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 /* The devfs code is contributed by Philipp Matthias Hahn 30 <pmhahn@titan.lahn.de> */ 31 32 #include <linux/kernel.h> 33 #include <linux/module.h> 34 #include <linux/fs.h> 35 #include <linux/slab.h> 36 #include <linux/smp_lock.h> 37 #include <linux/devfs_fs_kernel.h> 38 #include <linux/init.h> 39 #include <linux/i2c.h> 40 #include <linux/i2c-dev.h> 41 #include <asm/uaccess.h> 42 43 static struct i2c_client i2cdev_client_template; 44 45 struct i2c_dev { 46 int minor; 47 struct i2c_adapter *adap; 48 struct class_device class_dev; 49 struct completion released; /* FIXME, we need a class_device_unregister() */ 50 }; 51 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev) 52 53 #define I2C_MINORS 256 54 static struct i2c_dev *i2c_dev_array[I2C_MINORS]; 55 static DEFINE_SPINLOCK(i2c_dev_array_lock); 56 57 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index) 58 { 59 struct i2c_dev *i2c_dev; 60 61 spin_lock(&i2c_dev_array_lock); 62 i2c_dev = i2c_dev_array[index]; 63 spin_unlock(&i2c_dev_array_lock); 64 return i2c_dev; 65 } 66 67 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap) 68 { 69 struct i2c_dev *i2c_dev = NULL; 70 71 spin_lock(&i2c_dev_array_lock); 72 if ((i2c_dev_array[adap->nr]) && 73 (i2c_dev_array[adap->nr]->adap == adap)) 74 i2c_dev = i2c_dev_array[adap->nr]; 75 spin_unlock(&i2c_dev_array_lock); 76 return i2c_dev; 77 } 78 79 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap) 80 { 81 struct i2c_dev *i2c_dev; 82 83 i2c_dev = kmalloc(sizeof(*i2c_dev), GFP_KERNEL); 84 if (!i2c_dev) 85 return ERR_PTR(-ENOMEM); 86 memset(i2c_dev, 0x00, sizeof(*i2c_dev)); 87 88 spin_lock(&i2c_dev_array_lock); 89 if (i2c_dev_array[adap->nr]) { 90 spin_unlock(&i2c_dev_array_lock); 91 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n"); 92 goto error; 93 } 94 i2c_dev->minor = adap->nr; 95 i2c_dev_array[adap->nr] = i2c_dev; 96 spin_unlock(&i2c_dev_array_lock); 97 return i2c_dev; 98 error: 99 kfree(i2c_dev); 100 return ERR_PTR(-ENODEV); 101 } 102 103 static void return_i2c_dev(struct i2c_dev *i2c_dev) 104 { 105 spin_lock(&i2c_dev_array_lock); 106 i2c_dev_array[i2c_dev->minor] = NULL; 107 spin_unlock(&i2c_dev_array_lock); 108 } 109 110 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf) 111 { 112 struct i2c_dev *i2c_dev = to_i2c_dev(class_dev); 113 return sprintf(buf, "%s\n", i2c_dev->adap->name); 114 } 115 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL); 116 117 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count, 118 loff_t *offset) 119 { 120 char *tmp; 121 int ret; 122 123 struct i2c_client *client = (struct i2c_client *)file->private_data; 124 125 if (count > 8192) 126 count = 8192; 127 128 tmp = kmalloc(count,GFP_KERNEL); 129 if (tmp==NULL) 130 return -ENOMEM; 131 132 pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n", 133 iminor(file->f_dentry->d_inode), count); 134 135 ret = i2c_master_recv(client,tmp,count); 136 if (ret >= 0) 137 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret; 138 kfree(tmp); 139 return ret; 140 } 141 142 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count, 143 loff_t *offset) 144 { 145 int ret; 146 char *tmp; 147 struct i2c_client *client = (struct i2c_client *)file->private_data; 148 149 if (count > 8192) 150 count = 8192; 151 152 tmp = kmalloc(count,GFP_KERNEL); 153 if (tmp==NULL) 154 return -ENOMEM; 155 if (copy_from_user(tmp,buf,count)) { 156 kfree(tmp); 157 return -EFAULT; 158 } 159 160 pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n", 161 iminor(file->f_dentry->d_inode), count); 162 163 