drivers/net/wan: fix sparse warning: make symbol static
[linux-2.6/mini2440.git] / drivers / i2c / i2c-dev.c
blobc171988a9f517d7009319674265c47a10859a8c3
1 /*
2 i2c-dev.c - i2c-bus driver, char device interface
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>
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.
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.
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.
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 */
27 /* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/fs.h>
32 #include <linux/slab.h>
33 #include <linux/init.h>
34 #include <linux/list.h>
35 #include <linux/i2c.h>
36 #include <linux/i2c-dev.h>
37 #include <linux/smp_lock.h>
38 #include <asm/uaccess.h>
40 static struct i2c_driver i2cdev_driver;
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.
47 * The list of i2c_dev structures is parallel to the i2c_adapter lists
48 * maintained by the driver model, and is updated using notifications
49 * delivered to the i2cdev_driver.
51 struct i2c_dev {
52 struct list_head list;
53 struct i2c_adapter *adap;
54 struct device *dev;
57 #define I2C_MINORS 256
58 static LIST_HEAD(i2c_dev_list);
59 static DEFINE_SPINLOCK(i2c_dev_list_lock);
61 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
63 struct i2c_dev *i2c_dev;
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;
70 i2c_dev = NULL;
71 found:
72 spin_unlock(&i2c_dev_list_lock);
73 return i2c_dev;
76 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
78 struct i2c_dev *i2c_dev;
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);
86 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
87 if (!i2c_dev)
88 return ERR_PTR(-ENOMEM);
89 i2c_dev->adap = adap;
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;
97 static void return_i2c_dev(struct i2c_dev *i2c_dev)
99 spin_lock(&i2c_dev_list_lock);
100 list_del(&i2c_dev->list);
101 spin_unlock(&i2c_dev_list_lock);
102 kfree(i2c_dev);
105 static ssize_t show_adapter_name(struct device *dev,
106 struct device_attribute *attr, char *buf)
108 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
110 if (!i2c_dev)
111 return -ENODEV;
112 return sprintf(buf, "%s\n", i2c_dev->adap->name);
114 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
116 /* ------------------------------------------------------------------------- */
119 * After opening an instance of this character special file, a file
120 * descriptor starts out associated only with an i2c_adapter (and bus).
122 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
123 * traffic to any devices on the bus used by that adapter. That's because
124 * the i2c_msg vectors embed all the addressing information they need, and
125 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
126 * don't support that interface.
128 * To use read()/write() system calls on that file descriptor, or to use
129 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
130 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
131 * (never registered) i2c_client so it holds the addressing information
132 * needed by those system calls and by this SMBus interface.
135 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
136 loff_t *offset)
138 char *tmp;
139 int ret;
141 struct i2c_client *client = (struct i2c_client *)file->private_data;
143 if (count > 8192)
144 count = 8192;
146 tmp = kmalloc(count,GFP_KERNEL);
147 if (tmp==NULL)
148 return -ENOMEM;
150 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
151 iminor(file->f_path.dentry->d_inode), count);
153 ret = i2c_master_recv(client,tmp,count);
154 if (ret >= 0)
155 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
156 kfree(tmp);
157 return ret;
160 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
161 loff_t *offset)
163 int ret;
164 char *tmp;
165 struct i2c_client *client = (struct i2c_client *)file->private_data;
167 if (count > 8192)
168 count = 8192;
170 tmp = kmalloc(count,GFP_KERNEL);
171 if (tmp==NULL)
172 return -ENOMEM;
173 if (copy_from_user(tmp,buf,count)) {
174 kfree(tmp);
175 return -EFAULT;
178 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
179 iminor(file->f_path.dentry->d_inode), count);
181 ret = i2c_master_send(client,tmp,count);
