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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// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 i2c-dev.c - i2c-bus driver, char device interface
4
5 Copyright (C) 1995-97 Simon G. Vogl
6 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
7 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
8
9*/
10
11/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
12 But I have used so much of his original code and ideas that it seems
13 only fair to recognize him as co-author -- Frodo */
14
15/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
16
17#include <linux/cdev.h>
18#include <linux/compat.h>
19#include <linux/device.h>
20#include <linux/fs.h>
21#include <linux/i2c-dev.h>
22#include <linux/i2c.h>
23#include <linux/init.h>
24#include <linux/jiffies.h>
25#include <linux/kernel.h>
26#include <linux/list.h>
27#include <linux/module.h>
28#include <linux/notifier.h>
29#include <linux/slab.h>
30#include <linux/uaccess.h>
31
32/*
33 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
34 * slave (i2c_client) with which messages will be exchanged. It's coupled
35 * with a character special file which is accessed by user mode drivers.
36 *
37 * The list of i2c_dev structures is parallel to the i2c_adapter lists
38 * maintained by the driver model, and is updated using bus notifications.
39 */
40struct i2c_dev {
41 struct list_head list;
42 struct i2c_adapter *adap;
43 struct device dev;
44 struct cdev cdev;
45};
46
47#define I2C_MINORS (MINORMASK + 1)
48static LIST_HEAD(i2c_dev_list);
49static DEFINE_SPINLOCK(i2c_dev_list_lock);
50
51static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
52{
53 struct i2c_dev *i2c_dev;
54
55 spin_lock(&i2c_dev_list_lock);
56 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
57 if (i2c_dev->adap->nr == index)
58 goto found;
59 }
60 i2c_dev = NULL;
61found:
62 spin_unlock(&i2c_dev_list_lock);
63 return i2c_dev;
64}
65
66static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
67{
68 struct i2c_dev *i2c_dev;
69
70 if (adap->nr >= I2C_MINORS) {
71 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
72 adap->nr);
73 return ERR_PTR(-ENODEV);
74 }
75
76 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
77 if (!i2c_dev)
78 return ERR_PTR(-ENOMEM);
79 i2c_dev->adap = adap;
80
81 spin_lock(&i2c_dev_list_lock);
82 list_add_tail(&i2c_dev->list, &i2c_dev_list);
83 spin_unlock(&i2c_dev_list_lock);
84 return i2c_dev;
85}
86
87static void put_i2c_dev(struct i2c_dev *i2c_dev, bool del_cdev)
88{
89 spin_lock(&i2c_dev_list_lock);
90 list_del(&i2c_dev->list);
91 spin_unlock(&i2c_dev_list_lock);
92 if (del_cdev)
93 cdev_device_del(&i2c_dev->cdev, &i2c_dev->dev);
94 put_device(&i2c_dev->dev);
95}
96
97static ssize_t name_show(struct device *dev,
98 struct device_attribute *attr, char *buf)
99{
100 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
101
102 if (!i2c_dev)
103 return -ENODEV;
104 return sprintf(buf, "%s\n", i2c_dev->adap->name);
105}
106static DEVICE_ATTR_RO(name);
107
108static struct attribute *i2c_attrs[] = {
109 &dev_attr_name.attr,
110 NULL,
111};
112ATTRIBUTE_GROUPS(i2c);
113
114/* ------------------------------------------------------------------------- */
115
116/*
117 * After opening an instance of this character special file, a file
118 * descriptor starts out associated only with an i2c_adapter (and bus).
119 *
120 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
121 * traffic to any devices on the bus used by that adapter. That's because
122 * the i2c_msg vectors embed all the addressing information they need, and
123 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
124 * don't support that interface.
125 *
126 * To use read()/write() system calls on that file descriptor, or to use
127 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
128 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
129 * (never registered) i2c_client so it holds the addressing information
130 * needed by those system calls and by this SMBus interface.
