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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#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 if (count > 8192)
143 count = 8192;
144
145 tmp = kzalloc(count, GFP_KERNEL);
146 if (tmp == NULL)
147 return -ENOMEM;
148
149 pr_debug("i2c-%d reading %zu bytes.\n", 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-%d writing %zu bytes.\n", 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 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
444 return -EINVAL;
445
446 /*
447 * Put an arbitrary limit on the number of messages that can
448 * be sent at once
449 */
450 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
451 return -EINVAL;
452
453 rdwr_pa = memdup_array_user(rdwr_arg.msgs,
454 rdwr_arg.nmsgs, sizeof(struct i2c_msg));
455 if (IS_ERR(rdwr_pa))
456 return PTR_ERR(rdwr_pa);
457
458 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
459 }
460
461 case I2C_SMBUS: {
462 struct i2c_smbus_ioctl_data data_arg;
463 if (copy_from_user(&data_arg,
464 (struct i2c_smbus_ioctl_data __user *) arg,
465 sizeof(struct i2c_smbus_ioctl_data)))
466 return -EFAULT;
467 return i2cdev_ioctl_smbus(client, data_arg.read_write,
468 data_arg.command,
469 data_arg.size,
470 data_arg.data);
471 }
472 case I2C_RETRIES:
473 if (arg > INT_MAX)
474 return -EINVAL;
475
476 client->adapter->retries = arg;
477 break;
478 case I2C_TIMEOUT:
479 if (arg > INT_MAX)
480 return -EINVAL;
481
482 /* For historical reasons, user-space sets the timeout
483 * value in units of 10 ms.
484 */
485 client->adapter->timeout = msecs_to_jiffies(arg * 10);
486 break;
487 default:
488 /* NOTE: returning a fault code here could cause trouble
489 * in buggy userspace code. Some old kernel bugs returned
490 * zero in this case, and userspace code might accidentally
491 * have depended on that bug.
492 */
493 return -ENOTTY;
494 }
495 return 0;
496}
497
498#ifdef CONFIG_COMPAT
499
500struct i2c_smbus_ioctl_data32 {
501 u8 read_write;
502 u8 command;
503 u32 size;
504 compat_caddr_t data; /* union i2c_smbus_data *data */
505};
506
507struct i2c_msg32 {
508 u16 addr;
509 u16 flags;
510 u16 len;
511 compat_caddr_t buf;
512};
513
514struct i2c_rdwr_ioctl_data32 {
515 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
516 u32 nmsgs;
517};
518
519static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
520{
521 struct i2c_client *client = file->private_data;
522 unsigned long funcs;
523 switch (cmd) {
524 case I2C_FUNCS:
525 funcs = i2c_get_functionality(client->adapter);
526 return put_user(funcs, (compat_ulong_t __user *)arg);
527 case I2C_RDWR: {
528 struct i2c_rdwr_ioctl_data32 rdwr_arg;
529 struct i2c_msg32 __user *p;
530 struct i2c_msg *rdwr_pa;
531 int i;
532
533 if (copy_from_user(&rdwr_arg,
534 (struct i2c_rdwr_ioctl_data32 __user *)arg,
535 sizeof(rdwr_arg)))
536 return -EFAULT;
537
538 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
539 return -EINVAL;
540
541 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
542 return -EINVAL;
543
544 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
545 GFP_KERNEL);
546 if (!rdwr_pa)
547 return -ENOMEM;
548
549 p = compat_ptr(rdwr_arg.msgs);
550 for (i = 0; i < rdwr_arg.nmsgs; i++) {
551 struct i2c_msg32 umsg;
552 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
553 kfree(rdwr_pa);
554 return -EFAULT;
555 }
556 rdwr_pa[i] = (struct i2c_msg) {
557 .addr = umsg.addr,
558 .flags = umsg.flags,
559 .len = umsg.len,
560 .buf = (__force __u8 *)compat_ptr(umsg.buf),
561 };
562 }
563
564 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
565 }
566 case I2C_SMBUS: {
567 struct i2c_smbus_ioctl_data32 data32;
568 if (copy_from_user(&data32,
569 (void __user *) arg,
570 sizeof(data32)))
571 return -EFAULT;
572 return i2cdev_ioctl_smbus(client, data32.read_write,
573 data32.command,
574 data32.size,
575 compat_ptr(data32.data));
576 }
577 default:
578 return i2cdev_ioctl(file, cmd, arg);
579 }
580}
581#else
582#define compat_i2cdev_ioctl NULL
583#endif
584
585static int i2cdev_open(struct inode *inode, struct file *file)
586{
587 unsigned int minor = iminor(inode);
588 struct i2c_client *client;
589 struct i2c_adapter *adap;
590
591 adap = i2c_get_adapter(minor);
592 if (!adap)
593 return -ENODEV;
594
595 /* This creates an anonymous i2c_client, which may later be
596 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
597 *
598 * This client is ** NEVER REGISTERED ** with the driver model
599 * or I2C core code!! It just holds private copies of addressing
600 * information and maybe a PEC flag.
