Merge rsync://www.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[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 /* The devfs code is contributed by Philipp Matthias Hahn 
30    <pmhahn@titan.lahn.de> */
31
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/fs.h>
35 #include <linux/slab.h>
36 #include <linux/smp_lock.h>
37 #include <linux/devfs_fs_kernel.h>
38 #include <linux/init.h>
39 #include <linux/i2c.h>
40 #include <linux/i2c-dev.h>
41 #include <asm/uaccess.h>
42
43 static struct i2c_client i2cdev_client_template;
44
45 struct i2c_dev {
46         int minor;
47         struct i2c_adapter *adap;
48         struct class_device class_dev;
49         struct completion released;     /* FIXME, we need a class_device_unregister() */
50 };
51 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
52
53 #define I2C_MINORS      256
54 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
55 static DEFINE_SPINLOCK(i2c_dev_array_lock);
56
57 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
58 {
59         struct i2c_dev *i2c_dev;
60
61         spin_lock(&i2c_dev_array_lock);
62         i2c_dev = i2c_dev_array[index];
63         spin_unlock(&i2c_dev_array_lock);
64         return i2c_dev;
65 }
66
67 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
68 {
69         struct i2c_dev *i2c_dev = NULL;
70
71         spin_lock(&i2c_dev_array_lock);
72         if ((i2c_dev_array[adap->nr]) &&
73             (i2c_dev_array[adap->nr]->adap == adap))
74                 i2c_dev = i2c_dev_array[adap->nr];
75         spin_unlock(&i2c_dev_array_lock);
76         return i2c_dev;
77 }
78
79 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
80 {
81         struct i2c_dev *i2c_dev;
82
83         i2c_dev = kmalloc(sizeof(*i2c_dev), GFP_KERNEL);
84         if (!i2c_dev)
85                 return ERR_PTR(-ENOMEM);
86         memset(i2c_dev, 0x00, sizeof(*i2c_dev));
87
88         spin_lock(&i2c_dev_array_lock);
89         if (i2c_dev_array[adap->nr]) {
90                 spin_unlock(&i2c_dev_array_lock);
91                 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
92                 goto error;
93         }
94         i2c_dev->minor = adap->nr;
95         i2c_dev_array[adap->nr] = i2c_dev;
96         spin_unlock(&i2c_dev_array_lock);
97         return i2c_dev;
98 error:
99         kfree(i2c_dev);
100         return ERR_PTR(-ENODEV);
101 }
102
103 static void return_i2c_dev(struct i2c_dev *i2c_dev)
104 {
105         spin_lock(&i2c_dev_array_lock);
106         i2c_dev_array[i2c_dev->minor] = NULL;
107         spin_unlock(&i2c_dev_array_lock);
108 }
109
110 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
111 {
112         struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
113         return sprintf(buf, "%s\n", i2c_dev->adap->name);
114 }
115 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
116
117 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
118                             loff_t *offset)
119 {
120         char *tmp;
121         int ret;
122
123         struct i2c_client *client = (struct i2c_client *)file->private_data;
124
125         if (count > 8192)
126                 count = 8192;
127
128         tmp = kmalloc(count,GFP_KERNEL);
129         if (tmp==NULL)
130                 return -ENOMEM;
131
132         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
133                 iminor(file->f_dentry->d_inode), count);
134
135         ret = i2c_master_recv(client,tmp,count);
136         if (ret >= 0)
137                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
138         kfree(tmp);
139         return ret;
140 }
141
142 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
143                              loff_t *offset)
144 {
145         int ret;
146         char *tmp;
147         struct i2c_client *client = (struct i2c_client *)file->private_data;
148
149         if (count > 8192)
150                 count = 8192;
151
152         tmp = kmalloc(count,GFP_KERNEL);
153         if (tmp==NULL)
154                 return -ENOMEM;
155         if (copy_from_user(tmp,buf,count)) {
156                 kfree(tmp);
157                 return -EFAULT;
158         }
159
160         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
161                 iminor(file->f_dentry->d_inode), count);
162
163         ret = i2c_master_send(client,tmp,count);
164         kfree(tmp);
165         return ret;
166 }
167
168 static int i2cdev_ioctl(struct inode *inode, struct file *file,
169                 unsigned int cmd, unsigned long arg)
170 {
171         struct i2c_client *client = (struct i2c_client *)file->private_data;
172         struct i2c_rdwr_ioctl_data rdwr_arg;
173         struct i2c_smbus_ioctl_data data_arg;
174         union i2c_smbus_data temp;
175         struct i2c_msg *rdwr_pa;
176         u8 __user **data_ptrs;
177         int i,datasize,res;
178         unsigned long funcs;
179
180         dev_dbg(&client->adapter->dev, "i2c-%d ioctl, cmd: 0x%x, arg: %lx.\n",
