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/init.h>
  34 #include <linux/list.h>
  35 #include <linux/i2c.h>
  36 #include <linux/i2c-dev.h>
  37 #include <asm/uaccess.h>
  38
  39 static struct i2c_driver i2cdev_driver;
  40
  41 struct i2c_dev {
  42         struct list_head list;
  43         struct i2c_adapter *adap;
  44         struct device *dev;
  45 };
  46
  47 #define I2C_MINORS      256
  48 static LIST_HEAD(i2c_dev_list);
  49 static DEFINE_SPINLOCK(i2c_dev_list_lock);
  50
  51 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  52 {
  53         struct i2c_dev *i2c_dev;
  54
  55         spin_lock(&i2c_dev_list_lock);
  56         list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
  57                 if (i2c_dev->adap->nr == index)
  58                         goto found;
  59         }
  60         i2c_dev = NULL;
  61 found:
  62         spin_unlock(&i2c_dev_list_lock);
  63         return i2c_dev;
  64 }
  65
  66 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  67 {
  68         struct i2c_dev *i2c_dev;
  69
  70         if (adap->nr >= I2C_MINORS) {
  71                 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
  72                        adap->nr);
  73                 return ERR_PTR(-ENODEV);
  74         }
  75
  76         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  77         if (!i2c_dev)
  78                 return ERR_PTR(-ENOMEM);
  79         i2c_dev->adap = adap;
  80
  81         spin_lock(&i2c_dev_list_lock);
  82         list_add_tail(&i2c_dev->list, &i2c_dev_list);
  83         spin_unlock(&i2c_dev_list_lock);
  84         return i2c_dev;
  85 }
  86
  87 static void return_i2c_dev(struct i2c_dev *i2c_dev)
  88 {
  89         spin_lock(&i2c_dev_list_lock);
  90         list_del(&i2c_dev->list);
  91         spin_unlock(&i2c_dev_list_lock);
  92         kfree(i2c_dev);
  93 }
  94
  95 static ssize_t show_adapter_name(struct device *dev,
  96                                  struct device_attribute *attr, char *buf)
  97 {
  98         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
  99
 100         if (!i2c_dev)
 101                 return -ENODEV;
 102         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 103 }
 104 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 105
 106 static 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",
 122                 iminor(file->f_path.dentry->d_inode), count);
 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
 131 static 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",
 150                 iminor(file->f_path.dentry->d_inode), count);
 151
 152         ret = i2c_master_send(client,tmp,count);
 153         kfree(tmp);
 154         return ret;
 155 }
 156
 157 static 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
 169         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 170                 cmd, arg);
 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);
 196                 return put_user(funcs, (unsigned long __user *)arg);
 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
 204                 /* Put an arbitrary limit on the number of messages that can
 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                          * and don't let length change either. */
 231                         if ((rdwr_pa[i].len > 8192) ||
 232                             (rdwr_pa[i].flags & I2C_M_RECV_LEN)) {
 233                                 res = -EINVAL;
 234                                 break;
 235                         }
 236                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 237                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 238                         if(rdwr_pa[i].buf == NULL) {
 239                                 res = -ENOMEM;
 240                                 break;
 241                         }
 242                         if(copy_from_user(rdwr_pa[i].buf,
 243                                 data_ptrs[i],
 244                                 rdwr_pa[i].len)) {
 245                                         ++i; /* Needs to be kfreed too */
 246                                         res = -EFAULT;
 247                                 break;
 248                         }
 249                 }
 250                 if (res < 0) {
 251                         int j;
 252                         for (j = 0; j < i; ++j)
 253                                 kfree(rdwr_pa[j].buf);
 254                         kfree(data_ptrs);
 255                         kfree(rdwr_pa);
 256                         return res;
 257                 }
 258
 259                 res = i2c_transfer(client->adapter,
 260                         rdwr_pa,
 261                         rdwr_arg.nmsgs);
 262                 while(i-- > 0) {
 263                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 264                                 if(copy_to_user(
 265                                         data_ptrs[i],
 266                                         rdwr_pa[i].buf,
 267                                         rdwr_pa[i].len)) {
 268                                         res = -EFAULT;
 269                                 }
 270                         }
