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/config.h>
  33 #include <linux/kernel.h>
  34 #include <linux/module.h>
  35 #include <linux/fs.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>
  43
  44 static struct i2c_client i2cdev_client_template;
  45
  46 struct i2c_dev {
  47         int minor;
  48         struct i2c_adapter *adap;
  49         struct class_device class_dev;
  50         struct completion released;     /* FIXME, we need a class_device_unregister() */
  51 };
  52 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
  53
  54 #define I2C_MINORS      256
  55 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
  56 static spinlock_t i2c_dev_array_lock = SPIN_LOCK_UNLOCKED;
  57
  58 struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  59 {
  60         struct i2c_dev *i2c_dev;
  61
  62         spin_lock(&i2c_dev_array_lock);
  63         i2c_dev = i2c_dev_array[index];
  64         spin_unlock(&i2c_dev_array_lock);
  65         return i2c_dev;
  66 }
  67
  68 struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
  69 {
  70         struct i2c_dev *i2c_dev = NULL;
  71
  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);
  77         return i2c_dev;
  78 }
  79
  80 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  81 {
  82         struct i2c_dev *i2c_dev;
  83
  84         i2c_dev = kmalloc(sizeof(*i2c_dev), GFP_KERNEL);
  85         if (!i2c_dev)
  86                 return ERR_PTR(-ENOMEM);
  87         memset(i2c_dev, 0x00, sizeof(*i2c_dev));
  88
  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");
  93                 goto error;
  94         }
  95         i2c_dev->minor = adap->nr;
  96         i2c_dev_array[adap->nr] = i2c_dev;
  97         spin_unlock(&i2c_dev_array_lock);
  98         return i2c_dev;
  99 error:
 100         kfree(i2c_dev);
 101         return ERR_PTR(-ENODEV);
 102 }
 103
 104 static void return_i2c_dev(struct i2c_dev *i2c_dev)
 105 {
 106         spin_lock(&i2c_dev_array_lock);
 107         i2c_dev_array[i2c_dev->minor] = NULL;
 108         spin_unlock(&i2c_dev_array_lock);
 109 }
 110
 111 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 112 {
 113         struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
 114         return print_dev_t(buf, MKDEV(I2C_MAJOR, i2c_dev->minor));
 115 }
 116 static CLASS_DEVICE_ATTR(dev, S_IRUGO, show_dev, NULL);
 117
 118 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
 119 {
 120         struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
 121         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 122 }
 123 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 124
 125 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 126                             loff_t *offset)
 127 {
 128         char *tmp;
 129         int ret;
 130
 131         struct i2c_client *client = (struct i2c_client *)file->private_data;
 132
 133         if (count > 8192)
 134                 count = 8192;
 135
 136         tmp = kmalloc(count,GFP_KERNEL);
 137         if (tmp==NULL)
 138                 return -ENOMEM;
 139
 140         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
 141                 iminor(file->f_dentry->d_inode), count);
 142
 143         ret = i2c_master_recv(client,tmp,count);
 144         if (ret >= 0)
 145                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 146         kfree(tmp);
 147         return ret;
 148 }
 149
 150 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 151                              loff_t *offset)
 152 {
 153         int ret;
 154         char *tmp;
 155         struct i2c_client *client = (struct i2c_client *)file->private_data;
 156
 157         if (count > 8192)
 158                 count = 8192;
 159
 160         tmp = kmalloc(count,GFP_KERNEL);
 161         if (tmp==NULL)
 162                 return -ENOMEM;
 163         if (copy_from_user(tmp,buf,count)) {
 164                 kfree(tmp);
 165                 return -EFAULT;
 166         }
 167
 168         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
 169                 iminor(file->f_dentry->d_inode), count);
 170
 171         ret = i2c_master_send(client,tmp,count);
 172         kfree(tmp);
 173         return ret;
 174 }
 175
 176 int i2cdev_ioctl (struct inode *inode, struct file *file, unsigned int cmd,
 177                   unsigned long arg)
 178 {
 179         struct i2c_client *client = (struct i2c_client *)file->private_data;
 180         struct i2c_rdwr_ioctl_data rdwr_arg;
 181         struct i2c_smbus_ioctl_data data_arg;
 182         union i2c_smbus_data temp;
 183         struct i2c_msg *rdwr_pa;
 184         u8 __user **data_ptrs;
 185         int i,datasize,res;
 186         unsigned long funcs;
 187
 188         dev_dbg(&client->adapter->dev, "i2c-%d ioctl, cmd: 0x%x, arg: %lx.\n",
 189                 iminor(inode),cmd, arg);
 190
 191         switch ( cmd ) {
 192         case I2C_SLAVE:
 193         case I2C_SLAVE_FORCE:
 194                 if ((arg > 0x3ff) ||