131 */
132
133static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
134 loff_t *offset)
135{
136 char *tmp;
137 int ret;
138
139 struct i2c_client *client = file->private_data;
140
141 if (count > 8192)
142 count = 8192;
143
144 tmp = kzalloc(count, GFP_KERNEL);
145 if (tmp == NULL)
146 return -ENOMEM;
147
148 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
149 iminor(file_inode(file)), count);
150
151 ret = i2c_master_recv(client, tmp, count);
152 if (ret >= 0)
153 if (copy_to_user(buf, tmp, ret))
154 ret = -EFAULT;
155 kfree(tmp);
156 return ret;
157}
158
159static ssize_t i2cdev_write(struct file *file, const char __user *buf,
160 size_t count, loff_t *offset)
161{
162 int ret;
163 char *tmp;
164 struct i2c_client *client = file->private_data;
165
166 if (count > 8192)
167 count = 8192;
168
169 tmp = memdup_user(buf, count);
170 if (IS_ERR(tmp))
171 return PTR_ERR(tmp);
172
173 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
174 iminor(file_inode(file)), count);
175
176 ret = i2c_master_send(client, tmp, count);
177 kfree(tmp);
178 return ret;
179}
180
181static int i2cdev_check(struct device *dev, void *addrp)
182{
183 struct i2c_client *client = i2c_verify_client(dev);
184
185 if (!client || client->addr != *(unsigned int *)addrp)
186 return 0;
187
188 return dev->driver ? -EBUSY : 0;
189}
190
191/* walk up mux tree */
192static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
193{
194 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
195 int result;
196
197 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
198 if (!result && parent)
199 result = i2cdev_check_mux_parents(parent, addr);
200
201 return result;
202}
203
204/* recurse down mux tree */
205static int i2cdev_check_mux_children(struct device *dev, void *addrp)
206{
207 int result;
208
209 if (dev->type == &i2c_adapter_type)
210 result = device_for_each_child(dev, addrp,
211 i2cdev_check_mux_children);
212 else
213 result = i2cdev_check(dev, addrp);
214
215 return result;
216}
217
218/* This address checking function differs from the one in i2c-core
219 in that it considers an address with a registered device, but no
220 driver bound to it, as NOT busy. */
221static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
222{
223 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
224 int result = 0;
225
226 if (parent)
227 result = i2cdev_check_mux_parents(parent, addr);
228
229 if (!result)
230 result = device_for_each_child(&adapter->dev, &addr,
231 i2cdev_check_mux_children);
232
233 return result;
234}
235
236static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
237 unsigned nmsgs, struct i2c_msg *msgs)
238{
239 u8 __user **data_ptrs;
240 int i, res;
241
242 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
243 if (data_ptrs == NULL) {
244 kfree(msgs);
245 return -ENOMEM;
246 }
247
248 res = 0;
249 for (i = 0; i < nmsgs; i++) {
250 /* Limit the size of the message to a sane amount */
251 if (msgs[i].len > 8192) {
252 res = -EINVAL;
253 break;
254 }
255
256 data_ptrs[i] = (u8 __user *)msgs[i].buf;
257 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
258 if (IS_ERR(msgs[i].buf)) {
259 res = PTR_ERR(msgs[i].buf);
260 break;
261 }
262 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
263 msgs[i].flags |= I2C_M_DMA_SAFE;
264
265 /*
266 * If the message length is received from the slave (similar
267 * to SMBus block read), we must ensure that the buffer will
268 * be large enough to cope with a message length of
269 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
270 * drivers allow. The first byte in the buffer must be
271 * pre-filled with the number of extra bytes, which must be
272 * at least one to hold the message length, but can be
273 * greater (for example to account for a checksum byte at
274 * the end of the message.)
275 */
276 if (msgs[i].flags & I2C_M_RECV_LEN) {
277 if (!(msgs[i].flags & I2C_M_RD) ||
278 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
279 msgs[i].len < msgs[i].buf[0] +
280 I2C_SMBUS_BLOCK_MAX) {
281 i++;
282 res = -EINVAL;
283 break;
284 }
285
286 msgs[i].len = msgs[i].buf[0];
287 }
288 }
289 if (res < 0) {
290 int j;
291 for (j = 0; j < i; ++j)
292 kfree(msgs[j].buf);
293 kfree(data_ptrs);
294 kfree(msgs);
295 return res;
296 }
297
298 res = i2c_transfer(client->adapter, msgs, nmsgs);
299 while (i-- > 0) {
300 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
301 if (copy_to_user(data_ptrs[i], msgs[i].buf,
302 msgs[i].len))
303 res = -EFAULT;
304 }
305 kfree(msgs[i].buf);
306 }
307 kfree(data_ptrs);
308 kfree(msgs);
309 return res;
310}
311
312static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
313 u8 read_write, u8 command, u32 size,
314 union i2c_smbus_data __user *data)
315{
316 union i2c_smbus_data temp = {};
317 int datasize, res;
318
319 if ((size != I2C_SMBUS_BYTE) &&
320 (size != I2C_SMBUS_QUICK) &&
321 (size != I2C_SMBUS_BYTE_DATA) &&
322 (size != I2C_SMBUS_WORD_DATA) &&
323 (size != I2C_SMBUS_PROC_CALL) &&
