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 /* Adapter must support I2C transfers */
143 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
144 return -EOPNOTSUPP;
145
146 if (count > 8192)
147 count = 8192;
148
149 tmp = kzalloc(count, GFP_KERNEL);
150 if (tmp == NULL)
151 return -ENOMEM;
152
153 pr_debug("i2c-%d reading %zu bytes.\n", iminor(file_inode(file)), count);
154
155 ret = i2c_master_recv(client, tmp, count);
156 if (ret >= 0)
157 if (copy_to_user(buf, tmp, ret))
158 ret = -EFAULT;
159 kfree(tmp);
160 return ret;
161 }
162
i2cdev_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)163 static ssize_t i2cdev_write(struct file *file, const char __user *buf,
164 size_t count, loff_t *offset)
165 {
166 int ret;
167 char *tmp;
168 struct i2c_client *client = file->private_data;
169
170 /* Adapter must support I2C transfers */
171 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
172 return -EOPNOTSUPP;
173
174 if (count > 8192)
175 count = 8192;
176
177 tmp = memdup_user(buf, count);
178 if (IS_ERR(tmp))
179 return PTR_ERR(tmp);
180
181 pr_debug("i2c-%d writing %zu bytes.\n", iminor(file_inode(file)), count);
182
183 ret = i2c_master_send(client, tmp, count);
184 kfree(tmp);
185 return ret;
186 }
187
i2cdev_check(struct device * dev,void * addrp)188 static int i2cdev_check(struct device *dev, void *addrp)
189 {
190 struct i2c_client *client = i2c_verify_client(dev);
191
192 if (!client || client->addr != *(unsigned int *)addrp)
193 return 0;
194
195 return dev->driver ? -EBUSY : 0;
196 }
197
198 /* walk up mux tree */
i2cdev_check_mux_parents(struct i2c_adapter * adapter,int addr)199 static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
200 {
201 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
202 int result;
203
204 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
205 if (!result && parent)
206 result = i2cdev_check_mux_parents(parent, addr);
207
208 return result;
209 }
210
211 /* recurse down mux tree */
i2cdev_check_mux_children(struct device * dev,void * addrp)212 static int i2cdev_check_mux_children(struct device *dev, void *addrp)
213 {
214 int result;
215
216 if (dev->type == &i2c_adapter_type)
217 result = device_for_each_child(dev, addrp,
218 i2cdev_check_mux_children);
219 else
220 result = i2cdev_check(dev, addrp);
221
222 return result;
223 }
224
225 /* This address checking function differs from the one in i2c-core
226 in that it considers an address with a registered device, but no
227 driver bound to it, as NOT busy. */
i2cdev_check_addr(struct i2c_adapter * adapter,unsigned int addr)228 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
229 {
230 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
231 int result = 0;
232
233 if (parent)
234 result = i2cdev_check_mux_parents(parent, addr);
235
236 if (!result)
237 result = device_for_each_child(&adapter->dev, &addr,
238 i2cdev_check_mux_children);
239
240 return result;
241 }
242
i2cdev_ioctl_rdwr(struct i2c_client * client,unsigned nmsgs,struct i2c_msg * msgs)243 static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
244 unsigned nmsgs, struct i2c_msg *msgs)
245 {
246 u8 __user **data_ptrs;
247 int i, res;
248
249 /* Adapter must support I2C transfers */
250 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
251 return -EOPNOTSUPP;
252
253 data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
254 if (data_ptrs == NULL) {
255 kfree(msgs);
256 return -ENOMEM;
257 }
258
259 res = 0;
260 for (i = 0; i < nmsgs; i++) {
261 /* Limit the size of the message to a sane amount */
262 if (msgs[i].len > 8192) {
263 res = -EINVAL;
264 break;
265 }
266
267 data_ptrs[i] = (u8 __user *)msgs[i].buf;
268 msgs[i].buf = memdup_user(data_ptrs[i], msgs[i].len);
269 if (IS_ERR(msgs[i].buf)) {
270 res = PTR_ERR(msgs[i].buf);
271 break;
272 }
273 /* memdup_user allocates with GFP_KERNEL, so DMA is ok */
274 msgs[i].flags |= I2C_M_DMA_SAFE;
275
276 /*
277 * If the message length is received from the slave (similar
278 * to SMBus block read), we must ensure that the buffer will
279 * be large enough to cope with a message length of
280 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
281 * drivers allow. The first byte in the buffer must be
282 * pre-filled with the number of extra bytes, which must be
283 * at least one to hold the message length, but can be
284 * greater (for example to account for a checksum byte at
285 * the end of the message.)
