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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/device.h>
19#include <linux/fs.h>
20#include <linux/i2c-dev.h>
21#include <linux/i2c.h>
22#include <linux/init.h>
23#include <linux/jiffies.h>
24#include <linux/kernel.h>
25#include <linux/list.h>
26#include <linux/module.h>
27#include <linux/notifier.h>
28#include <linux/slab.h>
29#include <linux/uaccess.h>
30#include <linux/compat.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)
88{
89 spin_lock(&i2c_dev_list_lock);
90 list_del(&i2c_dev->list);
91 spin_unlock(&i2c_dev_list_lock);
92 kfree(i2c_dev);
93}
94
95static ssize_t name_show(struct device *dev,
96 struct device_attribute *attr, char *buf)
97{
98 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
99
100 if (!i2c_dev)
101 return -ENODEV;
102 return sprintf(buf, "%s\n", i2c_dev->adap->name);
103}
104static DEVICE_ATTR_RO(name);
105
106static struct attribute *i2c_attrs[] = {
107 &dev_attr_name.attr,
108 NULL,
109};
110ATTRIBUTE_GROUPS(i2c);
111
112/* ------------------------------------------------------------------------- */
113
114/*
115 * After opening an instance of this character special file, a file
116 * descriptor starts out associated only with an i2c_adapter (and bus).
117 *
118 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
119 * traffic to any devices on the bus used by that adapter. That's because
120 * the i2c_msg vectors embed all the addressing information they need, and
121 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
122 * don't support that interface.
123 *
124 * To use read()/write() system calls on that file descriptor, or to use
125 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
126 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
127 * (never registered) i2c_client so it holds the addressing information
128 * needed by those system calls and by this SMBus interface.
129 */
130
131static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
132 loff_t *offset)
133{
134 char *tmp;
135 int ret;
136
137 struct i2c_client *client = file->private_data;
138
139 if (count > 8192)
140 count = 8192;
141
142 tmp = kmalloc(count, GFP_KERNEL);
143 if (tmp == NULL)
144 return -ENOMEM;
145
146 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
147 iminor(file_inode(file)), count);
148
149 ret = i2c_master_recv(client, tmp, count);
150 if (ret >= 0)
151 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
152 kfree(tmp);
153 return ret;
154}
155
156static ssize_t i2cdev_write(struct file *file, const char __user *buf,
157 size_t count, loff_t *offset)
158{
159 int ret;
160 char *tmp;
161 struct i2c_client *client = file->private_data;
162
163 if (count > 8192)
164 count = 8192;
165
166 tmp = memdup_user(buf, count);
167 if (IS_ERR(tmp))
168 return PTR_ERR(tmp);
169
170 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
171 iminor(file_inode(file)), count);
172
173 ret = i2c_master_send(client, tmp, count);
174 kfree(tmp);
175 return ret;
176}
177
178static int i2cdev_check(struct device *dev, void *addrp)
179{
180 struct i2c_client *client = i2c_verify_client(dev);
181
182 if (!client || client->addr != *(unsigned int *)addrp)
183 return 0;
184
185 return dev->driver ? -EBUSY : 0;
186}
187
188/* walk up mux tree */
189static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
190{
191 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
192 int result;
193
194 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
195 if (!result && parent)
196 result = i2cdev_check_mux_parents(parent, addr);
197
198 return result;
199}
200
201/* recurse down mux tree */
202static int i2cdev_check_mux_children(struct device *dev, void *addrp)
203{
204 int result;
205
206 if (dev->type == &i2c_adapter_type)
207 result = device_for_each_child(dev, addrp,
208 i2cdev_check_mux_children);
209 else
210 result = i2cdev_check(dev, addrp);
211
212 return result;
213}
214
215/* This address checking function differs from the one in i2c-core
216 in that it considers an address with a registered device, but no
217 driver bound to it, as NOT busy. */
218static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
219{
220 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
221 int result = 0;
222
223 if (parent)
224 result = i2cdev_check_mux_parents(parent, addr);
225
226 if (!result)
227 result = device_for_each_child(&adapter->dev, &addr,
228 i2cdev_check_mux_children);
229
230 return result;
231}
232
233static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
234 unsigned nmsgs, struct i2c_msg *msgs)
235{
236 u8 __user **data_ptrs;
237 int i, res;
238
239 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
240 if (data_ptrs == NULL) {
241 kfree(msgs);
242 return -ENOMEM;
243 }
244
245 res = 0;
246 for (i = 0; i < nmsgs; i++) {
247 /* Limit the size of the message to a sane amount */
248 if (msgs[i].len > 8192) {
249 res = -EINVAL;
250 break;
251 }
252
253 data_ptrs[i] = (u8 __user *)msgs[i].buf;
254 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
255 if (IS_ERR(msgs[i].buf)) {
256 res = PTR_ERR(msgs[i].buf);
257 break;
258 }
259 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
260 msgs[i].flags |= I2C_M_DMA_SAFE;
261
262 /*
263 * If the message length is received from the slave (similar
264 * to SMBus block read), we must ensure that the buffer will
265 * be large enough to cope with a message length of
266 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
267 * drivers allow. The first byte in the buffer must be
268 * pre-filled with the number of extra bytes, which must be
269 * at least one to hold the message length, but can be
270 * greater (for example to account for a checksum byte at
271 * the end of the message.)
