blob: e0694e4d86c7364315aed961bf24c1869b79b5be [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
David Brownell438d6c22006-12-10 21:21:31 +01002 i2c-dev.c - i2c-bus driver, char device interface
Linus Torvalds1da177e2005-04-16 15:20:36 -07003
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/fs.h>
32#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <linux/init.h>
Jean Delvaref3b3aad2006-07-01 17:17:38 +020034#include <linux/list.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#include <linux/i2c.h>
36#include <linux/i2c-dev.h>
Jean Delvarecd97f392009-02-24 19:19:49 +010037#include <linux/jiffies.h>
Farid Hammaneae5624f2010-05-21 18:40:59 +020038#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Jean Delvare22f76e72006-07-01 17:20:57 +020040static struct i2c_driver i2cdev_driver;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
David Brownell907135a2007-11-15 19:24:01 +010042/*
43 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a
44 * slave (i2c_client) with which messages will be exchanged. It's coupled
45 * with a character special file which is accessed by user mode drivers.
46 *
47 * The list of i2c_dev structures is parallel to the i2c_adapter lists
48 * maintained by the driver model, and is updated using notifications
49 * delivered to the i2cdev_driver.
50 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070051struct i2c_dev {
Jean Delvaref3b3aad2006-07-01 17:17:38 +020052 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 struct i2c_adapter *adap;
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -070054 struct device *dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055};
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57#define I2C_MINORS 256
Jean Delvaref3b3aad2006-07-01 17:17:38 +020058static LIST_HEAD(i2c_dev_list);
59static DEFINE_SPINLOCK(i2c_dev_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
62{
63 struct i2c_dev *i2c_dev;
64
Jean Delvaref3b3aad2006-07-01 17:17:38 +020065 spin_lock(&i2c_dev_list_lock);
66 list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
67 if (i2c_dev->adap->nr == index)
68 goto found;
69 }
70 i2c_dev = NULL;
71found:
72 spin_unlock(&i2c_dev_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 return i2c_dev;
74}
75
Linus Torvalds1da177e2005-04-16 15:20:36 -070076static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
77{
78 struct i2c_dev *i2c_dev;
79
Jean Delvaref3b3aad2006-07-01 17:17:38 +020080 if (adap->nr >= I2C_MINORS) {
81 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
82 adap->nr);
83 return ERR_PTR(-ENODEV);
84 }
85
Deepak Saxena5263ebb2005-10-17 23:09:43 +020086 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 if (!i2c_dev)
88 return ERR_PTR(-ENOMEM);
Jean Delvare9455e4c2006-07-01 17:16:57 +020089 i2c_dev->adap = adap;
Jean Delvaref3b3aad2006-07-01 17:17:38 +020090
91 spin_lock(&i2c_dev_list_lock);
92 list_add_tail(&i2c_dev->list, &i2c_dev_list);
93 spin_unlock(&i2c_dev_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 return i2c_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095}
96
97static void return_i2c_dev(struct i2c_dev *i2c_dev)
98{
Jean Delvaref3b3aad2006-07-01 17:17:38 +020099 spin_lock(&i2c_dev_list_lock);
100 list_del(&i2c_dev->list);
101 spin_unlock(&i2c_dev_list_lock);
Jean Delvare07125ab2006-12-10 21:21:33 +0100102 kfree(i2c_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103}
104
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700105static ssize_t show_adapter_name(struct device *dev,
106 struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700108 struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
Greg Kroah-Hartman794721322005-12-06 15:33:15 -0800109
110 if (!i2c_dev)
111 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 return sprintf(buf, "%s\n", i2c_dev->adap->name);
113}
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700114static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
David Brownell907135a2007-11-15 19:24:01 +0100116/* ------------------------------------------------------------------------- */
117
118/*
119 * After opening an instance of this character special file, a file
120 * descriptor starts out associated only with an i2c_adapter (and bus).