601 */
602 client = kzalloc(sizeof(*client), GFP_KERNEL);
603 if (!client) {
604 i2c_put_adapter(adap);
605 return -ENOMEM;
606 }
607 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
608
609 client->adapter = adap;
610 file->private_data = client;
611
612 return 0;
613}
614
615static int i2cdev_release(struct inode *inode, struct file *file)
616{
617 struct i2c_client *client = file->private_data;
618
619 i2c_put_adapter(client->adapter);
620 kfree(client);
621 file->private_data = NULL;
622
623 return 0;
624}
625
626static const struct file_operations i2cdev_fops = {
627 .owner = THIS_MODULE,
628 .llseek = no_llseek,
629 .read = i2cdev_read,
630 .write = i2cdev_write,
631 .unlocked_ioctl = i2cdev_ioctl,
632 .compat_ioctl = compat_i2cdev_ioctl,
633 .open = i2cdev_open,
634 .release = i2cdev_release,
635};
636
637/* ------------------------------------------------------------------------- */
638
639static const struct class i2c_dev_class = {
640 .name = "i2c-dev",
641 .dev_groups = i2c_groups,
642};
643
644static void i2cdev_dev_release(struct device *dev)
645{
646 struct i2c_dev *i2c_dev;
647
648 i2c_dev = container_of(dev, struct i2c_dev, dev);
649 kfree(i2c_dev);
650}
651
652static int i2cdev_attach_adapter(struct device *dev)
653{
654 struct i2c_adapter *adap;
655 struct i2c_dev *i2c_dev;
656 int res;
657
658 if (dev->type != &i2c_adapter_type)
659 return NOTIFY_DONE;
660 adap = to_i2c_adapter(dev);
661
662 i2c_dev = get_free_i2c_dev(adap);
663 if (IS_ERR(i2c_dev))
664 return NOTIFY_DONE;
665
666 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
667 i2c_dev->cdev.owner = THIS_MODULE;
668
669 device_initialize(&i2c_dev->dev);
670 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
671 i2c_dev->dev.class = &i2c_dev_class;
672 i2c_dev->dev.parent = &adap->dev;
673 i2c_dev->dev.release = i2cdev_dev_release;
674
675 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
676 if (res)
677 goto err_put_i2c_dev;
678
679 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
680 if (res)
681 goto err_put_i2c_dev;
682
683 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
684 return NOTIFY_OK;
685
686err_put_i2c_dev:
687 put_i2c_dev(i2c_dev, false);
688 return NOTIFY_DONE;
689}
690
691static int i2cdev_detach_adapter(struct device *dev)
692{
693 struct i2c_adapter *adap;
694 struct i2c_dev *i2c_dev;
695
696 if (dev->type != &i2c_adapter_type)
697 return NOTIFY_DONE;
698 adap = to_i2c_adapter(dev);
699
700 i2c_dev = i2c_dev_get_by_minor(adap->nr);
701 if (!i2c_dev) /* attach_adapter must have failed */
702 return NOTIFY_DONE;
703
704 put_i2c_dev(i2c_dev, true);
705
706 pr_debug("adapter [%s] unregistered\n", adap->name);
707 return NOTIFY_OK;
708}
709
710static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
711 void *data)
712{