286 */
287 if (msgs[i].flags & I2C_M_RECV_LEN) {
288 if (!(msgs[i].flags & I2C_M_RD) ||
289 msgs[i].len < 1 || msgs[i].buf[0] < 1 ||
290 msgs[i].len < msgs[i].buf[0] +
291 I2C_SMBUS_BLOCK_MAX) {
292 i++;
293 res = -EINVAL;
294 break;
295 }
296
297 msgs[i].len = msgs[i].buf[0];
298 }
299 }
300 if (res < 0) {
301 int j;
302 for (j = 0; j < i; ++j)
303 kfree(msgs[j].buf);
304 kfree(data_ptrs);
305 kfree(msgs);
306 return res;
307 }
308
309 res = i2c_transfer(client->adapter, msgs, nmsgs);
310 while (i-- > 0) {
311 if (res >= 0 && (msgs[i].flags & I2C_M_RD)) {
312 if (copy_to_user(data_ptrs[i], msgs[i].buf,
313 msgs[i].len))
314 res = -EFAULT;
315 }
316 kfree(msgs[i].buf);
317 }
318 kfree(data_ptrs);
319 kfree(msgs);
320 return res;
321 }
322
i2cdev_ioctl_smbus(struct i2c_client * client,u8 read_write,u8 command,u32 size,union i2c_smbus_data __user * data)323 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
324 u8 read_write, u8 command, u32 size,
325 union i2c_smbus_data __user *data)
326 {
327 union i2c_smbus_data temp = {};
328 int datasize, res;
329
330 if ((size != I2C_SMBUS_BYTE) &&
331 (size != I2C_SMBUS_QUICK) &&
332 (size != I2C_SMBUS_BYTE_DATA) &&
333 (size != I2C_SMBUS_WORD_DATA) &&
334 (size != I2C_SMBUS_PROC_CALL) &&
335 (size != I2C_SMBUS_BLOCK_DATA) &&
336 (size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
337 (size != I2C_SMBUS_I2C_BLOCK_DATA) &&
338 (size != I2C_SMBUS_BLOCK_PROC_CALL)) {
339 dev_dbg(&client->adapter->dev,
340 "size out of range (%x) in ioctl I2C_SMBUS.\n",
341 size);
342 return -EINVAL;
343 }
344 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
345 so the check is valid if size==I2C_SMBUS_QUICK too. */
346 if ((read_write != I2C_SMBUS_READ) &&
347 (read_write != I2C_SMBUS_WRITE)) {
348 dev_dbg(&client->adapter->dev,
349 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
350 read_write);
351 return -EINVAL;
352 }
353
354 /* Note that command values are always valid! */
355
356 if ((size == I2C_SMBUS_QUICK) ||
357 ((size == I2C_SMBUS_BYTE) &&
358 (read_write == I2C_SMBUS_WRITE)))
359 /* These are special: we do not use data */
360 return i2c_smbus_xfer(client->adapter, client->addr,
361 client->flags, read_write,
362 command, size, NULL);
363
364 if (data == NULL) {
365 dev_dbg(&client->adapter->dev,
366 "data is NULL pointer in ioctl I2C_SMBUS.\n");
367 return -EINVAL;
368 }
369
370 if ((size == I2C_SMBUS_BYTE_DATA) ||
371 (size == I2C_SMBUS_BYTE))
372 datasize = sizeof(data->byte);
373 else if ((size == I2C_SMBUS_WORD_DATA) ||
374 (size == I2C_SMBUS_PROC_CALL))
375 datasize = sizeof(data->word);
376 else /* size == smbus block, i2c block, or block proc. call */
377 datasize = sizeof(data->block);
378
379 if ((size == I2C_SMBUS_PROC_CALL) ||
380 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
381 (size == I2C_SMBUS_I2C_BLOCK_DATA) ||
382 (read_write == I2C_SMBUS_WRITE)) {
383 if (copy_from_user(&temp, data, datasize))
384 return -EFAULT;
385 }
386 if (size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
387 /* Convert old I2C block commands to the new
388 convention. This preserves binary compatibility. */
389 size = I2C_SMBUS_I2C_BLOCK_DATA;
390 if (read_write == I2C_SMBUS_READ)
391 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
392 }
393 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
394 read_write, command, size, &temp);
395 if (!res && ((size == I2C_SMBUS_PROC_CALL) ||
396 (size == I2C_SMBUS_BLOCK_PROC_CALL) ||
397 (read_write == I2C_SMBUS_READ))) {
398 if (copy_to_user(data, &temp, datasize))
399 return -EFAULT;
400 }
401 return res;
402 }
403
i2cdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)404 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
405 {
406 struct i2c_client *client = file->private_data;
407 unsigned long funcs;
408
409 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
410 cmd, arg);
411
412 switch (cmd) {
413 case I2C_SLAVE:
414 case I2C_SLAVE_FORCE:
415 if ((arg > 0x3ff) ||
416 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
417 return -EINVAL;
418 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
419 return -EBUSY;
420 /* REVISIT: address could become busy later */
421 client->addr = arg;
422 return 0;
423 case I2C_TENBIT:
424 if (arg)
425 client->flags |= I2C_M_TEN;
426 else
427 client->flags &= ~I2C_M_TEN;
428 return 0;
429 case I2C_PEC:
430 /*
431 * Setting the PEC flag here won't affect kernel drivers,
432 * which will be using the i2c_client node registered with
433 * the driver model core. Likewise, when that client has
434 * the PEC flag already set, the i2c-dev driver won't see
435 * (or use) this setting.
