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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/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 = kmalloc(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 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
154 kfree(tmp);
155 return ret;
156}
157
158static ssize_t i2cdev_write(struct file *file, const char __user *buf,
159 size_t count, loff_t *offset)
160{
161 int ret;
162 char *tmp;
163 struct i2c_client *client = file->private_data;
164
165 if (count > 8192)
166 count = 8192;
167
168 tmp = memdup_user(buf, count);
169 if (IS_ERR(tmp))
170 return PTR_ERR(tmp);
171
172 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
173 iminor(file_inode(file)), count);
174
175 ret = i2c_master_send(client, tmp, count);
176 kfree(tmp);
177 return ret;
178}
179
180static int i2cdev_check(struct device *dev, void *addrp)
181{
182 struct i2c_client *client = i2c_verify_client(dev);
183
184 if (!client || client->addr != *(unsigned int *)addrp)
185 return 0;
186
187 return dev->driver ? -EBUSY : 0;
188}
189
190/* walk up mux tree */
191static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
192{
193 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
194 int result;
195
196 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
197 if (!result && parent)
198 result = i2cdev_check_mux_parents(parent, addr);
199
200 return result;
201}
202
203/* recurse down mux tree */
204static int i2cdev_check_mux_children(struct device *dev, void *addrp)
205{
206 int result;
207
208 if (dev->type == &i2c_adapter_type)
209 result = device_for_each_child(dev, addrp,
210 i2cdev_check_mux_children);
211 else
212 result = i2cdev_check(dev, addrp);
213
214 return result;
215}
216
217/* This address checking function differs from the one in i2c-core
218 in that it considers an address with a registered device, but no
219 driver bound to it, as NOT busy. */
220static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
221{
222 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
223 int result = 0;
224
225 if (parent)
226 result = i2cdev_check_mux_parents(parent, addr);
227
228 if (!result)
229 result = device_for_each_child(&adapter->dev, &addr,
230 i2cdev_check_mux_children);
231
232 return result;
233}
234
235static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
236 unsigned nmsgs, struct i2c_msg *msgs)
237{
238 u8 __user **data_ptrs;
239 int i, res;
240
241 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
242 if (data_ptrs == NULL) {
243 kfree(msgs);
244 return -ENOMEM;
245 }
246
247 res = 0;
248 for (i = 0; i < nmsgs; i++) {
249 /* Limit the size of the message to a sane amount */
250 if (msgs[i].len > 8192) {
251 res = -EINVAL;
252 break;
253 }
254
255 data_ptrs[i] = (u8 __user *)msgs[i].buf;
256 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
257 if (IS_ERR(msgs[i].buf)) {
258 res = PTR_ERR(msgs[i].buf);
259 break;
260 }
261 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
262 msgs[i].flags |= I2C_M_DMA_SAFE;
263
264 /*
265 * If the message length is received from the slave (similar
266 * to SMBus block read), we must ensure that the buffer will
267 * be large enough to cope with a message length of
268 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
269 * drivers allow. The first byte in the buffer must be
270 * pre-filled with the number of extra bytes, which must be
271 * at least one to hold the message length, but can be
272 * greater (for example to account for a checksum byte at
273 * the end of the message.)