713 struct device *dev = data;
714
715 switch (action) {
716 case BUS_NOTIFY_ADD_DEVICE:
717 return i2cdev_attach_adapter(dev);
718 case BUS_NOTIFY_DEL_DEVICE:
719 return i2cdev_detach_adapter(dev);
720 }
721
722 return NOTIFY_DONE;
723}
724
725static struct notifier_block i2cdev_notifier = {
726 .notifier_call = i2cdev_notifier_call,
727};
728
729/* ------------------------------------------------------------------------- */
730
731static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy)
732{
733 i2cdev_attach_adapter(dev);
734 return 0;
735}
736
737static int __exit i2c_dev_detach_adapter(struct device *dev, void *dummy)
738{
739 i2cdev_detach_adapter(dev);
740 return 0;
741}
742
743/*
744 * module load/unload record keeping
745 */
746
747static int __init i2c_dev_init(void)
748{
749 int res;
750
751 pr_info("i2c /dev entries driver\n");
752
753 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
754 if (res)
755 goto out;
756
757 res = class_register(&i2c_dev_class);
758 if (res)
759 goto out_unreg_chrdev;
760
761 /* Keep track of adapters which will be added or removed later */
762 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
763 if (res)
764 goto out_unreg_class;
765
766 /* Bind to already existing adapters right away */
767 i2c_for_each_dev(NULL, i2c_dev_attach_adapter);
768
769 return 0;
770
771out_unreg_class:
772 class_unregister(&i2c_dev_class);
773out_unreg_chrdev:
774 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
775out:
776 pr_err("Driver Initialisation failed\n");
777 return res;
778}
779
780static void __exit i2c_dev_exit(void)
781{
782 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
783 i2c_for_each_dev(NULL, i2c_dev_detach_adapter);
784 class_unregister(&i2c_dev_class);
785 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
786}
787
788MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
789MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
790MODULE_DESCRIPTION("I2C /dev entries driver");
791MODULE_LICENSE("GPL");
792
793module_init(i2c_dev_init);
794module_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/device.h>
19#include <linux/fs.h>
20#include <linux/i2c-dev.h>
21#include <linux/i2c.h>
22#include <linux/init.h>
23#include <linux/jiffies.h>
24#include <linux/kernel.h>
25#include <linux/list.h>
26#include <linux/module.h>
27#include <linux/notifier.h>
28#include <linux/slab.h>
29#include <linux/uaccess.h>
30#include <linux/compat.h>
31
32/*
33 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
34 * slave (i2c_client) with which messages will be exchanged. It's coupled
35 * with a character special file which is accessed by user mode drivers.
36 *
37 * The list of i2c_dev structures is parallel to the i2c_adapter lists
38 * maintained by the driver model, and is updated using bus notifications.