324 (size != I2C_SMBUS_BLOCK_DATA) &&
325 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
326 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
327 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
328 dev_dbg(&client->adapter->dev,
329 "size out of range (%x) in ioctl I2C_SMBUS.\n",
330 size);
331 return -EINVAL;
332 }
333 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
334 so the check is valid if size==I2C_SMBUS_QUICK too. */
335 if ((read_write != I2C_SMBUS_READ) &&
336 (read_write != I2C_SMBUS_WRITE)) {
337 dev_dbg(&client->adapter->dev,
338 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
339 read_write);
340 return -EINVAL;
341 }
342
343 /* Note that command values are always valid! */
344
345 if ((size == I2C_SMBUS_QUICK) ||
346 ((size == I2C_SMBUS_BYTE) &&
347 (read_write == I2C_SMBUS_WRITE)))
348 /* These are special: we do not use data */
349 return i2c_smbus_xfer(client->adapter, client->addr,
350 client->flags, read_write,
351 command, size, NULL);
352
353 if (data == NULL) {
354 dev_dbg(&client->adapter->dev,
355 "data is NULL pointer in ioctl I2C_SMBUS.\n");
356 return -EINVAL;
357 }
358
359 if ((size == I2C_SMBUS_BYTE_DATA) ||
360 (size == I2C_SMBUS_BYTE))
361 datasize = sizeof(data->byte);
362 else if ((size == I2C_SMBUS_WORD_DATA) ||
363 (size == I2C_SMBUS_PROC_CALL))
364 datasize = sizeof(data->word);
365 else /* size == smbus block, i2c block, or block proc. call */
366 datasize = sizeof(data->block);
367
368 if ((size == I2C_SMBUS_PROC_CALL) ||
369 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
370 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
371 (read_write == I2C_SMBUS_WRITE)) {
372 if (copy_from_user(&temp, data, datasize))
373 return -EFAULT;
374 }
375 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
376 /* Convert old I2C block commands to the new
377 convention. This preserves binary compatibility. */
378 size = I2C_SMBUS_I2C_BLOCK_DATA;
379 if (read_write == I2C_SMBUS_READ)
380 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
381 }
382 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
383 read_write, command, size, &temp);
384 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
385 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
386 (read_write == I2C_SMBUS_READ))) {
387 if (copy_to_user(data, &temp, datasize))
388 return -EFAULT;
389 }
390 return res;
391}
392
393static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
394{
395 struct i2c_client *client = file->private_data;
396 unsigned long funcs;
397
398 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
399 cmd, arg);
400
401 switch (cmd) {
402 case I2C_SLAVE:
403 case I2C_SLAVE_FORCE:
404 if ((arg > 0x3ff) ||
405 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
406 return -EINVAL;
407 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
408 return -EBUSY;
409 /* REVISIT: address could become busy later */
410 client->addr = arg;
411 return 0;
412 case I2C_TENBIT:
413 if (arg)
414 client->flags |= I2C_M_TEN;
415 else
416 client->flags &= ~I2C_M_TEN;
417 return 0;
418 case I2C_PEC:
419 /*
420 * Setting the PEC flag here won't affect kernel drivers,
421 * which will be using the i2c_client node registered with
422 * the driver model core. Likewise, when that client has
423 * the PEC flag already set, the i2c-dev driver won't see
424 * (or use) this setting.
425 */
426 if (arg)
427 client->flags |= I2C_CLIENT_PEC;
428 else
429 client->flags &= ~I2C_CLIENT_PEC;
430 return 0;
431 case I2C_FUNCS:
432 funcs = i2c_get_functionality(client->adapter);
433 return put_user(funcs, (unsigned long __user *)arg);
434
435 case I2C_RDWR: {
436 struct i2c_rdwr_ioctl_data rdwr_arg;
437 struct i2c_msg *rdwr_pa;
438
439 if (copy_from_user(&rdwr_arg,
440 (struct i2c_rdwr_ioctl_data __user *)arg,
441 sizeof(rdwr_arg)))
442 return -EFAULT;
443
444 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
445 return -EINVAL;
446
447 /*
448 * Put an arbitrary limit on the number of messages that can
449 * be sent at once
450 */
451 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
452 return -EINVAL;
453
454 rdwr_pa = memdup_user(rdwr_arg.msgs,
455 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
456 if (IS_ERR(rdwr_pa))
457 return PTR_ERR(rdwr_pa);
458
459 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
460 }
461
462 case I2C_SMBUS: {
463 struct i2c_smbus_ioctl_data data_arg;
464 if (copy_from_user(&data_arg,
465 (struct i2c_smbus_ioctl_data __user *) arg,
466 sizeof(struct i2c_smbus_ioctl_data)))
467 return -EFAULT;
468 return i2cdev_ioctl_smbus(client, data_arg.read_write,
469 data_arg.command,
470 data_arg.size,
471 data_arg.data);
472 }
473 case I2C_RETRIES:
474 if (arg > INT_MAX)
475 return -EINVAL;
476
477 client->adapter->retries = arg;
478 break;
479 case I2C_TIMEOUT:
480 if (arg > INT_MAX)
481 return -EINVAL;
482
483 /* For historical reasons, user-space sets the timeout
484 * value in units of 10 ms.
