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 <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 };
  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 = i2c_dev_get_by_minor(MINOR(class_dev->devt));
 108
 109         if (!i2c_dev)
 110                 return -ENODEV;
 111         return sprintf(buf, "%s\n", i2c_dev->adap->name);
 112 }
 113 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 114
 115 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
 116                             loff_t *offset)
 117 {
 118         char *tmp;
 119         int ret;
 120
 121         struct i2c_client *client = (struct i2c_client *)file->private_data;
 122
 123         if (count > 8192)
 124                 count = 8192;
 125
 126         tmp = kmalloc(count,GFP_KERNEL);
 127         if (tmp==NULL)
 128                 return -ENOMEM;
 129
 130         pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
 131                 iminor(file->f_dentry->d_inode), count);
 132
 133         ret = i2c_master_recv(client,tmp,count);
 134         if (ret >= 0)
 135                 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
 136         kfree(tmp);
 137         return ret;
 138 }
 139
 140 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
 141                              loff_t *offset)
 142 {
 143         int ret;
 144         char *tmp;
 145         struct i2c_client *client = (struct i2c_client *)file->private_data;
 146
 147         if (count > 8192)
 148                 count = 8192;
 149
 150         tmp = kmalloc(count,GFP_KERNEL);
 151         if (tmp==NULL)
 152                 return -ENOMEM;
 153         if (copy_from_user(tmp,buf,count)) {
 154                 kfree(tmp);
 155                 return -EFAULT;
 156         }
 157
 158         pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
 159                 iminor(file->f_dentry->d_inode), count);
 160
 161         ret = i2c_master_send(client,tmp,count);
 162         kfree(tmp);
 163         return ret;
 164 }
 165
 166 static int i2cdev_ioctl(struct inode *inode, struct file *file,
 167                 unsigned int cmd, unsigned long arg)
 168 {
 169         struct i2c_client *client = (struct i2c_client *)file->private_data;
 170         struct i2c_rdwr_ioctl_data rdwr_arg;
 171         struct i2c_smbus_ioctl_data data_arg;
 172         union i2c_smbus_data temp;
 173         struct i2c_msg *rdwr_pa;
 174         u8 __user **data_ptrs;
 175         int i,datasize,res;
 176         unsigned long funcs;
 177
 178         dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
 179                 cmd, arg);
 180
 181         switch ( cmd ) {
 182         case I2C_SLAVE:
 183         case I2C_SLAVE_FORCE:
 184                 if ((arg > 0x3ff) ||
 185                     (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
 186                         return -EINVAL;
 187                 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
 188                         return -EBUSY;
 189                 client->addr = arg;
 190                 return 0;
 191         case I2C_TENBIT:
 192                 if (arg)
 193                         client->flags |= I2C_M_TEN;
 194                 else
 195                         client->flags &= ~I2C_M_TEN;
 196                 return 0;
 197         case I2C_PEC:
 198                 if (arg)
 199                         client->flags |= I2C_CLIENT_PEC;
 200                 else
 201                         client->flags &= ~I2C_CLIENT_PEC;
 202                 return 0;
 203         case I2C_FUNCS:
 204                 funcs = i2c_get_functionality(client->adapter);
 205                 return (copy_to_user((unsigned long __user *)arg, &funcs,
 206                                      sizeof(unsigned long)))?-EFAULT:0;
 207
 208         case I2C_RDWR:
 209                 if (copy_from_user(&rdwr_arg,
 210                                    (struct i2c_rdwr_ioctl_data __user *)arg,
 211                                    sizeof(rdwr_arg)))
 212                         return -EFAULT;
 213
 214                 /* Put an arbitrary limit on the number of messages that can
 215                  * be sent at once */
 216                 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
 217                         return -EINVAL;
 218
 219                 rdwr_pa = (struct i2c_msg *)
 220                         kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
 221                         GFP_KERNEL);
 222
 223                 if (rdwr_pa == NULL) return -ENOMEM;
 224
 225                 if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
 226                                    rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
 227                         kfree(rdwr_pa);
 228                         return -EFAULT;
 229                 }
 230
 231                 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
 232                 if (data_ptrs == NULL) {
 233                         kfree(rdwr_pa);
 234                         return -ENOMEM;
 235                 }
 236
 237                 res = 0;
 238                 for( i=0; i<rdwr_arg.nmsgs; i++ ) {
