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1/*
2 i2c-dev.c - i2c-bus driver, char device interface
3
4 Copyright (C) 1995-97 Simon G. Vogl
5 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17*/
18
19/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
20 But I have used so much of his original code and ideas that it seems
21 only fair to recognize him as co-author -- Frodo */
22
23/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
24
25#include <linux/device.h>
26#include <linux/fs.h>
27#include <linux/i2c-dev.h>
28#include <linux/i2c.h>
29#include <linux/init.h>
30#include <linux/jiffies.h>
31#include <linux/kernel.h>
32#include <linux/list.h>
33#include <linux/module.h>
34#include <linux/notifier.h>
35#include <linux/slab.h>
36#include <linux/uaccess.h>
37
38/*
39 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
40 * slave (i2c_client) with which messages will be exchanged. It's coupled
41 * with a character special file which is accessed by user mode drivers.
42 *
43 * The list of i2c_dev structures is parallel to the i2c_adapter lists
44 * maintained by the driver model, and is updated using bus notifications.
45 */
46struct i2c_dev {
47 struct list_head list;
48 struct i2c_adapter *adap;
49 struct device *dev;
50};
51
52#define I2C_MINORS 256
53static LIST_HEAD(i2c_dev_list);
54static DEFINE_SPINLOCK(i2c_dev_list_lock);
55
56static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
57{
58 struct i2c_dev *i2c_dev;
59
60 spin_lock(&i2c_dev_list_lock);
61 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
62 if (i2c_dev->adap->nr == index)
63 goto found;
64 }
65 i2c_dev = NULL;
66found:
67 spin_unlock(&i2c_dev_list_lock);
68 return i2c_dev;
69}
70
71static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
72{
73 struct i2c_dev *i2c_dev;
74
75 if (adap->nr >= I2C_MINORS) {
76 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
77 adap->nr);
78 return ERR_PTR(-ENODEV);
79 }
80
81 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
82 if (!i2c_dev)
83 return ERR_PTR(-ENOMEM);
84 i2c_dev->adap = adap;
85
86 spin_lock(&i2c_dev_list_lock);
87 list_add_tail(&i2c_dev->list, &i2c_dev_list);
88 spin_unlock(&i2c_dev_list_lock);
89 return i2c_dev;
90}
91
92static void return_i2c_dev(struct i2c_dev *i2c_dev)
93{
94 spin_lock(&i2c_dev_list_lock);
95 list_del(&i2c_dev->list);
96 spin_unlock(&i2c_dev_list_lock);
97 kfree(i2c_dev);
98}
99
100static ssize_t name_show(struct device *dev,
101 struct device_attribute *attr, char *buf)
102{
103 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
104
105 if (!i2c_dev)
106 return -ENODEV;
107 return sprintf(buf, "%s\n", i2c_dev->adap->name);
108}
109static DEVICE_ATTR_RO(name);
110
111static struct attribute *i2c_attrs[] = {
112 &dev_attr_name.attr,
113 NULL,
114};
115ATTRIBUTE_GROUPS(i2c);
116
117/* ------------------------------------------------------------------------- */
118
119/*
120 * After opening an instance of this character special file, a file
121 * descriptor starts out associated only with an i2c_adapter (and bus).
122 *
123 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
124 * traffic to any devices on the bus used by that adapter. That's because
125 * the i2c_msg vectors embed all the addressing information they need, and
126 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
127 * don't support that interface.
128 *
129 * To use read()/write() system calls on that file descriptor, or to use
130 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
131 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
132 * (never registered) i2c_client so it holds the addressing information
133 * needed by those system calls and by this SMBus interface.
