2 i2c-dev.c - i2c-bus driver, char device interface
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>
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.
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.
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.
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 */
27 /* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
29 /* The devfs code is contributed by Philipp Matthias Hahn
30 <pmhahn@titan.lahn.de> */
32 #include <linux/kernel.h>
33 #include <linux/module.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>
43 static struct i2c_client i2cdev_client_template;
47 struct i2c_adapter *adap;
48 struct class_device class_dev;
49 struct completion released; /* FIXME, we need a class_device_unregister() */
51 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
53 #define I2C_MINORS 256
54 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
55 static DEFINE_SPINLOCK(i2c_dev_array_lock);
57 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
59 struct i2c_dev *i2c_dev;
61 spin_lock(&i2c_dev_array_lock);
62 i2c_dev = i2c_dev_array[index];
63 spin_unlock(&i2c_dev_array_lock);
67 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
69 struct i2c_dev *i2c_dev = NULL;
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);
79 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
81 struct i2c_dev *i2c_dev;
83 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
85 return ERR_PTR(-ENOMEM);
87 spin_lock(&i2c_dev_array_lock);
88 if (i2c_dev_array[adap->nr]) {
89 spin_unlock(&i2c_dev_array_lock);
90 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
93 i2c_dev->minor = adap->nr;
94 i2c_dev_array[adap->nr] = i2c_dev;
95 spin_unlock(&i2c_dev_array_lock);
99 return ERR_PTR(-ENODEV);
102 static void return_i2c_dev(struct i2c_dev *i2c_dev)
104 spin_lock(&i2c_dev_array_lock);
105 i2c_dev_array[i2c_dev->minor] = NULL;
106 spin_unlock(&i2c_dev_array_lock);
109 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
111 struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
112 return sprintf(buf, "%s\n", i2c_dev->adap->name);
114 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
116 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
122 struct i2c_client *client = (struct i2c_client *)file->private_data;
127 tmp = kmalloc(count,GFP_KERNEL);
131 pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
132 iminor(file->f_dentry->d_inode), count);
134 ret = i2c_master_recv(client,tmp,count);
136 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
141 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
146 struct i2c_client *client = (struct i2c_client *)file->private_data;
151 tmp = kmalloc(count,GFP_KERNEL);
154 if (copy_from_user(tmp,buf,count)) {
159 pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
160 iminor(file->f_dentry->d_inode), count);
162 ret = i2c_master_send(client,tmp,count);
167 static int i2cdev_ioctl(struct inode *inode, struct file *file,
168 unsigned int cmd, unsigned long arg)
170 struct i2c_client *client = (struct i2c_client *)file->private_data;
171 struct i2c_rdwr_ioctl_data rdwr_arg;
172 struct i2c_smbus_ioctl_data data_arg;
173 union i2c_smbus_data temp;
174 struct i2c_msg *rdwr_pa;
175 u8 __user **data_ptrs;
179 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
184 case I2C_SLAVE_FORCE:
186 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
188 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
194 client->flags |= I2C_M_TEN;
196 client->flags &= ~I2C_M_TEN;
200 client->flags |= I2C_CLIENT_PEC;
202 client->flags &= ~I2C_CLIENT_PEC;
205 funcs = i2c_get_functionality(client->adapter);
206 return (copy_to_user((unsigned long __user *)arg, &funcs,
207 sizeof(unsigned long)))?-EFAULT:0;
210 if (copy_from_user(&rdwr_arg,
211 (struct i2c_rdwr_ioctl_data __user *)arg,
215 /* Put an arbitrary limit on the number of messages that can
217 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
220 rdwr_pa = (struct i2c_msg *)
221 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
224 if (rdwr_pa == NULL) return -ENOMEM;
226 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
227 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
232 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
233 if (data_ptrs == NULL) {
239 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
240 /* Limit the size of the message to a sane amount */
241 if (rdwr_pa[i].len > 8192) {
245 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
246 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
247 if(rdwr_pa[i].buf == NULL) {
251 if(copy_from_user(rdwr_pa[i].buf,
254 ++i; /* Needs to be kfreed too */
261 for (j = 0; j < i; ++j)
262 kfree(rdwr_pa[j].buf);
268 res = i2c_transfer(client->adapter,
272 if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
280 kfree(rdwr_pa[i].buf);
287 if (copy_from_user(&data_arg,
288 (struct i2c_smbus_ioctl_data __user *) arg,
289 sizeof(struct i2c_smbus_ioctl_data)))
291 if ((data_arg.size != I2C_SMBUS_BYTE) &&
292 (data_arg.size != I2C_SMBUS_QUICK) &&