272 */
273 if (msgs[i].flags & I2C_M_RECV_LEN) {
274 if (!(msgs[i].flags & I2C_M_RD) ||
275 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
276 msgs[i].len < msgs[i].buf[0] +
277 I2C_SMBUS_BLOCK_MAX) {
278 i++;
279 res = -EINVAL;
280 break;
281 }
282
283 msgs[i].len = msgs[i].buf[0];
284 }
285 }
286 if (res < 0) {
287 int j;
288 for (j = 0; j < i; ++j)
289 kfree(msgs[j].buf);
290 kfree(data_ptrs);
291 kfree(msgs);
292 return res;
293 }
294
295 res = i2c_transfer(client->adapter, msgs, nmsgs);
296 while (i-- > 0) {
297 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
298 if (copy_to_user(data_ptrs[i], msgs[i].buf,
299 msgs[i].len))
300 res = -EFAULT;
301 }
302 kfree(msgs[i].buf);
303 }
304 kfree(data_ptrs);
305 kfree(msgs);
306 return res;
307}
308
309static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
310 u8 read_write, u8 command, u32 size,
311 union i2c_smbus_data __user *data)
312{
313 union i2c_smbus_data temp = {};
314 int datasize, res;
315
316 if ((size != I2C_SMBUS_BYTE) &&
317 (size != I2C_SMBUS_QUICK) &&
318 (size != I2C_SMBUS_BYTE_DATA) &&
319 (size != I2C_SMBUS_WORD_DATA) &&
320 (size != I2C_SMBUS_PROC_CALL) &&
321 (size != I2C_SMBUS_BLOCK_DATA) &&
322 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
323 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
324 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
325 dev_dbg(&client->adapter->dev,
326 "size out of range (%x) in ioctl I2C_SMBUS.\n",
327 size);
328 return -EINVAL;
329 }
330 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
331 so the check is valid if size==I2C_SMBUS_QUICK too. */
332 if ((read_write != I2C_SMBUS_READ) &&
333 (read_write != I2C_SMBUS_WRITE)) {
334 dev_dbg(&client->adapter->dev,
335 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
336 read_write);
337 return -EINVAL;
338 }
339
340 /* Note that command values are always valid! */
341
342 if ((size == I2C_SMBUS_QUICK) ||
343 ((size == I2C_SMBUS_BYTE) &&
344 (read_write == I2C_SMBUS_WRITE)))
345 /* These are special: we do not use data */
346 return i2c_smbus_xfer(client->adapter, client->addr,
347 client->flags, read_write,
348 command, size, NULL);
349
350 if (data == NULL) {
351 dev_dbg(&client->adapter->dev,
352 "data is NULL pointer in ioctl I2C_SMBUS.\n");
353 return -EINVAL;
354 }
355
356 if ((size == I2C_SMBUS_BYTE_DATA) ||
357 (size == I2C_SMBUS_BYTE))
358 datasize = sizeof(data->byte);
359 else if ((size == I2C_SMBUS_WORD_DATA) ||
360 (size == I2C_SMBUS_PROC_CALL))
361 datasize = sizeof(data->word);
362 else /* size == smbus block, i2c block, or block proc. call */
363 datasize = sizeof(data->block);
364
365 if ((size == I2C_SMBUS_PROC_CALL) ||
366 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
367 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
368 (read_write == I2C_SMBUS_WRITE)) {
369 if (copy_from_user(&temp, data, datasize))
370 return -EFAULT;
371 }
372 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
373 /* Convert old I2C block commands to the new
374 convention. This preserves binary compatibility. */
375 size = I2C_SMBUS_I2C_BLOCK_DATA;
376 if (read_write == I2C_SMBUS_READ)
