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/config.h>
33 #include <linux/kernel.h>
34 #include <linux/module.h>
36 #include <linux/slab.h>
37 #include <linux/smp_lock.h>
38 #include <linux/devfs_fs_kernel.h>
39 #include <linux/init.h>
40 #include <linux/i2c.h>
41 #include <linux/i2c-dev.h>
42 #include <asm/uaccess.h>
44 static struct i2c_client i2cdev_client_template;
48 struct i2c_adapter *adap;
49 struct class_device class_dev;
50 struct completion released; /* FIXME, we need a class_device_unregister() */
52 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
54 #define I2C_MINORS 256
55 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
56 static DEFINE_SPINLOCK(i2c_dev_array_lock);
58 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
60 struct i2c_dev *i2c_dev;
62 spin_lock(&i2c_dev_array_lock);
63 i2c_dev = i2c_dev_array[index];
64 spin_unlock(&i2c_dev_array_lock);
68 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
70 struct i2c_dev *i2c_dev = NULL;
72 spin_lock(&i2c_dev_array_lock);
73 if ((i2c_dev_array[adap->nr]) &&
74 (i2c_dev_array[adap->nr]->adap == adap))
75 i2c_dev = i2c_dev_array[adap->nr];
76 spin_unlock(&i2c_dev_array_lock);
80 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
82 struct i2c_dev *i2c_dev;
84 i2c_dev = kmalloc(sizeof(*i2c_dev), GFP_KERNEL);
86 return ERR_PTR(-ENOMEM);
87 memset(i2c_dev, 0x00, sizeof(*i2c_dev));
89 spin_lock(&i2c_dev_array_lock);
90 if (i2c_dev_array[adap->nr]) {
91 spin_unlock(&i2c_dev_array_lock);
92 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
95 i2c_dev->minor = adap->nr;
96 i2c_dev_array[adap->nr] = i2c_dev;
97 spin_unlock(&i2c_dev_array_lock);
101 return ERR_PTR(-ENODEV);
104 static void return_i2c_dev(struct i2c_dev *i2c_dev)
106 spin_lock(&i2c_dev_array_lock);
107 i2c_dev_array[i2c_dev->minor] = NULL;
108 spin_unlock(&i2c_dev_array_lock);
111 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
113 struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
114 return sprintf(buf, "%s\n", i2c_dev->adap->name);
116 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
118 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
124 struct i2c_client *client = (struct i2c_client *)file->private_data;
129 tmp = kmalloc(count,GFP_KERNEL);
133 pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
134 iminor(file->f_dentry->d_inode), count);
136 ret = i2c_master_recv(client,tmp,count);
138 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
143 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
148 struct i2c_client *client = (struct i2c_client *)file->private_data;
153 tmp = kmalloc(count,GFP_KERNEL);
156 if (copy_from_user(tmp,buf,count)) {
161 pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
162 iminor(file->f_dentry->d_inode), count);
164 ret = i2c_master_send(client,tmp,count);
169 static int i2cdev_ioctl(struct inode *inode, struct file *file,
170 unsigned int cmd, unsigned long arg)
172 struct i2c_client *client = (struct i2c_client *)file->private_data;
173 struct i2c_rdwr_ioctl_data rdwr_arg;
174 struct i2c_smbus_ioctl_data data_arg;
175 union i2c_smbus_data temp;
176 struct i2c_msg *rdwr_pa;
177 u8 __user **data_ptrs;
181 dev_dbg(&client->adapter->dev, "i2c-%d ioctl, cmd: 0x%x, arg: %lx.\n",
182 iminor(inode),cmd, arg);
186 case I2C_SLAVE_FORCE:
188 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
190 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
196 client->flags |= I2C_M_TEN;
198 client->flags &= ~I2C_M_TEN;
202 client->flags |= I2C_CLIENT_PEC;
204 client->flags &= ~I2C_CLIENT_PEC;
207 funcs = i2c_get_functionality(client->adapter);
208 return (copy_to_user((unsigned long __user *)arg, &funcs,