181                 iminor(inode),cmd, arg);
182
183         switch ( cmd ) {
184         case I2C_SLAVE:
185         case I2C_SLAVE_FORCE:
186                 if ((arg > 0x3ff) || 
187                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
188                         return -EINVAL;
189                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
190                         return -EBUSY;
191                 client->addr = arg;
192                 return 0;
193         case I2C_TENBIT:
194                 if (arg)
195                         client->flags |= I2C_M_TEN;
196                 else
197                         client->flags &= ~I2C_M_TEN;
198                 return 0;
199         case I2C_PEC:
200                 if (arg)
201                         client->flags |= I2C_CLIENT_PEC;
202                 else
203                         client->flags &= ~I2C_CLIENT_PEC;
204                 return 0;
205         case I2C_FUNCS:
206                 funcs = i2c_get_functionality(client->adapter);
207                 return (copy_to_user((unsigned long __user *)arg, &funcs,
208                                      sizeof(unsigned long)))?-EFAULT:0;
209
210         case I2C_RDWR:
211                 if (copy_from_user(&rdwr_arg, 
212                                    (struct i2c_rdwr_ioctl_data __user *)arg, 
213                                    sizeof(rdwr_arg)))
214                         return -EFAULT;
215
216                 /* Put an arbitrary limit on the number of messages that can
217                  * be sent at once */
218                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
219                         return -EINVAL;
220                 
221                 rdwr_pa = (struct i2c_msg *)
222                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), 
223                         GFP_KERNEL);
224
225                 if (rdwr_pa == NULL) return -ENOMEM;
226
227                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
228                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
229                         kfree(rdwr_pa);
230                         return -EFAULT;
231                 }
232
233                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
234                 if (data_ptrs == NULL) {
235                         kfree(rdwr_pa);
236                         return -ENOMEM;
237                 }
238
239                 res = 0;
240                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
241                         /* Limit the size of the message to a sane amount */
242                         if (rdwr_pa[i].len > 8192) {
243                                 res = -EINVAL;
244                                 break;
245                         }
246                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
247                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
248                         if(rdwr_pa[i].buf == NULL) {
249                                 res = -ENOMEM;
250                                 break;
251                         }
252                         if(copy_from_user(rdwr_pa[i].buf,
253                                 data_ptrs[i],
254                                 rdwr_pa[i].len)) {
255                                         ++i; /* Needs to be kfreed too */
256                                         res = -EFAULT;
257                                 break;
258                         }
259                 }
260                 if (res < 0) {
261                         int j;
262                         for (j = 0; j < i; ++j)
263                                 kfree(rdwr_pa[j].buf);
264                         kfree(data_ptrs);
265                         kfree(rdwr_pa);
266                         return res;
267                 }
268
269                 res = i2c_transfer(client->adapter,
270                         rdwr_pa,
271                         rdwr_arg.nmsgs);
272                 while(i-- > 0) {
273                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
274                                 if(copy_to_user(
275                                         data_ptrs[i],
276                                         rdwr_pa[i].buf,
277                                         rdwr_pa[i].len)) {
278                                         res = -EFAULT;
279                                 }
280                         }
281                         kfree(rdwr_pa[i].buf);
282                 }
283                 kfree(data_ptrs);
284                 kfree(rdwr_pa);
285                 return res;
286
287         case I2C_SMBUS:
288                 if (copy_from_user(&data_arg,
289                                    (struct i2c_smbus_ioctl_data __user *) arg,
290                                    sizeof(struct i2c_smbus_ioctl_data)))
291                         return -EFAULT;
