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