182 kfree(tmp);
183 return ret;
186 static int i2cdev_check(struct device *dev, void *addrp)
188 struct i2c_client *client = i2c_verify_client(dev);
190 if (!client || client->addr != *(unsigned int *)addrp)
191 return 0;
193 return dev->driver ? -EBUSY : 0;
196 /* This address checking function differs from the one in i2c-core
197 in that it considers an address with a registered device, but no
198 driver bound to it, as NOT busy. */
199 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
201 return device_for_each_child(&adapter->dev, &addr, i2cdev_check);
204 static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
205 unsigned long arg)
207 struct i2c_rdwr_ioctl_data rdwr_arg;
208 struct i2c_msg *rdwr_pa;
209 u8 __user **data_ptrs;
210 int i, res;
212 if (copy_from_user(&rdwr_arg,
213 (struct i2c_rdwr_ioctl_data __user *)arg,
214 sizeof(rdwr_arg)))
215 return -EFAULT;
217 /* Put an arbitrary limit on the number of messages that can
218 * be sent at once */
219 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
220 return -EINVAL;
222 rdwr_pa = (struct i2c_msg *)
223 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
224 GFP_KERNEL);
225 if (!rdwr_pa)
226 return -ENOMEM;
228 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
229 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
230 kfree(rdwr_pa);
231 return -EFAULT;
234 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
235 if (data_ptrs == NULL) {
236 kfree(rdwr_pa);
237 return -ENOMEM;
240 res = 0;
241 for (i = 0; i < rdwr_arg.nmsgs; i++) {
242 /* Limit the size of the message to a sane amount;
243 * and don't let length change either. */
244 if ((rdwr_pa[i].len > 8192) ||
245 (rdwr_pa[i].flags & I2C_M_RECV_LEN)) {
246 res = -EINVAL;
247 break;
249 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
250 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
251 if (rdwr_pa[i].buf == NULL) {
252 res = -ENOMEM;
253 break;
255 if (copy_from_user(rdwr_pa[i].buf, data_ptrs[i],
256 rdwr_pa[i].len)) {
257 ++i; /* Needs to be kfreed too */
258 res = -EFAULT;
259 break;
262 if (res < 0) {
263 int j;
264 for (j = 0; j < i; ++j)
265 kfree(rdwr_pa[j].buf);
266 kfree(data_ptrs);
267 kfree(rdwr_pa);
268 return res;
271 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
272 while (i-- > 0) {
273 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
274 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
275 rdwr_pa[i].len))
276 res = -EFAULT;
278 kfree(rdwr_pa[i].buf);
280 kfree(data_ptrs);
281 kfree(rdwr_pa);
282 return res;
285 static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
286 unsigned long arg)
288 struct i2c_smbus_ioctl_data data_arg;
289 union i2c_smbus_data temp;
290 int datasize, res;
292 if (copy_from_user(&data_arg,
293 (struct i2c_smbus_ioctl_data __user *) arg,
294 sizeof(struct i2c_smbus_ioctl_data)))
295 return -EFAULT;
296 if ((data_arg.size != I2C_SMBUS_BYTE) &&
297 (data_arg.size != I2C_SMBUS_QUICK) &&
298 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
299 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
300 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
301 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
302 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
303 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
304 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
305 dev_dbg(&client->adapter->dev,
306 "size out of range (%x) in ioctl I2C_SMBUS.\n",
307 data_arg.size);
308 return -EINVAL;
310 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
311 so the check is valid if size==I2C_SMBUS_QUICK too. */
312 if ((data_arg.read_write != I2C_SMBUS_READ) &&
313 (data_arg.read_write != I2C_SMBUS_WRITE)) {
314 dev_dbg(&client->adapter->dev,
315 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
316 data_arg.read_write);
317 return -EINVAL;
320 /* Note that command values are always valid! */
322 if ((data_arg.size == I2C_SMBUS_QUICK) ||
323 ((data_arg.size == I2C_SMBUS_BYTE) &&
324 (data_arg.read_write == I2C_SMBUS_WRITE)))
325 /* These are special: we do not use data */
326 return i2c_smbus_xfer(client->adapter, client->addr,
327 client->flags, data_arg.read_write,
328 data_arg.command, data_arg.size, NULL);