485 */
486 client->adapter->timeout = msecs_to_jiffies(arg * 10);
487 break;
488 default:
489 /* NOTE: returning a fault code here could cause trouble
490 * in buggy userspace code. Some old kernel bugs returned
491 * zero in this case, and userspace code might accidentally
492 * have depended on that bug.
493 */
494 return -ENOTTY;
495 }
496 return 0;
497}
498
499#ifdef CONFIG_COMPAT
500
501struct i2c_smbus_ioctl_data32 {
502 u8 read_write;
503 u8 command;
504 u32 size;
505 compat_caddr_t data; /* union i2c_smbus_data *data */
506};
507
508struct i2c_msg32 {
509 u16 addr;
510 u16 flags;
511 u16 len;
512 compat_caddr_t buf;
513};
514
515struct i2c_rdwr_ioctl_data32 {
516 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
517 u32 nmsgs;
518};
519
520static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
521{
522 struct i2c_client *client = file->private_data;
523 unsigned long funcs;
524 switch (cmd) {
525 case I2C_FUNCS:
526 funcs = i2c_get_functionality(client->adapter);
527 return put_user(funcs, (compat_ulong_t __user *)arg);
528 case I2C_RDWR: {
529 struct i2c_rdwr_ioctl_data32 rdwr_arg;
530 struct i2c_msg32 __user *p;
531 struct i2c_msg *rdwr_pa;
532 int i;
533
534 if (copy_from_user(&rdwr_arg,
535 (struct i2c_rdwr_ioctl_data32 __user *)arg,
536 sizeof(rdwr_arg)))
537 return -EFAULT;
538
539 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
540 return -EINVAL;
541
542 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
543 GFP_KERNEL);
544 if (!rdwr_pa)
545 return -ENOMEM;
546
547 p = compat_ptr(rdwr_arg.msgs);
548 for (i = 0; i < rdwr_arg.nmsgs; i++) {
549 struct i2c_msg32 umsg;
550 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
551 kfree(rdwr_pa);
552 return -EFAULT;
553 }
554 rdwr_pa[i] = (struct i2c_msg) {
555 .addr = umsg.addr,
556 .flags = umsg.flags,
557 .len = umsg.len,
558 .buf = compat_ptr(umsg.buf)
559 };
560 }
561
562 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
563 }
564 case I2C_SMBUS: {
565 struct i2c_smbus_ioctl_data32 data32;
566 if (copy_from_user(&data32,
567 (void __user *) arg,
568 sizeof(data32)))
569 return -EFAULT;
570 return i2cdev_ioctl_smbus(client, data32.read_write,
571 data32.command,
572 data32.size,
573 compat_ptr(data32.data));
574 }
575 default:
576 return i2cdev_ioctl(file, cmd, arg);
577 }
578}
579#else
580#define compat_i2cdev_ioctl NULL
581#endif
582
583static int i2cdev_open(struct inode *inode, struct file *file)
584{
585 unsigned int minor = iminor(inode);
586 struct i2c_client *client;
587 struct i2c_adapter *adap;
588
589 adap = i2c_get_adapter(minor);
590 if (!adap)
591 return -ENODEV;
592
593 /* This creates an anonymous i2c_client, which may later be
594 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
595 *
596 * This client is ** NEVER REGISTERED ** with the driver model
597 * or I2C core code!! It just holds private copies of addressing
598 * information and maybe a PEC flag.
