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