436 */
437 if (arg)
438 client->flags |= I2C_CLIENT_PEC;
439 else
440 client->flags &= ~I2C_CLIENT_PEC;
441 return 0;
442 case I2C_FUNCS:
443 funcs = i2c_get_functionality(client->adapter);
444 return put_user(funcs, (unsigned long __user *)arg);
445
446 case I2C_RDWR: {
447 struct i2c_rdwr_ioctl_data rdwr_arg;
448 struct i2c_msg *rdwr_pa;
449
450 if (copy_from_user(&rdwr_arg,
451 (struct i2c_rdwr_ioctl_data __user *)arg,
452 sizeof(rdwr_arg)))
453 return -EFAULT;
454
455 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
456 return -EINVAL;
457
458 /*
459 * Put an arbitrary limit on the number of messages that can
460 * be sent at once
461 */
462 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
463 return -EINVAL;
464
465 rdwr_pa = memdup_array_user(rdwr_arg.msgs,
466 rdwr_arg.nmsgs, sizeof(struct i2c_msg));
467 if (IS_ERR(rdwr_pa))
468 return PTR_ERR(rdwr_pa);
469
470 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
471 }
472
473 case I2C_SMBUS: {
474 struct i2c_smbus_ioctl_data data_arg;
475 if (copy_from_user(&data_arg,
476 (struct i2c_smbus_ioctl_data __user *) arg,
477 sizeof(struct i2c_smbus_ioctl_data)))
478 return -EFAULT;
479 return i2cdev_ioctl_smbus(client, data_arg.read_write,
480 data_arg.command,
481 data_arg.size,
482 data_arg.data);
483 }
484 case I2C_RETRIES:
485 if (arg > INT_MAX)
486 return -EINVAL;
487
488 client->adapter->retries = arg;
489 break;
490 case I2C_TIMEOUT:
491 if (arg > INT_MAX)
492 return -EINVAL;
493
494 /* For historical reasons, user-space sets the timeout
495 * value in units of 10 ms.
496 */
497 client->adapter->timeout = msecs_to_jiffies(arg * 10);
498 break;
499 default:
500 /* NOTE: returning a fault code here could cause trouble
501 * in buggy userspace code. Some old kernel bugs returned
502 * zero in this case, and userspace code might accidentally
503 * have depended on that bug.
