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 /* 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 = kmalloc(sizeof(*i2c_dev), GFP_KERNEL);
  84         if (!i2c_dev)
  85                 return ERR_PTR(-ENOMEM);
  86         memset(i2c_dev, 0x00, sizeof(*i2c_dev));
  87
  88         spin_lock(&i2c_dev_array_lock);
  89         if (i2c_dev_array[adap->nr]) {
  90                 spin_unlock(&i2c_dev_array_lock);
  91                 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
  92                 goto error;
  93         }
  94         i2c_dev->minor = adap->nr;
  95         i2c_dev_array[adap->nr] = i2c_dev;
  96         spin_unlock(&i2c_dev_array_lock);
  97         return i2c_dev;
  98 error:
  99         kfree(i2c_dev);
 100         return ERR_PTR(-ENODEV);
 101 }
 102
 103 static void return_i2c_dev(struct i2c_dev *i2c_dev)
 104 {
 105         spin_lock(&i2c_dev_array_lock);
 106         i2c_dev_array[i2c_dev->minor] = NULL;
 107         spin_unlock(&i2c_dev_array_lock);
 108 }
 109
 110 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
 111 {
 112         struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
 113         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 114 }
 115 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 116
 117 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 118                             loff_t *offset)
 119 {
 120         char *tmp;
 121         int ret;
 122
 123         struct i2c_client *client = (struct i2c_client *)file->private_data;
 124
 125         if (count > 8192)
 126                 count = 8192;
 127
 128         tmp = kmalloc(count,GFP_KERNEL);
 129         if (tmp==NULL)
 130                 return -ENOMEM;
 131
 132         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
 133                 iminor(file->f_dentry->d_inode), count);
 134
 135         ret = i2c_master_recv(client,tmp,count);
 136         if (ret >= 0)
 137                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 138         kfree(tmp);
 139         return ret;
 140 }
 141
 142 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 143                              loff_t *offset)
 144 {
 145         int ret;
 146         char *tmp;
 147         struct i2c_client *client = (struct i2c_client *)file->private_data;
 148
 149         if (count > 8192)
 150                 count = 8192;
 151
 152         tmp = kmalloc(count,GFP_KERNEL);
 153         if (tmp==NULL)
 154                 return -ENOMEM;
 155         if (copy_from_user(tmp,buf,count)) {
 156                 kfree(tmp);
 157                 return -EFAULT;
 158         }
 159
 160         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
 161                 iminor(file->f_dentry->d_inode), count);
 162
 163         ret = i2c_master_send(client,tmp,count);
 164         kfree(tmp);
 165         return ret;
 166 }
 167
 168 static int i2cdev_ioctl(struct inode *inode, struct file *file,
 169                 unsigned int cmd, unsigned long arg)
 170 {
 171         struct i2c_client *client = (struct i2c_client *)file->private_data;
 172         struct i2c_rdwr_ioctl_data rdwr_arg;
 173         struct i2c_smbus_ioctl_data data_arg;
 174         union i2c_smbus_data temp;
 175         struct i2c_msg *rdwr_pa;
 176         u8 __user **data_ptrs;
 177         int i,datasize,res;
 178         unsigned long funcs;
 179
 180         dev_dbg(&client->adapter->dev, "i2c-%d ioctl, cmd: 0x%x, arg: %lx.\n",
 181                 iminor(inode),cmd, arg);
 182
 183         switch ( cmd ) {
 184         case I2C_SLAVE:
 185         case I2C_SLAVE_FORCE:
 186                 if ((arg > 0x3ff) ||
 187                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 188                         return -EINVAL;
 189                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
 190                         return -EBUSY;
 191                 client->addr = arg;
 192                 return 0;
 193         case I2C_TENBIT:
 194                 if (arg)
 195                         client->flags |= I2C_M_TEN;
 196                 else
 197                         client->flags &= ~I2C_M_TEN;
 198                 return 0;
 199         case I2C_PEC:
 200                 if (arg)
 201                         client->flags |= I2C_CLIENT_PEC;
 202                 else
 203                         client->flags &= ~I2C_CLIENT_PEC;
 204                 return 0;
 205         case I2C_FUNCS:
 206                 funcs = i2c_get_functionality(client->adapter);
 207                 return (copy_to_user((unsigned long __user *)arg, &funcs,
 208                                      sizeof(unsigned long)))?-EFAULT:0;
 209
 210         case I2C_RDWR:
 211                 if (copy_from_user(&rdwr_arg,
 212                                    (struct i2c_rdwr_ioctl_data __user *)arg,
 213                                    sizeof(rdwr_arg)))
 214                         return -EFAULT;
 215
 216                 /* Put an arbitrary limit on the number of messages that can
 217                  * be sent at once */
 218                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 219                         return -EINVAL;
 220
 221                 rdwr_pa = (struct i2c_msg *)
 222                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 223                         GFP_KERNEL);
 224
 225                 if (rdwr_pa == NULL) return -ENOMEM;
 226
 227                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 228                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 229                         kfree(rdwr_pa);
 230                         return -EFAULT;
 231                 }
 232
 233                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 234                 if (data_ptrs == NULL) {