 195                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 196                         return -EINVAL;
 197                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
 198                         return -EBUSY;
 199                 client->addr = arg;
 200                 return 0;
 201         case I2C_TENBIT:
 202                 if (arg)
 203                         client->flags |= I2C_M_TEN;
 204                 else
 205                         client->flags &= ~I2C_M_TEN;
 206                 return 0;
 207         case I2C_PEC:
 208                 if (arg)
 209                         client->flags |= I2C_CLIENT_PEC;
 210                 else
 211                         client->flags &= ~I2C_CLIENT_PEC;
 212                 return 0;
 213         case I2C_FUNCS:
 214                 funcs = i2c_get_functionality(client->adapter);
 215                 return (copy_to_user((unsigned long __user *)arg, &funcs,
 216                                      sizeof(unsigned long)))?-EFAULT:0;
 217
 218         case I2C_RDWR:
 219                 if (copy_from_user(&rdwr_arg,
 220                                    (struct i2c_rdwr_ioctl_data __user *)arg,
 221                                    sizeof(rdwr_arg)))
 222                         return -EFAULT;
 223
 224                 /* Put an arbritrary limit on the number of messages that can
 225                  * be sent at once */
 226                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 227                         return -EINVAL;
 228
 229                 rdwr_pa = (struct i2c_msg *)
 230                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 231                         GFP_KERNEL);
 232
 233                 if (rdwr_pa == NULL) return -ENOMEM;
 234
 235                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 236                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 237                         kfree(rdwr_pa);
 238                         return -EFAULT;
 239                 }
 240
 241                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 242                 if (data_ptrs == NULL) {
 243                         kfree(rdwr_pa);
 244                         return -ENOMEM;
 245                 }
 246
 247                 res = 0;
 248                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
 249                         /* Limit the size of the message to a sane amount */
 250                         if (rdwr_pa[i].len > 8192) {
 251                                 res = -EINVAL;
 252                                 break;
 253                         }
 254                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 255                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 256                         if(rdwr_pa[i].buf == NULL) {
 257                                 res = -ENOMEM;
 258                                 break;
 259                         }
 260                         if(copy_from_user(rdwr_pa[i].buf,
 261                                 data_ptrs[i],
 262                                 rdwr_pa[i].len)) {
 263                                         ++i; /* Needs to be kfreed too */
 264                                         res = -EFAULT;
 265                                 break;
 266                         }
 267                 }
 268                 if (res < 0) {
 269                         int j;
 270                         for (j = 0; j < i; ++j)
 271                                 kfree(rdwr_pa[j].buf);
 272                         kfree(data_ptrs);
 273                         kfree(rdwr_pa);
 274                         return res;
 275                 }
 276
 277                 res = i2c_transfer(client->adapter,
 278                         rdwr_pa,
 279                         rdwr_arg.nmsgs);
 280                 while(i-- > 0) {
 281                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 282                                 if(copy_to_user(
 283                                         data_ptrs[i],
 284                                         rdwr_pa[i].buf,
 285                                         rdwr_pa[i].len)) {
 286                                         res = -EFAULT;
 287                                 }
 288                         }
 289                         kfree(rdwr_pa[i].buf);
 290                 }
 291                 kfree(data_ptrs);
 292                 kfree(rdwr_pa);
 293                 return res;
 294
 295         case I2C_SMBUS:
 296                 if (copy_from_user(&data_arg,
 297                                    (struct i2c_smbus_ioctl_data __user *) arg,
 298                                    sizeof(struct i2c_smbus_ioctl_data)))
 299                         return -EFAULT;
 300                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
 301                     (data_arg.size != I2C_SMBUS_QUICK) &&
