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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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
21*/
22
23/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
24 But I have used so much of his original code and ideas that it seems
25 only fair to recognize him as co-author -- Frodo */
26
27/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
28
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/device.h>
32#include <linux/notifier.h>
33#include <linux/fs.h>
34#include <linux/slab.h>
35#include <linux/init.h>
36#include <linux/list.h>
37#include <linux/i2c.h>
38#include <linux/i2c-dev.h>
39#include <linux/jiffies.h>
40#include <linux/uaccess.h>
41
42/*
43 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
44 * slave (i2c_client) with which messages will be exchanged. It's coupled
45 * with a character special file which is accessed by user mode drivers.
46 *
47 * The list of i2c_dev structures is parallel to the i2c_adapter lists
48 * maintained by the driver model, and is updated using bus notifications.
49 */
50struct i2c_dev {
51 struct list_head list;
52 struct i2c_adapter *adap;
53 struct device *dev;
54};
55
56#define I2C_MINORS 256
57static LIST_HEAD(i2c_dev_list);
58static DEFINE_SPINLOCK(i2c_dev_list_lock);
59
60static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
61{
62 struct i2c_dev *i2c_dev;
63
64 spin_lock(&i2c_dev_list_lock);
65 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
66 if (i2c_dev->adap->nr == index)
67 goto found;
68 }
69 i2c_dev = NULL;
70found:
71 spin_unlock(&i2c_dev_list_lock);
72 return i2c_dev;
73}
74
75static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
76{
77 struct i2c_dev *i2c_dev;
78
79 if (adap->nr >= I2C_MINORS) {
80 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
81 adap->nr);
82 return ERR_PTR(-ENODEV);
83 }
84
85 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
86 if (!i2c_dev)
87 return ERR_PTR(-ENOMEM);
88 i2c_dev->adap = adap;
89
90 spin_lock(&i2c_dev_list_lock);
91 list_add_tail(&i2c_dev->list, &i2c_dev_list);
92 spin_unlock(&i2c_dev_list_lock);
93 return i2c_dev;
94}
95
96static void return_i2c_dev(struct i2c_dev *i2c_dev)
97{
98 spin_lock(&i2c_dev_list_lock);
99 list_del(&i2c_dev->list);
100 spin_unlock(&i2c_dev_list_lock);
101 kfree(i2c_dev);
102}
103
104static ssize_t show_adapter_name(struct device *dev,
105 struct device_attribute *attr, char *buf)
106{
107 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
108
109 if (!i2c_dev)
110 return -ENODEV;
111 return sprintf(buf, "%s\n", i2c_dev->adap->name);
112}
113static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
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 = kmalloc(count, GFP_KERNEL);
146 if (tmp == NULL)
147 return -ENOMEM;
148
149 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
150 iminor(file->f_path.dentry->d_inode), count);
151
152 ret = i2c_master_recv(client, tmp, count);
153 if (ret >= 0)
154 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
155 kfree(tmp);
156 return ret;
157}
158
159static ssize_t i2cdev_write(struct file *file, const char __user *buf,
160 size_t count, loff_t *offset)
161{
162 int ret;
163 char *tmp;
164 struct i2c_client *client = file->private_data;
165
166 if (count > 8192)
167 count = 8192;
168
169 tmp = memdup_user(buf, count);
170 if (IS_ERR(tmp))
171 return PTR_ERR(tmp);
172
173 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
174 iminor(file->f_path.dentry->d_inode), count);
175
176 ret = i2c_master_send(client, tmp, count);
177 kfree(tmp);
178 return ret;
179}
180
181static int i2cdev_check(struct device *dev, void *addrp)
182{
183 struct i2c_client *client = i2c_verify_client(dev);
184
185 if (!client || client->addr != *(unsigned int *)addrp)
186 return 0;
187
188 return dev->driver ? -EBUSY : 0;
189}
190
191/* walk up mux tree */
192static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
193{
194 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
195 int result;
196
197 result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
198 if (!result && parent)
199 result = i2cdev_check_mux_parents(parent, addr);
200
201 return result;
202}
203
204/* recurse down mux tree */