 239                         /* Limit the size of the message to a sane amount */
 240                         if (rdwr_pa[i].len > 8192) {
 241                                 res = -EINVAL;
 242                                 break;
 243                         }
 244                         data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
 245                         rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
 246                         if(rdwr_pa[i].buf == NULL) {
 247                                 res = -ENOMEM;
 248                                 break;
 249                         }
 250                         if(copy_from_user(rdwr_pa[i].buf,
 251                                 data_ptrs[i],
 252                                 rdwr_pa[i].len)) {
 253                                         ++i; /* Needs to be kfreed too */
 254                                         res = -EFAULT;
 255                                 break;
 256                         }
 257                 }
 258                 if (res < 0) {
 259                         int j;
 260                         for (j = 0; j < i; ++j)
 261                                 kfree(rdwr_pa[j].buf);
 262                         kfree(data_ptrs);
 263                         kfree(rdwr_pa);
 264                         return res;
 265                 }
 266
 267                 res = i2c_transfer(client->adapter,
 268                         rdwr_pa,
 269                         rdwr_arg.nmsgs);
 270                 while(i-- > 0) {
 271                         if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
 272                                 if(copy_to_user(
 273                                         data_ptrs[i],
 274                                         rdwr_pa[i].buf,
 275                                         rdwr_pa[i].len)) {
 276                                         res = -EFAULT;
 277                                 }
 278                         }
 279                         kfree(rdwr_pa[i].buf);
 280                 }
 281                 kfree(data_ptrs);
 282                 kfree(rdwr_pa);
 283                 return res;
 284
 285         case I2C_SMBUS:
 286                 if (copy_from_user(&data_arg,
 287                                    (struct i2c_smbus_ioctl_data __user *) arg,
 288                                    sizeof(struct i2c_smbus_ioctl_data)))
 289                         return -EFAULT;
 290                 if ((data_arg.size != I2C_SMBUS_BYTE) &&
 291                     (data_arg.size != I2C_SMBUS_QUICK) &&
 292                     (data_arg.size != I2C_SMBUS_BYTE_DATA) &&
 293                     (data_arg.size != I2C_SMBUS_WORD_DATA) &&
 294                     (data_arg.size != I2C_SMBUS_PROC_CALL) &&
 295                     (data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
 296                     (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
 297                     (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
 298                         dev_dbg(&client->adapter->dev,
 299                                 "size out of range (%x) in ioctl I2C_SMBUS.\n",
 300                                 data_arg.size);
 301                         return -EINVAL;
 302                 }
 303                 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
 304                    so the check is valid if size==I2C_SMBUS_QUICK too. */
 305                 if ((data_arg.read_write != I2C_SMBUS_READ) &&
 306                     (data_arg.read_write != I2C_SMBUS_WRITE)) {
 307                         dev_dbg(&client->adapter->dev,
 308                                 "read_write out of range (%x) in ioctl I2C_SMBUS.\n",
 309                                 data_arg.read_write);
 310                         return -EINVAL;
 311                 }
 312
 313                 /* Note that command values are always valid! */
 314
 315                 if ((data_arg.size == I2C_SMBUS_QUICK) ||
 316                     ((data_arg.size == I2C_SMBUS_BYTE) &&
 317                     (data_arg.read_write == I2C_SMBUS_WRITE)))
 318                         /* These are special: we do not use data */
 319                         return i2c_smbus_xfer(client->adapter, client->addr,
 320                                               client->flags,
 321                                               data_arg.read_write,
 322                                               data_arg.command,
 323                                               data_arg.size, NULL);
 324
 325                 if (data_arg.data == NULL) {
 326                         dev_dbg(&client->adapter->dev,
 327                                 "data is NULL pointer in ioctl I2C_SMBUS.\n");
 328                         return -EINVAL;
 329                 }
 330
 331                 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
 332                     (data_arg.size == I2C_SMBUS_BYTE))
 333                         datasize = sizeof(data_arg.data->byte);
 334                 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