504 */
505 return -ENOTTY;
506 }
507 return 0;
508 }
509
510 #ifdef CONFIG_COMPAT
511
512 struct i2c_smbus_ioctl_data32 {
513 u8 read_write;
514 u8 command;
515 u32 size;
516 compat_caddr_t data; /* union i2c_smbus_data *data */
517 };
518
519 struct i2c_msg32 {
520 u16 addr;
521 u16 flags;
522 u16 len;
523 compat_caddr_t buf;
524 };
525
526 struct i2c_rdwr_ioctl_data32 {
527 compat_caddr_t msgs; /* struct i2c_msg __user *msgs */
528 u32 nmsgs;
529 };
530
compat_i2cdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)531 static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
532 {
533 struct i2c_client *client = file->private_data;
534 unsigned long funcs;
535 switch (cmd) {
536 case I2C_FUNCS:
537 funcs = i2c_get_functionality(client->adapter);
538 return put_user(funcs, (compat_ulong_t __user *)arg);
539 case I2C_RDWR: {
540 struct i2c_rdwr_ioctl_data32 rdwr_arg;
541 struct i2c_msg32 __user *p;
542 struct i2c_msg *rdwr_pa;
543 int i;
544
545 if (copy_from_user(&rdwr_arg,
546 (struct i2c_rdwr_ioctl_data32 __user *)arg,
547 sizeof(rdwr_arg)))
548 return -EFAULT;
549
550 if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0)
551 return -EINVAL;
552
553 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
554 return -EINVAL;
555
556 rdwr_pa = kmalloc_array(rdwr_arg.nmsgs, sizeof(struct i2c_msg),
557 GFP_KERNEL);
558 if (!rdwr_pa)
559 return -ENOMEM;
560
561 p = compat_ptr(rdwr_arg.msgs);
562 for (i = 0; i < rdwr_arg.nmsgs; i++) {
563 struct i2c_msg32 umsg;
564 if (copy_from_user(&umsg, p + i, sizeof(umsg))) {
565 kfree(rdwr_pa);
566 return -EFAULT;
567 }
568 rdwr_pa[i] = (struct i2c_msg) {
569 .addr = umsg.addr,
570 .flags = umsg.flags,
571 .len = umsg.len,
572 .buf = (__force __u8 *)compat_ptr(umsg.buf),
573 };
574 }
575
576 return i2cdev_ioctl_rdwr(client, rdwr_arg.nmsgs, rdwr_pa);
577 }
578 case I2C_SMBUS: {
579 struct i2c_smbus_ioctl_data32 data32;
580 if (copy_from_user(&data32,
581 (void __user *) arg,
582 sizeof(data32)))
583 return -EFAULT;
584 return i2cdev_ioctl_smbus(client, data32.read_write,
585 data32.command,
586 data32.size,
587 compat_ptr(data32.data));
588 }
589 default:
590 return i2cdev_ioctl(file, cmd, arg);
591 }
592 }
593 #else
594 #define compat_i2cdev_ioctl NULL
595 #endif
596
i2cdev_open(struct inode * inode,struct file * file)597 static int i2cdev_open(struct inode *inode, struct file *file)
598 {
599 unsigned int minor = iminor(inode);
600 struct i2c_client *client;
601 struct i2c_adapter *adap;
602
603 adap = i2c_get_adapter(minor);
604 if (!adap)
605 return -ENODEV;
606
607 /* This creates an anonymous i2c_client, which may later be
608 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
609 *
610 * This client is ** NEVER REGISTERED ** with the driver model
611 * or I2C core code!! It just holds private copies of addressing
612 * information and maybe a PEC flag.
613 */
614 client = kzalloc(sizeof(*client), GFP_KERNEL);
615 if (!client) {
616 i2c_put_adapter(adap);
617 return -ENOMEM;
618 }
619 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
620
621 client->adapter = adap;
622 file->private_data = client;
623
624 return 0;
625 }
626
i2cdev_release(struct inode * inode,struct file * file)627 static int i2cdev_release(struct inode *inode, struct file *file)
628 {
629 struct i2c_client *client = file->private_data;
630
631 i2c_put_adapter(client->adapter);
632 kfree(client);
633 file->private_data = NULL;
634
635 return 0;
636 }
637
638 static const struct file_operations i2cdev_fops = {
639 .owner = THIS_MODULE,
640 .llseek = no_llseek,
641 .read = i2cdev_read,
642 .write = i2cdev_write,
643 .unlocked_ioctl = i2cdev_ioctl,
644 .compat_ioctl = compat_i2cdev_ioctl,
645 .open = i2cdev_open,
646 .release = i2cdev_release,
647 };
648
649 /* ------------------------------------------------------------------------- */
650
651 static const struct class i2c_dev_class = {
652 .name = "i2c-dev",
653 .dev_groups = i2c_groups,
654 };
655
i2cdev_dev_release(struct device * dev)656 static void i2cdev_dev_release(struct device *dev)
657 {
658 struct i2c_dev *i2c_dev;
659
