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   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 /* The devfs code is contributed by Philipp Matthias Hahn
  30    <pmhahn@titan.lahn.de> */
  31
  32 #include <linux/kernel.h>
  33 #include <linux/module.h>
  34 #include <linux/fs.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>
  42
  43 static struct i2c_client i2cdev_client_template;
  44
  45 struct i2c_dev {
  46         int minor;
  47         struct i2c_adapter *adap;
  48         struct class_device class_dev;
  49         struct completion released;     /* FIXME, we need a class_device_unregister() */
  50 };
  51 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
  52
  53 #define I2C_MINORS      256
  54 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
  55 static DEFINE_SPINLOCK(i2c_dev_array_lock);
  56
  57 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  58 {
  59         struct i2c_dev *i2c_dev;
  60
  61         spin_lock(&i2c_dev_array_lock);
  62         i2c_dev = i2c_dev_array[index];
  63         spin_unlock(&i2c_dev_array_lock);
  64         return i2c_dev;
  65 }
  66
  67 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
  68 {
  69         struct i2c_dev *i2c_dev = NULL;
  70
  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);
  76         return i2c_dev;
  77 }
  78
  79 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  80 {
  81         struct i2c_dev *i2c_dev;
  82
  83         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  84         if (!i2c_dev)
  85                 return ERR_PTR(-ENOMEM);
  86
  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");
  91                 goto error;
  92         }
  93         i2c_dev->minor = adap->nr;
  94         i2c_dev_array[adap->nr] = i2c_dev;
  95         spin_unlock(&i2c_dev_array_lock);
  96         return i2c_dev;
  97 error:
  98         kfree(i2c_dev);
  99         return ERR_PTR(-ENODEV);
 100 }
 101
 102 static void return_i2c_dev(struct i2c_dev *i2c_dev)
 103 {
 104         spin_lock(&i2c_dev_array_lock);
 105         i2c_dev_array[i2c_dev->minor] = NULL;
 106         spin_unlock(&i2c_dev_array_lock);
 107 }
 108
 109 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
 110 {
 111         struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
 112         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 113 }
 114 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 115
 116 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 117                             loff_t *offset)
 118 {
 119         char *tmp;
 120         int ret;
 121
 122         struct i2c_client *client = (struct i2c_client *)file->private_data;
 123
 124         if (count > 8192)
 125                 count = 8192;
 126
 127         tmp = kmalloc(count,GFP_KERNEL);
 128         if (tmp==NULL)
 129                 return -ENOMEM;
 130
 131         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
 132                 iminor(file->f_dentry->d_inode), count);
 133
 134         ret = i2c_master_recv(client,tmp,count);
 135         if (ret >= 0)
 136                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 137         kfree(tmp);
 138         return ret;
 139 }
 140
 141 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 142                              loff_t *offset)
 143 {
 144         int ret;
 145         char *tmp;
 146         struct i2c_client *client = (struct i2c_client *)file->private_data;
 147
 148         if (count > 8192)
 149                 count = 8192;
 150
 151         tmp = kmalloc(count,GFP_KERNEL);
 152         if (tmp==NULL)
 153                 return -ENOMEM;
 154         if (copy_from_user(tmp,buf,count)) {
 155                 kfree(tmp);
 156                 return -EFAULT;
 157         }
 158
 159         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
 160                 iminor(file->f_dentry->d_inode), count);
 161
 162         ret = i2c_master_send(client,tmp,count);
 163         kfree(tmp);
 164         return ret;
 165 }
 166
 167 static int i2cdev_ioctl(struct inode *inode, struct file *file,
 168                 unsigned int cmd, unsigned long arg)
 169 {
 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;
 176         int i,datasize,res;
 177         unsigned long funcs;
 178
 179         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 180                 cmd, arg);
 181
 182         switch ( cmd ) {
 183         case I2C_SLAVE:
 184         case I2C_SLAVE_FORCE:
 185                 if ((arg > 0x3ff) ||
 186                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 187                         return -EINVAL;
 188                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
 189                         return -EBUSY;
 190                 client->addr = arg;
 191                 return 0;
 192         case I2C_TENBIT:
 193                 if (arg)
 194                         client->flags |= I2C_M_TEN;
 195                 else
 196                         client->flags &= ~I2C_M_TEN;