330 if (data_arg.data == NULL) {
331 dev_dbg(&client->adapter->dev,
332 "data is NULL pointer in ioctl I2C_SMBUS.\n");
333 return -EINVAL;
336 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
337 (data_arg.size == I2C_SMBUS_BYTE))
338 datasize = sizeof(data_arg.data->byte);
339 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
340 (data_arg.size == I2C_SMBUS_PROC_CALL))
341 datasize = sizeof(data_arg.data->word);
342 else /* size == smbus block, i2c block, or block proc. call */
343 datasize = sizeof(data_arg.data->block);
345 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
346 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
347 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
348 (data_arg.read_write == I2C_SMBUS_WRITE)) {
349 if (copy_from_user(&temp, data_arg.data, datasize))
350 return -EFAULT;
352 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
353 /* Convert old I2C block commands to the new
354 convention. This preserves binary compatibility. */
355 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
356 if (data_arg.read_write == I2C_SMBUS_READ)
357 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
359 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
360 data_arg.read_write, data_arg.command, data_arg.size, &temp);
361 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
362 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
363 (data_arg.read_write == I2C_SMBUS_READ))) {
364 if (copy_to_user(data_arg.data, &temp, datasize))
365 return -EFAULT;
367 return res;
370 static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
372 struct i2c_client *client = (struct i2c_client *)file->private_data;
373 unsigned long funcs;
375 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
376 cmd, arg);
378 switch ( cmd ) {
379 case I2C_SLAVE:
380 case I2C_SLAVE_FORCE:
381 /* NOTE: devices set up to work with "new style" drivers
382 * can't use I2C_SLAVE, even when the device node is not
383 * bound to a driver. Only I2C_SLAVE_FORCE will work.
385 * Setting the PEC flag here won't affect kernel drivers,
386 * which will be using the i2c_client node registered with
387 * the driver model core. Likewise, when that client has
388 * the PEC flag already set, the i2c-dev driver won't see
389 * (or use) this setting.
391 if ((arg > 0x3ff) ||
392 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
393 return -EINVAL;
394 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
395 return -EBUSY;
396 /* REVISIT: address could become busy later */
397 client->addr = arg;
398 return 0;
399 case I2C_TENBIT:
400 if (arg)
401 client->flags |= I2C_M_TEN;
402 else
403 client->flags &= ~I2C_M_TEN;
404 return 0;
405 case I2C_PEC:
406 if (arg)
407 client->flags |= I2C_CLIENT_PEC;
408 else
409 client->flags &= ~I2C_CLIENT_PEC;
410 return 0;
411 case I2C_FUNCS:
412 funcs = i2c_get_functionality(client->adapter);
413 return put_user(funcs, (unsigned long __user *)arg);
415 case I2C_RDWR:
416 return i2cdev_ioctl_rdrw(client, arg);
418 case I2C_SMBUS:
419 return i2cdev_ioctl_smbus(client, arg);
421 case I2C_RETRIES:
422 client->adapter->retries = arg;
423 break;
424 case I2C_TIMEOUT:
425 client->adapter->timeout = arg;
426 break;
427 default:
428 /* NOTE: returning a fault code here could cause trouble
429 * in buggy userspace code. Some old kernel bugs returned
430 * zero in this case, and userspace code might accidentally
431 * have depended on that bug.
433 return -ENOTTY;
435 return 0;
438 static int i2cdev_open(struct inode *inode, struct file *file)
440 unsigned int minor = iminor(inode);
441 struct i2c_client *client;
442 struct i2c_adapter *adap;
443 struct i2c_dev *i2c_dev;
444 int ret = 0;
446 lock_kernel();
447 i2c_dev = i2c_dev_get_by_minor(minor);
448 if (!i2c_dev) {
449 ret = -ENODEV;
450 goto out;
453 adap = i2c_get_adapter(i2c_dev->adap->nr);
454 if (!adap) {
455 ret = -ENODEV;
456 goto out;
459 /* This creates an anonymous i2c_client, which may later be
460 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
462 * This client is ** NEVER REGISTERED ** with the driver model
463 * or I2C core code!! It just holds private copies of addressing
464 * information and maybe a PEC flag.