377 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
378 }
379 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
380 read_write, command, size, &temp);
381 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
382 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
383 (read_write == I2C_SMBUS_READ))) {
384 if (copy_to_user(data, &temp, datasize))
385 return -EFAULT;
386 }
387 return res;
388}
389
390static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
391{
392 struct i2c_client *client = file->private_data;
393 unsigned long funcs;
394
395 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
396 cmd, arg);
397
398 switch (cmd) {
399 case I2C_SLAVE:
400 case I2C_SLAVE_FORCE:
401 if ((arg > 0x3ff) ||
402 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
403 return -EINVAL;
404 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
405 return -EBUSY;
406 /* REVISIT: address could become busy later */
407 client->addr = arg;
408 return 0;
409 case I2C_TENBIT:
410 if (arg)
411 client->flags |= I2C_M_TEN;
412 else
413 client->flags &= ~I2C_M_TEN;
414 return 0;
415 case I2C_PEC:
416 /*
417 * Setting the PEC flag here won't affect kernel drivers,
418 * which will be using the i2c_client node registered with
419 * the driver model core. Likewise, when that client has
420 * the PEC flag already set, the i2c-dev driver won't see
421 * (or use) this setting.
422 */
423 if (arg)
424 client->flags |= I2C_CLIENT_PEC;
425 else
426 client->flags &= ~I2C_CLIENT_PEC;
427 return 0;
428 case I2C_FUNCS:
429 funcs = i2c_get_functionality(client->adapter);
430 return put_user(funcs, (unsigned long __user *)arg);
431
432 case I2C_RDWR: {
433 struct i2c_rdwr_ioctl_data rdwr_arg;
434 struct i2c_msg *rdwr_pa;
435
436 if (copy_from_user(&rdwr_arg,
437 (struct i2c_rdwr_ioctl_data __user *)arg,
438 sizeof(rdwr_arg)))
439 return -EFAULT;
440
441 /* Put an arbitrary limit on the number of messages that can
442 * be sent at once */
443 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
444 return -EINVAL;
445
446 rdwr_pa = memdup_user(rdwr_arg.msgs,
447 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
448 if (IS_ERR(rdwr_pa))
449 return PTR_ERR(rdwr_pa);
450
451 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
452 }
453
454 case I2C_SMBUS: {
455 struct i2c_smbus_ioctl_data data_arg;
456 if (copy_from_user(&data_arg,
457 (struct i2c_smbus_ioctl_data __user *) arg,
458 sizeof(struct i2c_smbus_ioctl_data)))
459 return -EFAULT;
460 return i2cdev_ioctl_smbus(client, data_arg.read_write,
461 data_arg.command,
462 data_arg.size,
463 data_arg.data);
464 }
465 case I2C_RETRIES:
466 if (arg > INT_MAX)
467 return -EINVAL;
468
469 client->adapter->retries = arg;
470 break;
471 case I2C_TIMEOUT:
472 if (arg > INT_MAX)
473 return -EINVAL;
474
475 /* For historical reasons, user-space sets the timeout
476 * value in units of 10 ms.
477 */
478 client->adapter->timeout = msecs_to_jiffies(arg * 10);
479 break;
480 default:
481 /* NOTE: returning a fault code here could cause trouble
482 * in buggy userspace code. Some old kernel bugs returned
483 * zero in this case, and userspace code might accidentally
484 * have depended on that bug.