274 */
275 if (msgs[i].flags & I2C_M_RECV_LEN) {
276 if (!(msgs[i].flags & I2C_M_RD) ||
277 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
278 msgs[i].len < msgs[i].buf[0] +
279 I2C_SMBUS_BLOCK_MAX) {
280 i++;
281 res = -EINVAL;
282 break;
283 }
284
285 msgs[i].len = msgs[i].buf[0];
286 }
287 }
288 if (res < 0) {
289 int j;
290 for (j = 0; j < i; ++j)
291 kfree(msgs[j].buf);
292 kfree(data_ptrs);
293 kfree(msgs);
294 return res;
295 }
296
297 res = i2c_transfer(client->adapter, msgs, nmsgs);
298 while (i-- > 0) {
299 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
300 if (copy_to_user(data_ptrs[i], msgs[i].buf,
301 msgs[i].len))
302 res = -EFAULT;
303 }
304 kfree(msgs[i].buf);
305 }
306 kfree(data_ptrs);
307 kfree(msgs);
308 return res;
309}
310
311static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
312 u8 read_write, u8 command, u32 size,
313 union i2c_smbus_data __user *data)
314{
315 union i2c_smbus_data temp = {};
316 int datasize, res;
317
318 if ((size != I2C_SMBUS_BYTE) &&
319 (size != I2C_SMBUS_QUICK) &&
320 (size != I2C_SMBUS_BYTE_DATA) &&
321 (size != I2C_SMBUS_WORD_DATA) &&
322 (size != I2C_SMBUS_PROC_CALL) &&
323 (size != I2C_SMBUS_BLOCK_DATA) &&
324 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
325 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
326 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
327 dev_dbg(&client->adapter->dev,
328 "size out of range (%x) in ioctl I2C_SMBUS.\n",
329 size);
330 return -EINVAL;
331 }
332 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
333 so the check is valid if size==I2C_SMBUS_QUICK too. */
334 if ((read_write != I2C_SMBUS_READ) &&
335 (read_write != I2C_SMBUS_WRITE)) {
336 dev_dbg(&client->adapter->dev,
337 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
338 read_write);
339 return -EINVAL;
340 }
341
342 /* Note that command values are always valid! */
343
344 if ((size == I2C_SMBUS_QUICK) ||
345 ((size == I2C_SMBUS_BYTE) &&
346 (read_write == I2C_SMBUS_WRITE)))
347 /* These are special: we do not use data */
348 return i2c_smbus_xfer(client->adapter, client->addr,
349 client->flags, read_write,
350 command, size, NULL);
351
352 if (data == NULL) {
353 dev_dbg(&client->adapter->dev,
354 "data is NULL pointer in ioctl I2C_SMBUS.\n");
355 return -EINVAL;
356 }
357
358 if ((size == I2C_SMBUS_BYTE_DATA) ||
359 (size == I2C_SMBUS_BYTE))
360 datasize = sizeof(data->byte);
361 else if ((size == I2C_SMBUS_WORD_DATA) ||
362 (size == I2C_SMBUS_PROC_CALL))
363 datasize = sizeof(data->word);
364 else /* size == smbus block, i2c block, or block proc. call */
365 datasize = sizeof(data->block);
366
367 if ((size == I2C_SMBUS_PROC_CALL) ||
368 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
369 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
370 (read_write == I2C_SMBUS_WRITE)) {
371 if (copy_from_user(&temp, data, datasize))
372 return -EFAULT;
373 }
374 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
375 /* Convert old I2C block commands to the new
376 convention. This preserves binary compatibility. */
377 size = I2C_SMBUS_I2C_BLOCK_DATA;
378 if (read_write == I2C_SMBUS_READ)
379 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
380 }
381 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
382 read_write, command, size, &temp);
383 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
384 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
385 (read_write == I2C_SMBUS_READ))) {
386 if (copy_to_user(data, &temp, datasize))
387 return -EFAULT;
388 }
389 return res;
390}
391
392static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
393{
394 struct i2c_client *client = file->private_data;
395 unsigned long funcs;
396
397 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
398 cmd, arg);
399
400 switch (cmd) {
401 case I2C_SLAVE:
402 case I2C_SLAVE_FORCE:
403 if ((arg > 0x3ff) ||
404 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
405 return -EINVAL;
406 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
407 return -EBUSY;
408 /* REVISIT: address could become busy later */
409 client->addr = arg;
410 return 0;
411 case I2C_TENBIT:
412 if (arg)
413 client->flags |= I2C_M_TEN;
414 else
415 client->flags &= ~I2C_M_TEN;
416 return 0;
417 case I2C_PEC:
418 /*
419 * Setting the PEC flag here won't affect kernel drivers,
420 * which will be using the i2c_client node registered with
421 * the driver model core. Likewise, when that client has
422 * the PEC flag already set, the i2c-dev driver won't see
423 * (or use) this setting.