599 */
600 client = kzalloc(sizeof(*client), GFP_KERNEL);
601 if (!client) {
602 i2c_put_adapter(adap);
603 return -ENOMEM;
604 }
605 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
606
607 client->adapter = adap;
608 file->private_data = client;
609
610 return 0;
611}
612
613static int i2cdev_release(struct inode *inode, struct file *file)
614{
615 struct i2c_client *client = file->private_data;
616
617 i2c_put_adapter(client->adapter);
618 kfree(client);
619 file->private_data = NULL;
620
621 return 0;
622}
623
624static const struct file_operations i2cdev_fops = {
625 .owner = THIS_MODULE,
626 .llseek = no_llseek,
627 .read = i2cdev_read,
628 .write = i2cdev_write,
629 .unlocked_ioctl = i2cdev_ioctl,
630 .compat_ioctl = compat_i2cdev_ioctl,
631 .open = i2cdev_open,
632 .release = i2cdev_release,
633};
634
635/* ------------------------------------------------------------------------- */
636
637static struct class *i2c_dev_class;
638
639static void i2cdev_dev_release(struct device *dev)
640{
641 struct i2c_dev *i2c_dev;
642
643 i2c_dev = container_of(dev, struct i2c_dev, dev);
644 kfree(i2c_dev);
645}
646
647static int i2cdev_attach_adapter(struct device *dev, void *dummy)
648{
649 struct i2c_adapter *adap;
650 struct i2c_dev *i2c_dev;
651 int res;
652
653 if (dev->type != &i2c_adapter_type)
654 return 0;
655 adap = to_i2c_adapter(dev);
656
657 i2c_dev = get_free_i2c_dev(adap);
658 if (IS_ERR(i2c_dev))
659 return PTR_ERR(i2c_dev);
660
661 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
662 i2c_dev->cdev.owner = THIS_MODULE;
663
664 device_initialize(&i2c_dev->dev);
665 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
666 i2c_dev->dev.class = i2c_dev_class;
667 i2c_dev->dev.parent = &adap->dev;
668 i2c_dev->dev.release = i2cdev_dev_release;
669 dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
670
671 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
672 if (res) {
673 put_i2c_dev(i2c_dev, false);
674 return res;
675 }
676
677 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
678 adap->name, adap->nr);
679 return 0;
680}
681
682static int i2cdev_detach_adapter(struct device *dev, void *dummy)
683{
684 struct i2c_adapter *adap;
685 struct i2c_dev *i2c_dev;
686
687 if (dev->type != &i2c_adapter_type)
688 return 0;
689 adap = to_i2c_adapter(dev);
690
691 i2c_dev = i2c_dev_get_by_minor(adap->nr);
692 if (!i2c_dev) /* attach_adapter must have failed */
693 return 0;
694
695 put_i2c_dev(i2c_dev, true);
696
697 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
698 return 0;
699}
700
701static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
702 void *data)
703{
704 struct device *dev = data;
705
706 switch (action) {
707 case BUS_NOTIFY_ADD_DEVICE:
708 return i2cdev_attach_adapter(dev, NULL);
709 case BUS_NOTIFY_DEL_DEVICE:
710 return i2cdev_detach_adapter(dev, NULL);
711 }
712
713 return 0;
714}
715
716static struct notifier_block i2cdev_notifier = {
717 .notifier_call = i2cdev_notifier_call,
718};
719
720/* ------------------------------------------------------------------------- */
721
722/*
723 * module load/unload record keeping
724 */
725
726static int __init i2c_dev_init(void)
727{
728 int res;
729
730 printk(KERN_INFO "i2c /dev entries driver\n");
731
732 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
733 if (res)
734 goto out;
735
736 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
737 if (IS_ERR(i2c_dev_class)) {
738 res = PTR_ERR(i2c_dev_class);
739 goto out_unreg_chrdev;
740 }
741 i2c_dev_class->dev_groups = i2c_groups;
742
743 /* Keep track of adapters which will be added or removed later */
744 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
745 if (res)
746 goto out_unreg_class;
747
748 /* Bind to already existing adapters right away */
749 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
750
751 return 0;
752
753out_unreg_class:
754 class_destroy(i2c_dev_class);
755out_unreg_chrdev:
756 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
757out:
758 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
759 return res;
760}
761
762static void __exit i2c_dev_exit(void)
763{
764 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
765 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
766 class_destroy(i2c_dev_class);
767 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
768}
769
770MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
771MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
772MODULE_DESCRIPTION("I2C /dev entries driver");
773MODULE_LICENSE("GPL");
774
775module_init(i2c_dev_init);
776module_exit(i2c_dev_exit);