485 */
486 return -ENOTTY;
487 }
488 return 0;
489}
490
491#ifdef CONFIG_COMPAT
492
493struct i2c_smbus_ioctl_data32 {
494 u8 read_write;
495 u8 command;
496 u32 size;
497 compat_caddr_t data; /* union i2c_smbus_data *data */
498};
499
500struct i2c_msg32 {
501 u16 addr;
502 u16 flags;
503 u16 len;
504 compat_caddr_t buf;
505};
506
507struct i2c_rdwr_ioctl_data32 {
508 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
509 u32 nmsgs;
510};
511
512static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
513{
514 struct i2c_client *client = file->private_data;
515 unsigned long funcs;
516 switch (cmd) {
517 case I2C_FUNCS:
518 funcs = i2c_get_functionality(client->adapter);
519 return put_user(funcs, (compat_ulong_t __user *)arg);
520 case I2C_RDWR: {
521 struct i2c_rdwr_ioctl_data32 rdwr_arg;
522 struct i2c_msg32 *p;
523 struct i2c_msg *rdwr_pa;
524 int i;
525
526 if (copy_from_user(&rdwr_arg,
527 (struct i2c_rdwr_ioctl_data32 __user *)arg,
528 sizeof(rdwr_arg)))
529 return -EFAULT;
530
531 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
532 return -EINVAL;
533
534 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
535 GFP_KERNEL);
536 if (!rdwr_pa)
537 return -ENOMEM;
538
539 p = compat_ptr(rdwr_arg.msgs);
540 for (i = 0; i < rdwr_arg.nmsgs; i++) {
541 struct i2c_msg32 umsg;
542 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
543 kfree(rdwr_pa);
544 return -EFAULT;
545 }
546 rdwr_pa[i] = (struct i2c_msg) {
547 .addr = umsg.addr,
548 .flags = umsg.flags,
549 .len = umsg.len,
550 .buf = compat_ptr(umsg.buf)
551 };
552 }
553
554 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
555 }
556 case I2C_SMBUS: {
557 struct i2c_smbus_ioctl_data32 data32;
558 if (copy_from_user(&data32,
559 (void __user *) arg,
560 sizeof(data32)))
561 return -EFAULT;
562 return i2cdev_ioctl_smbus(client, data32.read_write,
563 data32.command,
564 data32.size,
565 compat_ptr(data32.data));
566 }
567 default:
568 return i2cdev_ioctl(file, cmd, arg);
569 }
570}
571#else
572#define compat_i2cdev_ioctl NULL
573#endif
574
575static int i2cdev_open(struct inode *inode, struct file *file)
576{
577 unsigned int minor = iminor(inode);
578 struct i2c_client *client;
579 struct i2c_adapter *adap;
580
581 adap = i2c_get_adapter(minor);
582 if (!adap)
583 return -ENODEV;
584
585 /* This creates an anonymous i2c_client, which may later be
586 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
587 *
588 * This client is ** NEVER REGISTERED ** with the driver model
589 * or I2C core code!! It just holds private copies of addressing
590 * information and maybe a PEC flag.
591 */
592 client = kzalloc(sizeof(*client), GFP_KERNEL);
593 if (!client) {
594 i2c_put_adapter(adap);
595 return -ENOMEM;
596 }
597 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
598
599 client->adapter = adap;
600 file->private_data = client;
601
602 return 0;
603}
604
605static int i2cdev_release(struct inode *inode, struct file *file)
606{
607 struct i2c_client *client = file->private_data;
608
609 i2c_put_adapter(client->adapter);
610 kfree(client);
611 file->private_data = NULL;
612
613 return 0;
614}
615
616static const struct file_operations i2cdev_fops = {
617 .owner = THIS_MODULE,
618 .llseek = no_llseek,
619 .read = i2cdev_read,
620 .write = i2cdev_write,
621 .unlocked_ioctl = i2cdev_ioctl,
622 .compat_ioctl = compat_i2cdev_ioctl,
623 .open = i2cdev_open,
624 .release = i2cdev_release,
625};
626
627/* ------------------------------------------------------------------------- */
628
629static struct class *i2c_dev_class;
630
631static int i2cdev_attach_adapter(struct device *dev, void *dummy)
632{
633 struct i2c_adapter *adap;
634 struct i2c_dev *i2c_dev;
635 int res;
636
637 if (dev->type != &i2c_adapter_type)
638 return 0;
639 adap = to_i2c_adapter(dev);
640
641 i2c_dev = get_free_i2c_dev(adap);
642 if (IS_ERR(i2c_dev))
643 return PTR_ERR(i2c_dev);
644
645 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
646 i2c_dev->cdev.owner = THIS_MODULE;
647 res = cdev_add(&i2c_dev->cdev, MKDEV(I2C_MAJOR, adap->nr), 1);
648 if (res)
649 goto error_cdev;
650