424 */
425 if (arg)
426 client->flags |= I2C_CLIENT_PEC;
427 else
428 client->flags &= ~I2C_CLIENT_PEC;
429 return 0;
430 case I2C_FUNCS:
431 funcs = i2c_get_functionality(client->adapter);
432 return put_user(funcs, (unsigned long __user *)arg);
433
434 case I2C_RDWR: {
435 struct i2c_rdwr_ioctl_data rdwr_arg;
436 struct i2c_msg *rdwr_pa;
437
438 if (copy_from_user(&rdwr_arg,
439 (struct i2c_rdwr_ioctl_data __user *)arg,
440 sizeof(rdwr_arg)))
441 return -EFAULT;
442
443 /* Put an arbitrary limit on the number of messages that can
444 * be sent at once */
445 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
446 return -EINVAL;
447
448 rdwr_pa = memdup_user(rdwr_arg.msgs,
449 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
450 if (IS_ERR(rdwr_pa))
451 return PTR_ERR(rdwr_pa);
452
453 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
454 }
455
456 case I2C_SMBUS: {
457 struct i2c_smbus_ioctl_data data_arg;
458 if (copy_from_user(&data_arg,
459 (struct i2c_smbus_ioctl_data __user *) arg,
460 sizeof(struct i2c_smbus_ioctl_data)))
461 return -EFAULT;
462 return i2cdev_ioctl_smbus(client, data_arg.read_write,
463 data_arg.command,
464 data_arg.size,
465 data_arg.data);
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
493#ifdef CONFIG_COMPAT
494
495struct i2c_smbus_ioctl_data32 {
496 u8 read_write;
497 u8 command;
498 u32 size;
499 compat_caddr_t data; /* union i2c_smbus_data *data */
500};
501
502struct i2c_msg32 {
503 u16 addr;
504 u16 flags;
505 u16 len;
506 compat_caddr_t buf;
507};
508
509struct i2c_rdwr_ioctl_data32 {
510 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
511 u32 nmsgs;
512};
513
514static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
515{
516 struct i2c_client *client = file->private_data;
517 unsigned long funcs;
518 switch (cmd) {
519 case I2C_FUNCS:
520 funcs = i2c_get_functionality(client->adapter);
521 return put_user(funcs, (compat_ulong_t __user *)arg);
522 case I2C_RDWR: {
523 struct i2c_rdwr_ioctl_data32 rdwr_arg;
524 struct i2c_msg32 *p;
525 struct i2c_msg *rdwr_pa;
526 int i;
527
528 if (copy_from_user(&rdwr_arg,
529 (struct i2c_rdwr_ioctl_data32 __user *)arg,
530 sizeof(rdwr_arg)))
531 return -EFAULT;
532
533 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
534 return -EINVAL;
535
536 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
537 GFP_KERNEL);
538 if (!rdwr_pa)
539 return -ENOMEM;
540
541 p = compat_ptr(rdwr_arg.msgs);
542 for (i = 0; i < rdwr_arg.nmsgs; i++) {
543 struct i2c_msg32 umsg;
544 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
545 kfree(rdwr_pa);
546 return -EFAULT;
547 }
548 rdwr_pa[i] = (struct i2c_msg) {
549 .addr = umsg.addr,
550 .flags = umsg.flags,
551 .len = umsg.len,
552 .buf = compat_ptr(umsg.buf)
553 };
554 }
555
556 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
557 }
558 case I2C_SMBUS: {
559 struct i2c_smbus_ioctl_data32 data32;
560 if (copy_from_user(&data32,
561 (void __user *) arg,
562 sizeof(data32)))
563 return -EFAULT;
564 return i2cdev_ioctl_smbus(client, data32.read_write,
565 data32.command,
566 data32.size,
567 compat_ptr(data32.data));
568 }
569 default:
570 return i2cdev_ioctl(file, cmd, arg);
571 }
572}
573#else
574#define compat_i2cdev_ioctl NULL
575#endif
576
577static int i2cdev_open(struct inode *inode, struct file *file)
578{
579 unsigned int minor = iminor(inode);
580 struct i2c_client *client;
581 struct i2c_adapter *adap;
582
583 adap = i2c_get_adapter(minor);
584 if (!adap)
585 return -ENODEV;
586
587 /* This creates an anonymous i2c_client, which may later be
588 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
589 *
590 * This client is ** NEVER REGISTERED ** with the driver model
591 * or I2C core code!! It just holds private copies of addressing
592 * information and maybe a PEC flag.
