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1/*
2 i2c-dev.c - i2c-bus driver, char device interface
3
4 Copyright (C) 1995-97 Simon G. Vogl
5 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17*/
18
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/cdev.h>
20#include <linux/compat.h>
21#include <linux/device.h>
22#include <linux/fs.h>
23#include <linux/i2c-dev.h>
24#include <linux/i2c.h>
25#include <linux/init.h>
26#include <linux/jiffies.h>
27#include <linux/kernel.h>
28#include <linux/list.h>
29#include <linux/module.h>
30#include <linux/notifier.h>
31#include <linux/slab.h>
32#include <linux/uaccess.h>
33
34/*
35 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
36 * slave (i2c_client) with which messages will be exchanged. It's coupled
37 * with a character special file which is accessed by user mode drivers.
38 *
39 * The list of i2c_dev structures is parallel to the i2c_adapter lists
40 * maintained by the driver model, and is updated using bus notifications.
41 */
42struct i2c_dev {
43 struct list_head list;
44 struct i2c_adapter *adap;
45 struct device dev;
46 struct cdev cdev;
47};
48
49#define I2C_MINORS (MINORMASK + 1)
50static LIST_HEAD(i2c_dev_list);
51static DEFINE_SPINLOCK(i2c_dev_list_lock);
52
53static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
54{
55 struct i2c_dev *i2c_dev;
56
57 spin_lock(&i2c_dev_list_lock);
58 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
59 if (i2c_dev->adap->nr == index)
60 goto found;
61 }
62 i2c_dev = NULL;
63found:
64 spin_unlock(&i2c_dev_list_lock);
65 return i2c_dev;
66}
67
68static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
69{
70 struct i2c_dev *i2c_dev;
71
72 if (adap->nr >= I2C_MINORS) {
73 pr_err("Out of device minors (%d)\n", adap->nr);
74 return ERR_PTR(-ENODEV);
75 }
76
77 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
78 if (!i2c_dev)
79 return ERR_PTR(-ENOMEM);
80 i2c_dev->adap = adap;
81
82 spin_lock(&i2c_dev_list_lock);
83 list_add_tail(&i2c_dev->list, &i2c_dev_list);
84 spin_unlock(&i2c_dev_list_lock);
85 return i2c_dev;
86}
87
88static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev)
89{
90 spin_lock(&i2c_dev_list_lock);
91 list_del(&i2c_dev->list);
92 spin_unlock(&i2c_dev_list_lock);
93 if (del_cdev)
94 cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev);
95 put_device(&i2c_dev->dev);
96}
97
98static ssize_t name_show(struct device *dev,
99 struct device_attribute *attr, char *buf)
100{
101 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
102
103 if (!i2c_dev)
104 return -ENODEV;
105 return sysfs_emit(buf, "%s\n", i2c_dev->adap->name);
106}
107static DEVICE_ATTR_RO(name);
108
109static struct attribute *i2c_attrs[] = {
110 &dev_attr_name.attr,
111 NULL,
112};
113ATTRIBUTE_GROUPS(i2c);
114
115/* ------------------------------------------------------------------------- */
116
117/*
118 * After opening an instance of this character special file, a file
119 * descriptor starts out associated only with an i2c_adapter (and bus).
120 *
121 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
122 * traffic to any devices on the bus used by that adapter. That's because
123 * the i2c_msg vectors embed all the addressing information they need, and
124 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
125 * don't support that interface.
126 *
127 * To use read()/write() system calls on that file descriptor, or to use
128 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
129 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
130 * (never registered) i2c_client so it holds the addressing information
131 * needed by those system calls and by this SMBus interface.