134 */
135
136static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
137 loff_t *offset)
138{
139 char *tmp;
140 int ret;
141
142 struct i2c_client *client = file->private_data;
143
144 if (count > 8192)
145 count = 8192;
146
147 tmp = kmalloc(count, GFP_KERNEL);
148 if (tmp == NULL)
149 return -ENOMEM;
150
151 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
152 iminor(file_inode(file)), count);
153
154 ret = i2c_master_recv(client, tmp, count);
155 if (ret >= 0)
156 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
157 kfree(tmp);
158 return ret;
159}
160
161static ssize_t i2cdev_write(struct file *file, const char __user *buf,
162 size_t count, loff_t *offset)
163{
164 int ret;
165 char *tmp;
166 struct i2c_client *client = file->private_data;
167
168 if (count > 8192)
169 count = 8192;
170
171 tmp = memdup_user(buf, count);
172 if (IS_ERR(tmp))
173 return PTR_ERR(tmp);
174
175 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
176 iminor(file_inode(file)), count);
177
178 ret = i2c_master_send(client, tmp, count);
179 kfree(tmp);
180 return ret;
181}
182
183static int i2cdev_check(struct device *dev, void *addrp)
184{
185 struct i2c_client *client = i2c_verify_client(dev);
186
187 if (!client || client->addr != *(unsigned int *)addrp)
188 return 0;
189
190 return dev->driver ? -EBUSY : 0;
191}
192
193/* walk up mux tree */
194static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
195{
196 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
197 int result;
198
199 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
200 if (!result && parent)
201 result = i2cdev_check_mux_parents(parent, addr);
202
203 return result;
204}
205
206/* recurse down mux tree */
207static int i2cdev_check_mux_children(struct device *dev, void *addrp)
208{
209 int result;
210
211 if (dev->type == &i2c_adapter_type)
212 result = device_for_each_child(dev, addrp,
213 i2cdev_check_mux_children);
214 else
215 result = i2cdev_check(dev, addrp);
216
217 return result;
218}
219
220/* This address checking function differs from the one in i2c-core
221 in that it considers an address with a registered device, but no
222 driver bound to it, as NOT busy. */
223static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
224{
225 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
226 int result = 0;
227
228 if (parent)
229 result = i2cdev_check_mux_parents(parent, addr);
230
231 if (!result)
232 result = device_for_each_child(&adapter->dev, &addr,
233 i2cdev_check_mux_children);
234
235 return result;
236}
237
238static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client,
239 unsigned long arg)
240{
241 struct i2c_rdwr_ioctl_data rdwr_arg;
242 struct i2c_msg *rdwr_pa;
243 u8 __user **data_ptrs;
244 int i, res;
245
246 if (copy_from_user(&rdwr_arg,
247 (struct i2c_rdwr_ioctl_data __user *)arg,
248 sizeof(rdwr_arg)))
249 return -EFAULT;
250
251 /* Put an arbitrary limit on the number of messages that can
252 * be sent at once */
253 if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
254 return -EINVAL;
255
256 rdwr_pa = memdup_user(rdwr_arg.msgs,
257 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
258 if (IS_ERR(rdwr_pa))
259 return PTR_ERR(rdwr_pa);
260
261 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
262 if (data_ptrs == NULL) {
263 kfree(rdwr_pa);
264 return -ENOMEM;
265 }
266
267 res = 0;
268 for (i = 0; i < rdwr_arg.nmsgs; i++) {
269 /* Limit the size of the message to a sane amount */
270 if (rdwr_pa[i].len > 8192) {
271 res = -EINVAL;
272 break;
273 }
274
275 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
276 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
277 if (IS_ERR(rdwr_pa[i].buf)) {
278 res = PTR_ERR(rdwr_pa[i].buf);
279 break;
280 }
281
282 /*
283 * If the message length is received from the slave (similar
284 * to SMBus block read), we must ensure that the buffer will
285 * be large enough to cope with a message length of
286 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
287 * drivers allow. The first byte in the buffer must be
288 * pre-filled with the number of extra bytes, which must be
289 * at least one to hold the message length, but can be
290 * greater (for example to account for a checksum byte at
291 * the end of the message.)
292 */
293 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
294 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
295 rdwr_pa[i].buf[0] < 1 ||
296 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
297 I2C_SMBUS_BLOCK_MAX) {
298 res = -EINVAL;
299 break;
300 }
301
302 rdwr_pa[i].len = rdwr_pa[i].buf[0];
303 }
304 }
305 if (res < 0) {
306 int j;
307 for (j = 0; j < i; ++j)
308 kfree(rdwr_pa[j].buf);
309 kfree(data_ptrs);
310 kfree(rdwr_pa);
311 return res;
312 }
313
314 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
315 while (i-- > 0) {
316 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
317 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
318 rdwr_pa[i].len))
319 res = -EFAULT;
320 }
321 kfree(rdwr_pa[i].buf);
322 }
323 kfree(data_ptrs);
324 kfree(rdwr_pa);
325 return res;
326}
327
328static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
329 unsigned long arg)
330{
331 struct i2c_smbus_ioctl_data data_arg;
332 union i2c_smbus_data temp;
333 int datasize, res;
334
335 if (copy_from_user(&data_arg,
336 (struct i2c_smbus_ioctl_data __user *) arg,
337 sizeof(struct i2c_smbus_ioctl_data)))
338 return -EFAULT;
339 if ((data_arg.size != I2C_SMBUS_BYTE) &&