 235                         kfree(rdwr_pa);
 236                         return -ENOMEM;
 237                 }
 238
 239                 res = 0;
 240                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
 241                         /* Limit the size of the message to a sane amount */
 242                         if (rdwr_pa[i].len > 8192) {
 243                                 res = -EINVAL;
 244                                 break;
 245                         }
 246                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 247                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 248                         if(rdwr_pa[i].buf == NULL) {
 249                                 res = -ENOMEM;
 250                                 break;
 251                         }
 252                         if(copy_from_user(rdwr_pa[i].buf,
 253                                 data_ptrs[i],
 254                                 rdwr_pa[i].len)) {
 255                                         ++i; /* Needs to be kfreed too */
 256                                         res = -EFAULT;
 257                                 break;
 258                         }
 259                 }
 260                 if (res < 0) {
 261                         int j;
 262                         for (j = 0; j < i; ++j)
 263                                 kfree(rdwr_pa[j].buf);
 264                         kfree(data_ptrs);
 265                         kfree(rdwr_pa);
 266                         return res;
 267                 }
 268
 269                 res = i2c_transfer(client->adapter,
 270                         rdwr_pa,
 271                         rdwr_arg.nmsgs);
 272                 while(i-- > 0) {
 273                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 274                                 if(copy_to_user(
 275                                         data_ptrs[i],
 276                                         rdwr_pa[i].buf,
 277                                         rdwr_pa[i].len)) {
 278                                         res = -EFAULT;
 279                                 }
 280                         }
 281                         kfree(rdwr_pa[i].buf);
 282                 }
 283                 kfree(data_ptrs);
 284                 kfree(rdwr_pa);
 285                 return res;
 286
 287         case I2C_SMBUS:
 288                 if (copy_from_user(&data_arg,
 289                                    (struct i2c_smbus_ioctl_data __user *) arg,
 290                                    sizeof(struct i2c_smbus_ioctl_data)))
 291                         return -EFAULT;
 292                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
 293                     (data_arg.size != I2C_SMBUS_QUICK) &&
 294                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 295                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 296                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 297                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 298                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 299                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 300                         dev_dbg(&client->adapter->dev,
 301                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
 302                                 data_arg.size);
 303                         return -EINVAL;
 304                 }
 305                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 306                    so the check is valid if size==I2C_SMBUS_QUICK too. */
 307                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
 308                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
 309                         dev_dbg(&client->adapter->dev,
 310                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 311                                 data_arg.read_write);
 312                         return -EINVAL;
 313                 }
 314
 315                 /* Note that command values are always valid! */
 316
 317                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
 318                     ((data_arg.size == I2C_SMBUS_BYTE) &&
 319                     (data_arg.read_write == I2C_SMBUS_WRITE)))
 320                         /* These are special: we do not use data */
 321                         return i2c_smbus_xfer(client->adapter, client->addr,
 322                                               client->flags,
 323                                               data_arg.read_write,
 324                                               data_arg.command,
 325                                               data_arg.size, NULL);
 326
 327                 if (data_arg.data == NULL) {
 328                         dev_dbg(&client->adapter->dev,
 329                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 330                         return -EINVAL;
 331                 }
 332
 333                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 334                     (data_arg.size == I2C_SMBUS_BYTE))
 335                         datasize = sizeof(data_arg.data->byte);
 336                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 337                          (data_arg.size == I2C_SMBUS_PROC_CALL))
 338                         datasize = sizeof(data_arg.data->word);
 339                 else /* size == smbus block, i2c block, or block proc. call */
 340                         datasize = sizeof(data_arg.data->block);
 341
 342                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 343                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 344                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