121 *
122 * Using the I2C_RDWR ioctl(), you can then *immediately* issue i2c_msg
123 * traffic to any devices on the bus used by that adapter. That's because
124 * the i2c_msg vectors embed all the addressing information they need, and
125 * are submitted directly to an i2c_adapter. However, SMBus-only adapters
126 * don't support that interface.
127 *
128 * To use read()/write() system calls on that file descriptor, or to use
129 * SMBus interfaces (and work with SMBus-only hosts!), you must first issue
130 * an I2C_SLAVE (or I2C_SLAVE_FORCE) ioctl. That configures an anonymous
131 * (never registered) i2c_client so it holds the addressing information
132 * needed by those system calls and by this SMBus interface.
133 */
134
Farid Hammaneae5624f2010-05-21 18:40:59 +0200135static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
136 loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137{
138 char *tmp;
139 int ret;
140
H Hartley Sweeten0be16c32010-05-21 18:40:57 +0200141 struct i2c_client *client = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
143 if (count > 8192)
144 count = 8192;
145
Farid Hammaneae5624f2010-05-21 18:40:59 +0200146 tmp = kmalloc(count, GFP_KERNEL);
147 if (tmp == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 return -ENOMEM;
149
David Brownell2ce5b342008-08-10 22:56:16 +0200150 pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
Josef Sipekcba0a122006-12-08 02:37:08 -0800151 iminor(file->f_path.dentry->d_inode), count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Farid Hammaneae5624f2010-05-21 18:40:59 +0200153 ret = i2c_master_recv(client, tmp, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 if (ret >= 0)
Farid Hammaneae5624f2010-05-21 18:40:59 +0200155 ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 kfree(tmp);
157 return ret;
158}
159
Farid Hammaneae5624f2010-05-21 18:40:59 +0200160static ssize_t i2cdev_write(struct file *file, const char __user *buf,
161 size_t count, loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162{
163 int ret;
164 char *tmp;
H Hartley Sweeten0be16c32010-05-21 18:40:57 +0200165 struct i2c_client *client = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166
167 if (count > 8192)
168 count = 8192;
169
Farid Hammaneae5624f2010-05-21 18:40:59 +0200170 tmp = kmalloc(count, GFP_KERNEL);
171 if (tmp == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 return -ENOMEM;
Farid Hammaneae5624f2010-05-21 18:40:59 +0200173 if (copy_from_user(tmp, buf, count)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 kfree(tmp);
175 return -EFAULT;
176 }
177
David Brownell2ce5b342008-08-10 22:56:16 +0200178 pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
Josef Sipekcba0a122006-12-08 02:37:08 -0800179 iminor(file->f_path.dentry->d_inode), count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
Farid Hammaneae5624f2010-05-21 18:40:59 +0200181 ret = i2c_master_send(client, tmp, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 kfree(tmp);
183 return ret;
184}
185
David Brownell9b766b82008-01-27 18:14:51 +0100186static int i2cdev_check(struct device *dev, void *addrp)
187{
188 struct i2c_client *client = i2c_verify_client(dev);
189
190 if (!client || client->addr != *(unsigned int *)addrp)
191 return 0;
192
193 return dev->driver ? -EBUSY : 0;
194}
195
Jean Delvarebd4217d2007-11-15 19:24:01 +0100196/* This address checking function differs from the one in i2c-core
197 in that it considers an address with a registered device, but no
David Brownell9b766b82008-01-27 18:14:51 +0100198 driver bound to it, as NOT busy. */
Jean Delvarebd4217d2007-11-15 19:24:01 +0100199static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
200{
David Brownell9b766b82008-01-27 18:14:51 +0100201 return device_for_each_child(&adapter->dev, &addr, i2cdev_check);
Jean Delvarebd4217d2007-11-15 19:24:01 +0100202}
203
Jean Delvaredba79972008-04-22 22:16:47 +0200204static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