340 (data_arg.size != I2C_SMBUS_QUICK) &&
341 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
342 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
343 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
344 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
345 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
346 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
347 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
348 dev_dbg(&client->adapter->dev,
349 "size out of range (%x) in ioctl I2C_SMBUS.\n",
350 data_arg.size);
351 return -EINVAL;
352 }
353 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
354 so the check is valid if size==I2C_SMBUS_QUICK too. */
355 if ((data_arg.read_write != I2C_SMBUS_READ) &&
356 (data_arg.read_write != I2C_SMBUS_WRITE)) {
357 dev_dbg(&client->adapter->dev,
358 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
359 data_arg.read_write);
360 return -EINVAL;
361 }
362
363 /* Note that command values are always valid! */
364
365 if ((data_arg.size == I2C_SMBUS_QUICK) ||
366 ((data_arg.size == I2C_SMBUS_BYTE) &&
367 (data_arg.read_write == I2C_SMBUS_WRITE)))
368 /* These are special: we do not use data */
369 return i2c_smbus_xfer(client->adapter, client->addr,
370 client->flags, data_arg.read_write,
371 data_arg.command, data_arg.size, NULL);
372
373 if (data_arg.data == NULL) {
374 dev_dbg(&client->adapter->dev,
375 "data is NULL pointer in ioctl I2C_SMBUS.\n");
376 return -EINVAL;
377 }
378
379 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
380 (data_arg.size == I2C_SMBUS_BYTE))
381 datasize = sizeof(data_arg.data->byte);
382 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
383 (data_arg.size == I2C_SMBUS_PROC_CALL))
384 datasize = sizeof(data_arg.data->word);
385 else /* size == smbus block, i2c block, or block proc. call */
386 datasize = sizeof(data_arg.data->block);
387
388 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
389 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
390 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
391 (data_arg.read_write == I2C_SMBUS_WRITE)) {
392 if (copy_from_user(&temp, data_arg.data, datasize))
393 return -EFAULT;
394 }
395 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
396 /* Convert old I2C block commands to the new
397 convention. This preserves binary compatibility. */
398 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
399 if (data_arg.read_write == I2C_SMBUS_READ)
400 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
401 }
402 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
403 data_arg.read_write, data_arg.command, data_arg.size, &temp);
404 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
405 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
406 (data_arg.read_write == I2C_SMBUS_READ))) {
407 if (copy_to_user(data_arg.data, &temp, datasize))
408 return -EFAULT;
409 }
410 return res;
411}
412
413static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
414{
415 struct i2c_client *client = file->private_data;
416 unsigned long funcs;
417
418 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
419 cmd, arg);
420
421 switch (cmd) {
422 case I2C_SLAVE:
423 case I2C_SLAVE_FORCE:
424 if ((arg > 0x3ff) ||
425 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
426 return -EINVAL;
427 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
428 return -EBUSY;
429 /* REVISIT: address could become busy later */
430 client->addr = arg;
431 return 0;
432 case I2C_TENBIT:
433 if (arg)
434 client->flags |= I2C_M_TEN;
435 else
436 client->flags &= ~I2C_M_TEN;
437 return 0;
438 case I2C_PEC:
439 /*
440 * Setting the PEC flag here won't affect kernel drivers,
441 * which will be using the i2c_client node registered with
442 * the driver model core. Likewise, when that client has
443 * the PEC flag already set, the i2c-dev driver won't see
444 * (or use) this setting.
445 */
446 if (arg)
447 client->flags |= I2C_CLIENT_PEC;
448 else
449 client->flags &= ~I2C_CLIENT_PEC;
450 return 0;
451 case I2C_FUNCS:
452 funcs = i2c_get_functionality(client->adapter);
453 return put_user(funcs, (unsigned long __user *)arg);
454
455 case I2C_RDWR:
456 return i2cdev_ioctl_rdwr(client, arg);
457
458 case I2C_SMBUS:
459 return i2cdev_ioctl_smbus(client, arg);
460
461 case I2C_RETRIES:
462 client->adapter->retries = arg;
463 break;
464 case I2C_TIMEOUT:
465 /* For historical reasons, user-space sets the timeout
466 * value in units of 10 ms.
467 */
468 client->adapter->timeout = msecs_to_jiffies(arg * 10);
469 break;
470 default:
471 /* NOTE: returning a fault code here could cause trouble
472 * in buggy userspace code. Some old kernel bugs returned
473 * zero in this case, and userspace code might accidentally
474 * have depended on that bug.
475 */
476 return -ENOTTY;
477 }
478 return 0;
479}
480
481static int i2cdev_open(struct inode *inode, struct file *file)
482{
483 unsigned int minor = iminor(inode);
484 struct i2c_client *client;
485 struct i2c_adapter *adap;
486 struct i2c_dev *i2c_dev;
487
488 i2c_dev = i2c_dev_get_by_minor(minor);
489 if (!i2c_dev)
490 return -ENODEV;
491
492 adap = i2c_get_adapter(i2c_dev->adap->nr);
493 if (!adap)
494 return -ENODEV;
495
496 /* This creates an anonymous i2c_client, which may later be
497 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
498 *
499 * This client is ** NEVER REGISTERED ** with the driver model
500 * or I2C core code!! It just holds private copies of addressing
501 * information and maybe a PEC flag.
