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/init.h>
  34 #include <linux/list.h>
  35 #include <linux/i2c.h>
  36 #include <linux/i2c-dev.h>
  37 #include <asm/uaccess.h>
  38
  39 static struct i2c_driver i2cdev_driver;
  40
  41 struct i2c_dev {
  42         struct list_head list;
  43         struct i2c_adapter *adap;
  44         struct device *dev;
  45 };
  46
  47 #define I2C_MINORS      256
  48 static LIST_HEAD(i2c_dev_list);
  49 static DEFINE_SPINLOCK(i2c_dev_list_lock);
  50
  51 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
  52 {
  53         struct i2c_dev *i2c_dev;
  54
  55         spin_lock(&i2c_dev_list_lock);
  56         list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
  57                 if (i2c_dev->adap->nr == index)
  58                         goto found;
  59         }
  60         i2c_dev = NULL;
  61 found:
  62         spin_unlock(&i2c_dev_list_lock);
  63         return i2c_dev;
  64 }
  65
  66 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
  67 {
  68         struct i2c_dev *i2c_dev;
  69
  70         if (adap->nr >= I2C_MINORS) {
  71                 printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
  72                        adap->nr);
  73                 return ERR_PTR(-ENODEV);
  74         }
  75
  76         i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
  77         if (!i2c_dev)
  78                 return ERR_PTR(-ENOMEM);
  79         i2c_dev->adap = adap;
  80
  81         spin_lock(&i2c_dev_list_lock);
  82         list_add_tail(&i2c_dev->list, &i2c_dev_list);
  83         spin_unlock(&i2c_dev_list_lock);
  84         return i2c_dev;
  85 }
  86
  87 static void return_i2c_dev(struct i2c_dev *i2c_dev)
  88 {
  89         spin_lock(&i2c_dev_list_lock);
  90         list_del(&i2c_dev->list);
  91         spin_unlock(&i2c_dev_list_lock);
  92         kfree(i2c_dev);
  93 }
  94
  95 static ssize_t show_adapter_name(struct device *dev,
  96                                  struct device_attribute *attr, char *buf)
  97 {
  98         struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
  99
 100         if (!i2c_dev)
 101                 return -ENODEV;
 102         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 103 }
 104 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 105
 106 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 107                             loff_t *offset)
 108 {
 109         char *tmp;
 110         int ret;
 111
 112         struct i2c_client *client = (struct i2c_client *)file->private_data;
 113
 114         if (count > 8192)
 115                 count = 8192;
 116
 117         tmp = kmalloc(count,GFP_KERNEL);
 118         if (tmp==NULL)
 119                 return -ENOMEM;
 120
 121         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
 122                 iminor(file->f_path.dentry->d_inode), count);
 123
 124         ret = i2c_master_recv(client,tmp,count);
 125         if (ret >= 0)
 126                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 127         kfree(tmp);
 128         return ret;
 129 }
 130
 131 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 132                              loff_t *offset)
 133 {
 134         int ret;
 135         char *tmp;
 136         struct i2c_client *client = (struct i2c_client *)file->private_data;
 137
 138         if (count > 8192)
 139                 count = 8192;
 140
 141         tmp = kmalloc(count,GFP_KERNEL);
 142         if (tmp==NULL)
 143                 return -ENOMEM;
 144         if (copy_from_user(tmp,buf,count)) {
 145                 kfree(tmp);
 146                 return -EFAULT;
 147         }
 148
 149         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
 150                 iminor(file->f_path.dentry->d_inode), count);
 151
 152         ret = i2c_master_send(client,tmp,count);
 153         kfree(tmp);
 154         return ret;
 155 }
 156
 157 static int i2cdev_ioctl(struct inode *inode, struct file *file,
 158                 unsigned int cmd, unsigned long arg)
 159 {
 160         struct i2c_client *client = (struct i2c_client *)file->private_data;
 161         struct i2c_rdwr_ioctl_data rdwr_arg;
 162         struct i2c_smbus_ioctl_data data_arg;
 163         union i2c_smbus_data temp;
 164         struct i2c_msg *rdwr_pa;
 165         u8 __user **data_ptrs;
 166         int i,datasize,res;
 167         unsigned long funcs;
 168
 169         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 170                 cmd, arg);
 171
 172         switch ( cmd ) {
 173         case I2C_SLAVE:
 174         case I2C_SLAVE_FORCE:
 175                 if ((arg > 0x3ff) ||
 176                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 177                         return -EINVAL;