593 */
594 client = kzalloc(sizeof(*client), GFP_KERNEL);
595 if (!client) {
596 i2c_put_adapter(adap);
597 return -ENOMEM;
598 }
599 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
600
601 client->adapter = adap;
602 file->private_data = client;
603
604 return 0;
605}
606
607static int i2cdev_release(struct inode *inode, struct file *file)
608{
609 struct i2c_client *client = file->private_data;
610
611 i2c_put_adapter(client->adapter);
612 kfree(client);
613 file->private_data = NULL;
614
615 return 0;
616}
617
618static const struct file_operations i2cdev_fops = {
619 .owner = THIS_MODULE,
620 .llseek = no_llseek,
621 .read = i2cdev_read,
622 .write = i2cdev_write,
623 .unlocked_ioctl = i2cdev_ioctl,
624 .compat_ioctl = compat_i2cdev_ioctl,
625 .open = i2cdev_open,
626 .release = i2cdev_release,
627};
628
629/* ------------------------------------------------------------------------- */
630
631static struct class *i2c_dev_class;
632
633static void i2cdev_dev_release(struct device *dev)
634{
635 struct i2c_dev *i2c_dev;
636
637 i2c_dev = container_of(dev, struct i2c_dev, dev);
638 kfree(i2c_dev);
639}
640
641static int i2cdev_attach_adapter(struct device *dev, void *dummy)
642{
643 struct i2c_adapter *adap;
644 struct i2c_dev *i2c_dev;
645 int res;
646
647 if (dev->type != &i2c_adapter_type)
648 return 0;
649 adap = to_i2c_adapter(dev);
650
651 i2c_dev = get_free_i2c_dev(adap);
652 if (IS_ERR(i2c_dev))
653 return PTR_ERR(i2c_dev);
654
655 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
656 i2c_dev->cdev.owner = THIS_MODULE;
657
658 device_initialize(&i2c_dev->dev);
659 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
660 i2c_dev->dev.class = i2c_dev_class;
661 i2c_dev->dev.parent = &adap->dev;
662 i2c_dev->dev.release = i2cdev_dev_release;
663 dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
664
665 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
666 if (res) {
667 put_i2c_dev(i2c_dev, false);
668 return res;
669 }
670
671 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
672 adap->name, adap->nr);
673 return 0;
674}
675
676static int i2cdev_detach_adapter(struct device *dev, void *dummy)
677{
678 struct i2c_adapter *adap;
679 struct i2c_dev *i2c_dev;
680
681 if (dev->type != &i2c_adapter_type)
682 return 0;
683 adap = to_i2c_adapter(dev);
684
685 i2c_dev = i2c_dev_get_by_minor(adap->nr);
686 if (!i2c_dev) /* attach_adapter must have failed */
687 return 0;
688
689 put_i2c_dev(i2c_dev, true);
690
691 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
692 return 0;
693}
694
695static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
696 void *data)
697{
698 struct device *dev = data;
699
700 switch (action) {
701 case BUS_NOTIFY_ADD_DEVICE:
702 return i2cdev_attach_adapter(dev, NULL);
703 case BUS_NOTIFY_DEL_DEVICE:
704 return i2cdev_detach_adapter(dev, NULL);
705 }
706
707 return 0;
708}
709
710static struct notifier_block i2cdev_notifier = {
711 .notifier_call = i2cdev_notifier_call,
712};
713
714/* ------------------------------------------------------------------------- */
715
716/*
717 * module load/unload record keeping
718 */
719
720static int __init i2c_dev_init(void)
721{
722 int res;
723
724 printk(KERN_INFO "i2c /dev entries driver\n");
725
726 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
727 if (res)
728 goto out;
729
730 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
731 if (IS_ERR(i2c_dev_class)) {
732 res = PTR_ERR(i2c_dev_class);
733 goto out_unreg_chrdev;
734 }
735 i2c_dev_class->dev_groups = i2c_groups;
736
737 /* Keep track of adapters which will be added or removed later */
738 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
739 if (res)
740 goto out_unreg_class;
741
742 /* Bind to already existing adapters right away */
743 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
744
745 return 0;
746
747out_unreg_class:
748 class_destroy(i2c_dev_class);
749out_unreg_chrdev:
750 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
751out:
752 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
753 return res;
754}
755
756static void __exit i2c_dev_exit(void)
757{
758 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
759 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
760 class_destroy(i2c_dev_class);
761 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
762}
763
764MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
765MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
766MODULE_DESCRIPTION("I2C /dev entries driver");
767MODULE_LICENSE("GPL");
768
769module_init(i2c_dev_init);
770module_exit(i2c_dev_exit);
1/*
2 i2c-dev.c - i2c-bus driver, char device interface
3
4 Copyright (C) 1995-97 Simon G. Vogl
5 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17*/
18
19/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
20 But I have used so much of his original code and ideas that it seems
21 only fair to recognize him as co-author -- Frodo */
22
23/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
24
25#include <linux/cdev.h>
26#include <linux/device.h>
27#include <linux/fs.h>
28#include <linux/i2c-dev.h>
29#include <linux/i2c.h>
30#include <linux/init.h>
31#include <linux/jiffies.h>
32#include <linux/kernel.h>
33#include <linux/list.h>
34#include <linux/module.h>
35#include <linux/notifier.h>
36#include <linux/slab.h>
37#include <linux/uaccess.h>
38
39/*
40 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
41 * slave (i2c_client) with which messages will be exchanged. It's coupled
42 * with a character special file which is accessed by user mode drivers.
