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/smp_lock.h>
  34 #include <linux/init.h>
  35 #include <linux/i2c.h>
  36 #include <linux/i2c-dev.h>
  37 #include <asm/uaccess.h>
  38
  39 static struct i2c_client i2cdev_client_template;
  40
  41 struct i2c_dev {
  42         int minor;
  43         struct i2c_adapter *adap;
  44         struct class_device class_dev;
  45         struct completion released;     /* FIXME, we need a class_device_unregister() */
  46 };
  47 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev)
  48
  49 #define I2C_MINORS      256
  50 static struct i2c_dev *i2c_dev_array[I2C_MINORS];
  51 static DEFINE_SPINLOCK(i2c_dev_array_lock);
  52
  53 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  54 {
  55         struct i2c_dev *i2c_dev;
  56
  57         spin_lock(&i2c_dev_array_lock);
  58         i2c_dev = i2c_dev_array[index];
  59         spin_unlock(&i2c_dev_array_lock);
  60         return i2c_dev;
  61 }
  62
  63 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
  64 {
  65         struct i2c_dev *i2c_dev = NULL;
  66
  67         spin_lock(&i2c_dev_array_lock);
  68         if ((i2c_dev_array[adap->nr]) &&
  69             (i2c_dev_array[adap->nr]->adap == adap))
  70                 i2c_dev = i2c_dev_array[adap->nr];
  71         spin_unlock(&i2c_dev_array_lock);
  72         return i2c_dev;
  73 }
  74
  75 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  76 {
  77         struct i2c_dev *i2c_dev;
  78
  79         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  80         if (!i2c_dev)
  81                 return ERR_PTR(-ENOMEM);
  82
  83         spin_lock(&i2c_dev_array_lock);
  84         if (i2c_dev_array[adap->nr]) {
  85                 spin_unlock(&i2c_dev_array_lock);
  86                 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
  87                 goto error;
  88         }
  89         i2c_dev->minor = adap->nr;
  90         i2c_dev_array[adap->nr] = i2c_dev;
  91         spin_unlock(&i2c_dev_array_lock);
  92         return i2c_dev;
  93 error:
  94         kfree(i2c_dev);
  95         return ERR_PTR(-ENODEV);
  96 }
  97
  98 static void return_i2c_dev(struct i2c_dev *i2c_dev)
  99 {
 100         spin_lock(&i2c_dev_array_lock);
 101         i2c_dev_array[i2c_dev->minor] = NULL;
 102         spin_unlock(&i2c_dev_array_lock);
 103 }
 104
 105 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf)
 106 {
 107         struct i2c_dev *i2c_dev = to_i2c_dev(class_dev);
 108         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 109 }
 110 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 111
 112 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 113                             loff_t *offset)
 114 {
 115         char *tmp;
 116         int ret;
 117
 118         struct i2c_client *client = (struct i2c_client *)file->private_data;
 119
 120         if (count > 8192)
 121                 count = 8192;
 122
 123         tmp = kmalloc(count,GFP_KERNEL);
 124         if (tmp==NULL)
 125                 return -ENOMEM;
 126
 127         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
 128                 iminor(file->f_dentry->d_inode), count);
 129
 130         ret = i2c_master_recv(client,tmp,count);
 131         if (ret >= 0)
 132                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 133         kfree(tmp);
 134         return ret;
 135 }
 136
 137 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 138                              loff_t *offset)
 139 {
 140         int ret;
 141         char *tmp;
 142         struct i2c_client *client = (struct i2c_client *)file->private_data;
 143
 144         if (count > 8192)
 145                 count = 8192;
 146
 147         tmp = kmalloc(count,GFP_KERNEL);
 148         if (tmp==NULL)
 149                 return -ENOMEM;
 150         if (copy_from_user(tmp,buf,count)) {
 151                 kfree(tmp);
 152                 return -EFAULT;
 153         }
 154
 155         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
 156                 iminor(file->f_dentry->d_inode), count);
 157
 158         ret = i2c_master_send(client,tmp,count);
 159         kfree(tmp);
 160         return ret;
 161 }
 162
 163 static int i2cdev_ioctl(struct inode *inode, struct file *file,
 164                 unsigned int cmd, unsigned long arg)
 165 {
 166         struct i2c_client *client = (struct i2c_client *)file->private_data;
 167         struct i2c_rdwr_ioctl_data rdwr_arg;
 168         struct i2c_smbus_ioctl_data data_arg;
 169         union i2c_smbus_data temp;
 170         struct i2c_msg *rdwr_pa;
 171         u8 __user **data_ptrs;
 172         int i,datasize,res;
 173         unsigned long funcs;
 174
 175         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 176                 cmd, arg);
 177
 178         switch ( cmd ) {
 179         case I2C_SLAVE:
 180         case I2C_SLAVE_FORCE:
 181                 if ((arg > 0x3ff) ||
 182                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 183                         return -EINVAL;
 184                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
 185                         return -EBUSY;
 186                 client->addr = arg;
 187                 return 0;
 188         case I2C_TENBIT:
 189                 if (arg)
 190                         client->flags |= I2C_M_TEN;
 191                 else
 192                         client->flags &= ~I2C_M_TEN;
 193                 return 0;
 194         case I2C_PEC:
 195                 if (arg)
 196                         client->flags |= I2C_CLIENT_PEC;
 197                 else
 198                         client->flags &= ~I2C_CLIENT_PEC;
 199                 return 0;
 200         case I2C_FUNCS:
 201                 funcs = i2c_get_functionality(client->adapter);
 202                 return (copy_to_user((unsigned long __user *)arg, &funcs,
 203                                      sizeof(unsigned long)))?-EFAULT:0;
 204
 205         case I2C_RDWR:
 206                 if (copy_from_user(&rdwr_arg,
 207                                    (struct i2c_rdwr_ioctl_data __user *)arg,
 208                                    sizeof(rdwr_arg)))
 209                         return -EFAULT;
 210
 211                 /* Put an arbitrary limit on the number of messages that can
 212                  * be sent at once */
 213                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 214                         return -EINVAL;
 215
 216                 rdwr_pa = (struct i2c_msg *)
 217                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 218                         GFP_KERNEL);
 219
 220                 if (rdwr_pa == NULL) return -ENOMEM;
 221
 222                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 223                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 224                         kfree(rdwr_pa);
 225                         return -EFAULT;
 226                 }
 227
 228                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 229                 if (data_ptrs == NULL) {
 230                         kfree(rdwr_pa);
 231                         return -ENOMEM;
 232                 }
 233
 234                 res = 0;
 235                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
 236                         /* Limit the size of the message to a sane amount */
 237                         if (rdwr_pa[i].len > 8192) {
 238                                 res = -EINVAL;
 239                                 break;
 240                         }
 241                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 242                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 243                         if(rdwr_pa[i].buf == NULL) {
 244                                 res = -ENOMEM;
 245                                 break;
 246                         }
 247                         if(copy_from_user(rdwr_pa[i].buf,
 248                                 data_ptrs[i],
 249                                 rdwr_pa[i].len)) {
 250                                         ++i; /* Needs to be kfreed too */
 251                                         res = -EFAULT;
 252                                 break;
 253                         }
 254                 }
 255                 if (res < 0) {
 256                         int j;
 257                         for (j = 0; j < i; ++j)
 258                                 kfree(rdwr_pa[j].buf);
 259                         kfree(data_ptrs);
 260                         kfree(rdwr_pa);
 261                         return res;
 262                 }
 263
 264                 res = i2c_transfer(client->adapter,
 265                         rdwr_pa,
 266                         rdwr_arg.nmsgs);
 267                 while(i-- > 0) {
 268                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 269                                 if(copy_to_user(
 270                                         data_ptrs[i],
 271                                         rdwr_pa[i].buf,
 272                                         rdwr_pa[i].len)) {
 273                                         res = -EFAULT;
 274                                 }
 275                         }
 276                         kfree(rdwr_pa[i].buf);
 277                 }
 278                 kfree(data_ptrs);
 279                 kfree(rdwr_pa);
 280                 return res;
 281
 282         case I2C_SMBUS:
 283                 if (copy_from_user(&data_arg,
 284                                    (struct i2c_smbus_ioctl_data __user *) arg,
 285                                    sizeof(struct i2c_smbus_ioctl_data)))
 286                         return -EFAULT;
 287                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