502 */
503 client = kzalloc(sizeof(*client), GFP_KERNEL);
504 if (!client) {
505 i2c_put_adapter(adap);
506 return -ENOMEM;
507 }
508 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
509
510 client->adapter = adap;
511 file->private_data = client;
512
513 return 0;
514}
515
516static int i2cdev_release(struct inode *inode, struct file *file)
517{
518 struct i2c_client *client = file->private_data;
519
520 i2c_put_adapter(client->adapter);
521 kfree(client);
522 file->private_data = NULL;
523
524 return 0;
525}
526
527static const struct file_operations i2cdev_fops = {
528 .owner = THIS_MODULE,
529 .llseek = no_llseek,
530 .read = i2cdev_read,
531 .write = i2cdev_write,
532 .unlocked_ioctl = i2cdev_ioctl,
533 .open = i2cdev_open,
534 .release = i2cdev_release,
535};
536
537/* ------------------------------------------------------------------------- */
538
539static struct class *i2c_dev_class;
540
541static int i2cdev_attach_adapter(struct device *dev, void *dummy)
542{
543 struct i2c_adapter *adap;
544 struct i2c_dev *i2c_dev;
545 int res;
546
547 if (dev->type != &i2c_adapter_type)
548 return 0;
549 adap = to_i2c_adapter(dev);
550
551 i2c_dev = get_free_i2c_dev(adap);
552 if (IS_ERR(i2c_dev))
553 return PTR_ERR(i2c_dev);
554
555 /* register this i2c device with the driver core */
556 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
557 MKDEV(I2C_MAJOR, adap->nr), NULL,
558 "i2c-%d", adap->nr);
559 if (IS_ERR(i2c_dev->dev)) {
560 res = PTR_ERR(i2c_dev->dev);
561 goto error;
562 }
563
564 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
565 adap->name, adap->nr);
566 return 0;
567error:
568 return_i2c_dev(i2c_dev);
569 return res;
570}
571
572static int i2cdev_detach_adapter(struct device *dev, void *dummy)
573{
574 struct i2c_adapter *adap;
575 struct i2c_dev *i2c_dev;
576
577 if (dev->type != &i2c_adapter_type)
578 return 0;
579 adap = to_i2c_adapter(dev);
580
581 i2c_dev = i2c_dev_get_by_minor(adap->nr);
582 if (!i2c_dev) /* attach_adapter must have failed */
583 return 0;
584
585 return_i2c_dev(i2c_dev);
586 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
587
588 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
589 return 0;
590}
591
592static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
593 void *data)
594{
595 struct device *dev = data;
596
597 switch (action) {
598 case BUS_NOTIFY_ADD_DEVICE:
599 return i2cdev_attach_adapter(dev, NULL);
600 case BUS_NOTIFY_DEL_DEVICE:
601 return i2cdev_detach_adapter(dev, NULL);
602 }
603
604 return 0;
605}
606
607static struct notifier_block i2cdev_notifier = {
608 .notifier_call = i2cdev_notifier_call,
609};
610
611/* ------------------------------------------------------------------------- */
612
613/*
614 * module load/unload record keeping
615 */
616
617static int __init i2c_dev_init(void)
618{
619 int res;
620
621 printk(KERN_INFO "i2c /dev entries driver\n");
622
623 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
624 if (res)
625 goto out;
626
627 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
628 if (IS_ERR(i2c_dev_class)) {
629 res = PTR_ERR(i2c_dev_class);
630 goto out_unreg_chrdev;
631 }
632 i2c_dev_class->dev_groups = i2c_groups;
633
634 /* Keep track of adapters which will be added or removed later */
635 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
636 if (res)
637 goto out_unreg_class;
638
639 /* Bind to already existing adapters right away */
640 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
641
642 return 0;
643
644out_unreg_class:
645 class_destroy(i2c_dev_class);
646out_unreg_chrdev:
647 unregister_chrdev(I2C_MAJOR, "i2c");
648out:
649 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
650 return res;
651}
652
653static void __exit i2c_dev_exit(void)
654{
655 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
656 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
657 class_destroy(i2c_dev_class);
658 unregister_chrdev(I2C_MAJOR, "i2c");
659}
660
661MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
662 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
663MODULE_DESCRIPTION("I2C /dev entries driver");
664MODULE_LICENSE("GPL");
665
666module_init(i2c_dev_init);
667module_exit(i2c_dev_exit);
1/*
2 i2c-dev.c - i2c-bus driver, char device interface
3
4 Copyright (C) 1995-97 Simon G. Vogl
5 Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
21 MA 02110-1301 USA.
22*/
23
24/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
25 But I have used so much of his original code and ideas that it seems
26 only fair to recognize him as co-author -- Frodo */
27
28/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
29
30#include <linux/kernel.h>
31#include <linux/module.h>
32#include <linux/device.h>
33#include <linux/notifier.h>
34#include <linux/fs.h>
35#include <linux/slab.h>
36#include <linux/init.h>
37#include <linux/list.h>
38#include <linux/i2c.h>
39#include <linux/i2c-dev.h>
40#include <linux/jiffies.h>
41#include <linux/uaccess.h>
42
43/*
44 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
45 * slave (i2c_client) with which messages will be exchanged. It's coupled
46 * with a character special file which is accessed by user mode drivers.
