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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
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);