43 *
44 * The list of i2c_dev structures is parallel to the i2c_adapter lists
45 * maintained by the driver model, and is updated using bus notifications.
46 */
47struct i2c_dev {
48 struct list_head list;
49 struct i2c_adapter *adap;
50 struct device *dev;
51 struct cdev cdev;
52};
53
54#define I2C_MINORS MINORMASK
55static LIST_HEAD(i2c_dev_list);
56static DEFINE_SPINLOCK(i2c_dev_list_lock);
57
58static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
59{
60 struct i2c_dev *i2c_dev;
61
62 spin_lock(&i2c_dev_list_lock);
63 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
64 if (i2c_dev->adap->nr == index)
65 goto found;
66 }
67 i2c_dev = NULL;
68found:
69 spin_unlock(&i2c_dev_list_lock);
70 return i2c_dev;
71}
72
73static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
74{
75 struct i2c_dev *i2c_dev;
76
77 if (adap->nr >= I2C_MINORS) {
78 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
79 adap->nr);
80 return ERR_PTR(-ENODEV);
81 }
82
83 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
84 if (!i2c_dev)
85 return ERR_PTR(-ENOMEM);
86 i2c_dev->adap = adap;
87
88 spin_lock(&i2c_dev_list_lock);
89 list_add_tail(&i2c_dev->list, &i2c_dev_list);
90 spin_unlock(&i2c_dev_list_lock);
91 return i2c_dev;
92}
93
94static void put_i2c_dev(struct i2c_dev *i2c_dev)
95{
96 spin_lock(&i2c_dev_list_lock);
97 list_del(&i2c_dev->list);
98 spin_unlock(&i2c_dev_list_lock);
99 kfree(i2c_dev);
100}
101
102static ssize_t name_show(struct device *dev,
103 struct device_attribute *attr, char *buf)
104{
105 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
106
107 if (!i2c_dev)
108 return -ENODEV;
109 return sprintf(buf, "%s\n", i2c_dev->adap->name);
110}
111static DEVICE_ATTR_RO(name);
112
113static struct attribute *i2c_attrs[] = {
114 &dev_attr_name.attr,
115 NULL,
116};
117ATTRIBUTE_GROUPS(i2c);
118
119/* ------------------------------------------------------------------------- */
120
121/*
122 * After opening an instance of this character special file, a file
123 * descriptor starts out associated only with an i2c_adapter (and bus).
124 *
125 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
126 * traffic to any devices on the bus used by that adapter. That's because
127 * the i2c_msg vectors embed all the addressing information they need, and
128 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
129 * don't support that interface.
130 *
131 * To use read()/write() system calls on that file descriptor, or to use
132 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
133 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
134 * (never registered) i2c_client so it holds the addressing information
135 * needed by those system calls and by this SMBus interface.
136 */
137
138static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
139 loff_t *offset)
140{
141 char *tmp;
142 int ret;
143
144 struct i2c_client *client = file->private_data;
145
146 if (count > 8192)
147 count = 8192;
148
149 tmp = kmalloc(count, GFP_KERNEL);
150 if (tmp == NULL)
151 return -ENOMEM;
152
153 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
154 iminor(file_inode(file)), count);
155
156 ret = i2c_master_recv(client, tmp, count);
157 if (ret >= 0)
158 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
159 kfree(tmp);
160 return ret;
161}
162
163static ssize_t i2cdev_write(struct file *file, const char __user *buf,
164 size_t count, loff_t *offset)
165{
166 int ret;
167 char *tmp;
168 struct i2c_client *client = file->private_data;
169
170 if (count > 8192)
171 count = 8192;
172
173 tmp = memdup_user(buf, count);
174 if (IS_ERR(tmp))
175 return PTR_ERR(tmp);
176
177 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
178 iminor(file_inode(file)), count);
179
180 ret = i2c_master_send(client, tmp, count);
181 kfree(tmp);
182 return ret;
183}
184
185static int i2cdev_check(struct device *dev, void *addrp)
186{
187 struct i2c_client *client = i2c_verify_client(dev);
188
189 if (!client || client->addr != *(unsigned int *)addrp)
190 return 0;
191
192 return dev->driver ? -EBUSY : 0;
193}
194
195/* walk up mux tree */
196static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
197{
198 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
199 int result;
200
201 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
202 if (!result && parent)
203 result = i2cdev_check_mux_parents(parent, addr);
204
205 return result;
206}
207
208/* recurse down mux tree */
209static int i2cdev_check_mux_children(struct device *dev, void *addrp)
210{