47 *
48 * The list of i2c_dev structures is parallel to the i2c_adapter lists
49 * maintained by the driver model, and is updated using bus notifications.
50 */
51struct i2c_dev {
52 struct list_head list;
53 struct i2c_adapter *adap;
54 struct device *dev;
55};
56
57#define I2C_MINORS 256
58static LIST_HEAD(i2c_dev_list);
59static DEFINE_SPINLOCK(i2c_dev_list_lock);
60
61static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
62{
63 struct i2c_dev *i2c_dev;
64
65 spin_lock(&i2c_dev_list_lock);
66 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
67 if (i2c_dev->adap->nr == index)
68 goto found;
69 }
70 i2c_dev = NULL;
71found:
72 spin_unlock(&i2c_dev_list_lock);
73 return i2c_dev;
74}
75
76static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
77{
78 struct i2c_dev *i2c_dev;
79
80 if (adap->nr >= I2C_MINORS) {
81 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
82 adap->nr);
83 return ERR_PTR(-ENODEV);
84 }
85
86 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
87 if (!i2c_dev)
88 return ERR_PTR(-ENOMEM);
89 i2c_dev->adap = adap;
90
91 spin_lock(&i2c_dev_list_lock);
92 list_add_tail(&i2c_dev->list, &i2c_dev_list);
93 spin_unlock(&i2c_dev_list_lock);
94 return i2c_dev;
95}
96
97static void return_i2c_dev(struct i2c_dev *i2c_dev)
98{
99 spin_lock(&i2c_dev_list_lock);
100 list_del(&i2c_dev->list);
101 spin_unlock(&i2c_dev_list_lock);
102 kfree(i2c_dev);
103}
104
105static ssize_t name_show(struct device *dev,
106 struct device_attribute *attr, char *buf)
107{
108 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
109
110 if (!i2c_dev)
111 return -ENODEV;
112 return sprintf(buf, "%s\n", i2c_dev->adap->name);
113}
114static DEVICE_ATTR_RO(name);
115
116static struct attribute *i2c_attrs[] = {
117 &dev_attr_name.attr,
118 NULL,
119};
120ATTRIBUTE_GROUPS(i2c);
121
122/* ------------------------------------------------------------------------- */
123
124/*
125 * After opening an instance of this character special file, a file
126 * descriptor starts out associated only with an i2c_adapter (and bus).
127 *
128 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
129 * traffic to any devices on the bus used by that adapter. That's because
130 * the i2c_msg vectors embed all the addressing information they need, and
131 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
132 * don't support that interface.
133 *
134 * To use read()/write() system calls on that file descriptor, or to use
135 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
136 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
137 * (never registered) i2c_client so it holds the addressing information
138 * needed by those system calls and by this SMBus interface.