 197                 return 0;
 198         case I2C_PEC:
 199                 if (arg)
 200                         client->flags |= I2C_CLIENT_PEC;
 201                 else
 202                         client->flags &= ~I2C_CLIENT_PEC;
 203                 return 0;
 204         case I2C_FUNCS:
 205                 funcs = i2c_get_functionality(client->adapter);
 206                 return (copy_to_user((unsigned long __user *)arg, &funcs,
 207                                      sizeof(unsigned long)))?-EFAULT:0;
 208
 209         case I2C_RDWR:
 210                 if (copy_from_user(&rdwr_arg,
 211                                    (struct i2c_rdwr_ioctl_data __user *)arg,
 212                                    sizeof(rdwr_arg)))
 213                         return -EFAULT;
 214
 215                 /* Put an arbitrary limit on the number of messages that can
 216                  * be sent at once */
 217                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 218                         return -EINVAL;
 219
 220                 rdwr_pa = (struct i2c_msg *)
 221                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 222                         GFP_KERNEL);
 223
 224                 if (rdwr_pa == NULL) return -ENOMEM;
 225
 226                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 227                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 228                         kfree(rdwr_pa);
 229                         return -EFAULT;
 230                 }
 231
 232                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 233                 if (data_ptrs == NULL) {
 234                         kfree(rdwr_pa);
 235                         return -ENOMEM;
 236                 }
 237
 238                 res = 0;
 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) {
 242                                 res = -EINVAL;
 243                                 break;
 244                         }
 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) {
 248                                 res = -ENOMEM;
 249                                 break;
 250                         }
 251                         if(copy_from_user(rdwr_pa[i].buf,
 252                                 data_ptrs[i],
 253                                 rdwr_pa[i].len)) {
 254                                         ++i; /* Needs to be kfreed too */
 255                                         res = -EFAULT;
 256                                 break;
 257                         }
 258                 }
 259                 if (res < 0) {
 260                         int j;
 261                         for (j = 0; j < i; ++j)
 262                                 kfree(rdwr_pa[j].buf);
 263                         kfree(data_ptrs);
 264                         kfree(rdwr_pa);
 265                         return res;
 266                 }
 267
 268                 res = i2c_transfer(client->adapter,
 269                         rdwr_pa,
 270                         rdwr_arg.nmsgs);
 271                 while(i-- > 0) {
 272                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 273                                 if(copy_to_user(
 274                                         data_ptrs[i],
 275                                         rdwr_pa[i].buf,
 276                                         rdwr_pa[i].len)) {
 277                                         res = -EFAULT;
 278                                 }
 279                         }
 280                         kfree(rdwr_pa[i].buf);
 281                 }
 282                 kfree(data_ptrs);
 283                 kfree(rdwr_pa);
 284                 return res;
 285
 286         case I2C_SMBUS:
 287                 if (copy_from_user(&data_arg,
 288                                    (struct i2c_smbus_ioctl_data __user *) arg,
 289                                    sizeof(struct i2c_smbus_ioctl_data)))
 290                         return -EFAULT;
 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",
 301                                 data_arg.size);
 302                         return -EINVAL;
 303                 }
 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);
 311                         return -EINVAL;
 312                 }
 313
 314                 /* Note that command values are always valid! */
 315
 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,
 321                                               client->flags,
 322                                               data_arg.read_write,
 323                                               data_arg.command,
 324                                               data_arg.size, NULL);
 325
 326                 if (data_arg.data == NULL) {
 327                         dev_dbg(&client->adapter->dev,
 328                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 329                         return -EINVAL;
 330                 }
 331
 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);
 340
