i2c: Use put_user instead of copy_to_user where possible
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / i2c / i2c-dev.c
CommitLineData
1da177e4
LT
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
1da177e4
LT
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>
1da177e4 34#include <linux/init.h>
f3b3aadb 35#include <linux/list.h>
1da177e4
LT
36#include <linux/i2c.h>
37#include <linux/i2c-dev.h>
38#include <asm/uaccess.h>
39
22f76e74 40static struct i2c_driver i2cdev_driver;
1da177e4
LT
41
42struct i2c_dev {
f3b3aadb 43 struct list_head list;
1da177e4 44 struct i2c_adapter *adap;
ac11d060 45 struct device *dev;
1da177e4 46};
1da177e4
LT
47
48#define I2C_MINORS 256
f3b3aadb
JD
49static LIST_HEAD(i2c_dev_list);
50static DEFINE_SPINLOCK(i2c_dev_list_lock);
1da177e4
LT
51
52static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
53{
54 struct i2c_dev *i2c_dev;
55
f3b3aadb
JD
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;
62found:
63 spin_unlock(&i2c_dev_list_lock);
1da177e4
LT
64 return i2c_dev;
65}
66
1da177e4
LT
67static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
68{
69 struct i2c_dev *i2c_dev;
70
f3b3aadb
JD
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
5263ebb5 77 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
1da177e4
LT
78 if (!i2c_dev)
79 return ERR_PTR(-ENOMEM);
9455e4c9 80 i2c_dev->adap = adap;
f3b3aadb
JD
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);
1da177e4 85 return i2c_dev;
1da177e4
LT
86}
87
88static void return_i2c_dev(struct i2c_dev *i2c_dev)
89{
f3b3aadb
JD
90 spin_lock(&i2c_dev_list_lock);
91 list_del(&i2c_dev->list);
92 spin_unlock(&i2c_dev_list_lock);
1da177e4
LT
93}
94
ac11d060
GKH
95static ssize_t show_adapter_name(struct device *dev,
96 struct device_attribute *attr, char *buf)
1da177e4 97{
ac11d060 98 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
79472132
GKH
99
100 if (!i2c_dev)
101 return -ENODEV;
1da177e4
LT
102 return sprintf(buf, "%s\n", i2c_dev->adap->name);
103}
ac11d060 104static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
1da177e4
LT
105
106static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
107 loff_t *offset)
108{
109 char *tmp;
110 int ret;
111
112 struct i2c_client *client = (struct i2c_client *)file->private_data;
113
114 if (count > 8192)
115 count = 8192;
116
117 tmp = kmalloc(count,GFP_KERNEL);
118 if (tmp==NULL)
119 return -ENOMEM;
120
121 pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
cba0a128 122 iminor(file->f_path.dentry->d_inode), count);
1da177e4
LT
123
124 ret = i2c_master_recv(client,tmp,count);
125 if (ret >= 0)
126 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
127 kfree(tmp);
128 return ret;
129}
130
131static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
132 loff_t *offset)
133{
134 int ret;
135 char *tmp;
136 struct i2c_client *client = (struct i2c_client *)file->private_data;
137
138 if (count > 8192)
139 count = 8192;
140
141 tmp = kmalloc(count,GFP_KERNEL);
142 if (tmp==NULL)
143 return -ENOMEM;
144 if (copy_from_user(tmp,buf,count)) {
145 kfree(tmp);
146 return -EFAULT;
147 }
148
149 pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
cba0a128 150 iminor(file->f_path.dentry->d_inode), count);
1da177e4
LT
151
152 ret = i2c_master_send(client,tmp,count);
153 kfree(tmp);
154 return ret;
155}
156
157static int i2cdev_ioctl(struct inode *inode, struct file *file,
158 unsigned int cmd, unsigned long arg)
159{
160 struct i2c_client *client = (struct i2c_client *)file->private_data;
161 struct i2c_rdwr_ioctl_data rdwr_arg;
162 struct i2c_smbus_ioctl_data data_arg;
163 union i2c_smbus_data temp;
164 struct i2c_msg *rdwr_pa;
165 u8 __user **data_ptrs;
166 int i,datasize,res;
167 unsigned long funcs;
168
e8aafcb2
JD
169 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
170 cmd, arg);
1da177e4
LT
171
172 switch ( cmd ) {
173 case I2C_SLAVE:
174 case I2C_SLAVE_FORCE:
175 if ((arg > 0x3ff) ||
176 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
177 return -EINVAL;
178 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
179 return -EBUSY;
180 client->addr = arg;
181 return 0;
182 case I2C_TENBIT:
183 if (arg)
184 client->flags |= I2C_M_TEN;
185 else