 271                         kfree(rdwr_pa[i].buf);
 272                 }
 273                 kfree(data_ptrs);
 274                 kfree(rdwr_pa);
 275                 return res;
 276
 277         case I2C_SMBUS:
 278                 if (copy_from_user(&data_arg,
 279                                    (struct i2c_smbus_ioctl_data __user *) arg,
 280                                    sizeof(struct i2c_smbus_ioctl_data)))
 281                         return -EFAULT;
 282                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
 283                     (data_arg.size != I2C_SMBUS_QUICK) &&
 284                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 285                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 286                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 287                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 288                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
 289                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 290                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 291                         dev_dbg(&client->adapter->dev,
 292                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
 293                                 data_arg.size);
 294                         return -EINVAL;
 295                 }
 296                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 297                    so the check is valid if size==I2C_SMBUS_QUICK too. */
 298                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
 299                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
 300                         dev_dbg(&client->adapter->dev,
 301                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 302                                 data_arg.read_write);
 303                         return -EINVAL;
 304                 }
 305
 306                 /* Note that command values are always valid! */
 307
 308                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
 309                     ((data_arg.size == I2C_SMBUS_BYTE) &&
 310                     (data_arg.read_write == I2C_SMBUS_WRITE)))
 311                         /* These are special: we do not use data */
 312                         return i2c_smbus_xfer(client->adapter, client->addr,
 313                                               client->flags,
 314                                               data_arg.read_write,
 315                                               data_arg.command,
 316                                               data_arg.size, NULL);
 317
 318                 if (data_arg.data == NULL) {
 319                         dev_dbg(&client->adapter->dev,
 320                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 321                         return -EINVAL;
 322                 }
 323
 324                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 325                     (data_arg.size == I2C_SMBUS_BYTE))
 326                         datasize = sizeof(data_arg.data->byte);
 327                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 328                          (data_arg.size == I2C_SMBUS_PROC_CALL))
 329                         datasize = sizeof(data_arg.data->word);
 330                 else /* size == smbus block, i2c block, or block proc. call */
 331                         datasize = sizeof(data_arg.data->block);
 332
 333                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 334                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 335                     (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
 336                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
 337                         if (copy_from_user(&temp, data_arg.data, datasize))
 338                                 return -EFAULT;
 339                 }
 340                 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
 341                         /* Convert old I2C block commands to the new
 342                            convention. This preserves binary compatibility. */
 343                         data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
 344                         if (data_arg.read_write == I2C_SMBUS_READ)
 345                                 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
 346                 }
 347                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 348                       data_arg.read_write,
 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))
 354                                 return -EFAULT;
 355                 }
 356                 return res;
 357         case I2C_RETRIES:
 358                 client->adapter->retries = arg;
 359                 break;
 360         case I2C_TIMEOUT:
 361                 client->adapter->timeout = arg;
 362                 break;
 363         default:
 364                 /* NOTE:  returning a fault code here could cause trouble
 365                  * in buggy userspace code.  Some old kernel bugs returned
 366                  * zero in this case, and userspace code might accidentally
 367                  * have depended on that bug.
