 result = device_for_each_child(&adapter->dev, &addr,
231 i2cdev_check_mux_children);
232
233 return result;
234}
235
236static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
237 unsigned nmsgs, struct i2c_msg *msgs)
238{
239 u8 __user **data_ptrs;
240 int i, res;
241
242 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
243 if (data_ptrs == NULL) {
244 kfree(msgs);
245 return -ENOMEM;
246 }
247
248 res = 0;
249 for (i = 0; i < nmsgs; i++) {
250 /* Limit the size of the message to a sane amount */
251 if (msgs[i].len > 8192) {
252 res = -EINVAL;
253 break;
254 }
255
256 data_ptrs[i] = (u8 __user *)msgs[i].buf;
257 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
258 if (IS_ERR(msgs[i].buf)) {
259 res = PTR_ERR(msgs[i].buf);
260 break;
261 }
262 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
263 msgs[i].flags |= I2C_M_DMA_SAFE;
264
265 /*
266 * If the message length is received from the slave (similar
267 * to SMBus block read), we must ensure that the buffer will
268 * be large enough to cope with a message length of
269 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
270 * drivers allow. The first byte in the buffer must be
271 * pre-filled with the number of extra bytes, which must be
272 * at least one to hold the message length, but can be
273 * greater (for example to account for a checksum byte at
274 * the end of the message.)
275 */
276 if (msgs[i].flags & I2C_M_RECV_LEN) {
277 if (!(msgs[i].flags & I2C_M_RD) ||
278 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
279 msgs[i].len < msgs[i].buf[0] +
280 I2C_SMBUS_BLOCK_MAX) {
281 i++;
282 res = -EINVAL;
283 break;
284 }
285
286 msgs[i].len = msgs[i].buf[0];
287 }
288 }
289 if (res < 0) {
290 int j;
291 for (j = 0; j < i; ++j)
292 kfree(msgs[j].buf);
293 kfree(data_ptrs);
294 kfree(msgs);
295 return res;
296 }
297
298 res = i2c_transfer(client->adapter, msgs, nmsgs);
299 while (i-- > 0) {
300 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
301 if (copy_to_user(data_ptrs[i], msgs[i].buf,
302 msgs[i].len))
303 res = -EFAULT;
304 }
305 kfree(msgs[i].buf);
306 }
307 kfree(data_ptrs);
308 kfree(msgs);
309 return res;
310}
311
312static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
313 u8 read_write, u8 command, u32 size,
314 union i2c_smbus_data __user *data)
315{
316 union i2c_smbus_data temp = {};
317 int datasize, res;
318
319 if ((size != I2C_SMBUS_BYTE) &&
320 (size != I2C_SMBUS_QUICK) &&
321 (size != I2C_SMBUS_BYTE_DATA) &&
322 (size != I2C_SMBUS_WORD_DATA) &&
323 (size != I2C_SMBUS_PROC_CALL) &&
324 (size != I2C_SMBUS_BLOCK_DATA) &&
325 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
326 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
327 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
328 dev_dbg(&client->adapter->dev,
329 "size out of range (%x) in ioctl I2C_SMBUS.\n",
330 size);
331 return -EINVAL;
332 }
333 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
334 so the check is valid if size==I2C_SMBUS_QUICK too. */
335 if ((read_write != I2C_SMBUS_READ) &&
336 (read_write != I2C_SMBUS_WRITE)) {
337 dev_dbg(&client->adapter->dev,
338 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
339 read_write);
340 return -EINVAL;
341 }
342
343 /* Note that command values are always valid! */
344
345 if ((size == I2C_SMBUS_QUICK) ||
346 ((size == I2C_SMBUS_BYTE) &&
347 (read_write == I2C_SMBUS_WRITE)))
348 /* These are special: we do not use data */
349 return i2c_smbus_xfer(client->adapter, client->addr,
350 client->flags, read_write,
351 command, size, NULL);
352
353 if (data == NULL) {
354 dev_dbg(&client->adapter->dev,
355 "data is NULL pointer in ioctl I2C_SMBUS.\n");
356 return -EINVAL;
357 }
358
359 if ((size == I2C_SMBUS_BYTE_DATA) ||