 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))
 345                                 return -EFAULT;
 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
 358         default:
 359                 return i2c_control(client,cmd,arg);
 360         }
 361         return 0;
 362 }
 363
 364 static int i2cdev_open(struct inode *inode, struct file *file)
 365 {
 366         unsigned int minor = iminor(inode);
 367         struct i2c_client *client;
 368         struct i2c_adapter *adap;
 369         struct i2c_dev *i2c_dev;
 370
 371         i2c_dev = i2c_dev_get_by_minor(minor);
 372         if (!i2c_dev)
 373                 return -ENODEV;
 374
 375         adap = i2c_get_adapter(i2c_dev->adap->nr);
 376         if (!adap)
 377                 return -ENODEV;
 378
 379         client = kmalloc(sizeof(*client), GFP_KERNEL);
 380         if (!client) {
 381                 i2c_put_adapter(adap);
 382                 return -ENOMEM;
 383         }
 384         memcpy(client, &i2cdev_client_template, sizeof(*client));
 385
 386         /* registered with adapter, passed as client to user */
 387         client->adapter = adap;
 388         file->private_data = client;
 389
 390         return 0;
 391 }
 392
 393 static int i2cdev_release(struct inode *inode, struct file *file)
 394 {
 395         struct i2c_client *client = file->private_data;
 396
 397         i2c_put_adapter(client->adapter);
 398         kfree(client);
 399         file->private_data = NULL;
 400
 401         return 0;
 402 }
 403
 404 static struct file_operations i2cdev_fops = {
 405         .owner          = THIS_MODULE,
 406         .llseek         = no_llseek,
 407         .read           = i2cdev_read,
 408         .write          = i2cdev_write,
 409         .ioctl          = i2cdev_ioctl,
 410         .open           = i2cdev_open,
 411         .release        = i2cdev_release,
 412 };
 413
 414 static void release_i2c_dev(struct class_device *dev)
 415 {
 416         struct i2c_dev *i2c_dev = to_i2c_dev(dev);
 417         complete(&i2c_dev->released);
 418 }
 419
 420 static struct class i2c_dev_class = {
 421         .name           = "i2c-dev",
 422         .release        = &release_i2c_dev,
 423 };
 424
 425 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 426 {
 427         struct i2c_dev *i2c_dev;
 428         int retval;
 429
 430         i2c_dev = get_free_i2c_dev(adap);
 431         if (IS_ERR(i2c_dev))
 432                 return PTR_ERR(i2c_dev);
 433
 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);
 438
 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;
 443         else
 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);
 449         if (retval)
 450                 goto error;
 451         class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
 452         return 0;
 453 error:
 454         return_i2c_dev(i2c_dev);
 455         kfree(i2c_dev);
 456         return retval;
 457 }
 458
 459 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 460 {
 461         struct i2c_dev *i2c_dev;
 462
 463         i2c_dev = i2c_dev_get_by_adapter(adap);
 464         if (!i2c_dev)
 465                 return -ENODEV;
 466
 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);
 472         kfree(i2c_dev);
 473
 474         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 475         return 0;
 476 }
 477
 478 static int i2cdev_detach_client(struct i2c_client *client)
 479 {
 480         return 0;
 481 }
 482
 483 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
 484                            void *arg)
 485 {
 486         return -1;
 487 }
 488
 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,
 498 };
 499
 500 static struct i2c_client i2cdev_client_template = {
 501         .name           = "I2C /dev entry",
 502         .addr           = -1,
 503         .driver         = &i2cdev_driver,
 504 };
 505
 506 static int __init i2c_dev_init(void)
 507 {
 508         int res;
 509
 510         printk(KERN_INFO "i2c /dev entries driver\n");
 511
 512         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 513         if (res)
 514                 goto out;
 515
 516         res = class_register(&i2c_dev_class);
 517         if (res)
 518                 goto out_unreg_chrdev;
 519
 520         res = i2c_add_driver(&i2cdev_driver);
 521         if (res)
 522                 goto out_unreg_class;
 523
 524         devfs_mk_dir("i2c");
 525
 526         return 0;
 527
 528 out_unreg_class:
 529         class_unregister(&i2c_dev_class);
 530 out_unreg_chrdev:
 531         unregister_chrdev(I2C_MAJOR, "i2c");
 532 out:
 533         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 534         return res;
 535 }
 536
 537 static void __exit i2c_dev_exit(void)
 538 {
 539         i2c_del_driver(&i2cdev_driver);
 540         class_unregister(&i2c_dev_class);
 541         devfs_remove("i2c");
 542         unregister_chrdev(I2C_MAJOR,"i2c");
 543 }
 544
 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");
 549
 550 module_init(i2c_dev_init);
 551 module_exit(i2c_dev_exit);