 178                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
 179                         return -EBUSY;
 180                 client->addr = arg;
 181                 return 0;
 182         case I2C_TENBIT:
 183                 if (arg)
 184                         client->flags |= I2C_M_TEN;
 185                 else
 186                         client->flags &= ~I2C_M_TEN;
 187                 return 0;
 188         case I2C_PEC:
 189                 if (arg)
 190                         client->flags |= I2C_CLIENT_PEC;
 191                 else
 192                         client->flags &= ~I2C_CLIENT_PEC;
 193                 return 0;
 194         case I2C_FUNCS:
 195                 funcs = i2c_get_functionality(client->adapter);
 196                 return put_user(funcs, (unsigned long __user *)arg);
 197
 198         case I2C_RDWR:
 199                 if (copy_from_user(&rdwr_arg,
 200                                    (struct i2c_rdwr_ioctl_data __user *)arg,
 201                                    sizeof(rdwr_arg)))
 202                         return -EFAULT;
 203
 204                 /* Put an arbitrary limit on the number of messages that can
 205                  * be sent at once */
 206                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 207                         return -EINVAL;
 208
 209                 rdwr_pa = (struct i2c_msg *)
 210                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 211                         GFP_KERNEL);
 212
 213                 if (rdwr_pa == NULL) return -ENOMEM;
 214
 215                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 216                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 217                         kfree(rdwr_pa);
 218                         return -EFAULT;
 219                 }
 220
 221                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 222                 if (data_ptrs == NULL) {
 223                         kfree(rdwr_pa);
 224                         return -ENOMEM;
 225                 }
 226
 227                 res = 0;
 228                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
 229                         /* Limit the size of the message to a sane amount */
 230                         if (rdwr_pa[i].len > 8192) {
 231                                 res = -EINVAL;
 232                                 break;
 233                         }
 234                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 235                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 236                         if(rdwr_pa[i].buf == NULL) {
 237                                 res = -ENOMEM;
 238                                 break;
 239                         }
 240                         if(copy_from_user(rdwr_pa[i].buf,
 241                                 data_ptrs[i],
 242                                 rdwr_pa[i].len)) {
 243                                         ++i; /* Needs to be kfreed too */
 244                                         res = -EFAULT;
 245                                 break;
 246                         }
 247                 }
 248                 if (res < 0) {
 249                         int j;
 250                         for (j = 0; j < i; ++j)
 251                                 kfree(rdwr_pa[j].buf);
 252                         kfree(data_ptrs);
 253                         kfree(rdwr_pa);
 254                         return res;
 255                 }
 256
 257                 res = i2c_transfer(client->adapter,
 258                         rdwr_pa,
 259                         rdwr_arg.nmsgs);
 260                 while(i-- > 0) {
 261                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 262                                 if(copy_to_user(
 263                                         data_ptrs[i],
 264                                         rdwr_pa[i].buf,
 265                                         rdwr_pa[i].len)) {
 266                                         res = -EFAULT;
 267                                 }
 268                         }
 269                         kfree(rdwr_pa[i].buf);
 270                 }
 271                 kfree(data_ptrs);
 272                 kfree(rdwr_pa);
 273                 return res;
 274
 275         case I2C_SMBUS:
 276                 if (copy_from_user(&data_arg,
 277                                    (struct i2c_smbus_ioctl_data __user *) arg,
 278                                    sizeof(struct i2c_smbus_ioctl_data)))
 279                         return -EFAULT;
 280                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
 281                     (data_arg.size != I2C_SMBUS_QUICK) &&