139 */
140
141static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
142 loff_t *offset)
143{
144 char *tmp;
145 int ret;
146
147 struct i2c_client *client = file->private_data;
148
149 if (count > 8192)
150 count = 8192;
151
152 tmp = kmalloc(count, GFP_KERNEL);
153 if (tmp == NULL)
154 return -ENOMEM;
155
156 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
157 iminor(file_inode(file)), count);
158
159 ret = i2c_master_recv(client, tmp, count);
160 if (ret >= 0)
161 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
162 kfree(tmp);
163 return ret;
164}
165
166static ssize_t i2cdev_write(struct file *file, const char __user *buf,
167 size_t count, loff_t *offset)
168{
169 int ret;
170 char *tmp;
171 struct i2c_client *client = file->private_data;
172
173 if (count > 8192)
174 count = 8192;
175
176 tmp = memdup_user(buf, count);
177 if (IS_ERR(tmp))
178 return PTR_ERR(tmp);
179
180 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
181 iminor(file_inode(file)), count);
182
183 ret = i2c_master_send(client, tmp, count);
184 kfree(tmp);
185 return ret;
186}
187
188static int i2cdev_check(struct device *dev, void *addrp)
189{
190 struct i2c_client *client = i2c_verify_client(dev);
191
192 if (!client || client->addr != *(unsigned int *)addrp)
193 return 0;
194
195 return dev->driver ? -EBUSY : 0;
196}
197
198/* walk up mux tree */
199static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
200{
201 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
202 int result;
203
204 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
205 if (!result && parent)
206 result = i2cdev_check_mux_parents(parent, addr);
207
208 return result;
209}
210
211/* recurse down mux tree */
212static int i2cdev_check_mux_children(struct device *dev, void *addrp)
213{
214 int result;
215
216 if (dev->type == &i2c_adapter_type)
217 result = device_for_each_child(dev, addrp,
218 i2cdev_check_mux_children);
219 else
220 result = i2cdev_check(dev, addrp);
221
222 return result;
223}
224
225/* This address checking function differs from the one in i2c-core
226 in that it considers an address with a registered device, but no
227 driver bound to it, as NOT busy. */
228static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
229{
230 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
231 int result = 0;
232
233 if (parent)
234 result = i2cdev_check_mux_parents(parent, addr);
235
236 if (!result)
237 result = device_for_each_child(&adapter->dev, &addr,
238 i2cdev_check_mux_children);
239
240 return result;
241}
242
243static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
244 unsigned long arg)
245{
246 struct i2c_rdwr_ioctl_data rdwr_arg;
247 struct i2c_msg *rdwr_pa;
248 u8 __user **data_ptrs;
249 int i, res;
250
251 if (copy_from_user(&rdwr_arg,
252 (struct i2c_rdwr_ioctl_data __user *)arg,
253 sizeof(rdwr_arg)))
254 return -EFAULT;
255
256 /* Put an arbitrary limit on the number of messages that can
257 * be sent at once */
258 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
259 return -EINVAL;
260
261 rdwr_pa = memdup_user(rdwr_arg.msgs,
262 rdwr_arg.nmsgs * sizeof(struct i2c_msg));
263 if (IS_ERR(rdwr_pa))
264 return PTR_ERR(rdwr_pa);
265
266 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
267 if (data_ptrs == NULL) {
268 kfree(rdwr_pa);
269 return -ENOMEM;
270 }
271
272 res = 0;
273 for (i = 0; i < rdwr_arg.nmsgs; i++) {
274 /* Limit the size of the message to a sane amount */
275 if (rdwr_pa[i].len > 8192) {
276 res = -EINVAL;
277 break;
278 }
279
280 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
281 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
282 if (IS_ERR(rdwr_pa[i].buf)) {
283 res = PTR_ERR(rdwr_pa[i].buf);
284 break;
285 }
286
287 /*
288 * If the message length is received from the slave (similar
289 * to SMBus block read), we must ensure that the buffer will
290 * be large enough to cope with a message length of
291 * I2C_SMBUS_BLOCK_MAX as this is the maximum underlying bus
292 * drivers allow. The first byte in the buffer must be
293 * pre-filled with the number of extra bytes, which must be
294 * at least one to hold the message length, but can be
295 * greater (for example to account for a checksum byte at
296 * the end of the message.)
297 */
298 if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
299 if (!(rdwr_pa[i].flags & I2C_M_RD) ||
300 rdwr_pa[i].buf[0] < 1 ||
301 rdwr_pa[i].len < rdwr_pa[i].buf[0] +
302 I2C_SMBUS_BLOCK_MAX) {
303 res = -EINVAL;
304 break;
305 }
306
307 rdwr_pa[i].len = rdwr_pa[i].buf[0];
308 }
309 }
310 if (res < 0) {
311 int j;
312 for (j = 0; j < i; ++j)
313 kfree(rdwr_pa[j].buf);
314 kfree(data_ptrs);
315 kfree(rdwr_pa);
316 return res;
317 }
318
319 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
320 while (i-- > 0) {
321 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
322 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
323 rdwr_pa[i].len))
324 res = -EFAULT;
325 }
326 kfree(rdwr_pa[i].buf);
327 }
328 kfree(data_ptrs);
329 kfree(rdwr_pa);
330 return res;
331}
332
333static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
334 unsigned long arg)
335{
336 struct i2c_smbus_ioctl_data data_arg;
337 union i2c_smbus_data temp;
338 int datasize, res;
339
340 if (copy_from_user(&data_arg,
341 (struct i2c_smbus_ioctl_data __user *) arg,
342 sizeof(struct i2c_smbus_ioctl_data)))
343 return -EFAULT;
344 if ((data_arg.size != I2C_SMBUS_BYTE) &&
345 (data_arg.size != I2C_SMBUS_QUICK) &&
346 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