132 */
133
134static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
135 loff_t *offset)
136{
137 char *tmp;
138 int ret;
139
140 struct i2c_client *client = file->private_data;
141
142 /* Adapter must support I2C transfers */
143 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
144 return -EOPNOTSUPP;
145
146 if (count > 8192)
147 count = 8192;
148
149 tmp = kzalloc(count, GFP_KERNEL);
150 if (tmp == NULL)
151 return -ENOMEM;
152
153 pr_debug("i2c-%d reading %zu bytes.\n", iminor(file_inode(file)), count);
154
155 ret = i2c_master_recv(client, tmp, count);
156 if (ret >= 0)
157 if (copy_to_user(buf, tmp, ret))
158 ret = -EFAULT;
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 /* Adapter must support I2C transfers */
171 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
172 return -EOPNOTSUPP;
173
174 if (count > 8192)
175 count = 8192;
176
177 tmp = memdup_user(buf, count);
178 if (IS_ERR(tmp))
179 return PTR_ERR(tmp);
180
181 pr_debug("i2c-%d writing %zu bytes.\n", iminor(file_inode(file)), count);
182
183 ret = i2c_master_send(client, tmp, count);
184 kfree(tmp);
185 return ret;
186}
187
188static int i2cdev_check(struct device *dev, void *addrp)
189{
190 struct i2c_client *client = i2c_verify_client(dev);
191
192 if (!client || client->addr != *(unsigned int *)addrp)
193 return 0;
194
195 return dev->driver ? -EBUSY : 0;
196}
197
198/* walk up mux tree */
199static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
200{
201 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
202 int result;
203
204 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
205 if (!result && parent)
206 result = i2cdev_check_mux_parents(parent, addr);
207
208 return result;
209}
210
211/* recurse down mux tree */
212static int i2cdev_check_mux_children(struct device *dev, void *addrp)
213{
214 int result;
215
216 if (dev->type == &i2c_adapter_type)
217 result = device_for_each_child(dev, addrp,
218 i2cdev_check_mux_children);
219 else
220 result = i2cdev_check(dev, addrp);
221
222 return result;
223}
224
225/* This address checking function differs from the one in i2c-core
226 in that it considers an address with a registered device, but no
227 driver bound to it, as NOT busy. */
228static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
229{
230 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
231 int result = 0;
232
233 if (parent)
234 result = i2cdev_check_mux_parents(parent, addr);
235
236 if (!result)
237 result = device_for_each_child(&adapter->dev, &addr,
238 i2cdev_check_mux_children);
239
240 return result;
241}
242
243static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
244 unsigned nmsgs, struct i2c_msg *msgs)
245{
246 u8 __user **data_ptrs;
247 int i, res;
248
249 /* Adapter must support I2C transfers */
250 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
251 return -EOPNOTSUPP;
252
253 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
254 if (!data_ptrs)
255 return -ENOMEM;
256
257 res = 0;
258 for (i = 0; i < nmsgs; i++) {
259 /* Limit the size of the message to a sane amount */
260 if (msgs[i].len > 8192) {
261 res = -EINVAL;
262 break;
263 }
264
265 data_ptrs[i] = (u8 __user *)msgs[i].buf;
266 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
267 if (IS_ERR(msgs[i].buf)) {
268 res = PTR_ERR(msgs[i].buf);
269 break;
270 }
271 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
272 msgs[i].flags |= I2C_M_DMA_SAFE;
273
274 /*
275 * If the message length is received from the slave (similar
276 * to SMBus block read), we must ensure that the buffer will
277 * be large enough to cope with a message length of
278 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
279 * drivers allow. The first byte in the buffer must be
280 * pre-filled with the number of extra bytes, which must be
281 * at least one to hold the message length, but can be
282 * greater (for example to account for a checksum byte at
283 * the end of the message.)
284 */
285 if (msgs[i].flags & I2C_M_RECV_LEN) {
286 if (!(msgs[i].flags & I2C_M_RD) ||
287 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
288 msgs[i].len < msgs[i].buf[0] +
289 I2C_SMBUS_BLOCK_MAX) {
290 i++;
291 res = -EINVAL;
292 break;
293 }
294
295 msgs[i].len = msgs[i].buf[0];
296 }
297 }
298 if (res < 0) {
299 int j;
300 for (j = 0; j < i; ++j)
301 kfree(msgs[j].buf);
302 kfree(data_ptrs);
303 return res;
304 }
305
306 res = i2c_transfer(client->adapter, msgs, nmsgs);
307 while (i-- > 0) {
308 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
309 if (copy_to_user(data_ptrs[i], msgs[i].buf,
310 msgs[i].len))
311 res = -EFAULT;
312 }
313 kfree(msgs[i].buf);
314 }
315 kfree(data_ptrs);
316 return res;
317}
318
319static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
320 u8 read_write, u8 command, u32 size,
321 union i2c_smbus_data __user *data)
322{
323 union i2c_smbus_data temp = {};
324 int datasize, res;
325