 282                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 283                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 284                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 285                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 286                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
 287                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 288                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 289                         dev_dbg(&client->adapter->dev,
 290                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
 291                                 data_arg.size);
 292                         return -EINVAL;
 293                 }
 294                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 295                    so the check is valid if size==I2C_SMBUS_QUICK too. */
 296                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
 297                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
 298                         dev_dbg(&client->adapter->dev,
 299                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 300                                 data_arg.read_write);
 301                         return -EINVAL;
 302                 }
 303
 304                 /* Note that command values are always valid! */
 305
 306                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
 307                     ((data_arg.size == I2C_SMBUS_BYTE) &&
 308                     (data_arg.read_write == I2C_SMBUS_WRITE)))
 309                         /* These are special: we do not use data */
 310                         return i2c_smbus_xfer(client->adapter, client->addr,
 311                                               client->flags,
 312                                               data_arg.read_write,
 313                                               data_arg.command,
 314                                               data_arg.size, NULL);
 315
 316                 if (data_arg.data == NULL) {
 317                         dev_dbg(&client->adapter->dev,
 318                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 319                         return -EINVAL;
 320                 }
 321
 322                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 323                     (data_arg.size == I2C_SMBUS_BYTE))
 324                         datasize = sizeof(data_arg.data->byte);
 325                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 326                          (data_arg.size == I2C_SMBUS_PROC_CALL))
 327                         datasize = sizeof(data_arg.data->word);
 328                 else /* size == smbus block, i2c block, or block proc. call */
 329                         datasize = sizeof(data_arg.data->block);
 330
 331                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 332                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 333                     (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
 334                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
 335                         if (copy_from_user(&temp, data_arg.data, datasize))
 336                                 return -EFAULT;
 337                 }
 338                 if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
 339                         /* Convert old I2C block commands to the new
 340                            convention. This preserves binary compatibility. */
 341                         data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
 342                         if (data_arg.read_write == I2C_SMBUS_READ)
 343                                 temp.block[0] = I2C_SMBUS_BLOCK_MAX;
 344                 }
 345                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 346                       data_arg.read_write,
 347                       data_arg.command,data_arg.size,&temp);
 348                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 349                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 350                               (data_arg.read_write == I2C_SMBUS_READ))) {
 351                         if (copy_to_user(data_arg.data, &temp, datasize))
 352                                 return -EFAULT;
 353                 }
 354                 return res;
 355
 356         default:
 357                 return i2c_control(client,cmd,arg);
 358         }
 359         return 0;
 360 }
 361
 362 static int i2cdev_open(struct inode *inode, struct file *file)
 363 {
 364         unsigned int minor = iminor(inode);
 365         struct i2c_client *client;
 366         struct i2c_adapter *adap;
 367         struct i2c_dev *i2c_dev;
 368
 369         i2c_dev = i2c_dev_get_by_minor(minor);
 370         if (!i2c_dev)