651 /* register this i2c device with the driver core */
652 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
653 MKDEV(I2C_MAJOR, adap->nr), NULL,
654 "i2c-%d", adap->nr);
655 if (IS_ERR(i2c_dev->dev)) {
656 res = PTR_ERR(i2c_dev->dev);
657 goto error;
658 }
659
660 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
661 adap->name, adap->nr);
662 return 0;
663error:
664 cdev_del(&i2c_dev->cdev);
665error_cdev:
666 put_i2c_dev(i2c_dev);
667 return res;
668}
669
670static int i2cdev_detach_adapter(struct device *dev, void *dummy)
671{
672 struct i2c_adapter *adap;
673 struct i2c_dev *i2c_dev;
674
675 if (dev->type != &i2c_adapter_type)
676 return 0;
677 adap = to_i2c_adapter(dev);
678
679 i2c_dev = i2c_dev_get_by_minor(adap->nr);
680 if (!i2c_dev) /* attach_adapter must have failed */
681 return 0;
682
683 cdev_del(&i2c_dev->cdev);
684 put_i2c_dev(i2c_dev);
685 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
686
687 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
688 return 0;
689}
690
691static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
692 void *data)
693{
694 struct device *dev = data;
695
696 switch (action) {
697 case BUS_NOTIFY_ADD_DEVICE:
698 return i2cdev_attach_adapter(dev, NULL);
699 case BUS_NOTIFY_DEL_DEVICE:
700 return i2cdev_detach_adapter(dev, NULL);
701 }
702
703 return 0;
704}
705
706static struct notifier_block i2cdev_notifier = {
707 .notifier_call = i2cdev_notifier_call,
708};
709
710/* ------------------------------------------------------------------------- */
711
712/*
713 * module load/unload record keeping
714 */
715
716static int __init i2c_dev_init(void)
717{
718 int res;
719
720 printk(KERN_INFO "i2c /dev entries driver\n");
721
722 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
723 if (res)
724 goto out;
725
726 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
727 if (IS_ERR(i2c_dev_class)) {
728 res = PTR_ERR(i2c_dev_class);
729 goto out_unreg_chrdev;
730 }
731 i2c_dev_class->dev_groups = i2c_groups;
732
733 /* Keep track of adapters which will be added or removed later */
734 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
735 if (res)
736 goto out_unreg_class;
737
738 /* Bind to already existing adapters right away */
739 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
740
741 return 0;
742
743out_unreg_class:
744 class_destroy(i2c_dev_class);
745out_unreg_chrdev:
746 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
747out:
748 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
749 return res;
750}
751
752static void __exit i2c_dev_exit(void)
753{
754 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
755 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
756 class_destroy(i2c_dev_class);
757 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
758}
759
760MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
761 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
762MODULE_DESCRIPTION("I2C /dev entries driver");
763MODULE_LICENSE("GPL");
764
765module_init(i2c_dev_init);
766module_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 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 show_adapter_name(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(name, S_IRUGO, show_adapter_name, NULL);
115
116/* ------------------------------------------------------------------------- */
117
118/*
119 * After opening an instance of this character special file, a file
120 * descriptor starts out associated only with an i2c_adapter (and bus).
121 *
122 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
123 * traffic to any devices on the bus used by that adapter. That's because
124 * the i2c_msg vectors embed all the addressing information they need, and
125 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
126 * don't support that interface.
127 *
128 * To use read()/write() system calls on that file descriptor, or to use
129 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
130 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
131 * (never registered) i2c_client so it holds the addressing information
132 * needed by those system calls and by this SMBus interface.