211 int result;
212
213 if (dev->type == &i2c_adapter_type)
214 result = device_for_each_child(dev, addrp,
215 i2cdev_check_mux_children);
216 else
217 result = i2cdev_check(dev, addrp);
218
219 return result;
220}
221
222/* This address checking function differs from the one in i2c-core
223 in that it considers an address with a registered device, but no
224 driver bound to it, as NOT busy. */
225static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
226{
227 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
228 int result = 0;
229
230 if (parent)
231 result = i2cdev_check_mux_parents(parent, addr);
232
233 if (!result)
234 result = device_for_each_child(&adapter->dev, &addr,
235 i2cdev_check_mux_children);
236
237 return result;
238}
239
240static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
241 unsigned long arg)
242{
243 struct i2c_rdwr_ioctl_data rdwr_arg;
244 struct i2c_msg *rdwr_pa;
245 u8 __user **data_ptrs;
246 int i, res;
247
248 if (copy_from_user(&rdwr_arg,
249 (struct i2c_rdwr_ioctl_data __user *)arg,
250 sizeof(rdwr_arg)))
251 return -EFAULT;
252
253 /* Put an arbitrary limit on the number of messages that can
254 * be sent at once */
255 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
256 return -EINVAL;
257
258 rdwr_pa = memdup_user(rdwr_arg.msgs,
259 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
260 if (IS_ERR(rdwr_pa))
261 return PTR_ERR(rdwr_pa);
262
263 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
264 if (data_ptrs == NULL) {
265 kfree(rdwr_pa);
266 return -ENOMEM;
267 }
268
269 res = 0;
270 for (i = 0; i < rdwr_arg.nmsgs; i++) {
271 /* Limit the size of the message to a sane amount */
272 if (rdwr_pa[i].len > 8192) {
273 res = -EINVAL;
274 break;
275 }
276
277 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
278 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
279 if (IS_ERR(rdwr_pa[i].buf)) {
280 res = PTR_ERR(rdwr_pa[i].buf);
281 break;
282 }
283
284 /*
285 * If the message length is received from the slave (similar
286 * to SMBus block read), we must ensure that the buffer will
287 * be large enough to cope with a message length of
288 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
289 * drivers allow. The first byte in the buffer must be
290 * pre-filled with the number of extra bytes, which must be
291 * at least one to hold the message length, but can be
292 * greater (for example to account for a checksum byte at
293 * the end of the message.)
294 */
295 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
296 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
297 rdwr_pa[i].buf[0] < 1 ||
298 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
299 I2C_SMBUS_BLOCK_MAX) {
300 res = -EINVAL;
301 break;
302 }
303
304 rdwr_pa[i].len = rdwr_pa[i].buf[0];
305 }
306 }
307 if (res < 0) {
308 int j;
309 for (j = 0; j < i; ++j)
310 kfree(rdwr_pa[j].buf);
311 kfree(data_ptrs);
312 kfree(rdwr_pa);
313 return res;
314 }
315
316 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
317 while (i-- > 0) {
318 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
319 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
320 rdwr_pa[i].len))
321 res = -EFAULT;
322 }
323 kfree(rdwr_pa[i].buf);
324 }
325 kfree(data_ptrs);
326 kfree(rdwr_pa);
327 return res;
328}
329
330static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
331 unsigned long arg)
332{
333 struct i2c_smbus_ioctl_data data_arg;
334 union i2c_smbus_data temp = {};
335 int datasize, res;
336
337 if (copy_from_user(&data_arg,
338 (struct i2c_smbus_ioctl_data __user *) arg,
339 sizeof(struct i2c_smbus_ioctl_data)))
340 return -EFAULT;
341 if ((data_arg.size != I2C_SMBUS_BYTE) &&
342 (data_arg.size != I2C_SMBUS_QUICK) &&
343 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
344 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
345 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
346 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
347 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
348 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
349 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
350 dev_dbg(&client->adapter->dev,
351 "size out of range (%x) in ioctl I2C_SMBUS.\n",
352 data_arg.size);
353 return -EINVAL;
354 }
355 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
356 so the check is valid if size==I2C_SMBUS_QUICK too. */
357 if ((data_arg.read_write != I2C_SMBUS_READ) &&
358 (data_arg.read_write != I2C_SMBUS_WRITE)) {
359 dev_dbg(&client->adapter->dev,