 371                 return -ENODEV;
 372
 373         adap = i2c_get_adapter(i2c_dev->adap->nr);
 374         if (!adap)
 375                 return -ENODEV;
 376
 377         client = kzalloc(sizeof(*client), GFP_KERNEL);
 378         if (!client) {
 379                 i2c_put_adapter(adap);
 380                 return -ENOMEM;
 381         }
 382         snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
 383         client->driver = &i2cdev_driver;
 384
 385         /* registered with adapter, passed as client to user */
 386         client->adapter = adap;
 387         file->private_data = client;
 388
 389         return 0;
 390 }
 391
 392 static int i2cdev_release(struct inode *inode, struct file *file)
 393 {
 394         struct i2c_client *client = file->private_data;
 395
 396         i2c_put_adapter(client->adapter);
 397         kfree(client);
 398         file->private_data = NULL;
 399
 400         return 0;
 401 }
 402
 403 static const struct file_operations i2cdev_fops = {
 404         .owner          = THIS_MODULE,
 405         .llseek         = no_llseek,
 406         .read           = i2cdev_read,
 407         .write          = i2cdev_write,
 408         .ioctl          = i2cdev_ioctl,
 409         .open           = i2cdev_open,
 410         .release        = i2cdev_release,
 411 };
 412
 413 static struct class *i2c_dev_class;
 414
 415 static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 416 {
 417         struct i2c_dev *i2c_dev;
 418         int res;
 419
 420         i2c_dev = get_free_i2c_dev(adap);
 421         if (IS_ERR(i2c_dev))
 422                 return PTR_ERR(i2c_dev);
 423
 424         /* register this i2c device with the driver core */
 425         i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
 426                                      MKDEV(I2C_MAJOR, adap->nr),
 427                                      "i2c-%d", adap->nr);
 428         if (IS_ERR(i2c_dev->dev)) {
 429                 res = PTR_ERR(i2c_dev->dev);
 430                 goto error;
 431         }
 432         res = device_create_file(i2c_dev->dev, &dev_attr_name);
 433         if (res)
 434                 goto error_destroy;
 435
 436         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 437                  adap->name, adap->nr);
 438         return 0;
 439 error_destroy:
 440         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 441 error:
 442         return_i2c_dev(i2c_dev);
 443         return res;
 444 }
 445
 446 static int i2cdev_detach_adapter(struct i2c_adapter *adap)
 447 {
 448         struct i2c_dev *i2c_dev;
 449
 450         i2c_dev = i2c_dev_get_by_minor(adap->nr);
 451         if (!i2c_dev) /* attach_adapter must have failed */
 452                 return 0;
 453
 454         device_remove_file(i2c_dev->dev, &dev_attr_name);
 455         return_i2c_dev(i2c_dev);
 456         device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
 457
 458         pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
 459         return 0;
 460 }
 461
 462 static int i2cdev_detach_client(struct i2c_client *client)
 463 {
 464         return 0;
 465 }
 466
 467 static struct i2c_driver i2cdev_driver = {
 468         .driver = {
 469                 .name   = "dev_driver",
 470         },
 471         .id             = I2C_DRIVERID_I2CDEV,
 472         .attach_adapter = i2cdev_attach_adapter,
 473         .detach_adapter = i2cdev_detach_adapter,
 474         .detach_client  = i2cdev_detach_client,
 475 };
 476
 477 static int __init i2c_dev_init(void)
 478 {
 479         int res;
 480
 481         printk(KERN_INFO "i2c /dev entries driver\n");
 482
 483         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 484         if (res)
 485                 goto out;
 486
 487         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
 488         if (IS_ERR(i2c_dev_class))
 489                 goto out_unreg_chrdev;
 490
 491         res = i2c_add_driver(&i2cdev_driver);
 492         if (res)
 493                 goto out_unreg_class;
 494
 495         return 0;
 496
 497 out_unreg_class:
 498         class_destroy(i2c_dev_class);
 499 out_unreg_chrdev:
 500         unregister_chrdev(I2C_MAJOR, "i2c");
 501 out:
 502         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 503         return res;
 504 }
 505
 506 static void __exit i2c_dev_exit(void)
 507 {
 508         i2c_del_driver(&i2cdev_driver);
 509         class_destroy(i2c_dev_class);
 510         unregister_chrdev(I2C_MAJOR,"i2c");
 511 }
 512
 513 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 514                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 515 MODULE_DESCRIPTION("I2C /dev entries driver");
 516 MODULE_LICENSE("GPL");
 517
 518 module_init(i2c_dev_init);
 519 module_exit(i2c_dev_exit);