133 */
134
135static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
136 loff_t *offset)
137{
138 char *tmp;
139 int ret;
140
141 struct i2c_client *client = file->private_data;
142
143 if (count > 8192)
144 count = 8192;
145
146 tmp = kmalloc(count, GFP_KERNEL);
147 if (tmp == NULL)
148 return -ENOMEM;
149
150 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
151 iminor(file->f_path.dentry->d_inode), count);
152
153 ret = i2c_master_recv(client, tmp, count);
154 if (ret >= 0)
155 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
156 kfree(tmp);
157 return ret;
158}
159
160static ssize_t i2cdev_write(struct file *file, const char __user *buf,
161 size_t count, loff_t *offset)
162{
163 int ret;
164 char *tmp;
165 struct i2c_client *client = file->private_data;
166
167 if (count > 8192)
168 count = 8192;
169
170 tmp = memdup_user(buf, count);
171 if (IS_ERR(tmp))
172 return PTR_ERR(tmp);
173
174 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
175 iminor(file->f_path.dentry->d_inode), count);
176
177 ret = i2c_master_send(client, tmp, count);
178 kfree(tmp);
179 return ret;
180}
181
182static int i2cdev_check(struct device *dev, void *addrp)
183{
184 struct i2c_client *client = i2c_verify_client(dev);
185
186 if (!client || client->addr != *(unsigned int *)addrp)
187 return 0;
188
189 return dev->driver ? -EBUSY : 0;
190}
191
192/* walk up mux tree */
193static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
194{
195 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
196 int result;
197
198 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
199 if (!result && parent)
200 result = i2cdev_check_mux_parents(parent, addr);
201
202 return result;
203}
204
205/* recurse down mux tree */
206static int i2cdev_check_mux_children(struct device *dev, void *addrp)
207{
208 int result;
209
210 if (dev->type == &i2c_adapter_type)
211 result = device_for_each_child(dev, addrp,
212 i2cdev_check_mux_children);
213 else
214 result = i2cdev_check(dev, addrp);
215
216 return result;
217}
218
219/* This address checking function differs from the one in i2c-core
220 in that it considers an address with a registered device, but no
221 driver bound to it, as NOT busy. */
222static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
223{
224 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
225 int result = 0;
226
227 if (parent)
228 result = i2cdev_check_mux_parents(parent, addr);
229
230 if (!result)
231 result = device_for_each_child(&adapter->dev, &addr,
232 i2cdev_check_mux_children);
233
234 return result;
235}
236
237static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
238 unsigned long arg)
239{
240 struct i2c_rdwr_ioctl_data rdwr_arg;
241 struct i2c_msg *rdwr_pa;
242 u8 __user **data_ptrs;
243 int i, res;
244
245 if (copy_from_user(&rdwr_arg,
246 (struct i2c_rdwr_ioctl_data __user *)arg,
247 sizeof(rdwr_arg)))
248 return -EFAULT;
249
250 /* Put an arbitrary limit on the number of messages that can
251 * be sent at once */
252 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
253 return -EINVAL;
254
255 rdwr_pa = memdup_user(rdwr_arg.msgs,
256 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
257 if (IS_ERR(rdwr_pa))
258 return PTR_ERR(rdwr_pa);
259
260 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
261 if (data_ptrs == NULL) {
262 kfree(rdwr_pa);
263 return -ENOMEM;
264 }
265
266 res = 0;
267 for (i = 0; i < rdwr_arg.nmsgs; i++) {
268 /* Limit the size of the message to a sane amount */
269 if (rdwr_pa[i].len > 8192) {
270 res = -EINVAL;
271 break;
272 }
273
274 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
275 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
276 if (IS_ERR(rdwr_pa[i].buf)) {
277 res = PTR_ERR(rdwr_pa[i].buf);
278 break;
279 }
280
281 /*
282 * If the message length is received from the slave (similar
283 * to SMBus block read), we must ensure that the buffer will
284 * be large enough to cope with a message length of
285 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
286 * drivers allow. The first byte in the buffer must be
287 * pre-filled with the number of extra bytes, which must be
288 * at least one to hold the message length, but can be
289 * greater (for example to account for a checksum byte at
290 * the end of the message.)