209 sizeof(unsigned long)))?-EFAULT:0;
212 if (copy_from_user(&rdwr_arg,
213 (struct i2c_rdwr_ioctl_data __user *)arg,
217 /* Put an arbritrary limit on the number of messages that can
219 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
222 rdwr_pa = (struct i2c_msg *)
223 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
226 if (rdwr_pa == NULL) return -ENOMEM;
228 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
229 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
234 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
235 if (data_ptrs == NULL) {
241 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
242 /* Limit the size of the message to a sane amount */
243 if (rdwr_pa[i].len > 8192) {
247 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
248 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
249 if(rdwr_pa[i].buf == NULL) {
253 if(copy_from_user(rdwr_pa[i].buf,
256 ++i; /* Needs to be kfreed too */
263 for (j = 0; j < i; ++j)
264 kfree(rdwr_pa[j].buf);
270 res = i2c_transfer(client->adapter,
274 if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
282 kfree(rdwr_pa[i].buf);
289 if (copy_from_user(&data_arg,
290 (struct i2c_smbus_ioctl_data __user *) arg,
291 sizeof(struct i2c_smbus_ioctl_data)))
293 if ((data_arg.size != I2C_SMBUS_BYTE) &&
294 (data_arg.size != I2C_SMBUS_QUICK) &&
295 (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
296 (data_arg.size != I2C_SMBUS_WORD_DATA) &&
297 (data_arg.size != I2C_SMBUS_PROC_CALL) &&
298 (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
299 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
300 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
301 dev_dbg(&client->adapter->dev,
302 "size out of range (%x) in ioctl I2C_SMBUS.\n",
306 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
307 so the check is valid if size==I2C_SMBUS_QUICK too. */
308 if ((data_arg.read_write != I2C_SMBUS_READ) &&
309 (data_arg.read_write != I2C_SMBUS_WRITE)) {
310 dev_dbg(&client->adapter->dev,
311 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
312 data_arg.read_write);
316 /* Note that command values are always valid! */
318 if ((data_arg.size == I2C_SMBUS_QUICK) ||
319 ((data_arg.size == I2C_SMBUS_BYTE) &&
320 (data_arg.read_write == I2C_SMBUS_WRITE)))
321 /* These are special: we do not use data */
322 return i2c_smbus_xfer(client->adapter, client->addr,
326 data_arg.size, NULL);
328 if (data_arg.data == NULL) {
329 dev_dbg(&client->adapter->dev,
330 "data is NULL pointer in ioctl I2C_SMBUS.\n");
334 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
335 (data_arg.size == I2C_SMBUS_BYTE))
336 datasize = sizeof(data_arg.data->byte);
337 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
338 (data_arg.size == I2C_SMBUS_PROC_CALL))
339 datasize = sizeof(data_arg.data->word);
340 else /* size == smbus block, i2c block, or block proc. call */
341 datasize = sizeof(data_arg.data->block);
343 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
344 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
345 (data_arg.read_write == I2C_SMBUS_WRITE)) {
346 if (copy_from_user(&temp, data_arg.data, datasize))
349 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
351 data_arg.command,data_arg.size,&temp);
352 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
353 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
354 (data_arg.read_write == I2C_SMBUS_READ))) {
355 if (copy_to_user(data_arg.data, &temp, datasize))
361 return i2c_control(client,cmd,arg);
366 static int i2cdev_open(struct inode *inode, struct file *file)
368 unsigned int minor = iminor(inode);
369 struct i2c_client *client;