360 (size == I2C_SMBUS_BYTE))
361 datasize = sizeof(data->byte);
362 else if ((size == I2C_SMBUS_WORD_DATA) ||
363 (size == I2C_SMBUS_PROC_CALL))
364 datasize = sizeof(data->word);
365 else /* size == smbus block, i2c block, or block proc. call */
366 datasize = sizeof(data->block);
367
368 if ((size == I2C_SMBUS_PROC_CALL) ||
369 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
370 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
371 (read_write == I2C_SMBUS_WRITE)) {
372 if (copy_from_user(&temp, data, datasize))
373 return -EFAULT;
374 }
375 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
376 /* Convert old I2C block commands to the new
377 convention. This preserves binary compatibility. */
378 size = I2C_SMBUS_I2C_BLOCK_DATA;
379 if (read_write == I2C_SMBUS_READ)
380 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
381 }
382 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
383 read_write, command, size, &temp);
384 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
385 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
386 (read_write == I2C_SMBUS_READ))) {
387 if (copy_to_user(data, &temp, datasize))
388 return -EFAULT;
389 }
390 return res;
391}
392
393static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
394{
395 struct i2c_client *client = file->private_data;
396 unsigned long funcs;
397
398 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
399 cmd, arg);
400
401 switch (cmd) {
402 case I2C_SLAVE:
403 case I2C_SLAVE_FORCE:
404 if ((arg > 0x3ff) ||
405 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
406 return -EINVAL;
407 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
408 return -EBUSY;
409 /* REVISIT: address could become busy later */
410 client->addr = arg;
411 return 0;
412 case I2C_TENBIT:
413 if (arg)
414 client->flags |= I2C_M_TEN;
415 else
416 client->flags &= ~I2C_M_TEN;
417 return 0;
418 case I2C_PEC:
419 /*
420 * Setting the PEC flag here won't affect kernel drivers,
421 * which will be using the i2c_client node registered with
422 * the driver model core. Likewise, when that client has
423 * the PEC flag already set, the i2c-dev driver won't see
424 * (or use) this setting.
425 */
426 if (arg)
427 client->flags |= I2C_CLIENT_PEC;
428 else
429 client->flags &= ~I2C_CLIENT_PEC;
430 return 0;
431 case I2C_FUNCS:
432 funcs = i2c_get_functionality(client->adapter);
433 return put_user(funcs, (unsigned long __user *)arg);
434
435 case I2C_RDWR: {
436 struct i2c_rdwr_ioctl_data rdwr_arg;
437 struct i2c_msg *rdwr_pa;
438
439 if (copy_from_user(&rdwr_arg,
440 (struct i2c_rdwr_ioctl_data __user *)arg,
441 sizeof(rdwr_arg)))
442 return -EFAULT;
443
444 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
445 return -EINVAL;
446
447 /*
448 * Put an arbitrary limit on the number of messages that can
449 * be sent at once
450 */
451 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
452 return -EINVAL;
453
454 rdwr_pa = memdup_user(rdwr_arg.msgs,
455 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
456 if (IS_ERR(rdwr_pa))
457 return PTR_ERR(rdwr_pa);
458
459 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
460 }
461
462 case I2C_SMBUS: {
463 struct i2c_smbus_ioctl_data data_arg;
464 if (copy_from_user(&data_arg,
465 (struct i2c_smbus_ioctl_data __user *) arg,
466 sizeof(struct i2c_smbus_ioctl_data)))
467 return -EFAULT;
468 return i2cdev_ioctl_smbus(client, data_arg.read_write,
469 data_arg.command,
470 data_arg.size,
471 data_arg.data);
472 }
473 case I2C_RETRIES:
474 if (arg > INT_MAX)
475 return -EINVAL;
476
477 client->adapter->retries = arg;
478 break;
479 case I2C_TIMEOUT:
480 if (arg > INT_MAX)
481 return -EINVAL;
482
483 /* For historical reasons, user-space sets the timeout
484 * value in units of 10 ms.
