Merge branch 'upstream' of git://electric-eye.fr.zoreil.com/home/romieu/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 #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/i2c.h>
36 #include <linux/i2c-dev.h>
37 #include <linux/platform_device.h>
38 #include <asm/uaccess.h>
39
40 static struct i2c_client i2cdev_client_template;
41
42 struct i2c_dev {
43         int minor;
44         struct i2c_adapter *adap;
45         struct class_device *class_dev;
46 };
47 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
48
49 #define I2C_MINORS      256
50 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
51 static DEFINE_SPINLOCK(i2c_dev_array_lock);
52
53 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
54 {
55         struct i2c_dev *i2c_dev;
56
57         spin_lock(&i2c_dev_array_lock);
58         i2c_dev = i2c_dev_array[index];
59         spin_unlock(&i2c_dev_array_lock);
60         return i2c_dev;
61 }
62
63 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
64 {
65         struct i2c_dev *i2c_dev = NULL;
66
67         spin_lock(&i2c_dev_array_lock);
68         if ((i2c_dev_array[adap->nr]) &&
69             (i2c_dev_array[adap->nr]->adap == adap))
70                 i2c_dev = i2c_dev_array[adap->nr];
71         spin_unlock(&i2c_dev_array_lock);
72         return i2c_dev;
73 }
74
75 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
76 {
77         struct i2c_dev *i2c_dev;
78
79         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
80         if (!i2c_dev)
81                 return ERR_PTR(-ENOMEM);
82
83         spin_lock(&i2c_dev_array_lock);
84         if (i2c_dev_array[adap->nr]) {
85                 spin_unlock(&i2c_dev_array_lock);
86                 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
87                 goto error;
88         }
89         i2c_dev->minor = adap->nr;
90         i2c_dev_array[adap->nr] = i2c_dev;
91         spin_unlock(&i2c_dev_array_lock);
92         return i2c_dev;
93 error:
94         kfree(i2c_dev);
95         return ERR_PTR(-ENODEV);
96 }
97
98 static void return_i2c_dev(struct i2c_dev *i2c_dev)
99 {
100         spin_lock(&i2c_dev_array_lock);
101         i2c_dev_array[i2c_dev->minor] = NULL;
102         spin_unlock(&i2c_dev_array_lock);
103 }
104
105 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
106 {
107         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(class_dev->devt));
108
109         if (!i2c_dev)
110                 return -ENODEV;
111         return sprintf(buf, "%s\n", i2c_dev->adap->name);
112 }
113 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
114
115 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
116                             loff_t *offset)
117 {
118         char *tmp;
119         int ret;
120
121         struct i2c_client *client = (struct i2c_client *)file->private_data;
122
123         if (count > 8192)
124                 count = 8192;
125
126         tmp = kmalloc(count,GFP_KERNEL);
127         if (tmp==NULL)
128                 return -ENOMEM;
129
130         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
131                 iminor(file->f_dentry->d_inode), count);
132
133         ret = i2c_master_recv(client,tmp,count);
134         if (ret >= 0)
135                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
136         kfree(tmp);
137         return ret;
138 }
139
140 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
141                              loff_t *offset)
142 {
143         int ret;
144         char *tmp;
145         struct i2c_client *client = (struct i2c_client *)file->private_data;
146
147         if (count > 8192)
148                 count = 8192;
149
150         tmp = kmalloc(count,GFP_KERNEL);
151         if (tmp==NULL)
152                 return -ENOMEM;
153         if (copy_from_user(tmp,buf,count)) {
154                 kfree(tmp);
155                 return -EFAULT;
156         }
157
158         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
159                 iminor(file->f_dentry->d_inode), count);
160
161         ret = i2c_master_send(client,tmp,count);
162         kfree(tmp);
163         return ret;
164 }
165
166 static int i2cdev_ioctl(struct inode *inode, struct file *file,
167                 unsigned int cmd, unsigned long arg)
168 {
169         struct i2c_client *client = (struct i2c_client *)file->private_data;
170         struct i2c_rdwr_ioctl_data rdwr_arg;
171         struct i2c_smbus_ioctl_data data_arg;
172         union i2c_smbus_data temp;
173         struct i2c_msg *rdwr_pa;
174         u8 __user **data_ptrs;
175         int i,datasize,res;
176         unsigned long funcs;
177
178         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
179                 cmd, arg);
180
181         switch ( cmd ) {
182         case I2C_SLAVE:
183         case I2C_SLAVE_FORCE:
184                 if ((arg > 0x3ff) || 
185                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
186                         return -EINVAL;
187                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
188                         return -EBUSY;
189                 client->addr = arg;
190                 return 0;
191         case I2C_TENBIT:
192                 if (arg)
193                         client->flags |= I2C_M_TEN;
194                 else
195                         client->flags &= ~I2C_M_TEN;
196                 return 0;
197         case I2C_PEC:
198                 if (arg)
199                         client->flags |= I2C_CLIENT_PEC;
200                 else
201                         client->flags &= ~I2C_CLIENT_PEC;
202                 return 0;
203         case I2C_FUNCS:
204                 funcs = i2c_get_functionality(client->adapter);
205                 return (copy_to_user((unsigned long __user *)arg, &funcs,
206                                      sizeof(unsigned long)))?-EFAULT:0;
207
208         case I2C_RDWR:
209                 if (copy_from_user(&rdwr_arg, 
210                                    (struct i2c_rdwr_ioctl_data __user *)arg, 
211                                    sizeof(rdwr_arg)))
212                         return -EFAULT;
213
214                 /* Put an arbitrary limit on the number of messages that can