39 */
40struct i2c_dev {
41 struct list_head list;
42 struct i2c_adapter *adap;
43 struct device *dev;
44 struct cdev cdev;
45};
46
47#define I2C_MINORS (MINORMASK + 1)
48static LIST_HEAD(i2c_dev_list);
49static DEFINE_SPINLOCK(i2c_dev_list_lock);
50
51static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
52{
53 struct i2c_dev *i2c_dev;
54
55 spin_lock(&i2c_dev_list_lock);
56 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
57 if (i2c_dev->adap->nr == index)
58 goto found;
59 }
60 i2c_dev = NULL;
61found:
62 spin_unlock(&i2c_dev_list_lock);
63 return i2c_dev;
64}
65
66static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
67{
68 struct i2c_dev *i2c_dev;
69
70 if (adap->nr >= I2C_MINORS) {
71 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
72 adap->nr);
73 return ERR_PTR(-ENODEV);
74 }
75
76 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
77 if (!i2c_dev)
78 return ERR_PTR(-ENOMEM);
79 i2c_dev->adap = adap;
80
81 spin_lock(&i2c_dev_list_lock);
82 list_add_tail(&i2c_dev->list, &i2c_dev_list);
83 spin_unlock(&i2c_dev_list_lock);
84 return i2c_dev;
85}
86
87static void put_i2c_dev(struct i2c_dev *i2c_dev)
88{
89 spin_lock(&i2c_dev_list_lock);
90 list_del(&i2c_dev->list);
91 spin_unlock(&i2c_dev_list_lock);
92 kfree(i2c_dev);
93}
94
95static ssize_t name_show(struct device *dev,
96 struct device_attribute *attr, char *buf)
97{
98 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
99
100 if (!i2c_dev)
101 return -ENODEV;
102 return sprintf(buf, "%s\n", i2c_dev->adap->name);
103}
104static DEVICE_ATTR_RO(name);
105
106static struct attribute *i2c_attrs[] = {
107 &dev_attr_name.attr,
108 NULL,
109};
110ATTRIBUTE_GROUPS(i2c);
111
112/* ------------------------------------------------------------------------- */
113
114/*
115 * After opening an instance of this character special file, a file
116 * descriptor starts out associated only with an i2c_adapter (and bus).
117 *
118 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
119 * traffic to any devices on the bus used by that adapter. That's because
120 * the i2c_msg vectors embed all the addressing information they need, and
121 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
122 * don't support that interface.
123 *
124 * To use read()/write() system calls on that file descriptor, or to use
125 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
126 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
127 * (never registered) i2c_client so it holds the addressing information
128 * needed by those system calls and by this SMBus interface.
129 */
130
131static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
132 loff_t *offset)
133{
134 char *tmp;
135 int ret;
136
137 struct i2c_client *client = file->private_data;
138
139 if (count > 8192)
140 count = 8192;
141
142 tmp = kmalloc(count, GFP_KERNEL);
143 if (tmp == NULL)
144 return -ENOMEM;
145
146 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
147 iminor(file_inode(file)), count);
148
149 ret = i2c_master_recv(client, tmp, count);
150 if (ret >= 0)
151 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
152 kfree(tmp);
153 return ret;
154}
155
156static ssize_t i2cdev_write(struct file *file, const char __user *buf,
157 size_t count, loff_t *offset)
158{
159 int ret;
160 char *tmp;
161 struct i2c_client *client = file->private_data;
162
163 if (count > 8192)
164 count = 8192;
165
166 tmp = memdup_user(buf, count);
167 if (IS_ERR(tmp))
168 return PTR_ERR(tmp);
169
170 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
171 iminor(file_inode(file)), count);
172
173 ret = i2c_master_send(client, tmp, count);
174 kfree(tmp);
175 return ret;
176}
177
178static int i2cdev_check(struct device *dev, void *addrp)
179{
180 struct i2c_client *client = i2c_verify_client(dev);
181
182 if (!client || client->addr != *(unsigned int *)addrp)
183 return 0;
184
185 return dev->driver ? -EBUSY : 0;
186}
187
188/* walk up mux tree */
189static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
190{
191 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
192 int result;
193
194 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