186 client->flags &= ~I2C_M_TEN;
187 return 0;
188 case I2C_PEC:
189 if (arg)
190 client->flags |= I2C_CLIENT_PEC;
191 else
192 client->flags &= ~I2C_CLIENT_PEC;
193 return 0;
194 case I2C_FUNCS:
195 funcs = i2c_get_functionality(client->adapter);
2c003e8e 196 return put_user(funcs, (unsigned long __user *)arg);
1da177e4
LT
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
d68a861d 204 /* Put an arbitrary limit on the number of messages that can
1da177e4
LT
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
353static 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
22f76e74 368 client = kzalloc(sizeof(*client), GFP_KERNEL);
1da177e4
LT
369 if (!client) {
370 i2c_put_adapter(adap);
371 return -ENOMEM;
372 }
22f76e74
JD
373 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
374 client->driver = &i2cdev_driver;
1da177e4
LT
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
383static 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
394static 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
79472132 404static struct class *i2c_dev_class;
1da177e4
LT
405
406static int i2cdev_attach_adapter(struct i2c_adapter *adap)
407{
408 struct i2c_dev *i2c_dev;
defcb46e 409 int res;
1da177e4
LT
410
411 i2c_dev = get_free_i2c_dev(adap);
412 if (IS_ERR(i2c_dev))
413 return PTR_ERR(i2c_dev);
414
1da177e4 415 /* register this i2c device with the driver core */
ac11d060
GKH
416 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
417 MKDEV(I2C_MAJOR, adap->nr),
418 "i2c-%d", adap->nr);
419 if (!i2c_dev->dev) {
defcb46e 420 res = -ENODEV;
1da177e4 421 goto error;
defcb46e 422 }
ac11d060 423 res = device_create_file(i2c_dev->dev, &dev_attr_name);
defcb46e
JD
424 if (res)
425 goto error_destroy;
b32d20dc
JD
426
427 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
428 adap->name, adap->nr);
1da177e4 429 return 0;
defcb46e 430error_destroy:
ac11d060 431 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
1da177e4
LT
432error:
433 return_i2c_dev(i2c_dev);
434 kfree(i2c_dev);
defcb46e 435 return res;
1da177e4
LT
436}
437
438static int i2cdev_detach_adapter(struct i2c_adapter *adap)
439{
440 struct i2c_dev *i2c_dev;
441
9455e4c9 442 i2c_dev = i2c_dev_get_by_minor(adap->nr);
b32d20dc
JD
443 if (!i2c_dev) /* attach_adapter must have failed */
444 return 0;
1da177e4 445
ac11d060 446 device_remove_file(i2c_dev->dev, &dev_attr_name);
1da177e4 447 return_i2c_dev(i2c_dev);
ac11d060 448 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
1da177e4
LT
449 kfree(i2c_dev);
450
b6d7b3d1 451 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
1da177e4
LT
452 return 0;
453}
454
455static int i2cdev_detach_client(struct i2c_client *client)
456{
457 return 0;
458}
459
1da177e4 460static struct i2c_driver i2cdev_driver = {
35d8b2e6 461 .driver = {
35d8b2e6
LR
462 .name = "dev_driver",
463 },
1da177e4 464 .id = I2C_DRIVERID_I2CDEV,
1da177e4
LT
465 .attach_adapter = i2cdev_attach_adapter,
466 .detach_adapter = i2cdev_detach_adapter,
467 .detach_client = i2cdev_detach_client,
1da177e4
LT
468};
469
1da177e4
LT
470static int __init i2c_dev_init(void)
471{
472 int res;
473
474 printk(KERN_INFO "i2c /dev entries driver\n");
475
476 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
477 if (res)
478 goto out;
479
79472132
GKH
480 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
481 if (IS_ERR(i2c_dev_class))
1da177e4
LT
482 goto out_unreg_chrdev;
483
484 res = i2c_add_driver(&i2cdev_driver);
485 if (res)
486 goto out_unreg_class;
487
1da177e4
LT
488 return 0;
489
490out_unreg_class:
79472132 491 class_destroy(i2c_dev_class);
1da177e4
LT
492out_unreg_chrdev:
493 unregister_chrdev(I2C_MAJOR, "i2c");
494out:
495 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
496 return res;
497}
498
499static void __exit i2c_dev_exit(void)
500{
501 i2c_del_driver(&i2cdev_driver);
79472132 502 class_destroy(i2c_dev_class);
1da177e4
LT
503 unregister_chrdev(I2C_MAJOR,"i2c");
504}
505
506MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
507 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
508MODULE_DESCRIPTION("I2C /dev entries driver");
509MODULE_LICENSE("GPL");
510
511module_init(i2c_dev_init);
512module_exit(i2c_dev_exit);