[PATCH] mark struct file_operations const 3
[linux-2.6.git] / drivers / i2c / i2c-dev.c
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/fs.h>
32 #include <linux/slab.h>
33 #include <linux/smp_lock.h>
34 #include <linux/init.h>
35 #include <linux/list.h>
36 #include <linux/i2c.h>
37 #include <linux/i2c-dev.h>
38 #include <asm/uaccess.h>
39
40 static struct i2c_driver i2cdev_driver;
41
42 struct i2c_dev {
43         struct list_head list;
44         struct i2c_adapter *adap;
45         struct device *dev;
46 };
47
48 #define I2C_MINORS      256
49 static LIST_HEAD(i2c_dev_list);
50 static DEFINE_SPINLOCK(i2c_dev_list_lock);
51
52 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
53 {
54         struct i2c_dev *i2c_dev;
55
56         spin_lock(&i2c_dev_list_lock);
57         list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
58                 if (i2c_dev->adap->nr == index)
59                         goto found;
60         }
61         i2c_dev = NULL;
62 found:
63         spin_unlock(&i2c_dev_list_lock);
64         return i2c_dev;
65 }
66
67 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
68 {
69         struct i2c_dev *i2c_dev;
70
71         if (adap->nr >= I2C_MINORS) {
72                 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
73                        adap->nr);
74                 return ERR_PTR(-ENODEV);
75         }
76
77         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
78         if (!i2c_dev)
79                 return ERR_PTR(-ENOMEM);
80         i2c_dev->adap = adap;
81
82         spin_lock(&i2c_dev_list_lock);
83         list_add_tail(&i2c_dev->list, &i2c_dev_list);
84         spin_unlock(&i2c_dev_list_lock);
85         return i2c_dev;
86 }
87
88 static void return_i2c_dev(struct i2c_dev *i2c_dev)
89 {
90         spin_lock(&i2c_dev_list_lock);
91         list_del(&i2c_dev->list);
92         spin_unlock(&i2c_dev_list_lock);
93         kfree(i2c_dev);
94 }
95
96 static ssize_t show_adapter_name(struct device *dev,
97                                  struct device_attribute *attr, char *buf)
98 {
99         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
100
101         if (!i2c_dev)
102                 return -ENODEV;
103         return sprintf(buf, "%s\n", i2c_dev->adap->name);
104 }
105 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
106
107 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
108                             loff_t *offset)
109 {
110         char *tmp;
111         int ret;
112
113         struct i2c_client *client = (struct i2c_client *)file->private_data;
114
115         if (count > 8192)
116                 count = 8192;
117
118         tmp = kmalloc(count,GFP_KERNEL);
119         if (tmp==NULL)
120                 return -ENOMEM;
121
122         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
123                 iminor(file->f_path.dentry->d_inode), count);
124
125         ret = i2c_master_recv(client,tmp,count);
126         if (ret >= 0)
127                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
128         kfree(tmp);
129         return ret;
130 }
131
132 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
133                              loff_t *offset)
134 {
135         int ret;
136         char *tmp;
137         struct i2c_client *client = (struct i2c_client *)file->private_data;
138
139         if (count > 8192)
140                 count = 8192;
141
142         tmp = kmalloc(count,GFP_KERNEL);
143         if (tmp==NULL)
144                 return -ENOMEM;
145         if (copy_from_user(tmp,buf,count)) {
146                 kfree(tmp);
147                 return -EFAULT;
148         }
149
150         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
151                 iminor(file->f_path.dentry->d_inode), count);
152
153         ret = i2c_master_send(client,tmp,count);
154         kfree(tmp);
155         return ret;
156 }
157
158 static int i2cdev_ioctl(struct inode *inode, struct file *file,
159                 unsigned int cmd, unsigned long arg)
160 {
161         struct i2c_client *client = (struct i2c_client *)file->private_data;
162         struct i2c_rdwr_ioctl_data rdwr_arg;
163         struct i2c_smbus_ioctl_data data_arg;
164         union i2c_smbus_data temp;
165         struct i2c_msg *rdwr_pa;
166         u8 __user **data_ptrs;
167         int i,datasize,res;
168         unsigned long funcs;
169
170         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
171                 cmd, arg);
172
173         switch ( cmd ) {
174         case I2C_SLAVE:
175         case I2C_SLAVE_FORCE:
176                 if ((arg > 0x3ff) ||
177                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
178                         return -EINVAL;
179                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
180                         return -EBUSY;
181                 client->addr = arg;
182                 return 0;
183         case I2C_TENBIT:
184                 if (arg)
185                         client->flags |= I2C_M_TEN;
186                 else
187                         client->flags &= ~I2C_M_TEN;
188                 return 0;
189         case I2C_PEC:
190                 if (arg)
191                         client->flags |= I2C_CLIENT_PEC;
192                 else
193                         client->flags &= ~I2C_CLIENT_PEC;
194                 return 0;
195         case I2C_FUNCS:
196                 funcs = i2c_get_functionality(client->adapter);
197                 return put_user(funcs, (unsigned long __user *)arg);
198
199         case I2C_RDWR:
200                 if (copy_from_user(&rdwr_arg,
201                                    (struct i2c_rdwr_ioctl_data __user *)arg,
202                                    sizeof(rdwr_arg)))
203                         return -EFAULT;
204
205                 /* Put an arbitrary limit on the number of messages that can
206                  * be sent at once */
207                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
208                         return -EINVAL;
209