195 if (!result && parent)
196 result = i2cdev_check_mux_parents(parent, addr);
197
198 return result;
199}
200
201/* recurse down mux tree */
202static int i2cdev_check_mux_children(struct device *dev, void *addrp)
203{
204 int result;
205
206 if (dev->type == &i2c_adapter_type)
207 result = device_for_each_child(dev, addrp,
208 i2cdev_check_mux_children);
209 else
210 result = i2cdev_check(dev, addrp);
211
212 return result;
213}
214
215/* This address checking function differs from the one in i2c-core
216 in that it considers an address with a registered device, but no
217 driver bound to it, as NOT busy. */
218static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
219{
220 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
221 int result = 0;
222
223 if (parent)
224 result = i2cdev_check_mux_parents(parent, addr);
225
226 if (!result)
227 result = device_for_each_child(&adapter->dev, &addr,
228 i2cdev_check_mux_children);
229
230 return result;
231}
232
233static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
234 unsigned nmsgs, struct i2c_msg *msgs)
235{
236 u8 __user **data_ptrs;
237 int i, res;
238
239 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
240 if (data_ptrs == NULL) {
241 kfree(msgs);
242 return -ENOMEM;
243 }
244
245 res = 0;
246 for (i = 0; i < nmsgs; i++) {
247 /* Limit the size of the message to a sane amount */
248 if (msgs[i].len > 8192) {
249 res = -EINVAL;
250 break;
251 }
252
253 data_ptrs[i] = (u8 __user *)msgs[i].buf;
254 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
255 if (IS_ERR(msgs[i].buf)) {
256 res = PTR_ERR(msgs[i].buf);
257 break;
258 }
259 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
260 msgs[i].flags |= I2C_M_DMA_SAFE;
261
262 /*
263 * If the message length is received from the slave (similar
264 * to SMBus block read), we must ensure that the buffer will
265 * be large enough to cope with a message length of
266 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
267 * drivers allow. The first byte in the buffer must be
268 * pre-filled with the number of extra bytes, which must be
269 * at least one to hold the message length, but can be
270 * greater (for example to account for a checksum byte at
271 * the end of the message.)
272 */
273 if (msgs[i].flags & I2C_M_RECV_LEN) {
274 if (!(msgs[i].flags & I2C_M_RD) ||
275 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
276 msgs[i].len < msgs[i].buf[0] +
277 I2C_SMBUS_BLOCK_MAX) {
278 i++;
279 res = -EINVAL;
280 break;
281 }
282
283 msgs[i].len = msgs[i].buf[0];
284 }
285 }
286 if (res < 0) {
287 int j;
288 for (j = 0; j < i; ++j)
289 kfree(msgs[j].buf);
290 kfree(data_ptrs);
291 kfree(msgs);
292 return res;
293 }
294
295 res = i2c_transfer(client->adapter, msgs, nmsgs);
296 while (i-- > 0) {
297 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
298 if (copy_to_user(data_ptrs[i], msgs[i].buf,
299 msgs[i].len))
300 res = -EFAULT;
301 }
302 kfree(msgs[i].buf);
303 }
304 kfree(data_ptrs);
305 kfree(msgs);
306 return res;
307}
308
309static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
310 u8 read_write, u8 command, u32 size,
311 union i2c_smbus_data __user *data)
312{
313 union i2c_smbus_data temp = {};
314 int datasize, res;
315
316 if ((size != I2C_SMBUS_BYTE) &&
317 (size != I2C_SMBUS_QUICK) &&
318 (size != I2C_SMBUS_BYTE_DATA) &&
319 (size != I2C_SMBUS_WORD_DATA) &&
320 (size != I2C_SMBUS_PROC_CALL) &&
321 (size != I2C_SMBUS_BLOCK_DATA) &&
322 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
323 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
324 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
325 dev_dbg(&client->adapter->dev,
326 "size out of range (%x) in ioctl I2C_SMBUS.\n",
327 size);
328 return -EINVAL;
329 }
330 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
331 so the check is valid if size==I2C_SMBUS_QUICK too. */
332 if ((read_write != I2C_SMBUS_READ) &&
333 (read_write != I2C_SMBUS_WRITE)) {
334 dev_dbg(&client->adapter->dev,
335 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
336 read_write);
337 return -EINVAL;
338 }
339
340 /* Note that command values are always valid! */