215                  * be sent at once */
216                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
217                         return -EINVAL;
218                 
219                 rdwr_pa = (struct i2c_msg *)
220                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), 
221                         GFP_KERNEL);
222
223                 if (rdwr_pa == NULL) return -ENOMEM;
224
225                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
226                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
227                         kfree(rdwr_pa);
228                         return -EFAULT;
229                 }
230
231                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
232                 if (data_ptrs == NULL) {
233                         kfree(rdwr_pa);
234                         return -ENOMEM;
235                 }
236
237                 res = 0;
238                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
239                         /* Limit the size of the message to a sane amount */
240                         if (rdwr_pa[i].len > 8192) {
241                                 res = -EINVAL;
242                                 break;
243                         }
244                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
245                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
246                         if(rdwr_pa[i].buf == NULL) {
247                                 res = -ENOMEM;
248                                 break;
249                         }
250                         if(copy_from_user(rdwr_pa[i].buf,
251                                 data_ptrs[i],
252                                 rdwr_pa[i].len)) {
253                                         ++i; /* Needs to be kfreed too */
254                                         res = -EFAULT;
255                                 break;
256                         }
257                 }
258                 if (res < 0) {
259                         int j;
260                         for (j = 0; j < i; ++j)
261                                 kfree(rdwr_pa[j].buf);
262                         kfree(data_ptrs);
263                         kfree(rdwr_pa);
264                         return res;
265                 }
266
267                 res = i2c_transfer(client->adapter,
268                         rdwr_pa,
269                         rdwr_arg.nmsgs);
270                 while(i-- > 0) {
271                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
272                                 if(copy_to_user(
273                                         data_ptrs[i],
274                                         rdwr_pa[i].buf,
275                                         rdwr_pa[i].len)) {
276                                         res = -EFAULT;
277                                 }
278                         }
279                         kfree(rdwr_pa[i].buf);
280                 }
281                 kfree(data_ptrs);
282                 kfree(rdwr_pa);
283                 return res;
284
285         case I2C_SMBUS:
286                 if (copy_from_user(&data_arg,
287                                    (struct i2c_smbus_ioctl_data __user *) arg,
288                                    sizeof(struct i2c_smbus_ioctl_data)))
289                         return -EFAULT;
290                 if ((data_arg.size != I2C_SMBUS_BYTE) && 
291                     (data_arg.size != I2C_SMBUS_QUICK) &&
292                     (data_arg.size != I2C_SMBUS_BYTE_DATA) && 
293                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
294                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
295                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
296                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
297                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
298                         dev_dbg(&client->adapter->dev,
299                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
300                                 data_arg.size);
301                         return -EINVAL;
302                 }
303                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 
304                    so the check is valid if size==I2C_SMBUS_QUICK too. */
305                 if ((data_arg.read_write != I2C_SMBUS_READ) && 
306                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
307                         dev_dbg(&client->adapter->dev, 
308                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
309                                 data_arg.read_write);
310                         return -EINVAL;
311                 }
312
313                 /* Note that command values are always valid! */
314
315                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
316                     ((data_arg.size == I2C_SMBUS_BYTE) && 
317                     (data_arg.read_write == I2C_SMBUS_WRITE)))
318                         /* These are special: we do not use data */
319                         return i2c_smbus_xfer(client->adapter, client->addr,
320                                               client->flags,
321                                               data_arg.read_write,
322                                               data_arg.command,
323                                               data_arg.size, NULL);
324
325                 if (data_arg.data == NULL) {
326                         dev_dbg(&client->adapter->dev,
327                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
328                         return -EINVAL;
329                 }
330
331                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
332                     (data_arg.size == I2C_SMBUS_BYTE))
333                         datasize = sizeof(data_arg.data->byte);
334                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) || 
335                          (data_arg.size == I2C_SMBUS_PROC_CALL))
336                         datasize = sizeof(data_arg.data->word);
337                 else /* size == smbus block, i2c block, or block proc. call */