660 i2c_dev = container_of(dev, struct i2c_dev, dev);
661 kfree(i2c_dev);
662 }
663
i2cdev_attach_adapter(struct device * dev)664 static int i2cdev_attach_adapter(struct device *dev)
665 {
666 struct i2c_adapter *adap;
667 struct i2c_dev *i2c_dev;
668 int res;
669
670 if (dev->type != &i2c_adapter_type)
671 return NOTIFY_DONE;
672 adap = to_i2c_adapter(dev);
673
674 i2c_dev = get_free_i2c_dev(adap);
675 if (IS_ERR(i2c_dev))
676 return NOTIFY_DONE;
677
678 cdev_init(&i2c_dev->cdev, &i2cdev_fops);
679 i2c_dev->cdev.owner = THIS_MODULE;
680
681 device_initialize(&i2c_dev->dev);
682 i2c_dev->dev.devt = MKDEV(I2C_MAJOR, adap->nr);
683 i2c_dev->dev.class = &i2c_dev_class;
684 i2c_dev->dev.parent = &adap->dev;
685 i2c_dev->dev.release = i2cdev_dev_release;
686
687 res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
688 if (res)
689 goto err_put_i2c_dev;
690
691 res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
692 if (res)
693 goto err_put_i2c_dev;
694
695 pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
696 return NOTIFY_OK;
697
698 err_put_i2c_dev:
699 put_i2c_dev(i2c_dev, false);
700 return NOTIFY_DONE;
701 }
702
i2cdev_detach_adapter(struct device * dev)703 static int i2cdev_detach_adapter(struct device *dev)
704 {
705 struct i2c_adapter *adap;
706 struct i2c_dev *i2c_dev;
707
708 if (dev->type != &i2c_adapter_type)
709 return NOTIFY_DONE;
710 adap = to_i2c_adapter(dev);
711
712 i2c_dev = i2c_dev_get_by_minor(adap->nr);
713 if (!i2c_dev) /* attach_adapter must have failed */
714 return NOTIFY_DONE;
715
716 put_i2c_dev(i2c_dev, true);
717
718 pr_debug("adapter [%s] unregistered\n", adap->name);
719 return NOTIFY_OK;
720 }
721
i2cdev_notifier_call(struct notifier_block * nb,unsigned long action,void * data)722 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
723 void *data)
724 {
725 struct device *dev = data;
726
727 switch (action) {
728 case BUS_NOTIFY_ADD_DEVICE:
729 return i2cdev_attach_adapter(dev);
730 case BUS_NOTIFY_DEL_DEVICE:
731 return i2cdev_detach_adapter(dev);
732 }
733
734 return NOTIFY_DONE;
735 }
736
737 static struct notifier_block i2cdev_notifier = {
738 .notifier_call = i2cdev_notifier_call,
739 };
740
741 /* ------------------------------------------------------------------------- */
742
i2c_dev_attach_adapter(struct device * dev,void * dummy)743 static int __init i2c_dev_attach_adapter(struct device *dev, void *dummy)
744 {
745 i2cdev_attach_adapter(dev);
746 return 0;
747 }
748
i2c_dev_detach_adapter(struct device * dev,void * dummy)749 static int __exit i2c_dev_detach_adapter(struct device *dev, void *dummy)
750 {
751 i2cdev_detach_adapter(dev);
752 return 0;
753 }
754
755 /*
756 * module load/unload record keeping
757 */
758
i2c_dev_init(void)759 static int __init i2c_dev_init(void)
760 {
761 int res;
762
763 pr_info("i2c /dev entries driver\n");
764
765 res = register_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS, "i2c");
766 if (res)
767 goto out;
768
769 res = class_register(&i2c_dev_class);
770 if (res)
771 goto out_unreg_chrdev;
772
773 /* Keep track of adapters which will be added or removed later */
774 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
775 if (res)
776 goto out_unreg_class;
777
778 /* Bind to already existing adapters right away */
779 i2c_for_each_dev(NULL, i2c_dev_attach_adapter);
780
781 return 0;
782
783 out_unreg_class:
784 class_unregister(&i2c_dev_class);
785 out_unreg_chrdev:
786 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
787 out:
788 pr_err("Driver Initialisation failed\n");
789 return res;
790 }
791
i2c_dev_exit(void)792 static void __exit i2c_dev_exit(void)
793 {
794 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
795 i2c_for_each_dev(NULL, i2c_dev_detach_adapter);
796 class_unregister(&i2c_dev_class);
797 unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS);
798 }
799
800 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
801 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
802 MODULE_DESCRIPTION("I2C /dev entries driver");
803 MODULE_LICENSE("GPL");
804
805 module_init(i2c_dev_init);
806 module_exit(i2c_dev_exit);
807