326 if ((size != I2C_SMBUS_BYTE) &&
327 (size != I2C_SMBUS_QUICK) &&
328 (size != I2C_SMBUS_BYTE_DATA) &&
329 (size != I2C_SMBUS_WORD_DATA) &&
330 (size != I2C_SMBUS_PROC_CALL) &&
331 (size != I2C_SMBUS_BLOCK_DATA) &&
332 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
333 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
334 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
335 dev_dbg(&client->adapter->dev,
336 "size out of range (%x) in ioctl I2C_SMBUS.\n",
337 size);
338 return -EINVAL;
339 }
340 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
341 so the check is valid if size==I2C_SMBUS_QUICK too. */
342 if ((read_write != I2C_SMBUS_READ) &&
343 (read_write != I2C_SMBUS_WRITE)) {
344 dev_dbg(&client->adapter->dev,
345 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
346 read_write);
347 return -EINVAL;
348 }
349
350 /* Note that command values are always valid! */
351
352 if ((size == I2C_SMBUS_QUICK) ||
353 ((size == I2C_SMBUS_BYTE) &&
354 (read_write == I2C_SMBUS_WRITE)))
355 /* These are special: we do not use data */
356 return i2c_smbus_xfer(client->adapter, client->addr,
357 client->flags, read_write,
358 command, size, NULL);
359
360 if (data == NULL) {
361 dev_dbg(&client->adapter->dev,
362 "data is NULL pointer in ioctl I2C_SMBUS.\n");
363 return -EINVAL;
364 }
365
366 if ((size == I2C_SMBUS_BYTE_DATA) ||
367 (size == I2C_SMBUS_BYTE))
368 datasize = sizeof(data->byte);
369 else if ((size == I2C_SMBUS_WORD_DATA) ||
370 (size == I2C_SMBUS_PROC_CALL))
371 datasize = sizeof(data->word);
372 else /* size == smbus block, i2c block, or block proc. call */
373 datasize = sizeof(data->block);
374
375 if ((size == I2C_SMBUS_PROC_CALL) ||
376 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
377 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
378 (read_write == I2C_SMBUS_WRITE)) {
379 if (copy_from_user(&temp, data, datasize))
380 return -EFAULT;
381 }
382 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
383 /* Convert old I2C block commands to the new
384 convention. This preserves binary compatibility. */
385 size = I2C_SMBUS_I2C_BLOCK_DATA;
386 if (read_write == I2C_SMBUS_READ)
387 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
388 }
389 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
390 read_write, command, size, &temp);
391 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
392 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
393 (read_write == I2C_SMBUS_READ))) {
394 if (copy_to_user(data, &temp, datasize))
395 return -EFAULT;
396 }
397 return res;
398}
399
400static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
401{
402 struct i2c_client *client = file->private_data;
403 unsigned long funcs;
404
405 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
406 cmd, arg);
407
408 switch (cmd) {
409 case I2C_SLAVE:
410 case I2C_SLAVE_FORCE:
411 if ((arg > 0x3ff) ||
412 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
413 return -EINVAL;
414 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
415 return -EBUSY;
416 /* REVISIT: address could become busy later */
417 client->addr = arg;
418 return 0;
419 case I2C_TENBIT:
420 if (arg)
421 client->flags |= I2C_M_TEN;
422 else
423 client->flags &= ~I2C_M_TEN;
424 return 0;
425 case I2C_PEC:
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)
434 client->flags |= I2C_CLIENT_PEC;
435 else
436 client->flags &= ~I2C_CLIENT_PEC;
437 return 0;
438 case I2C_FUNCS:
439 funcs = i2c_get_functionality(client->adapter);
440 return put_user(funcs, (unsigned long __user *)arg);
441
442 case I2C_RDWR: {
443 struct i2c_rdwr_ioctl_data rdwr_arg;
444 struct i2c_msg *rdwr_pa;
445 int res;
446
447 if (copy_from_user(&rdwr_arg,
448 (struct i2c_rdwr_ioctl_data __user *)arg,
449 sizeof(rdwr_arg)))
450 return -EFAULT;
451
452 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
453 return -EINVAL;
454
455 /*
456 * Put an arbitrary limit on the number of messages that can
457 * be sent at once
458 */
459 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
460 return -EINVAL;
461
462 rdwr_pa = memdup_array_user(rdwr_arg.msgs,
463 rdwr_arg.nmsgs, sizeof(struct i2c_msg));
464 if (IS_ERR(rdwr_pa))
465 return PTR_ERR(rdwr_pa);
466
467 res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
468 kfree(rdwr_pa);
469 return res;
470 }
471
472 case I2C_SMBUS: {
473 struct i2c_smbus_ioctl_data data_arg;
474 if (copy_from_user(&data_arg,
475 (struct i2c_smbus_ioctl_data __user *) arg,
476 sizeof(struct i2c_smbus_ioctl_data)))
477 return -EFAULT;
478 return i2cdev_ioctl_smbus(client, data_arg.read_write,
479 data_arg.command,
480 data_arg.size,
481 data_arg.data);
482 }
483 case I2C_RETRIES:
484 if (arg > INT_MAX)
485 return -EINVAL;
486
487 client->adapter->retries = arg;
488 break;
489 case I2C_TIMEOUT:
490 if (arg > INT_MAX)
491 return -EINVAL;
492
493 /* For historical reasons, user-space sets the timeout
494 * value in units of 10 ms.