466 client = kzalloc(sizeof(*client), GFP_KERNEL);
467 if (!client) {
468 i2c_put_adapter(adap);
469 ret = -ENOMEM;
470 goto out;
472 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
473 client->driver = &i2cdev_driver;
475 client->adapter = adap;
476 file->private_data = client;
478 out:
479 unlock_kernel();
480 return ret;
483 static int i2cdev_release(struct inode *inode, struct file *file)
485 struct i2c_client *client = file->private_data;
487 i2c_put_adapter(client->adapter);
488 kfree(client);
489 file->private_data = NULL;
491 return 0;
494 static const struct file_operations i2cdev_fops = {
495 .owner = THIS_MODULE,
496 .llseek = no_llseek,
497 .read = i2cdev_read,
498 .write = i2cdev_write,
499 .unlocked_ioctl = i2cdev_ioctl,
500 .open = i2cdev_open,
501 .release = i2cdev_release,
504 /* ------------------------------------------------------------------------- */
507 * The legacy "i2cdev_driver" is used primarily to get notifications when
508 * I2C adapters are added or removed, so that each one gets an i2c_dev
509 * and is thus made available to userspace driver code.
512 static struct class *i2c_dev_class;
514 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
516 struct i2c_dev *i2c_dev;
517 int res;
519 i2c_dev = get_free_i2c_dev(adap);
520 if (IS_ERR(i2c_dev))
521 return PTR_ERR(i2c_dev);
523 /* register this i2c device with the driver core */
524 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
525 MKDEV(I2C_MAJOR, adap->nr), NULL,
526 "i2c-%d", adap->nr);
527 if (IS_ERR(i2c_dev->dev)) {
528 res = PTR_ERR(i2c_dev->dev);
529 goto error;
531 res = device_create_file(i2c_dev->dev, &dev_attr_name);
532 if (res)
533 goto error_destroy;
535 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
536 adap->name, adap->nr);
537 return 0;
538 error_destroy:
539 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
540 error:
541 return_i2c_dev(i2c_dev);
542 return res;
545 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
547 struct i2c_dev *i2c_dev;
549 i2c_dev = i2c_dev_get_by_minor(adap->nr);
550 if (!i2c_dev) /* attach_adapter must have failed */
551 return 0;
553 device_remove_file(i2c_dev->dev, &dev_attr_name);
554 return_i2c_dev(i2c_dev);
555 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
557 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
558 return 0;
561 static struct i2c_driver i2cdev_driver = {
562 .driver = {
563 .name = "dev_driver",
565 .attach_adapter = i2cdev_attach_adapter,
566 .detach_adapter = i2cdev_detach_adapter,
569 /* ------------------------------------------------------------------------- */
572 * module load/unload record keeping
575 static int __init i2c_dev_init(void)
577 int res;
579 printk(KERN_INFO "i2c /dev entries driver\n");
581 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
582 if (res)
583 goto out;
585 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
586 if (IS_ERR(i2c_dev_class)) {
587 res = PTR_ERR(i2c_dev_class);
588 goto out_unreg_chrdev;
591 res = i2c_add_driver(&i2cdev_driver);
592 if (res)
593 goto out_unreg_class;
595 return 0;
597 out_unreg_class:
598 class_destroy(i2c_dev_class);
599 out_unreg_chrdev:
600 unregister_chrdev(I2C_MAJOR, "i2c");
601 out:
602 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
603 return res;
606 static void __exit i2c_dev_exit(void)
608 i2c_del_driver(&i2cdev_driver);
609 class_destroy(i2c_dev_class);
610 unregister_chrdev(I2C_MAJOR,"i2c");
613 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
614 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
615 MODULE_DESCRIPTION("I2C /dev entries driver");
616 MODULE_LICENSE("GPL");
618 module_init(i2c_dev_init);
619 module_exit(i2c_dev_exit);