360 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
361 data_arg.read_write);
362 return -EINVAL;
363 }
364
365 /* Note that command values are always valid! */
366
367 if ((data_arg.size == I2C_SMBUS_QUICK) ||
368 ((data_arg.size == I2C_SMBUS_BYTE) &&
369 (data_arg.read_write == I2C_SMBUS_WRITE)))
370 /* These are special: we do not use data */
371 return i2c_smbus_xfer(client->adapter, client->addr,
372 client->flags, data_arg.read_write,
373 data_arg.command, data_arg.size, NULL);
374
375 if (data_arg.data == NULL) {
376 dev_dbg(&client->adapter->dev,
377 "data is NULL pointer in ioctl I2C_SMBUS.\n");
378 return -EINVAL;
379 }
380
381 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
382 (data_arg.size == I2C_SMBUS_BYTE))
383 datasize = sizeof(data_arg.data->byte);
384 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
385 (data_arg.size == I2C_SMBUS_PROC_CALL))
386 datasize = sizeof(data_arg.data->word);
387 else /* size == smbus block, i2c block, or block proc. call */
388 datasize = sizeof(data_arg.data->block);
389
390 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
391 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
392 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
393 (data_arg.read_write == I2C_SMBUS_WRITE)) {
394 if (copy_from_user(&temp, data_arg.data, datasize))
395 return -EFAULT;
396 }
397 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
398 /* Convert old I2C block commands to the new
399 convention. This preserves binary compatibility. */
400 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
401 if (data_arg.read_write == I2C_SMBUS_READ)
402 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
403 }
404 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
405 data_arg.read_write, data_arg.command, data_arg.size, &temp);
406 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
407 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
408 (data_arg.read_write == I2C_SMBUS_READ))) {
409 if (copy_to_user(data_arg.data, &temp, datasize))
410 return -EFAULT;
411 }
412 return res;
413}
414
415static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
416{
417 struct i2c_client *client = file->private_data;
418 unsigned long funcs;
419
420 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
421 cmd, arg);
422
423 switch (cmd) {
424 case I2C_SLAVE:
425 case I2C_SLAVE_FORCE:
426 if ((arg > 0x3ff) ||
427 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
428 return -EINVAL;
429 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
430 return -EBUSY;
431 /* REVISIT: address could become busy later */
432 client->addr = arg;
433 return 0;
434 case I2C_TENBIT:
435 if (arg)
436 client->flags |= I2C_M_TEN;
437 else
438 client->flags &= ~I2C_M_TEN;
439 return 0;
440 case I2C_PEC:
441 /*
442 * Setting the PEC flag here won't affect kernel drivers,
443 * which will be using the i2c_client node registered with
444 * the driver model core. Likewise, when that client has
445 * the PEC flag already set, the i2c-dev driver won't see
446 * (or use) this setting.
447 */
448 if (arg)
449 client->flags |= I2C_CLIENT_PEC;
450 else
451 client->flags &= ~I2C_CLIENT_PEC;
452 return 0;
453 case I2C_FUNCS:
454 funcs = i2c_get_functionality(client->adapter);
455 return put_user(funcs, (unsigned long __user *)arg);
456
457 case I2C_RDWR:
458 return i2cdev_ioctl_rdwr(client, arg);
459
460 case I2C_SMBUS:
461 return i2cdev_ioctl_smbus(client, arg);
462
463 case I2C_RETRIES:
464 client->adapter->retries = arg;
465 break;
466 case I2C_TIMEOUT:
467 /* For historical reasons, user-space sets the timeout
468 * value in units of 10 ms.
469 */
470 client->adapter->timeout = msecs_to_jiffies(arg * 10);
471 break;
472 default:
473 /* NOTE: returning a fault code here could cause trouble
474 * in buggy userspace code. Some old kernel bugs returned
475 * zero in this case, and userspace code might accidentally
476 * have depended on that bug.
477 */
478 return -ENOTTY;
479 }
480 return 0;
481}
482
483static int i2cdev_open(struct inode *inode, struct file *file)
484{
485 unsigned int minor = iminor(inode);
486 struct i2c_client *client;
487 struct i2c_adapter *adap;
488
489 adap = i2c_get_adapter(minor);
490 if (!adap)
491 return -ENODEV;
492
493 /* This creates an anonymous i2c_client, which may later be
494 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
495 *
496 * This client is ** NEVER REGISTERED ** with the driver model
497 * or I2C core code!! It just holds private copies of addressing
498 * information and maybe a PEC flag.