205static int i2cdev_check_mux_children(struct device *dev, void *addrp)
206{
207 int result;
208
209 if (dev->type == &i2c_adapter_type)
210 result = device_for_each_child(dev, addrp,
211 i2cdev_check_mux_children);
212 else
213 result = i2cdev_check(dev, addrp);
214
215 return result;
216}
217
218/* This address checking function differs from the one in i2c-core
219 in that it considers an address with a registered device, but no
220 driver bound to it, as NOT busy. */
221static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
222{
223 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
224 int result = 0;
225
226 if (parent)
227 result = i2cdev_check_mux_parents(parent, addr);
228
229 if (!result)
230 result = device_for_each_child(&adapter->dev, &addr,
231 i2cdev_check_mux_children);
232
233 return result;
234}
235
236static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
237 unsigned long arg)
238{
239 struct i2c_rdwr_ioctl_data rdwr_arg;
240 struct i2c_msg *rdwr_pa;
241 u8 __user **data_ptrs;
242 int i, res;
243
244 if (copy_from_user(&rdwr_arg,
245 (struct i2c_rdwr_ioctl_data __user *)arg,
246 sizeof(rdwr_arg)))
247 return -EFAULT;
248
249 /* Put an arbitrary limit on the number of messages that can
250 * be sent at once */
251 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
252 return -EINVAL;
253
254 rdwr_pa = kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), GFP_KERNEL);
255 if (!rdwr_pa)
256 return -ENOMEM;
257
258 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
259 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
260 kfree(rdwr_pa);
261 return -EFAULT;
262 }
263
264 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
265 if (data_ptrs == NULL) {
266 kfree(rdwr_pa);
267 return -ENOMEM;
268 }
269
270 res = 0;
271 for (i = 0; i < rdwr_arg.nmsgs; i++) {
272 /* Limit the size of the message to a sane amount;
273 * and don't let length change either. */
274 if ((rdwr_pa[i].len > 8192) ||
275 (rdwr_pa[i].flags & I2C_M_RECV_LEN)) {
276 res = -EINVAL;
277 break;
278 }
279 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
280 rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
281 if (IS_ERR(rdwr_pa[i].buf)) {
282 res = PTR_ERR(rdwr_pa[i].buf);
283 break;
284 }
285 }
286 if (res < 0) {
287 int j;
288 for (j = 0; j < i; ++j)
289 kfree(rdwr_pa[j].buf);
290 kfree(data_ptrs);
291 kfree(rdwr_pa);
292 return res;
293 }
294
295 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
296 while (i-- > 0) {
297 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
298 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
299 rdwr_pa[i].len))
300 res = -EFAULT;
301 }
302 kfree(rdwr_pa[i].buf);
303 }
304 kfree(data_ptrs);
305 kfree(rdwr_pa);
306 return res;
307}
308
309static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
310 unsigned long arg)
311{
312 struct i2c_smbus_ioctl_data data_arg;
313 union i2c_smbus_data temp;
314 int datasize, res;
315
316 if (copy_from_user(&data_arg,
317 (struct i2c_smbus_ioctl_data __user *) arg,
318 sizeof(struct i2c_smbus_ioctl_data)))
319 return -EFAULT;
320 if ((data_arg.size != I2C_SMBUS_BYTE) &&
321 (data_arg.size != I2C_SMBUS_QUICK) &&
322 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
323 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
324 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
325 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
326 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
327 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
328 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
329 dev_dbg(&client->adapter->dev,
330 "size out of range (%x) in ioctl I2C_SMBUS.\n",
331 data_arg.size);
332 return -EINVAL;
333 }
334 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
335 so the check is valid if size==I2C_SMBUS_QUICK too. */
336 if ((data_arg.read_write != I2C_SMBUS_READ) &&
337 (data_arg.read_write != I2C_SMBUS_WRITE)) {
338 dev_dbg(&client->adapter->dev,
339 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
340 data_arg.read_write);
341 return -EINVAL;
342 }
343
344 /* Note that command values are always valid! */
345
346 if ((data_arg.size == I2C_SMBUS_QUICK) ||
347 ((data_arg.size == I2C_SMBUS_BYTE) &&