341
342 if ((size == I2C_SMBUS_QUICK) ||
343 ((size == I2C_SMBUS_BYTE) &&
344 (read_write == I2C_SMBUS_WRITE)))
345 /* These are special: we do not use data */
346 return i2c_smbus_xfer(client->adapter, client->addr,
347 client->flags, read_write,
348 command, size, NULL);
349
350 if (data == NULL) {
351 dev_dbg(&client->adapter->dev,
352 "data is NULL pointer in ioctl I2C_SMBUS.\n");
353 return -EINVAL;
354 }
355
356 if ((size == I2C_SMBUS_BYTE_DATA) ||
357 (size == I2C_SMBUS_BYTE))
358 datasize = sizeof(data->byte);
359 else if ((size == I2C_SMBUS_WORD_DATA) ||
360 (size == I2C_SMBUS_PROC_CALL))
361 datasize = sizeof(data->word);
362 else /* size == smbus block, i2c block, or block proc. call */
363 datasize = sizeof(data->block);
364
365 if ((size == I2C_SMBUS_PROC_CALL) ||
366 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
367 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
368 (read_write == I2C_SMBUS_WRITE)) {
369 if (copy_from_user(&temp, data, datasize))
370 return -EFAULT;
371 }
372 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
373 /* Convert old I2C block commands to the new
374 convention. This preserves binary compatibility. */
375 size = I2C_SMBUS_I2C_BLOCK_DATA;
376 if (read_write == I2C_SMBUS_READ)
377 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
378 }
379 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
380 read_write, command, size, &temp);
381 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
382 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
383 (read_write == I2C_SMBUS_READ))) {
384 if (copy_to_user(data, &temp, datasize))
385 return -EFAULT;
386 }
387 return res;
388}
389
390static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
391{
392 struct i2c_client *client = file->private_data;
393 unsigned long funcs;
394
395 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
396 cmd, arg);
397
398 switch (cmd) {
399 case I2C_SLAVE:
400 case I2C_SLAVE_FORCE:
401 if ((arg > 0x3ff) ||
402 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
403 return -EINVAL;
404 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
405 return -EBUSY;
406 /* REVISIT: address could become busy later */
407 client->addr = arg;
408 return 0;
409 case I2C_TENBIT:
410 if (arg)
411 client->flags |= I2C_M_TEN;
412 else
413 client->flags &= ~I2C_M_TEN;
414 return 0;
415 case I2C_PEC:
416 /*
417 * Setting the PEC flag here won't affect kernel drivers,
418 * which will be using the i2c_client node registered with
419 * the driver model core. Likewise, when that client has
420 * the PEC flag already set, the i2c-dev driver won't see
421 * (or use) this setting.
422 */
423 if (arg)
424 client->flags |= I2C_CLIENT_PEC;
425 else
426 client->flags &= ~I2C_CLIENT_PEC;
427 return 0;
428 case I2C_FUNCS:
429 funcs = i2c_get_functionality(client->adapter);
430 return put_user(funcs, (unsigned long __user *)arg);
431
432 case I2C_RDWR: {
433 struct i2c_rdwr_ioctl_data rdwr_arg;
434 struct i2c_msg *rdwr_pa;
435
436 if (copy_from_user(&rdwr_arg,
437 (struct i2c_rdwr_ioctl_data __user *)arg,
438 sizeof(rdwr_arg)))
439 return -EFAULT;
440
441 /* Put an arbitrary limit on the number of messages that can
442 * be sent at once */
443 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
444 return -EINVAL;
445
446 rdwr_pa = memdup_user(rdwr_arg.msgs,
447 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
448 if (IS_ERR(rdwr_pa))
449 return PTR_ERR(rdwr_pa);
450
451 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
452 }
453
454 case I2C_SMBUS: {
455 struct i2c_smbus_ioctl_data data_arg;
456 if (copy_from_user(&data_arg,
457 (struct i2c_smbus_ioctl_data __user *) arg,
458 sizeof(struct i2c_smbus_ioctl_data)))
459 return -EFAULT;
460 return i2cdev_ioctl_smbus(client, data_arg.read_write,
461 data_arg.command,
462 data_arg.size,
463 data_arg.data);
464 }
465 case I2C_RETRIES:
466 if (arg > INT_MAX)
467 return -EINVAL;
468
469 client->adapter->retries = arg;
470 break;
471 case I2C_TIMEOUT:
472 if (arg > INT_MAX)
473 return -EINVAL;
474
475 /* For historical reasons, user-space sets the timeout
476 * value in units of 10 ms.
