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); 520