205 unsigned long arg)
206{
207 struct i2c_rdwr_ioctl_data rdwr_arg;
208 struct i2c_msg *rdwr_pa;
209 u8 __user **data_ptrs;
210 int i, res;
211
212 if (copy_from_user(&rdwr_arg,
213 (struct i2c_rdwr_ioctl_data __user *)arg,
214 sizeof(rdwr_arg)))
215 return -EFAULT;
216
217 /* Put an arbitrary limit on the number of messages that can
218 * be sent at once */
219 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
220 return -EINVAL;
221
222 rdwr_pa = (struct i2c_msg *)
223 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
224 GFP_KERNEL);
225 if (!rdwr_pa)
226 return -ENOMEM;
227
228 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
229 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
230 kfree(rdwr_pa);
231 return -EFAULT;
232 }
233
234 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
235 if (data_ptrs == NULL) {
236 kfree(rdwr_pa);
237 return -ENOMEM;
238 }
239
240 res = 0;
241 for (i = 0; i < rdwr_arg.nmsgs; i++) {
242 /* Limit the size of the message to a sane amount;
243 * and don't let length change either. */
244 if ((rdwr_pa[i].len > 8192) ||
245 (rdwr_pa[i].flags & I2C_M_RECV_LEN)) {
246 res = -EINVAL;
247 break;
248 }
249 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
250 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
251 if (rdwr_pa[i].buf == NULL) {
252 res = -ENOMEM;
253 break;
254 }
255 if (copy_from_user(rdwr_pa[i].buf, data_ptrs[i],
256 rdwr_pa[i].len)) {
257 ++i; /* Needs to be kfreed too */
258 res = -EFAULT;
259 break;
260 }
261 }
262 if (res < 0) {
263 int j;
264 for (j = 0; j < i; ++j)
265 kfree(rdwr_pa[j].buf);
266 kfree(data_ptrs);
267 kfree(rdwr_pa);
268 return res;
269 }
270
271 res = i2c_transfer(client->adapter, rdwr_pa, rdwr_arg.nmsgs);
272 while (i-- > 0) {
273 if (res >= 0 && (rdwr_pa[i].flags & I2C_M_RD)) {
274 if (copy_to_user(data_ptrs[i], rdwr_pa[i].buf,
275 rdwr_pa[i].len))
276 res = -EFAULT;
277 }
278 kfree(rdwr_pa[i].buf);
279 }
280 kfree(data_ptrs);
281 kfree(rdwr_pa);
282 return res;
283}
284
285static noinline int i2cdev_ioctl_smbus(struct i2c_client *client,
286 unsigned long arg)
287{
288 struct i2c_smbus_ioctl_data data_arg;
289 union i2c_smbus_data temp;
290 int datasize, res;
291
292 if (copy_from_user(&data_arg,
293 (struct i2c_smbus_ioctl_data __user *) arg,
294 sizeof(struct i2c_smbus_ioctl_data)))
295 return -EFAULT;
296 if ((data_arg.size != I2C_SMBUS_BYTE) &&
297 (data_arg.size != I2C_SMBUS_QUICK) &&
298 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
299 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
300 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
301 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
302 (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
303 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
304 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
305 dev_dbg(&client->adapter->dev,
306 "size out of range (%x) in ioctl I2C_SMBUS.\n",
307 data_arg.size);
308 return -EINVAL;
309 }
310 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
311 so the check is valid if size==I2C_SMBUS_QUICK too. */
312 if ((data_arg.read_write != I2C_SMBUS_READ) &&
313 (data_arg.read_write != I2C_SMBUS_WRITE)) {
314 dev_dbg(&client->adapter->dev,
315 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
316 data_arg.read_write);
317 return -EINVAL;
318 }
319
320 /* Note that command values are always valid! */
321
322 if ((data_arg.size == I2C_SMBUS_QUICK) ||
323 ((data_arg.size == I2C_SMBUS_BYTE) &&
324 (data_arg.read_write == I2C_SMBUS_WRITE)))
325 /* These are special: we do not use data */
326 return i2c_smbus_xfer(client->adapter, client->addr,
327 client->flags, data_arg.read_write,
328 data_arg.command, data_arg.size, NULL);
329
330 if (data_arg.data == NULL) {
331 dev_dbg(&client->adapter->dev,
332 "data is NULL pointer in ioctl I2C_SMBUS.\n");
333 return -EINVAL;
334 }
335
336 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
337 (data_arg.size == I2C_SMBUS_BYTE))