291 */
292 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
293 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
294 rdwr_pa[i].buf[0] < 1 ||
295 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
296 I2C_SMBUS_BLOCK_MAX) {
297 res = -EINVAL;
298 break;
299 }
300
301 rdwr_pa[i].len = rdwr_pa[i].buf[0];
302 }
303 }
304 if (res < 0) {
305 int j;
306 for (j = 0; j < i; ++j)
307 kfree(rdwr_pa[j].buf);
308 kfree(data_ptrs);
309 kfree(rdwr_pa);
310 return res;
311 }
312
313 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
314 while (i-- > 0) {
315 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
316 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
317 rdwr_pa[i].len))
318 res = -EFAULT;
319 }
320 kfree(rdwr_pa[i].buf);
321 }
322 kfree(data_ptrs);
323 kfree(rdwr_pa);
324 return res;
325}
326
327static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
328 unsigned long arg)
329{
330 struct i2c_smbus_ioctl_data data_arg;
331 union i2c_smbus_data temp;
332 int datasize, res;
333
334 if (copy_from_user(&data_arg,
335 (struct i2c_smbus_ioctl_data __user *) arg,
336 sizeof(struct i2c_smbus_ioctl_data)))
337 return -EFAULT;
338 if ((data_arg.size != I2C_SMBUS_BYTE) &&
339 (data_arg.size != I2C_SMBUS_QUICK) &&
340 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
341 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
342 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
343 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
344 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
345 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
346 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
347 dev_dbg(&client->adapter->dev,
348 "size out of range (%x) in ioctl I2C_SMBUS.\n",
349 data_arg.size);
350 return -EINVAL;
351 }
352 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
353 so the check is valid if size==I2C_SMBUS_QUICK too. */
354 if ((data_arg.read_write != I2C_SMBUS_READ) &&
355 (data_arg.read_write != I2C_SMBUS_WRITE)) {
356 dev_dbg(&client->adapter->dev,
357 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
358 data_arg.read_write);
359 return -EINVAL;
360 }
361
362 /* Note that command values are always valid! */
363
364 if ((data_arg.size == I2C_SMBUS_QUICK) ||
365 ((data_arg.size == I2C_SMBUS_BYTE) &&
366 (data_arg.read_write == I2C_SMBUS_WRITE)))
367 /* These are special: we do not use data */
368 return i2c_smbus_xfer(client->adapter, client->addr,
369 client->flags, data_arg.read_write,
370 data_arg.command, data_arg.size, NULL);
371
372 if (data_arg.data == NULL) {
373 dev_dbg(&client->adapter->dev,
374 "data is NULL pointer in ioctl I2C_SMBUS.\n");
375 return -EINVAL;
376 }
377
378 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
379 (data_arg.size == I2C_SMBUS_BYTE))
380 datasize = sizeof(data_arg.data->byte);
381 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
382 (data_arg.size == I2C_SMBUS_PROC_CALL))
383 datasize = sizeof(data_arg.data->word);
384 else /* size == smbus block, i2c block, or block proc. call */
385 datasize = sizeof(data_arg.data->block);
386
387 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
388 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
389 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
390 (data_arg.read_write == I2C_SMBUS_WRITE)) {
391 if (copy_from_user(&temp, data_arg.data, datasize))
392 return -EFAULT;
393 }
394 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
395 /* Convert old I2C block commands to the new
396 convention. This preserves binary compatibility. */
397 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
398 if (data_arg.read_write == I2C_SMBUS_READ)
399 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
400 }
401 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
402 data_arg.read_write, data_arg.command, data_arg.size, &temp);
403 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
404 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
405 (data_arg.read_write == I2C_SMBUS_READ))) {
406 if (copy_to_user(data_arg.data, &temp, datasize))
407 return -EFAULT;
408 }
409 return res;
410}
411
412static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
413{
414 struct i2c_client *client = file->private_data;
415 unsigned long funcs;
416
417 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
418 cmd, arg);
419
420 switch (cmd) {
421 case I2C_SLAVE:
422 case I2C_SLAVE_FORCE:
423 /* NOTE: devices set up to work with "new style" drivers
424 * can't use I2C_SLAVE, even when the device node is not
425 * bound to a driver. Only I2C_SLAVE_FORCE will work.
426 *
427 * Setting the PEC flag here won't affect kernel drivers,
428 * which will be using the i2c_client node registered with
429 * the driver model core. Likewise, when that client has
430 * the PEC flag already set, the i2c-dev driver won't see
431 * (or use) this setting.