347 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
348 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
349 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
350 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
351 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
352 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
353 dev_dbg(&client->adapter->dev,
354 "size out of range (%x) in ioctl I2C_SMBUS.\n",
355 data_arg.size);
356 return -EINVAL;
357 }
358 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
359 so the check is valid if size==I2C_SMBUS_QUICK too. */
360 if ((data_arg.read_write != I2C_SMBUS_READ) &&
361 (data_arg.read_write != I2C_SMBUS_WRITE)) {
362 dev_dbg(&client->adapter->dev,
363 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
364 data_arg.read_write);
365 return -EINVAL;
366 }
367
368 /* Note that command values are always valid! */
369
370 if ((data_arg.size == I2C_SMBUS_QUICK) ||
371 ((data_arg.size == I2C_SMBUS_BYTE) &&
372 (data_arg.read_write == I2C_SMBUS_WRITE)))
373 /* These are special: we do not use data */
374 return i2c_smbus_xfer(client->adapter, client->addr,
375 client->flags, data_arg.read_write,
376 data_arg.command, data_arg.size, NULL);
377
378 if (data_arg.data == NULL) {
379 dev_dbg(&client->adapter->dev,
380 "data is NULL pointer in ioctl I2C_SMBUS.\n");
381 return -EINVAL;
382 }
383
384 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
385 (data_arg.size == I2C_SMBUS_BYTE))
386 datasize = sizeof(data_arg.data->byte);
387 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
388 (data_arg.size == I2C_SMBUS_PROC_CALL))
389 datasize = sizeof(data_arg.data->word);
390 else /* size == smbus block, i2c block, or block proc. call */
391 datasize = sizeof(data_arg.data->block);
392
393 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
394 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
395 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
396 (data_arg.read_write == I2C_SMBUS_WRITE)) {
397 if (copy_from_user(&temp, data_arg.data, datasize))
398 return -EFAULT;
399 }
400 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
401 /* Convert old I2C block commands to the new
402 convention. This preserves binary compatibility. */
403 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
404 if (data_arg.read_write == I2C_SMBUS_READ)
405 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
406 }
407 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
408 data_arg.read_write, data_arg.command, data_arg.size, &temp);
409 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
410 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
411 (data_arg.read_write == I2C_SMBUS_READ))) {
412 if (copy_to_user(data_arg.data, &temp, datasize))
413 return -EFAULT;
414 }
415 return res;
416}
417
418static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
419{
420 struct i2c_client *client = file->private_data;
421 unsigned long funcs;
422
423 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
424 cmd, arg);
425
426 switch (cmd) {
427 case I2C_SLAVE:
428 case I2C_SLAVE_FORCE:
429 /* NOTE: devices set up to work with "new style" drivers
430 * can't use I2C_SLAVE, even when the device node is not
431 * bound to a driver. Only I2C_SLAVE_FORCE will work.
432 *
433 * Setting the PEC flag here won't affect kernel drivers,
434 * which will be using the i2c_client node registered with
435 * the driver model core. Likewise, when that client has
436 * the PEC flag already set, the i2c-dev driver won't see
437 * (or use) this setting.
438 */
439 if ((arg > 0x3ff) ||
440 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
441 return -EINVAL;
442 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
443 return -EBUSY;
444 /* REVISIT: address could become busy later */
445 client->addr = arg;
446 return 0;
447 case I2C_TENBIT:
448 if (arg)
449 client->flags |= I2C_M_TEN;
450 else
451 client->flags &= ~I2C_M_TEN;
452 return 0;
453 case I2C_PEC:
454 if (arg)
455 client->flags |= I2C_CLIENT_PEC;
456 else
457 client->flags &= ~I2C_CLIENT_PEC;
458 return 0;
459 case I2C_FUNCS:
460 funcs = i2c_get_functionality(client->adapter);
461 return put_user(funcs, (unsigned long __user *)arg);
462
463 case I2C_RDWR:
464 return i2cdev_ioctl_rdrw(client, arg);
465
466 case I2C_SMBUS:
467 return i2cdev_ioctl_smbus(client, arg);
468
469 case I2C_RETRIES:
470 client->adapter->retries = arg;
471 break;
472 case I2C_TIMEOUT:
473 /* For historical reasons, user-space sets the timeout
474 * value in units of 10 ms.
475 */
476 client->adapter->timeout = msecs_to_jiffies(arg * 10);
477 break;
478 default:
479 /* NOTE: returning a fault code here could cause trouble
480 * in buggy userspace code. Some old kernel bugs returned
481 * zero in this case, and userspace code might accidentally
482 * have depended on that bug.
483 */
484 return -ENOTTY;
485 }
486 return 0;
487}
488
489static int i2cdev_open(struct inode *inode, struct file *file)
490{
491 unsigned int minor = iminor(inode);
492 struct i2c_client *client;
493 struct i2c_adapter *adap;
494 struct i2c_dev *i2c_dev;
495
496 i2c_dev = i2c_dev_get_by_minor(minor);
497 if (!i2c_dev)
498 return -ENODEV;
499
500 adap = i2c_get_adapter(i2c_dev->adap->nr);
501 if (!adap)
502 return -ENODEV;
503
504 /* This creates an anonymous i2c_client, which may later be
505 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
506 *
507 * This client is ** NEVER REGISTERED ** with the driver model
508 * or I2C core code!! It just holds private copies of addressing
509 * information and maybe a PEC flag.