292                 if ((data_arg.size != I2C_SMBUS_BYTE) && 
293                     (data_arg.size != I2C_SMBUS_QUICK) &&
294                     (data_arg.size != I2C_SMBUS_BYTE_DATA) && 
295                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
296                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
297                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
298                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
299                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
300                         dev_dbg(&client->adapter->dev,
301                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
302                                 data_arg.size);
303                         return -EINVAL;
304                 }
305                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 
306                    so the check is valid if size==I2C_SMBUS_QUICK too. */
307                 if ((data_arg.read_write != I2C_SMBUS_READ) && 
308                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
309                         dev_dbg(&client->adapter->dev, 
310                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
311                                 data_arg.read_write);
312                         return -EINVAL;
313                 }
314
315                 /* Note that command values are always valid! */
316
317                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
318                     ((data_arg.size == I2C_SMBUS_BYTE) && 
319                     (data_arg.read_write == I2C_SMBUS_WRITE)))
320                         /* These are special: we do not use data */
321                         return i2c_smbus_xfer(client->adapter, client->addr,
322                                               client->flags,
323                                               data_arg.read_write,
324                                               data_arg.command,
325                                               data_arg.size, NULL);
326
327                 if (data_arg.data == NULL) {
328                         dev_dbg(&client->adapter->dev,
329                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
330                         return -EINVAL;
331                 }
332
333                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
334                     (data_arg.size == I2C_SMBUS_BYTE))
335                         datasize = sizeof(data_arg.data->byte);
336                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) || 
337                          (data_arg.size == I2C_SMBUS_PROC_CALL))
338                         datasize = sizeof(data_arg.data->word);
339                 else /* size == smbus block, i2c block, or block proc. call */
340                         datasize = sizeof(data_arg.data->block);
341
342                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) || 
343                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 
344                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
345                         if (copy_from_user(&temp, data_arg.data, datasize))
346                                 return -EFAULT;
347                 }
348                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
349                       data_arg.read_write,
350                       data_arg.command,data_arg.size,&temp);
351                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) || 
352                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 
353                               (data_arg.read_write == I2C_SMBUS_READ))) {
354                         if (copy_to_user(data_arg.data, &temp, datasize))
355                                 return -EFAULT;
356                 }
357                 return res;
358
359         default:
360                 return i2c_control(client,cmd,arg);
361         }
362         return 0;
363 }
364
365 static int i2cdev_open(struct inode *inode, struct file *file)
366 {
367         unsigned int minor = iminor(inode);
368         struct i2c_client *client;
369         struct i2c_adapter *adap;
370         struct i2c_dev *i2c_dev;
371
372         i2c_dev = i2c_dev_get_by_minor(minor);
373         if (!i2c_dev)
374                 return -ENODEV;
375
376         adap = i2c_get_adapter(i2c_dev->adap->nr);
377         if (!adap)
378                 return -ENODEV;
379
380         client = kmalloc(sizeof(*client), GFP_KERNEL);
381         if (!client) {
382                 i2c_put_adapter(adap);
383                 return -ENOMEM;
384         }
385         memcpy(client, &i2cdev_client_template, sizeof(*client));
386
387         /* registered with adapter, passed as client to user */
388         client->adapter = adap;
389         file->private_data = client;
390
391         return 0;
392 }
393
394 static int i2cdev_release(struct inode *inode, struct file *file)
395 {