 288                     (data_arg.size != I2C_SMBUS_QUICK) &&
 289                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 290                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 291                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 292                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 293                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 294                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 295                         dev_dbg(&client->adapter->dev,
 296                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
 297                                 data_arg.size);
 298                         return -EINVAL;
 299                 }
 300                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 301                    so the check is valid if size==I2C_SMBUS_QUICK too. */
 302                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
 303                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
 304                         dev_dbg(&client->adapter->dev,
 305                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 306                                 data_arg.read_write);
 307                         return -EINVAL;
 308                 }
 309
 310                 /* Note that command values are always valid! */
 311
 312                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
 313                     ((data_arg.size == I2C_SMBUS_BYTE) &&
 314                     (data_arg.read_write == I2C_SMBUS_WRITE)))
 315                         /* These are special: we do not use data */
 316                         return i2c_smbus_xfer(client->adapter, client->addr,
 317                                               client->flags,
 318                                               data_arg.read_write,
 319                                               data_arg.command,
 320                                               data_arg.size, NULL);
 321
 322                 if (data_arg.data == NULL) {
 323                         dev_dbg(&client->adapter->dev,
 324                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 325                         return -EINVAL;
 326                 }
 327
 328                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 329                     (data_arg.size == I2C_SMBUS_BYTE))
 330                         datasize = sizeof(data_arg.data->byte);
 331                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 332                          (data_arg.size == I2C_SMBUS_PROC_CALL))
 333                         datasize = sizeof(data_arg.data->word);
 334                 else /* size == smbus block, i2c block, or block proc. call */
 335                         datasize = sizeof(data_arg.data->block);
 336
 337                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 338                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 339                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
 340                         if (copy_from_user(&temp, data_arg.data, datasize))
 341                                 return -EFAULT;
 342                 }
 343                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 344                       data_arg.read_write,
 345                       data_arg.command,data_arg.size,&temp);
 346                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 347                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 348                               (data_arg.read_write == I2C_SMBUS_READ))) {
 349                         if (copy_to_user(data_arg.data, &temp, datasize))
 350                                 return -EFAULT;
 351                 }
 352                 return res;
 353
 354         default:
 355                 return i2c_control(client,cmd,arg);
 356         }
 357         return 0;
 358 }
 359
 360 static int i2cdev_open(struct inode *inode, struct file *file)
 361 {
 362         unsigned int minor = iminor(inode);
 363         struct i2c_client *client;
 364         struct i2c_adapter *adap;
 365         struct i2c_dev *i2c_dev;
 366
 367         i2c_dev = i2c_dev_get_by_minor(minor);
 368         if (!i2c_dev)
 369                 return -ENODEV;
 370
 371         adap = i2c_get_adapter(i2c_dev->adap->nr);
 372         if (!adap)
 373                 return -ENODEV;
 374
 375         client = kmalloc(sizeof(*client), GFP_KERNEL);
 376         if (!client) {
 377                 i2c_put_adapter(adap);
 378                 return -ENOMEM;
 379         }
 380         memcpy(client, &i2cdev_client_template, sizeof(*client));
 381
 382         /* registered with adapter, passed as client to user */
 383         client->adapter = adap;
 384         file->private_data = client;
 385
 386         return 0;
 387 }
 388
 389 static int i2cdev_release(struct inode *inode, struct file *file)