348 (data_arg.read_write == I2C_SMBUS_WRITE)))
349 /* These are special: we do not use data */
350 return i2c_smbus_xfer(client->adapter, client->addr,
351 client->flags, data_arg.read_write,
352 data_arg.command, data_arg.size, NULL);
353
354 if (data_arg.data == NULL) {
355 dev_dbg(&client->adapter->dev,
356 "data is NULL pointer in ioctl I2C_SMBUS.\n");
357 return -EINVAL;
358 }
359
360 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
361 (data_arg.size == I2C_SMBUS_BYTE))
362 datasize = sizeof(data_arg.data->byte);
363 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
364 (data_arg.size == I2C_SMBUS_PROC_CALL))
365 datasize = sizeof(data_arg.data->word);
366 else /* size == smbus block, i2c block, or block proc. call */
367 datasize = sizeof(data_arg.data->block);
368
369 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
370 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
371 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
372 (data_arg.read_write == I2C_SMBUS_WRITE)) {
373 if (copy_from_user(&temp, data_arg.data, datasize))
374 return -EFAULT;
375 }
376 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
377 /* Convert old I2C block commands to the new
378 convention. This preserves binary compatibility. */
379 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
380 if (data_arg.read_write == I2C_SMBUS_READ)
381 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
382 }
383 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
384 data_arg.read_write, data_arg.command, data_arg.size, &temp);
385 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
386 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
387 (data_arg.read_write == I2C_SMBUS_READ))) {
388 if (copy_to_user(data_arg.data, &temp, datasize))
389 return -EFAULT;
390 }
391 return res;
392}
393
394static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
395{
396 struct i2c_client *client = file->private_data;
397 unsigned long funcs;
398
399 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
400 cmd, arg);
401
402 switch (cmd) {
403 case I2C_SLAVE:
404 case I2C_SLAVE_FORCE:
405 /* NOTE: devices set up to work with "new style" drivers
406 * can't use I2C_SLAVE, even when the device node is not
407 * bound to a driver. Only I2C_SLAVE_FORCE will work.
408 *
409 * Setting the PEC flag here won't affect kernel drivers,
410 * which will be using the i2c_client node registered with
411 * the driver model core. Likewise, when that client has
412 * the PEC flag already set, the i2c-dev driver won't see
413 * (or use) this setting.
414 */
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 if (arg)
431 client->flags |= I2C_CLIENT_PEC;
432 else
433 client->flags &= ~I2C_CLIENT_PEC;
434 return 0;
435 case I2C_FUNCS:
436 funcs = i2c_get_functionality(client->adapter);
437 return put_user(funcs, (unsigned long __user *)arg);
438
439 case I2C_RDWR:
440 return i2cdev_ioctl_rdrw(client, arg);
441
442 case I2C_SMBUS:
443 return i2cdev_ioctl_smbus(client, arg);
444
445 case I2C_RETRIES:
446 client->adapter->retries = arg;
447 break;
448 case I2C_TIMEOUT:
449 /* For historical reasons, user-space sets the timeout
450 * value in units of 10 ms.
451 */
452 client->adapter->timeout = msecs_to_jiffies(arg * 10);
453 break;
454 default:
455 /* NOTE: returning a fault code here could cause trouble
456 * in buggy userspace code. Some old kernel bugs returned
457 * zero in this case, and userspace code might accidentally
458 * have depended on that bug.
459 */
460 return -ENOTTY;
461 }
462 return 0;
463}
464
465static int i2cdev_open(struct inode *inode, struct file *file)
466{
467 unsigned int minor = iminor(inode);
468 struct i2c_client *client;
469 struct i2c_adapter *adap;
470 struct i2c_dev *i2c_dev;
471
472 i2c_dev = i2c_dev_get_by_minor(minor);
473 if (!i2c_dev)
474 return -ENODEV;
475
476 adap = i2c_get_adapter(i2c_dev->adap->nr);
477 if (!adap)
478 return -ENODEV;
479
480 /* This creates an anonymous i2c_client, which may later be
481 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
482 *
483 * This client is ** NEVER REGISTERED ** with the driver model
484 * or I2C core code!! It just holds private copies of addressing
485 * information and maybe a PEC flag.