432 */
433 if ((arg > 0x3ff) ||
434 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
435 return -EINVAL;
436 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
437 return -EBUSY;
438 /* REVISIT: address could become busy later */
439 client->addr = arg;
440 return 0;
441 case I2C_TENBIT:
442 if (arg)
443 client->flags |= I2C_M_TEN;
444 else
445 client->flags &= ~I2C_M_TEN;
446 return 0;
447 case I2C_PEC:
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_rdrw(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 struct i2c_dev *i2c_dev;
489
490 i2c_dev = i2c_dev_get_by_minor(minor);
491 if (!i2c_dev)
492 return -ENODEV;
493
494 adap = i2c_get_adapter(i2c_dev->adap->nr);
495 if (!adap)
496 return -ENODEV;
497
498 /* This creates an anonymous i2c_client, which may later be
499 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
500 *
501 * This client is ** NEVER REGISTERED ** with the driver model
502 * or I2C core code!! It just holds private copies of addressing
503 * information and maybe a PEC flag.
504 */
505 client = kzalloc(sizeof(*client), GFP_KERNEL);
506 if (!client) {
507 i2c_put_adapter(adap);
508 return -ENOMEM;
509 }
510 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
511
512 client->adapter = adap;
513 file->private_data = client;
514
515 return 0;
516}
517
518static int i2cdev_release(struct inode *inode, struct file *file)
519{
520 struct i2c_client *client = file->private_data;
521
522 i2c_put_adapter(client->adapter);
523 kfree(client);
524 file->private_data = NULL;
525
526 return 0;
527}
528
529static const struct file_operations i2cdev_fops = {
530 .owner = THIS_MODULE,
531 .llseek = no_llseek,
532 .read = i2cdev_read,
533 .write = i2cdev_write,
534 .unlocked_ioctl = i2cdev_ioctl,
535 .open = i2cdev_open,
536 .release = i2cdev_release,
537};
538
539/* ------------------------------------------------------------------------- */
540
541static struct class *i2c_dev_class;
542
543static int i2cdev_attach_adapter(struct device *dev, void *dummy)
544{
545 struct i2c_adapter *adap;
546 struct i2c_dev *i2c_dev;
547 int res;
548
549 if (dev->type != &i2c_adapter_type)
550 return 0;
551 adap = to_i2c_adapter(dev);
552
553 i2c_dev = get_free_i2c_dev(adap);
554 if (IS_ERR(i2c_dev))
555 return PTR_ERR(i2c_dev);
556
557 /* register this i2c device with the driver core */
558 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
559 MKDEV(I2C_MAJOR, adap->nr), NULL,
560 "i2c-%d", adap->nr);
561 if (IS_ERR(i2c_dev->dev)) {
562 res = PTR_ERR(i2c_dev->dev);
563 goto error;
564 }
565 res = device_create_file(i2c_dev->dev, &dev_attr_name);
566 if (res)
567 goto error_destroy;
568
569 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
570 adap->name, adap->nr);
571 return 0;
572error_destroy:
573 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
574error:
575 return_i2c_dev(i2c_dev);
576 return res;
577}
578
579static int i2cdev_detach_adapter(struct device *dev, void *dummy)
580{
581 struct i2c_adapter *adap;
582 struct i2c_dev *i2c_dev;
583
584 if (dev->type != &i2c_adapter_type)
585 return 0;
586 adap = to_i2c_adapter(dev);
587
588 i2c_dev = i2c_dev_get_by_minor(adap->nr);
589 if (!i2c_dev) /* attach_adapter must have failed */
590 return 0;
591
592 device_remove_file(i2c_dev->dev, &dev_attr_name);
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
641 /* Keep track of adapters which will be added or removed later */
642 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
643 if (res)
644 goto out_unreg_class;
645
646 /* Bind to already existing adapters right away */
647 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
648
649 return 0;
650
651out_unreg_class:
652 class_destroy(i2c_dev_class);
653out_unreg_chrdev:
654 unregister_chrdev(I2C_MAJOR, "i2c");
655out:
656 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
657 return res;
658}
659
660static void __exit i2c_dev_exit(void)
661{
662 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
663 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
664 class_destroy(i2c_dev_class);
665 unregister_chrdev(I2C_MAJOR, "i2c");
666}
667
668MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
669 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
670MODULE_DESCRIPTION("I2C /dev entries driver");
671MODULE_LICENSE("GPL");
672
673module_init(i2c_dev_init);
674module_exit(i2c_dev_exit);