338 datasize = sizeof(data_arg.data->byte);
339 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
340 (data_arg.size == I2C_SMBUS_PROC_CALL))
341 datasize = sizeof(data_arg.data->word);
342 else /* size == smbus block, i2c block, or block proc. call */
343 datasize = sizeof(data_arg.data->block);
344
345 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
346 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
347 (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
348 (data_arg.read_write == I2C_SMBUS_WRITE)) {
349 if (copy_from_user(&temp, data_arg.data, datasize))
350 return -EFAULT;
351 }
352 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
353 /* Convert old I2C block commands to the new
354 convention. This preserves binary compatibility. */
355 data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
356 if (data_arg.read_write == I2C_SMBUS_READ)
357 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
358 }
359 res = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
360 data_arg.read_write, data_arg.command, data_arg.size, &temp);
361 if (!res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
362 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
363 (data_arg.read_write == I2C_SMBUS_READ))) {
364 if (copy_to_user(data_arg.data, &temp, datasize))
365 return -EFAULT;
366 }
367 return res;
368}
369
Alan Cox77e38bf2008-07-14 22:38:27 +0200370static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371{
H Hartley Sweeten0be16c32010-05-21 18:40:57 +0200372 struct i2c_client *client = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 unsigned long funcs;
374
Jean Delvaree8aafcb2005-10-07 23:06:27 +0200375 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
376 cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
Farid Hammaneae5624f2010-05-21 18:40:59 +0200378 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 case I2C_SLAVE:
380 case I2C_SLAVE_FORCE:
David Brownell907135a2007-11-15 19:24:01 +0100381 /* NOTE: devices set up to work with "new style" drivers
382 * can't use I2C_SLAVE, even when the device node is not
383 * bound to a driver. Only I2C_SLAVE_FORCE will work.
384 *
385 * Setting the PEC flag here won't affect kernel drivers,
386 * which will be using the i2c_client node registered with
387 * the driver model core. Likewise, when that client has
388 * the PEC flag already set, the i2c-dev driver won't see
389 * (or use) this setting.
390 */
David Brownell438d6c22006-12-10 21:21:31 +0100391 if ((arg > 0x3ff) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
393 return -EINVAL;
Jean Delvarebd4217d2007-11-15 19:24:01 +0100394 if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 return -EBUSY;
Jean Delvarebd4217d2007-11-15 19:24:01 +0100396 /* REVISIT: address could become busy later */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 client->addr = arg;
398 return 0;
399 case I2C_TENBIT:
400 if (arg)
401 client->flags |= I2C_M_TEN;
402 else
403 client->flags &= ~I2C_M_TEN;
404 return 0;
405 case I2C_PEC:
406 if (arg)
407 client->flags |= I2C_CLIENT_PEC;
408 else
409 client->flags &= ~I2C_CLIENT_PEC;
410 return 0;
411 case I2C_FUNCS:
412 funcs = i2c_get_functionality(client->adapter);
Jean Delvare2c003e82006-12-10 21:21:30 +0100413 return put_user(funcs, (unsigned long __user *)arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414
415 case I2C_RDWR:
Jean Delvaredba79972008-04-22 22:16:47 +0200416 return i2cdev_ioctl_rdrw(client, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
418 case I2C_SMBUS:
Jean Delvaredba79972008-04-22 22:16:47 +0200419 return i2cdev_ioctl_smbus(client, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420
David Brownell53be7952007-10-13 23:56:32 +0200421 case I2C_RETRIES:
422 client->adapter->retries = arg;
423 break;
424 case I2C_TIMEOUT:
Jean Delvarecd97f392009-02-24 19:19:49 +0100425 /* For historical reasons, user-space sets the timeout
426 * value in units of 10 ms.
