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