477 */
478 client->adapter->timeout = msecs_to_jiffies(arg * 10);
479 break;
480 default:
481 /* NOTE: returning a fault code here could cause trouble
482 * in buggy userspace code. Some old kernel bugs returned
483 * zero in this case, and userspace code might accidentally
484 * have depended on that bug.
485 */
486 return -ENOTTY;
487 }
488 return 0;
489}
490
491#ifdef CONFIG_COMPAT
492
493struct i2c_smbus_ioctl_data32 {
494 u8 read_write;
495 u8 command;
496 u32 size;
497 compat_caddr_t data; /* union i2c_smbus_data *data */
498};
499
500struct i2c_msg32 {
501 u16 addr;
502 u16 flags;
503 u16 len;
504 compat_caddr_t buf;
505};
506
507struct i2c_rdwr_ioctl_data32 {
508 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
509 u32 nmsgs;
510};
511
512static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
513{
514 struct i2c_client *client = file->private_data;
515 unsigned long funcs;
516 switch (cmd) {
517 case I2C_FUNCS:
518 funcs = i2c_get_functionality(client->adapter);
519 return put_user(funcs, (compat_ulong_t __user *)arg);
520 case I2C_RDWR: {
521 struct i2c_rdwr_ioctl_data32 rdwr_arg;
522 struct i2c_msg32 *p;
523 struct i2c_msg *rdwr_pa;
524 int i;
525
526 if (copy_from_user(&rdwr_arg,
527 (struct i2c_rdwr_ioctl_data32 __user *)arg,
528 sizeof(rdwr_arg)))
529 return -EFAULT;
530
531 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
532 return -EINVAL;
533
534 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
535 GFP_KERNEL);
536 if (!rdwr_pa)
537 return -ENOMEM;
538
539 p = compat_ptr(rdwr_arg.msgs);
540 for (i = 0; i < rdwr_arg.nmsgs; i++) {
541 struct i2c_msg32 umsg;
542 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
543 kfree(rdwr_pa);
544 return -EFAULT;
545 }
546 rdwr_pa[i] = (struct i2c_msg) {
547 .addr = umsg.addr,
548 .flags = umsg.flags,
549 .len = umsg.len,
550 .buf = compat_ptr(umsg.buf)
551 };
552 }
553
554 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
555 }
556 case I2C_SMBUS: {
557 struct i2c_smbus_ioctl_data32 data32;
558 if (copy_from_user(&data32,
559 (void __user *) arg,
560 sizeof(data32)))
561 return -EFAULT;
562 return i2cdev_ioctl_smbus(client, data32.read_write,
563 data32.command,
564 data32.size,
565 compat_ptr(data32.data));
566 }
567 default:
568 return i2cdev_ioctl(file, cmd, arg);
569 }
570}
571#else
572#define compat_i2cdev_ioctl NULL
573#endif
574
575static int i2cdev_open(struct inode *inode, struct file *file)
576{
577 unsigned int minor = iminor(inode);
578 struct i2c_client *client;
579 struct i2c_adapter *adap;
580
581 adap = i2c_get_adapter(minor);
582 if (!adap)
583 return -ENODEV;
584
585 /* This creates an anonymous i2c_client, which may later be
586 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
587 *
588 * This client is ** NEVER REGISTERED ** with the driver model
589 * or I2C core code!! It just holds private copies of addressing
590 * information and maybe a PEC flag.