427 */
428 client->adapter->timeout = msecs_to_jiffies(arg * 10);
David Brownell53be7952007-10-13 23:56:32 +0200429 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 default:
David Brownell53be7952007-10-13 23:56:32 +0200431 /* NOTE: returning a fault code here could cause trouble
432 * in buggy userspace code. Some old kernel bugs returned
433 * zero in this case, and userspace code might accidentally
434 * have depended on that bug.
435 */
436 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 }
438 return 0;
439}
440
441static int i2cdev_open(struct inode *inode, struct file *file)
442{
443 unsigned int minor = iminor(inode);
444 struct i2c_client *client;
445 struct i2c_adapter *adap;
446 struct i2c_dev *i2c_dev;
447
448 i2c_dev = i2c_dev_get_by_minor(minor);
Vincent Sanders9669f542009-12-06 17:06:26 +0100449 if (!i2c_dev)
450 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451
452 adap = i2c_get_adapter(i2c_dev->adap->nr);
Vincent Sanders9669f542009-12-06 17:06:26 +0100453 if (!adap)
454 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
David Brownell907135a2007-11-15 19:24:01 +0100456 /* This creates an anonymous i2c_client, which may later be
457 * pointed to some address using I2C_SLAVE or I2C_SLAVE_FORCE.
458 *
459 * This client is ** NEVER REGISTERED ** with the driver model
460 * or I2C core code!! It just holds private copies of addressing
461 * information and maybe a PEC flag.
462 */
Jean Delvare22f76e72006-07-01 17:20:57 +0200463 client = kzalloc(sizeof(*client), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 if (!client) {
465 i2c_put_adapter(adap);
Vincent Sanders9669f542009-12-06 17:06:26 +0100466 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 }
Jean Delvare22f76e72006-07-01 17:20:57 +0200468 snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
469 client->driver = &i2cdev_driver;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 client->adapter = adap;
472 file->private_data = client;
473
Vincent Sanders9669f542009-12-06 17:06:26 +0100474 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475}
476
477static int i2cdev_release(struct inode *inode, struct file *file)
478{
479 struct i2c_client *client = file->private_data;
480
481 i2c_put_adapter(client->adapter);
482 kfree(client);
483 file->private_data = NULL;
484
485 return 0;
486}
487
Arjan van de Ven2b8693c2007-02-12 00:55:32 -0800488static const struct file_operations i2cdev_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 .owner = THIS_MODULE,
490 .llseek = no_llseek,
491 .read = i2cdev_read,
492 .write = i2cdev_write,
Alan Cox77e38bf2008-07-14 22:38:27 +0200493 .unlocked_ioctl = i2cdev_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 .open = i2cdev_open,
495 .release = i2cdev_release,
496};
497
David Brownell907135a2007-11-15 19:24:01 +0100498/* ------------------------------------------------------------------------- */
499
500/*
501 * The legacy "i2cdev_driver" is used primarily to get notifications when
502 * I2C adapters are added or removed, so that each one gets an i2c_dev
503 * and is thus made available to userspace driver code.