210                 rdwr_pa = (struct i2c_msg *)
211                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
212                         GFP_KERNEL);
213
214                 if (rdwr_pa == NULL) return -ENOMEM;
215
216                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
217                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
218                         kfree(rdwr_pa);
219                         return -EFAULT;
220                 }
221
222                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
223                 if (data_ptrs == NULL) {
224                         kfree(rdwr_pa);
225                         return -ENOMEM;
226                 }
227
228                 res = 0;
229                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
230                         /* Limit the size of the message to a sane amount */
231                         if (rdwr_pa[i].len > 8192) {
232                                 res = -EINVAL;
233                                 break;
234                         }
235                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
236                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
237                         if(rdwr_pa[i].buf == NULL) {
238                                 res = -ENOMEM;
239                                 break;
240                         }
241                         if(copy_from_user(rdwr_pa[i].buf,
242                                 data_ptrs[i],
243                                 rdwr_pa[i].len)) {
244                                         ++i; /* Needs to be kfreed too */
245                                         res = -EFAULT;
246                                 break;
247                         }
248                 }
249                 if (res < 0) {
250                         int j;
251                         for (j = 0; j < i; ++j)
252                                 kfree(rdwr_pa[j].buf);
253                         kfree(data_ptrs);
254                         kfree(rdwr_pa);
255                         return res;
256                 }
257
258                 res = i2c_transfer(client->adapter,
259                         rdwr_pa,
260                         rdwr_arg.nmsgs);
261                 while(i-- > 0) {
262                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
263                                 if(copy_to_user(
264                                         data_ptrs[i],
265                                         rdwr_pa[i].buf,
266                                         rdwr_pa[i].len)) {
267                                         res = -EFAULT;
268                                 }
269                         }
270                         kfree(rdwr_pa[i].buf);
271                 }
272                 kfree(data_ptrs);
273                 kfree(rdwr_pa);
274                 return res;
275
276         case I2C_SMBUS:
277                 if (copy_from_user(&data_arg,
278                                    (struct i2c_smbus_ioctl_data __user *) arg,
279                                    sizeof(struct i2c_smbus_ioctl_data)))
280                         return -EFAULT;
281                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
282                     (data_arg.size != I2C_SMBUS_QUICK) &&
283                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
284                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
285                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
286                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
287                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
288                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
289                         dev_dbg(&client->adapter->dev,
290                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
291                                 data_arg.size);
292                         return -EINVAL;
293                 }
294                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
295                    so the check is valid if size==I2C_SMBUS_QUICK too. */
296                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
297                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
298                         dev_dbg(&client->adapter->dev,
299                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
300                                 data_arg.read_write);
301                         return -EINVAL;
302                 }
303
304                 /* Note that command values are always valid! */
305
306                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
307                     ((data_arg.size == I2C_SMBUS_BYTE) &&
308                     (data_arg.read_write == I2C_SMBUS_WRITE)))
309                         /* These are special: we do not use data */
310                         return i2c_smbus_xfer(client->adapter, client->addr,
311                                               client->flags,
312                                               data_arg.read_write,
313                                               data_arg.command,
314                                               data_arg.size, NULL);
315
316                 if (data_arg.data == NULL) {
317                         dev_dbg(&client->adapter->dev,
318                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
319                         return -EINVAL;
320                 }
321
322                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
323                     (data_arg.size == I2C_SMBUS_BYTE))
324                         datasize = sizeof(data_arg.data->byte);
325                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
326                          (data_arg.size == I2C_SMBUS_PROC_CALL))
327                         datasize = sizeof(data_arg.data->word);
328                 else /* size == smbus block, i2c block, or block proc. call */
329                         datasize = sizeof(data_arg.data->block);