 302                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 303                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 304                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 305                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 306                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 307                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 308                         dev_dbg(&client->adapter->dev,
 309                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
 310                                 data_arg.size);
 311                         return -EINVAL;
 312                 }
 313                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 314                    so the check is valid if size==I2C_SMBUS_QUICK too. */
 315                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
 316                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
 317                         dev_dbg(&client->adapter->dev,
 318                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 319                                 data_arg.read_write);
 320                         return -EINVAL;
 321                 }
 322
 323                 /* Note that command values are always valid! */
 324
 325                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
 326                     ((data_arg.size == I2C_SMBUS_BYTE) &&
 327                     (data_arg.read_write == I2C_SMBUS_WRITE)))
 328                         /* These are special: we do not use data */
 329                         return i2c_smbus_xfer(client->adapter, client->addr,
 330                                               client->flags,
 331                                               data_arg.read_write,
 332                                               data_arg.command,
 333                                               data_arg.size, NULL);
 334
 335                 if (data_arg.data == NULL) {
 336                         dev_dbg(&client->adapter->dev,
 337                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 338                         return -EINVAL;
 339                 }
 340
 341                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 342                     (data_arg.size == I2C_SMBUS_BYTE))
 343                         datasize = sizeof(data_arg.data->byte);
 344                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 345                          (data_arg.size == I2C_SMBUS_PROC_CALL))
 346                         datasize = sizeof(data_arg.data->word);
 347                 else /* size == smbus block, i2c block, or block proc. call */
 348                         datasize = sizeof(data_arg.data->block);
 349
 350                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 351                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 352                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
 353                         if (copy_from_user(&temp, data_arg.data, datasize))
 354                                 return -EFAULT;
 355                 }
 356                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 357                       data_arg.read_write,
 358                       data_arg.command,data_arg.size,&temp);
 359                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 360                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 361                               (data_arg.read_write == I2C_SMBUS_READ))) {
 362                         if (copy_to_user(data_arg.data, &temp, datasize))
 363                                 return -EFAULT;
 364                 }
 365                 return res;
 366
 367         default:
 368                 return i2c_control(client,cmd,arg);
 369         }
 370         return 0;
 371 }
 372
 373 static int i2cdev_open(struct inode *inode, struct file *file)
 374 {
 375         unsigned int minor = iminor(inode);
 376         struct i2c_client *client;
 377         struct i2c_adapter *adap;
 378         struct i2c_dev *i2c_dev;
 379
 380         i2c_dev = i2c_dev_get_by_minor(minor);
 381         if (!i2c_dev)
 382                 return -ENODEV;
 383
 384         adap = i2c_get_adapter(i2c_dev->adap->nr);
 385         if (!adap)
 386                 return -ENODEV;
 387
 388         client = kmalloc(sizeof(*client), GFP_KERNEL);
 389         if (!client) {
 390                 i2c_put_adapter(adap);
 391                 return -ENOMEM;
 392         }
 393         memcpy(client, &i2cdev_client_template, sizeof(*client));
 394
 395         /* registered with adapter, passed as client to user */
 396         client->adapter = adap;
 397         file->private_data = client;
 398
 399         return 0;
 400 }
 401
 402 static int i2cdev_release(struct inode *inode, struct file *file)
 403 {
 404         struct i2c_client *client = file->private_data;
 405
 406         i2c_put_adapter(client->adapter);
 407         kfree(client);