495 */
496 client->adapter->timeout = msecs_to_jiffies(arg * 10);
497 break;
498 default:
499 /* NOTE: returning a fault code here could cause trouble
500 * in buggy userspace code. Some old kernel bugs returned
501 * zero in this case, and userspace code might accidentally
502 * have depended on that bug.
503 */
504 return -ENOTTY;
505 }
506 return 0;
507}
508
509#ifdef CONFIG_COMPAT
510
511struct i2c_smbus_ioctl_data32 {
512 u8 read_write;
513 u8 command;
514 u32 size;
515 compat_caddr_t data; /* union i2c_smbus_data *data */
516};
517
518struct i2c_msg32 {
519 u16 addr;
520 u16 flags;
521 u16 len;
522 compat_caddr_t buf;
523};
524
525struct i2c_rdwr_ioctl_data32 {
526 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
527 u32 nmsgs;
528};
529
530static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
531{
532 struct i2c_client *client = file->private_data;
533 unsigned long funcs;
534 switch (cmd) {
535 case I2C_FUNCS:
536 funcs = i2c_get_functionality(client->adapter);
537 return put_user(funcs, (compat_ulong_t __user *)arg);
538 case I2C_RDWR: {
539 struct i2c_rdwr_ioctl_data32 rdwr_arg;
540 struct i2c_msg32 __user *p;
541 struct i2c_msg *rdwr_pa;
542 int i, res;
543
544 if (copy_from_user(&rdwr_arg,
545 (struct i2c_rdwr_ioctl_data32 __user *)arg,
546 sizeof(rdwr_arg)))
547 return -EFAULT;
548
549 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
550 return -EINVAL;
551
552 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
553 return -EINVAL;
554
555 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
556 GFP_KERNEL);
557 if (!rdwr_pa)
558 return -ENOMEM;
559
560 p = compat_ptr(rdwr_arg.msgs);
561 for (i = 0; i < rdwr_arg.nmsgs; i++) {
562 struct i2c_msg32 umsg;
563 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
564 kfree(rdwr_pa);
565 return -EFAULT;
566 }
567 rdwr_pa[i] = (struct i2c_msg) {
568 .addr = umsg.addr,
569 .flags = umsg.flags,
570 .len = umsg.len,
571 .buf = (__force __u8 *)compat_ptr(umsg.buf),
572 };
573 }
574
575 res = i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
576 kfree(rdwr_pa);
577 return res;
578 }
579 case I2C_SMBUS: {
580 struct i2c_smbus_ioctl_data32 data32;
581 if (copy_from_user(&data32,
582 (void __user *) arg,
583 sizeof(data32)))
584 return -EFAULT;
585 return i2cdev_ioctl_smbus(client, data32.read_write,
586 data32.command,
587 data32.size,
588 compat_ptr(data32.data));
589 }
590 default:
591 return i2cdev_ioctl(file, cmd, arg);
592 }
593}
594#else
595#define compat_i2cdev_ioctl NULL
596#endif
597
598static int i2cdev_open(struct inode *inode, struct file *file)
599{
600 unsigned int minor = iminor(inode);
601 struct i2c_client *client;
602 struct i2c_adapter *adap;
603
604 adap = i2c_get_adapter(minor);
605 if (!adap)
606 return -ENODEV;
607
608 /* This creates an anonymous i2c_client, which may later be
609 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
610 *
611 * This client is ** NEVER REGISTERED ** with the driver model
612 * or I2C core code!! It just holds private copies of addressing
613 * information and maybe a PEC flag.