370 struct i2c_adapter *adap;
371 struct i2c_dev *i2c_dev;
373 i2c_dev = i2c_dev_get_by_minor(minor);
377 adap = i2c_get_adapter(i2c_dev->adap->nr);
381 client = kmalloc(sizeof(*client), GFP_KERNEL);
383 i2c_put_adapter(adap);
386 memcpy(client, &i2cdev_client_template, sizeof(*client));
388 /* registered with adapter, passed as client to user */
389 client->adapter = adap;
390 file->private_data = client;
395 static int i2cdev_release(struct inode *inode, struct file *file)
397 struct i2c_client *client = file->private_data;
399 i2c_put_adapter(client->adapter);
401 file->private_data = NULL;
406 static struct file_operations i2cdev_fops = {
407 .owner = THIS_MODULE,
410 .write = i2cdev_write,
411 .ioctl = i2cdev_ioctl,
413 .release = i2cdev_release,
416 static void release_i2c_dev(struct class_device *dev)
418 struct i2c_dev *i2c_dev = to_i2c_dev(dev);
419 complete(&i2c_dev->released);
422 static struct class i2c_dev_class = {
424 .release = &release_i2c_dev,
427 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
429 struct i2c_dev *i2c_dev;
432 i2c_dev = get_free_i2c_dev(adap);
434 return PTR_ERR(i2c_dev);
436 devfs_mk_cdev(MKDEV(I2C_MAJOR, i2c_dev->minor),
437 S_IFCHR|S_IRUSR|S_IWUSR, "i2c/%d", i2c_dev->minor);
438 dev_dbg(&adap->dev, "Registered as minor %d\n", i2c_dev->minor);
440 /* register this i2c device with the driver core */
441 i2c_dev->adap = adap;
442 if (adap->dev.parent == &platform_bus)
443 i2c_dev->class_dev.dev = &adap->dev;
445 i2c_dev->class_dev.dev = adap->dev.parent;
446 i2c_dev->class_dev.class = &i2c_dev_class;
447 i2c_dev->class_dev.devt = MKDEV(I2C_MAJOR, i2c_dev->minor);
448 snprintf(i2c_dev->class_dev.class_id, BUS_ID_SIZE, "i2c-%d", i2c_dev->minor);
449 retval = class_device_register(&i2c_dev->class_dev);
452 class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
455 return_i2c_dev(i2c_dev);
460 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
462 struct i2c_dev *i2c_dev;
464 i2c_dev = i2c_dev_get_by_adapter(adap);
468 init_completion(&i2c_dev->released);
469 devfs_remove("i2c/%d", i2c_dev->minor);
470 return_i2c_dev(i2c_dev);
471 class_device_unregister(&i2c_dev->class_dev);
472 wait_for_completion(&i2c_dev->released);
475 dev_dbg(&adap->dev, "Adapter unregistered\n");
479 static int i2cdev_detach_client(struct i2c_client *client)
484 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
490 static struct i2c_driver i2cdev_driver = {
491 .owner = THIS_MODULE,
492 .name = "dev_driver",
493 .id = I2C_DRIVERID_I2CDEV,
494 .flags = I2C_DF_NOTIFY,
495 .attach_adapter = i2cdev_attach_adapter,
496 .detach_adapter = i2cdev_detach_adapter,
497 .detach_client = i2cdev_detach_client,
498 .command = i2cdev_command,
501 static struct i2c_client i2cdev_client_template = {
502 .name = "I2C /dev entry",
504 .driver = &i2cdev_driver,
507 static int __init i2c_dev_init(void)
511 printk(KERN_INFO "i2c /dev entries driver\n");
513 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
517 res = class_register(&i2c_dev_class);
519 goto out_unreg_chrdev;
521 res = i2c_add_driver(&i2cdev_driver);
523 goto out_unreg_class;
530 class_unregister(&i2c_dev_class);
532 unregister_chrdev(I2C_MAJOR, "i2c");
534 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
538 static void __exit i2c_dev_exit(void)
540 i2c_del_driver(&i2cdev_driver);
541 class_unregister(&i2c_dev_class);
543 unregister_chrdev(I2C_MAJOR,"i2c");
546 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
547 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
548 MODULE_DESCRIPTION("I2C /dev entries driver");
549 MODULE_LICENSE("GPL");
551 module_init(i2c_dev_init);
552 module_exit(i2c_dev_exit);