 408         file->private_data = NULL;
 409
 410         return 0;
 411 }
 412
 413 static struct file_operations i2cdev_fops = {
 414         .owner          = THIS_MODULE,
 415         .llseek         = no_llseek,
 416         .read           = i2cdev_read,
 417         .write          = i2cdev_write,
 418         .ioctl          = i2cdev_ioctl,
 419         .open           = i2cdev_open,
 420         .release        = i2cdev_release,
 421 };
 422
 423 static void release_i2c_dev(struct class_device *dev)
 424 {
 425         struct i2c_dev *i2c_dev = to_i2c_dev(dev);
 426         complete(&i2c_dev->released);
 427 }
 428
 429 static struct class i2c_dev_class = {
 430         .name           = "i2c-dev",
 431         .release        = &release_i2c_dev,
 432 };
 433
 434 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 435 {
 436         struct i2c_dev *i2c_dev;
 437         int retval;
 438
 439         i2c_dev = get_free_i2c_dev(adap);
 440         if (IS_ERR(i2c_dev))
 441                 return PTR_ERR(i2c_dev);
 442
 443         devfs_mk_cdev(MKDEV(I2C_MAJOR, i2c_dev->minor),
 444                         S_IFCHR|S_IRUSR|S_IWUSR, "i2c/%d", i2c_dev->minor);
 445         dev_dbg(&adap->dev, "Registered as minor %d\n", i2c_dev->minor);
 446
 447         /* register this i2c device with the driver core */
 448         i2c_dev->adap = adap;
 449         if (adap->dev.parent == &platform_bus)
 450                 i2c_dev->class_dev.dev = &adap->dev;
 451         else
 452                 i2c_dev->class_dev.dev = adap->dev.parent;
 453         i2c_dev->class_dev.class = &i2c_dev_class;
 454         snprintf(i2c_dev->class_dev.class_id, BUS_ID_SIZE, "i2c-%d", i2c_dev->minor);
 455         retval = class_device_register(&i2c_dev->class_dev);
 456         if (retval)
 457                 goto error;
 458         class_device_create_file(&i2c_dev->class_dev, &class_device_attr_dev);
 459         class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
 460         return 0;
 461 error:
 462         return_i2c_dev(i2c_dev);
 463         kfree(i2c_dev);
 464         return retval;
 465 }
 466
 467 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 468 {
 469         struct i2c_dev *i2c_dev;
 470
 471         i2c_dev = i2c_dev_get_by_adapter(adap);
 472         if (!i2c_dev)
 473                 return -ENODEV;
 474
 475         init_completion(&i2c_dev->released);
 476         devfs_remove("i2c/%d", i2c_dev->minor);
 477         return_i2c_dev(i2c_dev);
 478         class_device_unregister(&i2c_dev->class_dev);
 479         wait_for_completion(&i2c_dev->released);
 480         kfree(i2c_dev);
 481
 482         dev_dbg(&adap->dev, "Adapter unregistered\n");
 483         return 0;
 484 }
 485
 486 static int i2cdev_detach_client(struct i2c_client *client)
 487 {
 488         return 0;
 489 }
 490
 491 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
 492                            void *arg)
 493 {
 494         return -1;
 495 }
 496
 497 static struct i2c_driver i2cdev_driver = {
 498         .owner          = THIS_MODULE,
 499         .name           = "dev_driver",
 500         .id             = I2C_DRIVERID_I2CDEV,
 501         .flags          = I2C_DF_NOTIFY,
 502         .attach_adapter = i2cdev_attach_adapter,
 503         .detach_adapter = i2cdev_detach_adapter,
 504         .detach_client  = i2cdev_detach_client,
 505         .command        = i2cdev_command,
 506 };
 507
 508 static struct i2c_client i2cdev_client_template = {
 509         .name           = "I2C /dev entry",
 510         .id             = 1,
 511         .addr           = -1,
 512         .driver         = &i2cdev_driver,
 513 };
 514
 515 static int __init i2c_dev_init(void)
 516 {
 517         int res;
 518
 519         printk(KERN_INFO "i2c /dev entries driver\n");
 520
 521         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 522         if (res)
 523                 goto out;
 524
 525         res = class_register(&i2c_dev_class);
 526         if (res)
 527                 goto out_unreg_chrdev;
 528
 529         res = i2c_add_driver(&i2cdev_driver);
 530         if (res)
 531                 goto out_unreg_class;
 532
 533         devfs_mk_dir("i2c");
 534
 535         return 0;
 536
 537 out_unreg_class:
 538         class_unregister(&i2c_dev_class);
 539 out_unreg_chrdev:
 540         unregister_chrdev(I2C_MAJOR, "i2c");
 541 out:
 542         printk(KERN_ERR "%s: Driver Initialisation failed", __FILE__);
 543         return res;
 544 }
 545
 546 static void __exit i2c_dev_exit(void)
 547 {
 548         i2c_del_driver(&i2cdev_driver);
 549         class_unregister(&i2c_dev_class);
 550         devfs_remove("i2c");
 551         unregister_chrdev(I2C_MAJOR,"i2c");
 552 }
 553
 554 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 555                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 556 MODULE_DESCRIPTION("I2C /dev entries driver");
 557 MODULE_LICENSE("GPL");
 558
 559 module_init(i2c_dev_init);
 560 module_exit(i2c_dev_exit);