486 */
487 client = kzalloc(sizeof(*client), GFP_KERNEL);
488 if (!client) {
489 i2c_put_adapter(adap);
490 return -ENOMEM;
491 }
492 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
493
494 client->adapter = adap;
495 file->private_data = client;
496
497 return 0;
498}
499
500static int i2cdev_release(struct inode *inode, struct file *file)
501{
502 struct i2c_client *client = file->private_data;
503
504 i2c_put_adapter(client->adapter);
505 kfree(client);
506 file->private_data = NULL;
507
508 return 0;
509}
510
511static const struct file_operations i2cdev_fops = {
512 .owner = THIS_MODULE,
513 .llseek = no_llseek,
514 .read = i2cdev_read,
515 .write = i2cdev_write,
516 .unlocked_ioctl = i2cdev_ioctl,
517 .open = i2cdev_open,
518 .release = i2cdev_release,
519};
520
521/* ------------------------------------------------------------------------- */
522
523static struct class *i2c_dev_class;
524
525static int i2cdev_attach_adapter(struct device *dev, void *dummy)
526{
527 struct i2c_adapter *adap;
528 struct i2c_dev *i2c_dev;
529 int res;
530
531 if (dev->type != &i2c_adapter_type)
532 return 0;
533 adap = to_i2c_adapter(dev);
534
535 i2c_dev = get_free_i2c_dev(adap);
536 if (IS_ERR(i2c_dev))
537 return PTR_ERR(i2c_dev);
538
539 /* register this i2c device with the driver core */
540 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
541 MKDEV(I2C_MAJOR, adap->nr), NULL,
542 "i2c-%d", adap->nr);
543 if (IS_ERR(i2c_dev->dev)) {
544 res = PTR_ERR(i2c_dev->dev);
545 goto error;
546 }
547 res = device_create_file(i2c_dev->dev, &dev_attr_name);
548 if (res)
549 goto error_destroy;
550
551 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
552 adap->name, adap->nr);
553 return 0;
554error_destroy:
555 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
556error:
557 return_i2c_dev(i2c_dev);
558 return res;
559}
560
561static int i2cdev_detach_adapter(struct device *dev, void *dummy)
562{
563 struct i2c_adapter *adap;
564 struct i2c_dev *i2c_dev;
565
566 if (dev->type != &i2c_adapter_type)
567 return 0;
568 adap = to_i2c_adapter(dev);
569
570 i2c_dev = i2c_dev_get_by_minor(adap->nr);
571 if (!i2c_dev) /* attach_adapter must have failed */
572 return 0;
573
574 device_remove_file(i2c_dev->dev, &dev_attr_name);
575 return_i2c_dev(i2c_dev);
576 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
577
578 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
579 return 0;
580}
581
582int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
583 void *data)
584{
585 struct device *dev = data;
586
587 switch (action) {
588 case BUS_NOTIFY_ADD_DEVICE:
589 return i2cdev_attach_adapter(dev, NULL);
590 case BUS_NOTIFY_DEL_DEVICE:
591 return i2cdev_detach_adapter(dev, NULL);
592 }
593
594 return 0;
595}
596
597static struct notifier_block i2cdev_notifier = {
598 .notifier_call = i2cdev_notifier_call,
599};
600
601/* ------------------------------------------------------------------------- */
602
603/*
604 * module load/unload record keeping
605 */
606
607static int __init i2c_dev_init(void)
608{
609 int res;
610
611 printk(KERN_INFO "i2c /dev entries driver\n");
612
613 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
614 if (res)
615 goto out;
616
617 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
618 if (IS_ERR(i2c_dev_class)) {
619 res = PTR_ERR(i2c_dev_class);
620 goto out_unreg_chrdev;
621 }
622
623 /* Keep track of adapters which will be added or removed later */
624 res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
625 if (res)
626 goto out_unreg_class;
627
628 /* Bind to already existing adapters right away */
629 i2c_for_each_dev(NULL, i2cdev_attach_adapter);
630
631 return 0;
632
633out_unreg_class:
634 class_destroy(i2c_dev_class);
635out_unreg_chrdev:
636 unregister_chrdev(I2C_MAJOR, "i2c");
637out:
638 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
639 return res;
640}
641
642static void __exit i2c_dev_exit(void)
643{
644 bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);
645 i2c_for_each_dev(NULL, i2cdev_detach_adapter);
646 class_destroy(i2c_dev_class);
647 unregister_chrdev(I2C_MAJOR, "i2c");
648}
649
650MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
651 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
652MODULE_DESCRIPTION("I2C /dev entries driver");
653MODULE_LICENSE("GPL");
654
655module_init(i2c_dev_init);
656module_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);