 335                          (data_arg.size == I2C_SMBUS_PROC_CALL))
 336                         datasize = sizeof(data_arg.data->word);
 337                 else /* size == smbus block, i2c block, or block proc. call */
 338                         datasize = sizeof(data_arg.data->block);
 339
 340                 if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 341                     (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 342                     (data_arg.read_write == I2C_SMBUS_WRITE)) {
 343                         if (copy_from_user(&temp, data_arg.data, datasize))
 344                                 return -EFAULT;
 345                 }
 346                 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 347                       data_arg.read_write,
 348                       data_arg.command,data_arg.size,&temp);
 349                 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
 350                               (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
 351                               (data_arg.read_write == I2C_SMBUS_READ))) {
 352                         if (copy_to_user(data_arg.data, &temp, datasize))
 353                                 return -EFAULT;
 354                 }
 355                 return res;
 356
 357         default:
 358                 return i2c_control(client,cmd,arg);
 359         }
 360         return 0;
 361 }
 362
 363 static int i2cdev_open(struct inode *inode, struct file *file)
 364 {
 365         unsigned int minor = iminor(inode);
 366         struct i2c_client *client;
 367         struct i2c_adapter *adap;
 368         struct i2c_dev *i2c_dev;
 369
 370         i2c_dev = i2c_dev_get_by_minor(minor);
 371         if (!i2c_dev)
 372                 return -ENODEV;
 373
 374         adap = i2c_get_adapter(i2c_dev->adap->nr);
 375         if (!adap)
 376                 return -ENODEV;
 377
 378         client = kmalloc(sizeof(*client), GFP_KERNEL);
 379         if (!client) {
 380                 i2c_put_adapter(adap);
 381                 return -ENOMEM;
 382         }
 383         memcpy(client, &i2cdev_client_template, sizeof(*client));
 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 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         struct device *dev;
 419
 420         i2c_dev = get_free_i2c_dev(adap);
 421         if (IS_ERR(i2c_dev))
 422                 return PTR_ERR(i2c_dev);
 423
 424         pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
 425                  adap->name, i2c_dev->minor);
 426
 427         /* register this i2c device with the driver core */
 428         i2c_dev->adap = adap;
 429         if (adap->dev.parent == &platform_bus)
 430                 dev = &adap->dev;
 431         else
 432                 dev = adap->dev.parent;
 433         i2c_dev->class_dev = class_device_create(i2c_dev_class, NULL,
 434                                                  MKDEV(I2C_MAJOR, i2c_dev->minor),
 435                                                  dev, "i2c-%d", i2c_dev->minor);
 436         if (!i2c_dev->class_dev)
 437                 goto error;
 438         class_device_create_file(i2c_dev->class_dev, &class_device_attr_name);
 439         return 0;
 440 error:
 441         return_i2c_dev(i2c_dev);
 442         kfree(i2c_dev);
 443         return -ENODEV;
 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_adapter(adap);
 451         if (!i2c_dev)
 452                 return -ENODEV;
 453
 454         return_i2c_dev(i2c_dev);
 455         class_device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, i2c_dev->minor));
 456         kfree(i2c_dev);
 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 struct i2c_client i2cdev_client_template = {
 478         .name           = "I2C /dev entry",
 479         .addr           = -1,
 480         .driver         = &i2cdev_driver,
 481 };
 482
 483 static int __init i2c_dev_init(void)
 484 {
 485         int res;
 486
 487         printk(KERN_INFO "i2c /dev entries driver\n");
 488
 489         res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
 490         if (res)
 491                 goto out;
 492
 493         i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
 494         if (IS_ERR(i2c_dev_class))
 495                 goto out_unreg_chrdev;
 496
 497         res = i2c_add_driver(&i2cdev_driver);
 498         if (res)
 499                 goto out_unreg_class;
 500
 501         return 0;
 502
 503 out_unreg_class:
 504         class_destroy(i2c_dev_class);
 505 out_unreg_chrdev:
 506         unregister_chrdev(I2C_MAJOR, "i2c");
 507 out:
 508         printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 509         return res;
 510 }
 511
 512 static void __exit i2c_dev_exit(void)
 513 {
 514         i2c_del_driver(&i2cdev_driver);
 515         class_destroy(i2c_dev_class);
 516         unregister_chrdev(I2C_MAJOR,"i2c");
 517 }
 518
 519 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 520                 "Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 521 MODULE_DESCRIPTION("I2C /dev entries driver");
 522 MODULE_LICENSE("GPL");
 523
 524 module_init(i2c_dev_init);
 525 module_exit(i2c_dev_exit);