614 */
615 client = kzalloc(sizeof(*client), GFP_KERNEL);
616 if (!client) {
617 i2c_put_adapter(adap);
618 return -ENOMEM;
619 }
620 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
621
622 client->adapter = adap;
623 file->private_data = client;
624
625 return 0;
626}
627
628static int i2cdev_release(struct inode *inode, struct file *file)
629{
630 struct i2c_client *client = file->private_data;
631
632 i2c_put_adapter(client->adapter);
633 kfree(client);
634 file->private_data = NULL;
635
636 return 0;
637}
638
639static const struct file_operations i2cdev_fops = {
640 .owner = THIS_MODULE,
641 .read = i2cdev_read,
642 .write = i2cdev_write,
643 .unlocked_ioctl = i2cdev_ioctl,
644 .compat_ioctl = compat_i2cdev_ioctl,
645 .open = i2cdev_open,
646 .release = i2cdev_release,
647};
648
649/* ------------------------------------------------------------------------- */
650
651static const struct class i2c_dev_class = {
652 .name = "i2c-dev",
653 .dev_groups = i2c_groups,
654};
655
656static void i2cdev_dev_release(struct device *dev)
657{
658 struct i2c_dev *i2c_dev;
659
660 i2c_dev = container_of(dev, struct i2c_dev, dev);
661 kfree(i2c_dev);
662}
663
664static int i2cdev_attach_adapter(struct device *dev)
665{
666 struct i2c_adapter *adap;
667 struct i2c_dev *i2c_dev;
668 int res;
669
670 if (dev->type != &i2c_adapter_type)
671 return NOTIFY_DONE;
672 adap = to_i2c_adapter(dev);
673
674 i2c_dev = get_free_i2c_dev(adap);
675 if (IS_ERR(i2c_dev))
676 return NOTIFY_DONE;
677
678 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
679 i2c_dev->cdev.owner = THIS_MODULE;
680
681 device_initialize(&i2c_dev->dev);
682 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
683 i2c_dev->dev.class = &i2c_dev_class;
684 i2c_dev->dev.parent = &adap->dev;
685 i2c_dev->dev.release = i2cdev_dev_release;
686
687 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
688 if (res)
689 goto err_put_i2c_dev;
690
691 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
692 if (res)
693 goto err_put_i2c_dev;
694
695 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
696 return NOTIFY_OK;
697
698err_put_i2c_dev:
699 put_i2c_dev(i2c_dev, false);
700 return NOTIFY_DONE;
701}
702
703static int i2cdev_detach_adapter(struct device *dev)
704{
705 struct i2c_adapter *adap;
706 struct i2c_dev *i2c_dev;
707
708 if (dev->type != &i2c_adapter_type)
709 return NOTIFY_DONE;
710 adap = to_i2c_adapter(dev);
711
712 i2c_dev = i2c_dev_get_by_minor(adap->nr);
713 if (!i2c_dev) /* attach_adapter must have failed */
714 return NOTIFY_DONE;
715
716 put_i2c_dev(i2c_dev, true);
717
718 pr_debug("adapter [%s] unregistered\n", adap->name);
719 return NOTIFY_OK;
720}
721
722static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
723 void *data)
724{
725 struct device *dev = data;
726
727 switch (action) {
728 case BUS_NOTIFY_ADD_DEVICE:
729 return i2cdev_attach_adapter(dev);
730 case BUS_NOTIFY_DEL_DEVICE:
731 return i2cdev_detach_adapter(dev);
732 }
733
734 return NOTIFY_DONE;
735}
736
737static struct notifier_block i2cdev_notifier = {
738 .notifier_call = i2cdev_notifier_call,
739};
740
741/* ------------------------------------------------------------------------- */
742
743static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy)
744{
745 i2cdev_attach_adapter(dev);
746 return 0;
747}
748
749static int __exit i2c_dev_detach_adapter(struct device *dev, void *dummy)
750{
751 i2cdev_detach_adapter(dev);
752 return 0;
753}
754
755/*
756 * module load/unload record keeping
757 */
758
759static int __init i2c_dev_init(void)
760{
761 int res;
762
763 pr_info("i2c /dev entries driver\n");
764
765 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
766 if (res)
767 goto out;
768
769 res = class_register(&i2c_dev_class);
770 if (res)
771 goto out_unreg_chrdev;
772
773 /* Keep track of adapters which will be added or removed later */
774 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
775 if (res)
776 goto out_unreg_class;
777
778 /* Bind to already existing adapters right away */
779 i2c_for_each_dev(NULL, i2c_dev_attach_adapter);
780
781 return 0;
782
783out_unreg_class:
784 class_unregister(&i2c_dev_class);
785out_unreg_chrdev:
786 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
787out:
788 pr_err("Driver Initialisation failed\n");
789 return res;
790}
791
792static void __exit i2c_dev_exit(void)
793{
794 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
795 i2c_for_each_dev(NULL, i2c_dev_detach_adapter);
796 class_unregister(&i2c_dev_class);
797 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
798}
799
800MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
801MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
802MODULE_DESCRIPTION("I2C /dev entries driver");
803MODULE_LICENSE("GPL");
804
805module_init(i2c_dev_init);
806module_exit(i2c_dev_exit);