293 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
294 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
295 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
296 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
297 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
298 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
299 dev_dbg(&client->adapter->dev,
300 "size out of range (%x) in ioctl I2C_SMBUS.\n",
304 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
305 so the check is valid if size==I2C_SMBUS_QUICK too. */
306 if ((data_arg.read_write != I2C_SMBUS_READ) &&
307 (data_arg.read_write != I2C_SMBUS_WRITE)) {
308 dev_dbg(&client->adapter->dev,
309 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
310 data_arg.read_write);
314 /* Note that command values are always valid! */
316 if ((data_arg.size == I2C_SMBUS_QUICK) ||
317 ((data_arg.size == I2C_SMBUS_BYTE) &&
318 (data_arg.read_write == I2C_SMBUS_WRITE)))
319 /* These are special: we do not use data */
320 return i2c_smbus_xfer(client->adapter, client->addr,
324 data_arg.size, NULL);
326 if (data_arg.data == NULL) {
327 dev_dbg(&client->adapter->dev,
328 "data is NULL pointer in ioctl I2C_SMBUS.\n");
332 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
333 (data_arg.size == I2C_SMBUS_BYTE))
334 datasize = sizeof(data_arg.data->byte);
335 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
336 (data_arg.size == I2C_SMBUS_PROC_CALL))
337 datasize = sizeof(data_arg.data->word);
338 else /* size == smbus block, i2c block, or block proc. call */
339 datasize = sizeof(data_arg.data->block);
341 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
342 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
343 (data_arg.read_write == I2C_SMBUS_WRITE)) {
344 if (copy_from_user(&temp, data_arg.data, datasize))
347 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
349 data_arg.command,data_arg.size,&temp);
350 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
351 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
352 (data_arg.read_write == I2C_SMBUS_READ))) {
353 if (copy_to_user(data_arg.data, &temp, datasize))
359 return i2c_control(client,cmd,arg);
364 static int i2cdev_open(struct inode *inode, struct file *file)
366 unsigned int minor = iminor(inode);
367 struct i2c_client *client;
368 struct i2c_adapter *adap;
369 struct i2c_dev *i2c_dev;
371 i2c_dev = i2c_dev_get_by_minor(minor);
375 adap = i2c_get_adapter(i2c_dev->adap->nr);
379 client = kmalloc(sizeof(*client), GFP_KERNEL);
381 i2c_put_adapter(adap);
384 memcpy(client, &i2cdev_client_template, sizeof(*client));
386 /* registered with adapter, passed as client to user */
387 client->adapter = adap;
388 file->private_data = client;
393 static int i2cdev_release(struct inode *inode, struct file *file)
395 struct i2c_client *client = file->private_data;
397 i2c_put_adapter(client->adapter);
399 file->private_data = NULL;
404 static struct file_operations i2cdev_fops = {
405 .owner = THIS_MODULE,
408 .write = i2cdev_write,
409 .ioctl = i2cdev_ioctl,
411 .release = i2cdev_release,
414 static void release_i2c_dev(struct class_device *dev)
416 struct i2c_dev *i2c_dev = to_i2c_dev(dev);
417 complete(&i2c_dev->released);
420 static struct class i2c_dev_class = {
422 .release = &release_i2c_dev,
425 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
427 struct i2c_dev *i2c_dev;
430 i2c_dev = get_free_i2c_dev(adap);
432 return PTR_ERR(i2c_dev);
434 devfs_mk_cdev(MKDEV(I2C_MAJOR, i2c_dev->minor),
435 S_IFCHR|S_IRUSR|S_IWUSR, "i2c/%d", i2c_dev->minor);
436 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
437 adap->name, i2c_dev->minor);
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;
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);
451 class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
454 return_i2c_dev(i2c_dev);
459 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
461 struct i2c_dev *i2c_dev;
463 i2c_dev = i2c_dev_get_by_adapter(adap);
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);
474 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
478 static int i2cdev_detach_client(struct i2c_client *client)
483 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
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,
500 static struct i2c_client i2cdev_client_template = {
501 .name = "I2C /dev entry",
503 .driver = &i2cdev_driver,
506 static int __init i2c_dev_init(void)
510 printk(KERN_INFO "i2c /dev entries driver\n");
512 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
516 res = class_register(&i2c_dev_class);
518 goto out_unreg_chrdev;
520 res = i2c_add_driver(&i2cdev_driver);
522 goto out_unreg_class;
529 class_unregister(&i2c_dev_class);
531 unregister_chrdev(I2C_MAJOR, "i2c");
533 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
537 static void __exit i2c_dev_exit(void)
539 i2c_del_driver(&i2cdev_driver);
540 class_unregister(&i2c_dev_class);
542 unregister_chrdev(I2C_MAJOR,"i2c");
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");
550 module_init(i2c_dev_init);
551 module_exit(i2c_dev_exit);