ret = i2c_master_send(client,tmp,count); 164 kfree(tmp); 165 return ret; 166 } 167 168 static int i2cdev_ioctl(struct inode *inode, struct file *file, 169 unsigned int cmd, unsigned long arg) 170 { 171 struct i2c_client *client = (struct i2c_client *)file->private_data; 172 struct i2c_rdwr_ioctl_data rdwr_arg; 173 struct i2c_smbus_ioctl_data data_arg; 174 union i2c_smbus_data temp; 175 struct i2c_msg *rdwr_pa; 176 u8 __user **data_ptrs; 177 int i,datasize,res; 178 unsigned long funcs; 179 180 dev_dbg(&client->adapter->dev, "i2c-%d ioctl, cmd: 0x%x, arg: %lx.\n", 181 iminor(inode),cmd, arg); 182 183 switch ( cmd ) { 184 case I2C_SLAVE: 185 case I2C_SLAVE_FORCE: 186 if ((arg > 0x3ff) || 187 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 188 return -EINVAL; 189 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg)) 190 return -EBUSY; 191 client->addr = arg; 192 return 0; 193 case I2C_TENBIT: 194 if (arg) 195 client->flags |= I2C_M_TEN; 196 else 197 client->flags &= ~I2C_M_TEN; 198 return 0; 199 case I2C_PEC: 200 if (arg) 201 client->flags |= I2C_CLIENT_PEC; 202 else 203 client->flags &= ~I2C_CLIENT_PEC; 204 return 0; 205 case I2C_FUNCS: 206 funcs = i2c_get_functionality(client->adapter); 207 return (copy_to_user((unsigned long __user *)arg, &funcs, 208 sizeof(unsigned long)))?-EFAULT:0; 209 210 case I2C_RDWR: 211 if (copy_from_user(&rdwr_arg, 212 (struct i2c_rdwr_ioctl_data __user *)arg, 213 sizeof(rdwr_arg))) 214 return -EFAULT; 215 216 /* Put an arbitrary limit on the number of messages that can 217 * be sent at once */ 218 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS) 219 return -EINVAL; 220 221 rdwr_pa = (struct i2c_msg *) 222 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), 223 GFP_KERNEL); 224 225 if (rdwr_pa == NULL) return -ENOMEM; 226 227 if (copy_from_user(rdwr_pa, rdwr_arg.msgs, 228 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) { 229 kfree(rdwr_pa); 230 return -EFAULT; 231 } 232 233 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL); 234 if (data_ptrs == NULL) { 235 kfree(rdwr_pa); 236 return -ENOMEM; 237 } 238 239 res = 0; 240 for( i=0; i<rdwr_arg.nmsgs; i++ ) { 241 /* Limit the size of the message to a sane amount */ 242 if (rdwr_pa[i].len > 8192) { 243 res = -EINVAL; 244 break; 245 } 246 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf; 247 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL); 248 if(rdwr_pa[i].buf == NULL) { 249 res = -ENOMEM; 250 break; 251 } 252 if(copy_from_user(rdwr_pa[i].buf, 253 data_ptrs[i], 254 rdwr_pa[i].len)) { 255 ++i; /* Needs to be kfreed too */ 256 res = -EFAULT; 257 break; 258 } 259 } 260 if (res < 0) { 261 int j; 262 for (j = 0; j < i; ++j) 263 kfree(rdwr_pa[j].buf); 264 kfree(data_ptrs); 265 kfree(rdwr_pa); 266 return res; 267 } 268 269 res = i2c_transfer(client->adapter, 270 rdwr_pa, 271 rdwr_arg.nmsgs); 272 while(i-- > 0) { 273 if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) { 274 if(copy_to_user( 275 data_ptrs[i], 276 rdwr_pa[i].buf, 277 rdwr_pa[i].len)) { 278 res = -EFAULT; 279 } 280 } 281 kfree(rdwr_pa[i].buf); 282 } 283 kfree(data_ptrs); 284 kfree(rdwr_pa); 285 return res; 286 287 case I2C_SMBUS: 288 if (copy_from_user(&data_arg, 289 (struct i2c_smbus_ioctl_data __user *) arg, 290 sizeof(struct i2c_smbus_ioctl_data))) 291 return -EFAULT; 292 if ((data_arg.size != I2C_SMBUS_BYTE) && 293 (data_arg.size != I2C_SMBUS_QUICK) && 294 (data_arg.size != I2C_SMBUS_BYTE_DATA) && 295 (data_arg.size != I2C_SMBUS_WORD_DATA) && 296 (data_arg.size != I2C_SMBUS_PROC_CALL) && 297 (data_arg.size != I2C_SMBUS_BLOCK_DATA) && 298 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) && 299 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) { 300 dev_dbg(&client->adapter->dev, 301 "size out of range (%x) in ioctl I2C_SMBUS.