330
331                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
332                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
333                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
334                         if (copy_from_user(&temp, data_arg.data, datasize))
335                                 return -EFAULT;
336                 }
337                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
338                       data_arg.read_write,
339                       data_arg.command,data_arg.size,&temp);
340                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
341                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
342                               (data_arg.read_write == I2C_SMBUS_READ))) {
343                         if (copy_to_user(data_arg.data, &temp, datasize))
344                                 return -EFAULT;
345                 }
346                 return res;
347
348         default:
349                 return i2c_control(client,cmd,arg);
350         }
351         return 0;
352 }
353
354 static int i2cdev_open(struct inode *inode, struct file *file)
355 {
356         unsigned int minor = iminor(inode);
357         struct i2c_client *client;
358         struct i2c_adapter *adap;
359         struct i2c_dev *i2c_dev;
360
361         i2c_dev = i2c_dev_get_by_minor(minor);
362         if (!i2c_dev)
363                 return -ENODEV;
364
365         adap = i2c_get_adapter(i2c_dev->adap->nr);
366         if (!adap)
367                 return -ENODEV;
368
369         client = kzalloc(sizeof(*client), GFP_KERNEL);
370         if (!client) {
371                 i2c_put_adapter(adap);
372                 return -ENOMEM;
373         }
374         snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
375         client->driver = &i2cdev_driver;
376
377         /* registered with adapter, passed as client to user */
378         client->adapter = adap;
379         file->private_data = client;
380
381         return 0;
382 }
383
384 static int i2cdev_release(struct inode *inode, struct file *file)
385 {
386         struct i2c_client *client = file->private_data;
387
388         i2c_put_adapter(client->adapter);
389         kfree(client);
390         file->private_data = NULL;
391
392         return 0;
393 }
394
395 static const struct file_operations i2cdev_fops = {
396         .owner          = THIS_MODULE,
397         .llseek         = no_llseek,
398         .read           = i2cdev_read,
399         .write          = i2cdev_write,
400         .ioctl          = i2cdev_ioctl,
401         .open           = i2cdev_open,
402         .release        = i2cdev_release,
403 };
404
405 static struct class *i2c_dev_class;
406
407 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
408 {
409         struct i2c_dev *i2c_dev;
410         int res;
411
412         i2c_dev = get_free_i2c_dev(adap);
413         if (IS_ERR(i2c_dev))
414                 return PTR_ERR(i2c_dev);
415
416         /* register this i2c device with the driver core */
417         i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
418                                      MKDEV(I2C_MAJOR, adap->nr),
419                                      "i2c-%d", adap->nr);
420         if (IS_ERR(i2c_dev->dev)) {
421                 res = PTR_ERR(i2c_dev->dev);
422                 goto error;
423         }
424         res = device_create_file(i2c_dev->dev, &dev_attr_name);
425         if (res)
426                 goto error_destroy;
427
428         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
429                  adap->name, adap->nr);
430         return 0;
431 error_destroy:
432         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
433 error:
434         return_i2c_dev(i2c_dev);
435         return res;
436 }
437
438 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
439 {
440         struct i2c_dev *i2c_dev;
441
442         i2c_dev = i2c_dev_get_by_minor(adap->nr);
443         if (!i2c_dev) /* attach_adapter must have failed */
444                 return 0;
445
446         device_remove_file(i2c_dev->dev, &dev_attr_name);
447         return_i2c_dev(i2c_dev);
448         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
449
450         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
451         return 0;
452 }
453
454 static int i2cdev_detach_client(struct i2c_client *client)
455 {
456         return 0;
457 }
458
459 static struct i2c_driver i2cdev_driver = {
460         .driver = {
461                 .name   = "dev_driver",
462         },
463         .id             = I2C_DRIVERID_I2CDEV,
464         .attach_adapter = i2cdev_attach_adapter,
465         .detach_adapter = i2cdev_detach_adapter,
466         .detach_client  = i2cdev_detach_client,
467 };
468
469 static int __init i2c_dev_init(void)
470 {
471         int res;
472
473         printk(KERN_INFO "i2c /dev entries driver\n");
474
475         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
476         if (res)
477                 goto out;
478
479         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
480         if (IS_ERR(i2c_dev_class))
481                 goto out_unreg_chrdev;
482
483         res = i2c_add_driver(&i2cdev_driver);
484         if (res)
485                 goto out_unreg_class;
486
487         return 0;
488
489 out_unreg_class:
490         class_destroy(i2c_dev_class);
491 out_unreg_chrdev:
492         unregister_chrdev(I2C_MAJOR, "i2c");
493 out:
494         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
495         return res;
496 }
497
498 static void __exit i2c_dev_exit(void)
499 {
500         i2c_del_driver(&i2cdev_driver);
501         class_destroy(i2c_dev_class);
502         unregister_chrdev(I2C_MAJOR,"i2c");
503 }
504
505 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
506                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
507 MODULE_DESCRIPTION("I2C /dev entries driver");
508 MODULE_LICENSE("GPL");
509
510 module_init(i2c_dev_init);
511 module_exit(i2c_dev_exit);