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