510 */
511 client = kzalloc(sizeof(*client), GFP_KERNEL);
512 if (!client) {
513 i2c_put_adapter(adap);
514 return -ENOMEM;
515 }
516 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
517
518 client->adapter = adap;
519 file->private_data = client;
520
521 return 0;
522}
523
524static int i2cdev_release(struct inode *inode, struct file *file)
525{
526 struct i2c_client *client = file->private_data;
527
528 i2c_put_adapter(client->adapter);
529 kfree(client);
530 file->private_data = NULL;
531
532 return 0;
533}
534
535static const struct file_operations i2cdev_fops = {
536 .owner = THIS_MODULE,
537 .llseek = no_llseek,
538 .read = i2cdev_read,
539 .write = i2cdev_write,
540 .unlocked_ioctl = i2cdev_ioctl,
541 .open = i2cdev_open,
542 .release = i2cdev_release,
543};
544
545/* ------------------------------------------------------------------------- */
546
547static struct class *i2c_dev_class;
548
549static int i2cdev_attach_adapter(struct device *dev, void *dummy)
550{
551 struct i2c_adapter *adap;
552 struct i2c_dev *i2c_dev;
553 int res;
554
555 if (dev->type != &i2c_adapter_type)
556 return 0;
557 adap = to_i2c_adapter(dev);
558
559 i2c_dev = get_free_i2c_dev(adap);
560 if (IS_ERR(i2c_dev))
561 return PTR_ERR(i2c_dev);
562
563 /* register this i2c device with the driver core */
564 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
565 MKDEV(I2C_MAJOR, adap->nr), NULL,
566 "i2c-%d", adap->nr);
567 if (IS_ERR(i2c_dev->dev)) {
568 res = PTR_ERR(i2c_dev->dev);
569 goto error;
570 }
571
572 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
573 adap->name, adap->nr);
574 return 0;
575error:
576 return_i2c_dev(i2c_dev);
577 return res;
578}
579
580static int i2cdev_detach_adapter(struct device *dev, void *dummy)
581{
582 struct i2c_adapter *adap;
583 struct i2c_dev *i2c_dev;
584
585 if (dev->type != &i2c_adapter_type)
586 return 0;
587 adap = to_i2c_adapter(dev);
588
589 i2c_dev = i2c_dev_get_by_minor(adap->nr);
590 if (!i2c_dev) /* attach_adapter must have failed */
591 return 0;
592
593 return_i2c_dev(i2c_dev);
594 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
595
596 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
597 return 0;
598}
599
600static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
601 void *data)
602{
603 struct device *dev = data;
604
605 switch (action) {
606 case BUS_NOTIFY_ADD_DEVICE:
607 return i2cdev_attach_adapter(dev, NULL);
608 case BUS_NOTIFY_DEL_DEVICE:
609 return i2cdev_detach_adapter(dev, NULL);
610 }
611
612 return 0;
613}
614
615static struct notifier_block i2cdev_notifier = {
616 .notifier_call = i2cdev_notifier_call,
617};
618
619/* ------------------------------------------------------------------------- */
620
621/*
622 * module load/unload record keeping
623 */
624
625static int __init i2c_dev_init(void)
626{
627 int res;
628
629 printk(KERN_INFO "i2c /dev entries driver\n");
630
631 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
632 if (res)
633 goto out;
634
635 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
636 if (IS_ERR(i2c_dev_class)) {
637 res = PTR_ERR(i2c_dev_class);
638 goto out_unreg_chrdev;
639 }
640 i2c_dev_class->dev_groups = i2c_groups;
641
642 /* Keep track of adapters which will be added or removed later */
643 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
644 if (res)
645 goto out_unreg_class;
646
647 /* Bind to already existing adapters right away */
648 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
649
650 return 0;
651
652out_unreg_class:
653 class_destroy(i2c_dev_class);
654out_unreg_chrdev:
655 unregister_chrdev(I2C_MAJOR, "i2c");
656out:
657 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
658 return res;
659}
660
661static void __exit i2c_dev_exit(void)
662{
663 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
664 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
665 class_destroy(i2c_dev_class);
666 unregister_chrdev(I2C_MAJOR, "i2c");
667}
668
669MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
670 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
671MODULE_DESCRIPTION("I2C /dev entries driver");
672MODULE_LICENSE("GPL");
673
674module_init(i2c_dev_init);
675module_exit(i2c_dev_exit);