485 */
486 client->adapter->timeout = msecs_to_jiffies(arg * 10);
487 break;
488 default:
489 /* NOTE: returning a fault code here could cause trouble
490 * in buggy userspace code. Some old kernel bugs returned
491 * zero in this case, and userspace code might accidentally
492 * have depended on that bug.
493 */
494 return -ENOTTY;
495 }
496 return 0;
497}
498
499#ifdef CONFIG_COMPAT
500
501struct i2c_smbus_ioctl_data32 {
502 u8 read_write;
503 u8 command;
504 u32 size;
505 compat_caddr_t data; /* union i2c_smbus_data *data */
506};
507
508struct i2c_msg32 {
509 u16 addr;
510 u16 flags;
511 u16 len;
512 compat_caddr_t buf;
513};
514
515struct i2c_rdwr_ioctl_data32 {
516 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
517 u32 nmsgs;
518};
519
520static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
521{
522 struct i2c_client *client = file->private_data;
523 unsigned long funcs;
524 switch (cmd) {
525 case I2C_FUNCS:
526 funcs = i2c_get_functionality(client->adapter);
527 return put_user(funcs, (compat_ulong_t __user *)arg);
528 case I2C_RDWR: {
529 struct i2c_rdwr_ioctl_data32 rdwr_arg;
530 struct i2c_msg32 __user *p;
531 struct i2c_msg *rdwr_pa;
532 int i;
533
534 if (copy_from_user(&rdwr_arg,
535 (struct i2c_rdwr_ioctl_data32 __user *)arg,
536 sizeof(rdwr_arg)))
537 return -EFAULT;
538
539 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
540 return -EINVAL;
541
542 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
543 GFP_KERNEL);
544 if (!rdwr_pa)
545 return -ENOMEM;
546
547 p = compat_ptr(rdwr_arg.msgs);
548 for (i = 0; i < rdwr_arg.nmsgs; i++) {
549 struct i2c_msg32 umsg;
550 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
551 kfree(rdwr_pa);
552 return -EFAULT;
553 }
554 rdwr_pa[i] = (struct i2c_msg) {
555 .addr = umsg.addr,
556 .flags = umsg.flags,
557 .len = umsg.len,
558 .buf = compat_ptr(umsg.buf)
559 };
560 }
561
562 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
563 }
564 case I2C_SMBUS: {
565 struct i2c_smbus_ioctl_data32 data32;
566 if (copy_from_user(&data32,
567 (void __user *) arg,
568 sizeof(data32)))
569 return -EFAULT;
570 return i2cdev_ioctl_smbus(client, data32.read_write,
571 data32.command,
572 data32.size,
573 compat_ptr(data32.data));
574 }
575 default:
576 return i2cdev_ioctl(file, cmd, arg);
577 }
578}
579#else
580#define compat_i2cdev_ioctl NULL
581#endif
582
583static int i2cdev_open(struct inode *inode, struct file *file)
584{
585 unsigned int minor = iminor(inode);
586 struct i2c_client *client;
587 struct i2c_adapter *adap;
588
589 adap = i2c_get_adapter(minor);
590 if (!adap)
591 return -ENODEV;
592
593 /* This creates an anonymous i2c_client, which may later be
594 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
595 *
596 * This client is ** NEVER REGISTERED ** with the driver model
597 * or I2C core code!! It just holds private copies of addressing
598 * information and maybe a PEC flag.