338                         datasize = sizeof(data_arg.data->block);
339
340                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) || 
341                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 
342                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
343                         if (copy_from_user(&temp, data_arg.data, datasize))
344                                 return -EFAULT;
345                 }
346                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
347                       data_arg.read_write,
348                       data_arg.command,data_arg.size,&temp);
349                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) || 
350                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 
351                               (data_arg.read_write == I2C_SMBUS_READ))) {
352                         if (copy_to_user(data_arg.data, &temp, datasize))
353                                 return -EFAULT;
354                 }
355                 return res;
356
357         default:
358                 return i2c_control(client,cmd,arg);
359         }
360         return 0;
361 }
362
363 static int i2cdev_open(struct inode *inode, struct file *file)
364 {
365         unsigned int minor = iminor(inode);
366         struct i2c_client *client;
367         struct i2c_adapter *adap;
368         struct i2c_dev *i2c_dev;
369
370         i2c_dev = i2c_dev_get_by_minor(minor);
371         if (!i2c_dev)
372                 return -ENODEV;
373
374         adap = i2c_get_adapter(i2c_dev->adap->nr);
375         if (!adap)
376                 return -ENODEV;
377
378         client = kmalloc(sizeof(*client), GFP_KERNEL);
379         if (!client) {
380                 i2c_put_adapter(adap);
381                 return -ENOMEM;
382         }
383         memcpy(client, &i2cdev_client_template, sizeof(*client));
384
385         /* registered with adapter, passed as client to user */
386         client->adapter = adap;
387         file->private_data = client;
388
389         return 0;
390 }
391
392 static int i2cdev_release(struct inode *inode, struct file *file)
393 {
394         struct i2c_client *client = file->private_data;
395
396         i2c_put_adapter(client->adapter);
397         kfree(client);
398         file->private_data = NULL;
399
400         return 0;
401 }
402
403 static struct file_operations i2cdev_fops = {
404         .owner          = THIS_MODULE,
405         .llseek         = no_llseek,
406         .read           = i2cdev_read,
407         .write          = i2cdev_write,
408         .ioctl          = i2cdev_ioctl,
409         .open           = i2cdev_open,
410         .release        = i2cdev_release,
411 };
412
413 static struct class *i2c_dev_class;
414
415 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
416 {
417         struct i2c_dev *i2c_dev;
418         struct device *dev;
419
420         i2c_dev = get_free_i2c_dev(adap);
421         if (IS_ERR(i2c_dev))
422                 return PTR_ERR(i2c_dev);
423
424         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
425                  adap->name, i2c_dev->minor);
426
427         /* register this i2c device with the driver core */
428         i2c_dev->adap = adap;
429         dev = &adap->dev;
430         i2c_dev->class_dev = class_device_create(i2c_dev_class, NULL,
431                                                  MKDEV(I2C_MAJOR, i2c_dev->minor),
432                                                  dev, "i2c-%d", i2c_dev->minor);
433         if (!i2c_dev->class_dev)
434                 goto error;
435         class_device_create_file(i2c_dev->class_dev, &class_device_attr_name);
436         return 0;
437 error:
438         return_i2c_dev(i2c_dev);
439         kfree(i2c_dev);
440         return -ENODEV;
441 }
442
443 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
444 {
445         struct i2c_dev *i2c_dev;
446
447         i2c_dev = i2c_dev_get_by_adapter(adap);
448         if (!i2c_dev)
449                 return -ENODEV;
450
451         return_i2c_dev(i2c_dev);
452         class_device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, i2c_dev->minor));
453         kfree(i2c_dev);
454
455         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
456         return 0;
457 }
458
459 static int i2cdev_detach_client(struct i2c_client *client)
460 {
461         return 0;
462 }
463
464 static struct i2c_driver i2cdev_driver = {
465         .driver = {
466                 .name   = "dev_driver",
467         },
468         .id             = I2C_DRIVERID_I2CDEV,
469         .attach_adapter = i2cdev_attach_adapter,
470         .detach_adapter = i2cdev_detach_adapter,
471         .detach_client  = i2cdev_detach_client,
472 };
473
474 static struct i2c_client i2cdev_client_template = {
475         .name           = "I2C /dev entry",
476         .addr           = -1,
477         .driver         = &i2cdev_driver,
478 };
479
480 static int __init i2c_dev_init(void)
481 {
482         int res;
483
484         printk(KERN_INFO "i2c /dev entries driver\n");
485
486         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
487         if (res)
488                 goto out;
489
490         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
491         if (IS_ERR(i2c_dev_class))
492                 goto out_unreg_chrdev;
493
494         res = i2c_add_driver(&i2cdev_driver);
495         if (res)
496                 goto out_unreg_class;
497
498         return 0;
499
500 out_unreg_class:
501         class_destroy(i2c_dev_class);
502 out_unreg_chrdev:
503         unregister_chrdev(I2C_MAJOR, "i2c");
504 out:
505         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
506         return res;
507 }
508
509 static void __exit i2c_dev_exit(void)
510 {
511         i2c_del_driver(&i2cdev_driver);
512         class_destroy(i2c_dev_class);
513         unregister_chrdev(I2C_MAJOR,"i2c");
514 }
515
516 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
517                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
518 MODULE_DESCRIPTION("I2C /dev entries driver");
519 MODULE_LICENSE("GPL");
520
521 module_init(i2c_dev_init);
522 module_exit(i2c_dev_exit);