 345                         if (copy_from_user(&temp, data_arg.data, datasize))
 346                                 return -EFAULT;
 347                 }
 348                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 349                       data_arg.read_write,
 350                       data_arg.command,data_arg.size,&temp);
 351                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 352                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 353                               (data_arg.read_write == I2C_SMBUS_READ))) {
 354                         if (copy_to_user(data_arg.data, &temp, datasize))
 355                                 return -EFAULT;
 356                 }
 357                 return res;
 358
 359         default:
 360                 return i2c_control(client,cmd,arg);
 361         }
 362         return 0;
 363 }
 364
 365 static int i2cdev_open(struct inode *inode, struct file *file)
 366 {
 367         unsigned int minor = iminor(inode);
 368         struct i2c_client *client;
 369         struct i2c_adapter *adap;
 370         struct i2c_dev *i2c_dev;
 371
 372         i2c_dev = i2c_dev_get_by_minor(minor);
 373         if (!i2c_dev)
 374                 return -ENODEV;
 375
 376         adap = i2c_get_adapter(i2c_dev->adap->nr);
 377         if (!adap)
 378                 return -ENODEV;
 379
 380         client = kmalloc(sizeof(*client), GFP_KERNEL);
 381         if (!client) {
 382                 i2c_put_adapter(adap);
 383                 return -ENOMEM;
 384         }
 385         memcpy(client, &i2cdev_client_template, sizeof(*client));
 386
 387         /* registered with adapter, passed as client to user */
 388         client->adapter = adap;
 389         file->private_data = client;
 390
 391         return 0;
 392 }
 393
 394 static int i2cdev_release(struct inode *inode, struct file *file)
 395 {
 396         struct i2c_client *client = file->private_data;
 397
 398         i2c_put_adapter(client->adapter);
 399         kfree(client);
 400         file->private_data = NULL;
 401
 402         return 0;
 403 }
 404
 405 static struct file_operations i2cdev_fops = {
 406         .owner          = THIS_MODULE,
 407         .llseek         = no_llseek,
 408         .read           = i2cdev_read,
 409         .write          = i2cdev_write,
 410         .ioctl          = i2cdev_ioctl,
 411         .open           = i2cdev_open,
 412         .release        = i2cdev_release,
 413 };
 414
 415 static void release_i2c_dev(struct class_device *dev)
 416 {
 417         struct i2c_dev *i2c_dev = to_i2c_dev(dev);
 418         complete(&i2c_dev->released);
 419 }
 420
 421 static struct class i2c_dev_class = {
 422         .name           = "i2c-dev",
 423         .release        = &release_i2c_dev,
 424 };
 425
 426 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 427 {
 428         struct i2c_dev *i2c_dev;
 429         int retval;
 430
 431         i2c_dev = get_free_i2c_dev(adap);
 432         if (IS_ERR(i2c_dev))
 433                 return PTR_ERR(i2c_dev);
 434
 435         devfs_mk_cdev(MKDEV(I2C_MAJOR, i2c_dev->minor),
 436                         S_IFCHR|S_IRUSR|S_IWUSR, "i2c/%d", i2c_dev->minor);
 437         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 438                  adap->name, i2c_dev->minor);
 439
 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;
 444         else
 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);
 450         if (retval)
 451                 goto error;
 452         class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
 453         return 0;
 454 error:
 455         return_i2c_dev(i2c_dev);
 456         kfree(i2c_dev);
 457         return retval;
 458 }
 459
 460 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 461 {
 462         struct i2c_dev *i2c_dev;
 463
 464         i2c_dev = i2c_dev_get_by_adapter(adap);
 465         if (!i2c_dev)
 466                 return -ENODEV;
 467
 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);
 473         kfree(i2c_dev);
 474
 475         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 476         return 0;
 477 }
 478
 479 static int i2cdev_detach_client(struct i2c_client *client)
 480 {
 481         return 0;
 482 }
 483
 484 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
 485                            void *arg)
 486 {
 487         return -1;
 488 }
 489
 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,
 499 };
 500
 501 static struct i2c_client i2cdev_client_template = {
 502         .name           = "I2C /dev entry",
 503         .addr           = -1,
 504         .driver         = &i2cdev_driver,
 505 };
 506
 507 static int __init i2c_dev_init(void)
 508 {
 509         int res;
 510
 511         printk(KERN_INFO "i2c /dev entries driver\n");
 512
 513         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 514         if (res)
 515                 goto out;
 516
 517         res = class_register(&i2c_dev_class);
 518         if (res)
 519                 goto out_unreg_chrdev;
 520
 521         res = i2c_add_driver(&i2cdev_driver);
 522         if (res)
 523                 goto out_unreg_class;
 524
 525         devfs_mk_dir("i2c");
 526
 527         return 0;
 528
 529 out_unreg_class:
 530         class_unregister(&i2c_dev_class);
 531 out_unreg_chrdev:
 532         unregister_chrdev(I2C_MAJOR, "i2c");
 533 out:
 534         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 535         return res;
 536 }
 537
 538 static void __exit i2c_dev_exit(void)
 539 {
 540         i2c_del_driver(&i2cdev_driver);
 541         class_unregister(&i2c_dev_class);
 542         devfs_remove("i2c");
 543         unregister_chrdev(I2C_MAJOR,"i2c");
 544 }
 545
 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");
 550
 551 module_init(i2c_dev_init);
 552 module_exit(i2c_dev_exit);