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 */
42 struct 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)
50 static LIST_HEAD(i2c_dev_list);
51 static DEFINE_SPINLOCK(i2c_dev_list_lock);
52
i2c_dev_get_by_minor(unsigned index)53 static 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;
63 found:
64 spin_unlock(&i2c_dev_list_lock);
65 return i2c_dev;
66 }
67
get_free_i2c_dev(struct i2c_adapter * adap)68 static 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
put_i2c_dev(struct i2c_dev * i2c_dev,bool del_cdev)88 static 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
name_show(struct device * dev,struct device_attribute * attr,char * buf)98 static 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 }
107 static DEVICE_ATTR_RO(name);
108
109 static struct attribute *i2c_attrs[] = {
110 &dev_attr_name.attr,
111 NULL,
112 };
113 ATTRIBUTE_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
i2cdev_read(struct file * file,char __user * buf,size_t count,loff_t * offset)134 static 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
i2cdev_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)159 static 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
i2cdev_check(struct device * dev,void * addrp)180 static 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 */
i2cdev_check_mux_parents(struct i2c_adapter * adapter,int addr)191 static 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 */
i2cdev_check_mux_children(struct device * dev,void * addrp)204 static 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. */
i2cdev_check_addr(struct i2c_adapter * adapter,unsigned int addr)220 static 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
i2cdev_ioctl_rdwr(struct i2c_client * client,unsigned nmsgs,struct i2c_msg * msgs)235 static 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
i2cdev_ioctl_smbus(struct i2c_client * client,u8 read_write,u8 command,u32 size,union i2c_smbus_data __user * data)311 static 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
i2cdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)392 static 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
500 struct 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
507 struct i2c_msg32 {
508 u16 addr;
509 u16 flags;
510 u16 len;
511 compat_caddr_t buf;
512 };
513
514 struct i2c_rdwr_ioctl_data32 {
515 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
516 u32 nmsgs;
517 };
518
compat_i2cdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)519 static 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 = 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
i2cdev_open(struct inode * inode,struct file * file)585 static 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
i2cdev_release(struct inode * inode,struct file * file)615 static 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
626 static 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
639 static struct class *i2c_dev_class;
640
i2cdev_dev_release(struct device * dev)641 static void i2cdev_dev_release(struct device *dev)
642 {
643 struct i2c_dev *i2c_dev;
644
645 i2c_dev = container_of(dev, struct i2c_dev, dev);
646 kfree(i2c_dev);
647 }
648
i2cdev_attach_adapter(struct device * dev,void * dummy)649 static int i2cdev_attach_adapter(struct device *dev, void *dummy)
650 {
651 struct i2c_adapter *adap;
652 struct i2c_dev *i2c_dev;
653 int res;
654
655 if (dev->type != &i2c_adapter_type)
656 return 0;
657 adap = to_i2c_adapter(dev);
658
659 i2c_dev = get_free_i2c_dev(adap);
660 if (IS_ERR(i2c_dev))
661 return PTR_ERR(i2c_dev);
662
663 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
664 i2c_dev->cdev.owner = THIS_MODULE;
665
666 device_initialize(&i2c_dev->dev);
667 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
668 i2c_dev->dev.class = i2c_dev_class;
669 i2c_dev->dev.parent = &adap->dev;
670 i2c_dev->dev.release = i2cdev_dev_release;
671
672 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
673 if (res)
674 goto err_put_i2c_dev;
675
676 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
677 if (res)
678 goto err_put_i2c_dev;
679
680 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
681 return 0;
682
683 err_put_i2c_dev:
684 put_i2c_dev(i2c_dev, false);
685 return res;
686 }
687
i2cdev_detach_adapter(struct device * dev,void * dummy)688 static int i2cdev_detach_adapter(struct device *dev, void *dummy)
689 {
690 struct i2c_adapter *adap;
691 struct i2c_dev *i2c_dev;
692
693 if (dev->type != &i2c_adapter_type)
694 return 0;
695 adap = to_i2c_adapter(dev);
696
697 i2c_dev = i2c_dev_get_by_minor(adap->nr);
698 if (!i2c_dev) /* attach_adapter must have failed */
699 return 0;
700
701 put_i2c_dev(i2c_dev, true);
702
703 pr_debug("adapter [%s] unregistered\n", adap->name);
704 return 0;
705 }
706
i2cdev_notifier_call(struct notifier_block * nb,unsigned long action,void * data)707 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
708 void *data)
709 {
710 struct device *dev = data;
711
712 switch (action) {
713 case BUS_NOTIFY_ADD_DEVICE:
714 return i2cdev_attach_adapter(dev, NULL);
715 case BUS_NOTIFY_DEL_DEVICE:
716 return i2cdev_detach_adapter(dev, NULL);
717 }
718
719 return 0;
720 }
721
722 static struct notifier_block i2cdev_notifier = {
723 .notifier_call = i2cdev_notifier_call,
724 };
725
726 /* ------------------------------------------------------------------------- */
727
728 /*
729 * module load/unload record keeping
730 */
731
i2c_dev_init(void)732 static int __init i2c_dev_init(void)
733 {
734 int res;
735
736 pr_info("i2c /dev entries driver\n");
737
738 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
739 if (res)
740 goto out;
741
742 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
743 if (IS_ERR(i2c_dev_class)) {
744 res = PTR_ERR(i2c_dev_class);
745 goto out_unreg_chrdev;
746 }
747 i2c_dev_class->dev_groups = i2c_groups;
748
749 /* Keep track of adapters which will be added or removed later */
750 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
751 if (res)
752 goto out_unreg_class;
753
754 /* Bind to already existing adapters right away */
755 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
756
757 return 0;
758
759 out_unreg_class:
760 class_destroy(i2c_dev_class);
761 out_unreg_chrdev:
762 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
763 out:
764 pr_err("Driver Initialisation failed\n");
765 return res;
766 }
767
i2c_dev_exit(void)768 static void __exit i2c_dev_exit(void)
769 {
770 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
771 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
772 class_destroy(i2c_dev_class);
773 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
774 }
775
776 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
777 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
778 MODULE_DESCRIPTION("I2C /dev entries driver");
779 MODULE_LICENSE("GPL");
780
781 module_init(i2c_dev_init);
782 module_exit(i2c_dev_exit);
783