396         struct i2c_client *client = file->private_data;
397
398         i2c_put_adapter(client->adapter);
399         kfree(client);
400         file->private_data = NULL;
401
402         return 0;
403 }
404
405 static struct file_operations i2cdev_fops = {
406         .owner          = THIS_MODULE,
407         .llseek         = no_llseek,
408         .read           = i2cdev_read,
409         .write          = i2cdev_write,
410         .ioctl          = i2cdev_ioctl,
411         .open           = i2cdev_open,
412         .release        = i2cdev_release,
413 };
414
415 static void release_i2c_dev(struct class_device *dev)
416 {
417         struct i2c_dev *i2c_dev = to_i2c_dev(dev);
418         complete(&i2c_dev->released);
419 }
420
421 static struct class i2c_dev_class = {
422         .name           = "i2c-dev",
423         .release        = &release_i2c_dev,
424 };
425
426 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
427 {
428         struct i2c_dev *i2c_dev;
429         int retval;
430
431         i2c_dev = get_free_i2c_dev(adap);
432         if (IS_ERR(i2c_dev))
433                 return PTR_ERR(i2c_dev);
434
435         devfs_mk_cdev(MKDEV(I2C_MAJOR, i2c_dev->minor),
436                         S_IFCHR|S_IRUSR|S_IWUSR, "i2c/%d", i2c_dev->minor);
437         dev_dbg(&adap->dev, "Registered as minor %d\n", i2c_dev->minor);
438
439         /* register this i2c device with the driver core */
440         i2c_dev->adap = adap;
441         if (adap->dev.parent == &platform_bus)
442                 i2c_dev->class_dev.dev = &adap->dev;
443         else
444                 i2c_dev->class_dev.dev = adap->dev.parent;
445         i2c_dev->class_dev.class = &i2c_dev_class;
446         i2c_dev->class_dev.devt = MKDEV(I2C_MAJOR, i2c_dev->minor);
447         snprintf(i2c_dev->class_dev.class_id, BUS_ID_SIZE, "i2c-%d", i2c_dev->minor);
448         retval = class_device_register(&i2c_dev->class_dev);
449         if (retval)
450                 goto error;
451         class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
452         return 0;
453 error:
454         return_i2c_dev(i2c_dev);
455         kfree(i2c_dev);
456         return retval;
457 }
458
459 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
460 {
461         struct i2c_dev *i2c_dev;
462
463         i2c_dev = i2c_dev_get_by_adapter(adap);
464         if (!i2c_dev)
465                 return -ENODEV;
466
467         init_completion(&i2c_dev->released);
468         devfs_remove("i2c/%d", i2c_dev->minor);
469         return_i2c_dev(i2c_dev);
470         class_device_unregister(&i2c_dev->class_dev);
471         wait_for_completion(&i2c_dev->released);
472         kfree(i2c_dev);
473
474         dev_dbg(&adap->dev, "Adapter unregistered\n");
475         return 0;
476 }
477
478 static int i2cdev_detach_client(struct i2c_client *client)
479 {
480         return 0;
481 }
482
483 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
484                            void *arg)
485 {
486         return -1;
487 }
488
489 static struct i2c_driver i2cdev_driver = {
490         .owner          = THIS_MODULE,
491         .name           = "dev_driver",
492         .id             = I2C_DRIVERID_I2CDEV,
493         .flags          = I2C_DF_NOTIFY,
494         .attach_adapter = i2cdev_attach_adapter,
495         .detach_adapter = i2cdev_detach_adapter,
496         .detach_client  = i2cdev_detach_client,
497         .command        = i2cdev_command,
498 };
499
500 static struct i2c_client i2cdev_client_template = {
501         .name           = "I2C /dev entry",
502         .addr           = -1,
503         .driver         = &i2cdev_driver,
504 };
505
506 static int __init i2c_dev_init(void)
507 {
508         int res;
509
510         printk(KERN_INFO "i2c /dev entries driver\n");
511
512         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
513         if (res)
514                 goto out;
515
516         res = class_register(&i2c_dev_class);
517         if (res)
518                 goto out_unreg_chrdev;
519
520         res = i2c_add_driver(&i2cdev_driver);
521         if (res)
522                 goto out_unreg_class;
523
524         devfs_mk_dir("i2c");
525
526         return 0;
527
528 out_unreg_class:
529         class_unregister(&i2c_dev_class);
530 out_unreg_chrdev:
531         unregister_chrdev(I2C_MAJOR, "i2c");
532 out:
533         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
534         return res;
535 }
536
537 static void __exit i2c_dev_exit(void)
538 {
539         i2c_del_driver(&i2cdev_driver);
540         class_unregister(&i2c_dev_class);
541         devfs_remove("i2c");
542         unregister_chrdev(I2C_MAJOR,"i2c");
543 }
544
545 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
546                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
547 MODULE_DESCRIPTION("I2C /dev entries driver");
548 MODULE_LICENSE("GPL");
549
550 module_init(i2c_dev_init);
551 module_exit(i2c_dev_exit);