 390 {
 391         struct i2c_client *client = file->private_data;
 392
 393         i2c_put_adapter(client->adapter);
 394         kfree(client);
 395         file->private_data = NULL;
 396
 397         return 0;
 398 }
 399
 400 static struct file_operations i2cdev_fops = {
 401         .owner          = THIS_MODULE,
 402         .llseek         = no_llseek,
 403         .read           = i2cdev_read,
 404         .write          = i2cdev_write,
 405         .ioctl          = i2cdev_ioctl,
 406         .open           = i2cdev_open,
 407         .release        = i2cdev_release,
 408 };
 409
 410 static void release_i2c_dev(struct class_device *dev)
 411 {
 412         struct i2c_dev *i2c_dev = to_i2c_dev(dev);
 413         complete(&i2c_dev->released);
 414 }
 415
 416 static struct class i2c_dev_class = {
 417         .name           = "i2c-dev",
 418         .release        = &release_i2c_dev,
 419 };
 420
 421 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 422 {
 423         struct i2c_dev *i2c_dev;
 424         int retval;
 425
 426         i2c_dev = get_free_i2c_dev(adap);
 427         if (IS_ERR(i2c_dev))
 428                 return PTR_ERR(i2c_dev);
 429
 430         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 431                  adap->name, i2c_dev->minor);
 432
 433         /* register this i2c device with the driver core */
 434         i2c_dev->adap = adap;
 435         if (adap->dev.parent == &platform_bus)
 436                 i2c_dev->class_dev.dev = &adap->dev;
 437         else
 438                 i2c_dev->class_dev.dev = adap->dev.parent;
 439         i2c_dev->class_dev.class = &i2c_dev_class;
 440         i2c_dev->class_dev.devt = MKDEV(I2C_MAJOR, i2c_dev->minor);
 441         snprintf(i2c_dev->class_dev.class_id, BUS_ID_SIZE, "i2c-%d", i2c_dev->minor);
 442         retval = class_device_register(&i2c_dev->class_dev);
 443         if (retval)
 444                 goto error;
 445         class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name);
 446         return 0;
 447 error:
 448         return_i2c_dev(i2c_dev);
 449         kfree(i2c_dev);
 450         return retval;
 451 }
 452
 453 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 454 {
 455         struct i2c_dev *i2c_dev;
 456
 457         i2c_dev = i2c_dev_get_by_adapter(adap);
 458         if (!i2c_dev)
 459                 return -ENODEV;
 460
 461         init_completion(&i2c_dev->released);
 462         return_i2c_dev(i2c_dev);
 463         class_device_unregister(&i2c_dev->class_dev);
 464         wait_for_completion(&i2c_dev->released);
 465         kfree(i2c_dev);
 466
 467         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 468         return 0;
 469 }
 470
 471 static int i2cdev_detach_client(struct i2c_client *client)
 472 {
 473         return 0;
 474 }
 475
 476 static int i2cdev_command(struct i2c_client *client, unsigned int cmd,
 477                            void *arg)
 478 {
 479         return -1;
 480 }
 481
 482 static struct i2c_driver i2cdev_driver = {
 483         .owner          = THIS_MODULE,
 484         .name           = "dev_driver",
 485         .id             = I2C_DRIVERID_I2CDEV,
 486         .flags          = I2C_DF_NOTIFY,
 487         .attach_adapter = i2cdev_attach_adapter,
 488         .detach_adapter = i2cdev_detach_adapter,
 489         .detach_client  = i2cdev_detach_client,
 490         .command        = i2cdev_command,
 491 };
 492
 493 static struct i2c_client i2cdev_client_template = {
 494         .name           = "I2C /dev entry",
 495         .addr           = -1,
 496         .driver         = &i2cdev_driver,
 497 };
 498
 499 static int __init i2c_dev_init(void)
 500 {
 501         int res;
 502
 503         printk(KERN_INFO "i2c /dev entries driver\n");
 504
 505         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 506         if (res)
 507                 goto out;
 508
 509         res = class_register(&i2c_dev_class);
 510         if (res)
 511                 goto out_unreg_chrdev;
 512
 513         res = i2c_add_driver(&i2cdev_driver);
 514         if (res)
 515                 goto out_unreg_class;
 516
 517         return 0;
 518
 519 out_unreg_class:
 520         class_unregister(&i2c_dev_class);
 521 out_unreg_chrdev:
 522         unregister_chrdev(I2C_MAJOR, "i2c");
 523 out:
 524         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 525         return res;
 526 }
 527
 528 static void __exit i2c_dev_exit(void)
 529 {
 530         i2c_del_driver(&i2cdev_driver);
 531         class_unregister(&i2c_dev_class);
 532         unregister_chrdev(I2C_MAJOR,"i2c");
 533 }
 534
 535 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 536                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 537 MODULE_DESCRIPTION("I2C /dev entries driver");
 538 MODULE_LICENSE("GPL");
 539
 540 module_init(i2c_dev_init);
 541 module_exit(i2c_dev_exit);