591 */
592 client = kzalloc(sizeof(*client), GFP_KERNEL);
593 if (!client) {
594 i2c_put_adapter(adap);
595 return -ENOMEM;
596 }
597 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
598
599 client->adapter = adap;
600 file->private_data = client;
601
602 return 0;
603}
604
605static int i2cdev_release(struct inode *inode, struct file *file)
606{
607 struct i2c_client *client = file->private_data;
608
609 i2c_put_adapter(client->adapter);
610 kfree(client);
611 file->private_data = NULL;
612
613 return 0;
614}
615
616static const struct file_operations i2cdev_fops = {
617 .owner = THIS_MODULE,
618 .llseek = no_llseek,
619 .read = i2cdev_read,
620 .write = i2cdev_write,
621 .unlocked_ioctl = i2cdev_ioctl,
622 .compat_ioctl = compat_i2cdev_ioctl,
623 .open = i2cdev_open,
624 .release = i2cdev_release,
625};
626
627/* ------------------------------------------------------------------------- */
628
629static struct class *i2c_dev_class;
630
631static int i2cdev_attach_adapter(struct device *dev, void *dummy)
632{
633 struct i2c_adapter *adap;
634 struct i2c_dev *i2c_dev;
635 int res;
636
637 if (dev->type != &i2c_adapter_type)
638 return 0;
639 adap = to_i2c_adapter(dev);
640
641 i2c_dev = get_free_i2c_dev(adap);
642 if (IS_ERR(i2c_dev))
643 return PTR_ERR(i2c_dev);
644
645 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
646 i2c_dev->cdev.owner = THIS_MODULE;
647 res = cdev_add(&i2c_dev->cdev, MKDEV(I2C_MAJOR, adap->nr), 1);
648 if (res)
649 goto error_cdev;
650
651 /* register this i2c device with the driver core */
652 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
653 MKDEV(I2C_MAJOR, adap->nr), NULL,
654 "i2c-%d", adap->nr);
655 if (IS_ERR(i2c_dev->dev)) {
656 res = PTR_ERR(i2c_dev->dev);
657 goto error;
658 }
659
660 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
661 adap->name, adap->nr);
662 return 0;
663error:
664 cdev_del(&i2c_dev->cdev);
665error_cdev:
666 put_i2c_dev(i2c_dev);
667 return res;
668}
669
670static int i2cdev_detach_adapter(struct device *dev, void *dummy)
671{
672 struct i2c_adapter *adap;
673 struct i2c_dev *i2c_dev;
674
675 if (dev->type != &i2c_adapter_type)
676 return 0;
677 adap = to_i2c_adapter(dev);
678
679 i2c_dev = i2c_dev_get_by_minor(adap->nr);
680 if (!i2c_dev) /* attach_adapter must have failed */
681 return 0;
682
683 cdev_del(&i2c_dev->cdev);
684 put_i2c_dev(i2c_dev);
685 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
686
687 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
688 return 0;
689}
690
691static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
692 void *data)
693{
694 struct device *dev = data;
695
696 switch (action) {
697 case BUS_NOTIFY_ADD_DEVICE:
698 return i2cdev_attach_adapter(dev, NULL);
699 case BUS_NOTIFY_DEL_DEVICE:
700 return i2cdev_detach_adapter(dev, NULL);
701 }
702
703 return 0;
704}
705
706static struct notifier_block i2cdev_notifier = {
707 .notifier_call = i2cdev_notifier_call,
708};
709
710/* ------------------------------------------------------------------------- */
711
712/*
713 * module load/unload record keeping
714 */
715
716static int __init i2c_dev_init(void)
717{
718 int res;
719
720 printk(KERN_INFO "i2c /dev entries driver\n");
721
722 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
723 if (res)
724 goto out;
725
726 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
727 if (IS_ERR(i2c_dev_class)) {
728 res = PTR_ERR(i2c_dev_class);
729 goto out_unreg_chrdev;
730 }
731 i2c_dev_class->dev_groups = i2c_groups;
732
733 /* Keep track of adapters which will be added or removed later */
734 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
735 if (res)
736 goto out_unreg_class;
737
738 /* Bind to already existing adapters right away */
739 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
740
741 return 0;
742
743out_unreg_class:
744 class_destroy(i2c_dev_class);
745out_unreg_chrdev:
746 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
747out:
748 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
749 return res;
750}
751
752static void __exit i2c_dev_exit(void)
753{
754 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
755 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
756 class_destroy(i2c_dev_class);
757 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
758}
759
760MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
761 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
762MODULE_DESCRIPTION("I2C /dev entries driver");
763MODULE_LICENSE("GPL");
764
765module_init(i2c_dev_init);
766module_exit(i2c_dev_exit);