 368                  */
 369                 return -ENOTTY;
 370         }
 371         return 0;
 372 }
 373
 374 static int i2cdev_open(struct inode *inode, struct file *file)
 375 {
 376         unsigned int minor = iminor(inode);
 377         struct i2c_client *client;
 378         struct i2c_adapter *adap;
 379         struct i2c_dev *i2c_dev;
 380
 381         i2c_dev = i2c_dev_get_by_minor(minor);
 382         if (!i2c_dev)
 383                 return -ENODEV;
 384
 385         adap = i2c_get_adapter(i2c_dev->adap->nr);
 386         if (!adap)
 387                 return -ENODEV;
 388
 389         client = kzalloc(sizeof(*client), GFP_KERNEL);
 390         if (!client) {
 391                 i2c_put_adapter(adap);
 392                 return -ENOMEM;
 393         }
 394         snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 395         client->driver = &i2cdev_driver;
 396
 397         /* registered with adapter, passed as client to user */
 398         client->adapter = adap;
 399         file->private_data = client;
 400
 401         return 0;
 402 }
 403
 404 static int i2cdev_release(struct inode *inode, struct file *file)
 405 {
 406         struct i2c_client *client = file->private_data;
 407
 408         i2c_put_adapter(client->adapter);
 409         kfree(client);
 410         file->private_data = NULL;
 411
 412         return 0;
 413 }
 414
 415 static const struct file_operations i2cdev_fops = {
 416         .owner          = THIS_MODULE,
 417         .llseek         = no_llseek,
 418         .read           = i2cdev_read,
 419         .write          = i2cdev_write,
 420         .ioctl          = i2cdev_ioctl,
 421         .open           = i2cdev_open,
 422         .release        = i2cdev_release,
 423 };
 424
 425 static struct class *i2c_dev_class;
 426
 427 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 428 {
 429         struct i2c_dev *i2c_dev;
 430         int res;
 431
 432         i2c_dev = get_free_i2c_dev(adap);
 433         if (IS_ERR(i2c_dev))
 434                 return PTR_ERR(i2c_dev);
 435
 436         /* register this i2c device with the driver core */
 437         i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
 438                                      MKDEV(I2C_MAJOR, adap->nr),
 439                                      "i2c-%d", adap->nr);
 440         if (IS_ERR(i2c_dev->dev)) {
 441                 res = PTR_ERR(i2c_dev->dev);
 442                 goto error;
 443         }
 444         res = device_create_file(i2c_dev->dev, &dev_attr_name);
 445         if (res)
 446                 goto error_destroy;
 447
 448         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 449                  adap->name, adap->nr);
 450         return 0;
 451 error_destroy:
 452         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 453 error:
 454         return_i2c_dev(i2c_dev);
 455         return res;
 456 }
 457
 458 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 459 {
 460         struct i2c_dev *i2c_dev;
 461
 462         i2c_dev = i2c_dev_get_by_minor(adap->nr);
 463         if (!i2c_dev) /* attach_adapter must have failed */
 464                 return 0;
 465
 466         device_remove_file(i2c_dev->dev, &dev_attr_name);
 467         return_i2c_dev(i2c_dev);
 468         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 469
 470         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 471         return 0;
 472 }
 473
 474 static int i2cdev_detach_client(struct i2c_client *client)
 475 {
 476         return 0;
 477 }
 478
 479 static struct i2c_driver i2cdev_driver = {
 480         .driver = {
 481                 .name   = "dev_driver",
 482         },
 483         .id             = I2C_DRIVERID_I2CDEV,
 484         .attach_adapter = i2cdev_attach_adapter,
 485         .detach_adapter = i2cdev_detach_adapter,
 486         .detach_client  = i2cdev_detach_client,
 487 };
 488
 489 static int __init i2c_dev_init(void)
 490 {
 491         int res;
 492
 493         printk(KERN_INFO "i2c /dev entries driver\n");
 494
 495         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 496         if (res)
 497                 goto out;
 498
 499         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
 500         if (IS_ERR(i2c_dev_class))
 501                 goto out_unreg_chrdev;
 502
 503         res = i2c_add_driver(&i2cdev_driver);
 504         if (res)
 505                 goto out_unreg_class;
 506
 507         return 0;
 508
 509 out_unreg_class:
 510         class_destroy(i2c_dev_class);
 511 out_unreg_chrdev:
 512         unregister_chrdev(I2C_MAJOR, "i2c");
 513 out:
 514         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 515         return res;
 516 }
 517
 518 static void __exit i2c_dev_exit(void)
 519 {
 520         i2c_del_driver(&i2cdev_driver);
 521         class_destroy(i2c_dev_class);
 522         unregister_chrdev(I2C_MAJOR,"i2c");
 523 }
 524
 525 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 526                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 527 MODULE_DESCRIPTION("I2C /dev entries driver");
 528 MODULE_LICENSE("GPL");
 529
 530 module_init(i2c_dev_init);
 531 module_exit(i2c_dev_exit);