599 */
600 client = kzalloc(sizeof(*client), GFP_KERNEL);
601 if (!client) {
602 i2c_put_adapter(adap);
603 return -ENOMEM;
604 }
605 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
606
607 client->adapter = adap;
608 file->private_data = client;
609
610 return 0;
611}
612
613static int i2cdev_release(struct inode *inode, struct file *file)
614{
615 struct i2c_client *client = file->private_data;
616
617 i2c_put_adapter(client->adapter);
618 kfree(client);
619 file->private_data = NULL;
620
621 return 0;
622}
623
624static const struct file_operations i2cdev_fops = {
625 .owner = THIS_MODULE,
626 .llseek = no_llseek,
627 .read = i2cdev_read,
628 .write = i2cdev_write,
629 .unlocked_ioctl = i2cdev_ioctl,
630 .compat_ioctl = compat_i2cdev_ioctl,
631 .open = i2cdev_open,
632 .release = i2cdev_release,
633};
634
635/* ------------------------------------------------------------------------- */
636
637static struct class *i2c_dev_class;
638
639static void i2cdev_dev_release(struct device *dev)
640{
641 struct i2c_dev *i2c_dev;
642
643 i2c_dev = container_of(dev, struct i2c_dev, dev);
644 kfree(i2c_dev);
645}
646
647static int i2cdev_attach_adapter(struct device *dev, void *dummy)
648{
649 struct i2c_adapter *adap;
650 struct i2c_dev *i2c_dev;
651 int res;
652
653 if (dev->type != &i2c_adapter_type)
654 return 0;
655 adap = to_i2c_adapter(dev);
656
657 i2c_dev = get_free_i2c_dev(adap);
658 if (IS_ERR(i2c_dev))
659 return PTR_ERR(i2c_dev);
660
661 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
662 i2c_dev->cdev.owner = THIS_MODULE;
663
664 device_initialize(&i2c_dev->dev);
665 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
666 i2c_dev->dev.class = i2c_dev_class;
667 i2c_dev->dev.parent = &adap->dev;
668 i2c_dev->dev.release = i2cdev_dev_release;
669 dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
670
671 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
672 if (res) {
673 put_i2c_dev(i2c_dev, false);
674 return res;
675 }
676
677 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
678 adap->name, adap->nr);
679 return 0;
680}
681
682static int i2cdev_detach_adapter(struct device *dev, void *dummy)
683{
684 struct i2c_adapter *adap;
685 struct i2c_dev *i2c_dev;
686
687 if (dev->type != &i2c_adapter_type)
688 return 0;
689 adap = to_i2c_adapter(dev);
690
691 i2c_dev = i2c_dev_get_by_minor(adap->nr);
692 if (!i2c_dev) /* attach_adapter must have failed */
693 return 0;
694
695 put_i2c_dev(i2c_dev, true);
696
697 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
698 return 0;
699}
700
701static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
702 void *data)
703{
704 struct device *dev = data;
705
706 switch (action) {
707 case BUS_NOTIFY_ADD_DEVICE:
708 return i2cdev_attach_adapter(dev, NULL);
709 case BUS_NOTIFY_DEL_DEVICE:
710 return i2cdev_detach_adapter(dev, NULL);
711 }
712
713 return 0;
714}
715
716static struct notifier_block i2cdev_notifier = {
717 .notifier_call = i2cdev_notifier_call,
718};
719
720/* ------------------------------------------------------------------------- */
721
722/*
723 * module load/unload record keeping
724 */
725
726static int __init i2c_dev_init(void)
727{
728 int res;
729
730 printk(KERN_INFO "i2c /dev entries driver\n");
731
732 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
733 if (res)
734 goto out;
735
736 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
737 if (IS_ERR(i2c_dev_class)) {
738 res = PTR_ERR(i2c_dev_class);
739 goto out_unreg_chrdev;
740 }
741 i2c_dev_class->dev_groups = i2c_groups;
742
743 /* Keep track of adapters which will be added or removed later */
744 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
745 if (res)
746 goto out_unreg_class;
747
748 /* Bind to already existing adapters right away */
749 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
750
751 return 0;
752
753out_unreg_class:
754 class_destroy(i2c_dev_class);
755out_unreg_chrdev:
756 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
757out:
758 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
759 return res;
760}
761
762static void __exit i2c_dev_exit(void)
763{
764 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
765 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
766 class_destroy(i2c_dev_class);
767 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
768}
769
770MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
771MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
772MODULE_DESCRIPTION("I2C /dev entries driver");
773MODULE_LICENSE("GPL");
774
775module_init(i2c_dev_init);
776module_exit(i2c_dev_exit);