504 */
505
Greg Kroah-Hartman794721322005-12-06 15:33:15 -0800506static struct class *i2c_dev_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
508static int i2cdev_attach_adapter(struct i2c_adapter *adap)
509{
510 struct i2c_dev *i2c_dev;
Jean Delvaredefcb462006-08-15 18:30:24 +0200511 int res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512
513 i2c_dev = get_free_i2c_dev(adap);
514 if (IS_ERR(i2c_dev))
515 return PTR_ERR(i2c_dev);
516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 /* register this i2c device with the driver core */
Greg Kroah-Hartmana9b12612008-07-21 20:03:34 -0700518 i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
519 MKDEV(I2C_MAJOR, adap->nr), NULL,
520 "i2c-%d", adap->nr);
Akinobu Mita3bacb362006-12-10 21:21:33 +0100521 if (IS_ERR(i2c_dev->dev)) {
522 res = PTR_ERR(i2c_dev->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 goto error;
Jean Delvaredefcb462006-08-15 18:30:24 +0200524 }
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700525 res = device_create_file(i2c_dev->dev, &dev_attr_name);
Jean Delvaredefcb462006-08-15 18:30:24 +0200526 if (res)
527 goto error_destroy;
Jean Delvareb32d20d2006-09-03 22:19:25 +0200528
529 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
530 adap->name, adap->nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 return 0;
Jean Delvaredefcb462006-08-15 18:30:24 +0200532error_destroy:
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700533 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534error:
535 return_i2c_dev(i2c_dev);
Jean Delvaredefcb462006-08-15 18:30:24 +0200536 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537}
538
539static int i2cdev_detach_adapter(struct i2c_adapter *adap)
540{
541 struct i2c_dev *i2c_dev;
542
Jean Delvare9455e4c2006-07-01 17:16:57 +0200543 i2c_dev = i2c_dev_get_by_minor(adap->nr);
Jean Delvareb32d20d2006-09-03 22:19:25 +0200544 if (!i2c_dev) /* attach_adapter must have failed */
545 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700547 device_remove_file(i2c_dev->dev, &dev_attr_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 return_i2c_dev(i2c_dev);
Greg Kroah-Hartmanac11d062006-07-03 13:46:24 -0700549 device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550
Jean Delvareb6d7b3d2005-07-31 19:02:53 +0200551 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 return 0;
553}
554
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555static struct i2c_driver i2cdev_driver = {
Laurent Riffard35d8b2e2005-11-26 20:34:05 +0100556 .driver = {
Laurent Riffard35d8b2e2005-11-26 20:34:05 +0100557 .name = "dev_driver",
558 },
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 .attach_adapter = i2cdev_attach_adapter,
560 .detach_adapter = i2cdev_detach_adapter,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561};
562
David Brownell907135a2007-11-15 19:24:01 +0100563/* ------------------------------------------------------------------------- */
564
565/*
566 * module load/unload record keeping
567 */
568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569static int __init i2c_dev_init(void)
570{
571 int res;
572
573 printk(KERN_INFO "i2c /dev entries driver\n");
574
575 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
576 if (res)
577 goto out;
578
Greg Kroah-Hartman794721322005-12-06 15:33:15 -0800579 i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
Sven Wegenere74783e2008-09-24 13:39:21 +0200580 if (IS_ERR(i2c_dev_class)) {
581 res = PTR_ERR(i2c_dev_class);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 goto out_unreg_chrdev;
Sven Wegenere74783e2008-09-24 13:39:21 +0200583 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584
585 res = i2c_add_driver(&i2cdev_driver);
586 if (res)
587 goto out_unreg_class;
588
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 return 0;
590
591out_unreg_class:
Greg Kroah-Hartman794721322005-12-06 15:33:15 -0800592 class_destroy(i2c_dev_class);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593out_unreg_chrdev:
594 unregister_chrdev(I2C_MAJOR, "i2c");
595out:
596 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
597 return res;
598}
599
600static void __exit i2c_dev_exit(void)
601{
602 i2c_del_driver(&i2cdev_driver);
Greg Kroah-Hartman794721322005-12-06 15:33:15 -0800603 class_destroy(i2c_dev_class);
Farid Hammaneae5624f2010-05-21 18:40:59 +0200604 unregister_chrdev(I2C_MAJOR, "i2c");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605}
606
607MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
608 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
609MODULE_DESCRIPTION("I2C /dev entries driver");
610MODULE_LICENSE("GPL");
611
612module_init(i2c_dev_init);
613module_exit(i2c_dev_exit);