\n", 302 data_arg.size); 303 return -EINVAL; 304 } 305 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 306 so the check is valid if size==I2C_SMBUS_QUICK too. */ 307 if ((data_arg.read_write != I2C_SMBUS_READ) && 308 (data_arg.read_write != I2C_SMBUS_WRITE)) { 309 dev_dbg(&client->adapter->dev, 310 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 311 data_arg.read_write); 312 return -EINVAL; 313 } 314 315 /* Note that command values are always valid! */ 316 317 if ((data_arg.size == I2C_SMBUS_QUICK) || 318 ((data_arg.size == I2C_SMBUS_BYTE) && 319 (data_arg.read_write == I2C_SMBUS_WRITE))) 320 /* These are special: we do not use data */ 321 return i2c_smbus_xfer(client->adapter, client->addr, 322 client->flags, 323 data_arg.read_write, 324 data_arg.command, 325 data_arg.size, NULL); 326 327 if (data_arg.data == NULL) { 328 dev_dbg(&client->adapter->dev, 329 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 330 return -EINVAL; 331 } 332 333 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) || 334 (data_arg.size == I2C_SMBUS_BYTE)) 335 datasize = sizeof(data_arg.data->byte); 336 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) || 337 (data_arg.size == I2C_SMBUS_PROC_CALL)) 338 datasize = sizeof(data_arg.data->word); 339 else /* size == smbus block, i2c block, or block proc. call */ 340 datasize = sizeof(data_arg.data->block); 341 342 if ((data_arg.size == I2C_SMBUS_PROC_CALL) || 343 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 344 (data_arg.read_write == I2C_SMBUS_WRITE)) { 345 if (copy_from_user(&temp, data_arg.data, datasize)) 346 return -EFAULT; 347 } 348 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags, 349 data_arg.read_write, 350 data_arg.command,data_arg.size,&temp); 351 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) || 352 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 353 (data_arg.read_write == I2C_SMBUS_READ))) { 354 if (copy_to_user(data_arg.data, &temp, datasize)) 355 return -EFAULT; 356 } 357 return res; 358 359 default: 360 return i2c_control(client,cmd,arg); 361 } 362 return 0; 363 } 364 365 static int i2cdev_open(struct inode *inode, struct file *file) 366 { 367 unsigned int minor = iminor(inode); 368 struct i2c_client *client; 369 struct i2c_adapter *adap; 370 struct i2c_dev *i2c_dev; 371 372 i2c_dev = i2c_dev_get_by_minor(minor); 373 if (!i2c_dev) 374 return -ENODEV; 375 376 adap = i2c_get_adapter(i2c_dev->adap->nr); 377 if (!adap) 378 return -ENODEV; 379 380 client = kmalloc(sizeof(*client), GFP_KERNEL); 381 if (!client) { 382 i2c_put_adapter(adap); 383 return -ENOMEM; 384 } 385 memcpy(client, &i2cdev_client_template, sizeof(*client)); 386 387 /* registered with adapter, passed as client to user */ 388 client->adapter = adap; 389 file->private_data = client; 390 391 return 0; 392 } 393 394 static int i2cdev_release(struct inode *inode, struct file *file) 395 { 396 struct i2c_client *client = file->private_data; 397 398 i2c_put_adapter(client->adapter); 399 kfree(client); 400 file->private_data = NULL; 401 402 return 0; 403 } 404 405 static struct file_operations i2cdev_fops = { 406 .owner = THIS_MODULE, 407 .llseek = no_llseek, 408 .read = i2cdev_read, 409 .write = i2cdev_write, 410 .ioctl = i2cdev_ioctl, 411 .open = i2cdev_open, 412 .release = i2cdev_release, 413 }; 414 415 static void release_i2c_dev(struct class_device *dev) 416 { 417 struct i2c_dev *i2c_dev = to_i2c_dev(dev); 418 complete(&i2c_dev->released); 419 } 420 421 static struct class i2c_dev_class = { 422 .name = "i2c-dev", 423 .release = &release_i2c_dev, 424 }; 425 426 static int i2cdev_attach_adapter(struct i2c_adapter *adap) 427 { 428 struct i2c_dev *i2c_dev; 429 int retval; 430 431 i2c_dev = get_free_i2c_dev(adap); 432 if (IS_ERR(i2c_dev)) 433 return PTR_ERR(i2c_dev); 434 435 devfs_mk_cdev(MKDEV(I2C_MAJOR, i2c_dev->minor), 436 S_IFCHR|S_IRUSR|S_IWUSR, "i2c/%d", i2c_dev->minor); 437 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n", 438 adap->name, i2c_dev->minor); 439 440 /* register this i2c device with the driver core */ 441 i2c_dev->adap = adap; 442 if (adap->dev.parent == &platform_bus) 443 i2c_dev->class_dev.dev = &adap->dev; 444 else 445 i2c_dev->class_dev.dev = adap->dev.parent; 446 i2c_dev->class_dev.class = &i2c_dev_class; 447 i2c_dev->class_dev.devt = MKDEV(I2C_MAJOR, i2c_dev->minor); 448 snprintf(i2c_dev->class_dev.class_id, BUS_ID_SIZE, "i2c-%d", i2c_dev->minor); 449 retval = class_device_register(&i2c_dev->class_dev); 450 if (retval) 451 goto error; 452 class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name); 453 return 0; 454 error: 455 return_i2c_dev(i2c_dev); 456 kfree(i2c_dev); 457 return retval; 458 } 459 460 static int i2cdev_detach_adapter(struct i2c_adapter *adap) 461 { 462 struct i2c_dev *i2c_dev; 463 464 i2c_dev = i2c_dev_get_by_adapter(adap); 465 if (!i2c_dev) 466 return -ENODEV; 467 468 init_completion(&i2c_dev->released); 469 devfs_remove("i2c/%d", i2c_dev->minor); 470 return_i2c_dev(i2c_dev); 471 class_device_unregister(&i2c_dev->class_dev); 472 wait_for_completion(&i2c_dev->released); 473 kfree(i2c_dev); 474 475 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name); 476 return 0; 477 } 478 479 static int i2cdev_detach_client(struct i2c_client *client) 480 { 481 return 0; 482 } 483 484 static int i2cdev_command(struct i2c_client *client, unsigned int cmd, 485 void *arg) 486 { 487 return -1; 488 } 489 490 static struct i2c_driver i2cdev_driver = { 491 .owner = THIS_MODULE, 492 .name = "dev_driver", 493 .id = I2C_DRIVERID_I2CDEV, 494 .flags = I2C_DF_NOTIFY, 495 .attach_adapter = i2cdev_attach_adapter, 496 .detach_adapter = i2cdev_detach_adapter, 497 .detach_client = i2cdev_detach_client, 498 .command = i2cdev_command, 499 }; 500 501 static struct i2c_client i2cdev_client_template = { 502 .name = "I2C /dev entry", 503 .addr = -1, 504 .driver = &i2cdev_driver, 505 }; 506 507 static int __init i2c_dev_init(void) 508 { 509 int res; 510 511 printk(KERN_INFO "i2c /dev entries driver\n"); 512 513 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops); 514 if (res) 515 goto out; 516 517 res = class_register(&i2c_dev_class); 518 if (res) 519 goto out_unreg_chrdev; 520 521 res = i2c_add_driver(&i2cdev_driver); 522 if (res) 523 goto out_unreg_class; 524 525 devfs_mk_dir("i2c"); 526 527 return 0; 528 529 out_unreg_class: 530 class_unregister(&i2c_dev_class); 531 out_unreg_chrdev: 532 unregister_chrdev(I2C_MAJOR, "i2c"); 533 out: 534 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__); 535 return res; 536 } 537 538 static void __exit i2c_dev_exit(void) 539 { 540 i2c_del_driver(&i2cdev_driver); 541 class_unregister(&i2c_dev_class); 542 devfs_remove("i2c"); 543 unregister_chrdev(I2C_MAJOR,"i2c"); 544 } 545 546 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and " 547 "Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 548 MODULE_DESCRIPTION("I2C /dev entries driver"); 549 MODULE_LICENSE("GPL"); 550 551 module_init(i2c_dev_init); 552 module_exit(i2c_dev_exit); 553