499 */
500 client = kzalloc(sizeof(*client), GFP_KERNEL);
501 if (!client) {
502 i2c_put_adapter(adap);
503 return -ENOMEM;
504 }
505 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
506
507 client->adapter = adap;
508 file->private_data = client;
509
510 return 0;
511}
512
513static int i2cdev_release(struct inode *inode, struct file *file)
514{
515 struct i2c_client *client = file->private_data;
516
517 i2c_put_adapter(client->adapter);
518 kfree(client);
519 file->private_data = NULL;
520
521 return 0;
522}
523
524static const struct file_operations i2cdev_fops = {
525 .owner = THIS_MODULE,
526 .llseek = no_llseek,
527 .read = i2cdev_read,
528 .write = i2cdev_write,
529 .unlocked_ioctl = i2cdev_ioctl,
530 .open = i2cdev_open,
531 .release = i2cdev_release,
532};
533
534/* ------------------------------------------------------------------------- */
535
536static struct class *i2c_dev_class;
537
538static int i2cdev_attach_adapter(struct device *dev, void *dummy)
539{
540 struct i2c_adapter *adap;
541 struct i2c_dev *i2c_dev;
542 int res;
543
544 if (dev->type != &i2c_adapter_type)
545 return 0;
546 adap = to_i2c_adapter(dev);
547
548 i2c_dev = get_free_i2c_dev(adap);
549 if (IS_ERR(i2c_dev))
550 return PTR_ERR(i2c_dev);
551
552 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
553 i2c_dev->cdev.owner = THIS_MODULE;
554 res = cdev_add(&i2c_dev->cdev, MKDEV(I2C_MAJOR, adap->nr), 1);
555 if (res)
556 goto error_cdev;
557
558 /* register this i2c device with the driver core */
559 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
560 MKDEV(I2C_MAJOR, adap->nr), NULL,
561 "i2c-%d", adap->nr);
562 if (IS_ERR(i2c_dev->dev)) {
563 res = PTR_ERR(i2c_dev->dev);
564 goto error;
565 }
566
567 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
568 adap->name, adap->nr);
569 return 0;
570error:
571 cdev_del(&i2c_dev->cdev);
572error_cdev:
573 put_i2c_dev(i2c_dev);
574 return res;
575}
576
577static int i2cdev_detach_adapter(struct device *dev, void *dummy)
578{
579 struct i2c_adapter *adap;
580 struct i2c_dev *i2c_dev;
581
582 if (dev->type != &i2c_adapter_type)
583 return 0;
584 adap = to_i2c_adapter(dev);
585
586 i2c_dev = i2c_dev_get_by_minor(adap->nr);
587 if (!i2c_dev) /* attach_adapter must have failed */
588 return 0;
589
590 cdev_del(&i2c_dev->cdev);
591 put_i2c_dev(i2c_dev);
592 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
593
594 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
595 return 0;
596}
597
598static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
599 void *data)
600{
601 struct device *dev = data;
602
603 switch (action) {
604 case BUS_NOTIFY_ADD_DEVICE:
605 return i2cdev_attach_adapter(dev, NULL);
606 case BUS_NOTIFY_DEL_DEVICE:
607 return i2cdev_detach_adapter(dev, NULL);
608 }
609
610 return 0;
611}
612
613static struct notifier_block i2cdev_notifier = {
614 .notifier_call = i2cdev_notifier_call,
615};
616
617/* ------------------------------------------------------------------------- */
618
619/*
620 * module load/unload record keeping
621 */
622
623static int __init i2c_dev_init(void)
624{
625 int res;
626
627 printk(KERN_INFO "i2c /dev entries driver\n");
628
629 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
630 if (res)
631 goto out;
632
633 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
634 if (IS_ERR(i2c_dev_class)) {
635 res = PTR_ERR(i2c_dev_class);
636 goto out_unreg_chrdev;
637 }
638 i2c_dev_class->dev_groups = i2c_groups;
639
640 /* Keep track of adapters which will be added or removed later */
641 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
642 if (res)
643 goto out_unreg_class;
644
645 /* Bind to already existing adapters right away */
646 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
647
648 return 0;
649
650out_unreg_class:
651 class_destroy(i2c_dev_class);
652out_unreg_chrdev:
653 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
654out:
655 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
656 return res;
657}
658
659static void __exit i2c_dev_exit(void)
660{
661 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
662 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
663 class_destroy(i2c_dev_class);
664 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
665}
666
667MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
668 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
669MODULE_DESCRIPTION("I2C /dev entries driver");
670MODULE_LICENSE("GPL");
671
672module_init(i2c_dev_init);
673module_exit(i2c_dev_exit);