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 struct completion released; /* FIXME, we need a class_device_unregister() */ 47 }; 48 #define to_i2c_dev(d) container_of(d, struct i2c_dev, class_dev) 49 50 #define I2C_MINORS 256 51 static struct i2c_dev *i2c_dev_array[I2C_MINORS]; 52 static DEFINE_SPINLOCK(i2c_dev_array_lock); 53 54 static struct i2c_dev *i2c_dev_get_by_minor(unsigned index) 55 { 56 struct i2c_dev *i2c_dev; 57 58 spin_lock(&i2c_dev_array_lock); 59 i2c_dev = i2c_dev_array[index]; 60 spin_unlock(&i2c_dev_array_lock); 61 return i2c_dev; 62 } 63 64 static struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap) 65 { 66 struct i2c_dev *i2c_dev = NULL; 67 68 spin_lock(&i2c_dev_array_lock); 69 if ((i2c_dev_array[adap->nr]) && 70 (i2c_dev_array[adap->nr]->adap == adap)) 71 i2c_dev = i2c_dev_array[adap->nr]; 72 spin_unlock(&i2c_dev_array_lock); 73 return i2c_dev; 74 } 75 76 static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap) 77 { 78 struct i2c_dev *i2c_dev; 79 80 i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL); 81 if (!i2c_dev) 82 return ERR_PTR(-ENOMEM); 83 84 spin_lock(&i2c_dev_array_lock); 85 if (i2c_dev_array[adap->nr]) { 86 spin_unlock(&i2c_dev_array_lock); 87 dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n"); 88 goto error; 89 } 90 i2c_dev->minor = adap->nr; 91 i2c_dev_array[adap->nr] = i2c_dev; 92 spin_unlock(&i2c_dev_array_lock); 93 return i2c_dev; 94 error: 95 kfree(i2c_dev); 96 return ERR_PTR(-ENODEV); 97 } 98 99 static void return_i2c_dev(struct i2c_dev *i2c_dev) 100 { 101 spin_lock(&i2c_dev_array_lock); 102 i2c_dev_array[i2c_dev->minor] = NULL; 103 spin_unlock(&i2c_dev_array_lock); 104 } 105 106 static ssize_t show_adapter_name(struct class_device *class_dev, char *buf) 107 { 108 struct i2c_dev *i2c_dev = to_i2c_dev(class_dev); 109 return sprintf(buf, "%s\n", i2c_dev->adap->name); 110 } 111 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL); 112 113 static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count, 114 loff_t *offset) 115 { 116 char *tmp; 117 int ret; 118 119 struct i2c_client *client = (struct i2c_client *)file->private_data; 120 121 if (count > 8192) 122 count = 8192; 123 124 tmp = kmalloc(count,GFP_KERNEL); 125 if (tmp==NULL) 126 return -ENOMEM; 127 128 pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n", 129 iminor(file->f_dentry->d_inode), count); 130 131 ret = i2c_master_recv(client,tmp,count); 132 if (ret >= 0) 133 ret = copy_to_user(buf,tmp,count)?-EFAULT:ret; 134 kfree(tmp); 135 return ret; 136 } 137 138 static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count, 139 loff_t *offset) 140 { 141 int ret; 142 char *tmp; 143 struct i2c_client *client = (struct i2c_client *)file->private_data; 144 145 if (count > 8192) 146 count = 8192; 147 148 tmp = kmalloc(count,GFP_KERNEL); 149 if (tmp==NULL) 150 return -ENOMEM; 151 if (copy_from_user(tmp,buf,count)) { 152 kfree(tmp); 153 return -EFAULT; 154 } 155 156 pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n", 157 iminor(file->f_dentry->d_inode), count); 158 159 ret = i2c_master_send(client,tmp,count); 160 kfree(tmp); 161 return ret; 162 } 163 164 static int i2cdev_ioctl(struct inode *inode, struct file *file, 165 unsigned int cmd, unsigned long arg) 166 { 167 struct i2c_client *client = (struct i2c_client *)file->private_data; 168 struct i2c_rdwr_ioctl_data rdwr_arg; 169 struct i2c_smbus_ioctl_data data_arg; 170 union i2c_smbus_data temp; 171 struct i2c_msg *rdwr_pa; 172 u8 __user **data_ptrs; 173 int i,datasize,res; 174 unsigned long funcs; 175 176 dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", 177 cmd, arg); 178 179 switch ( cmd ) { 180 case I2C_SLAVE: 181 case I2C_SLAVE_FORCE: 182 if ((arg > 0x3ff) || 183 (((client->flags & I2C_M_TEN) == 0) && arg > 0x7f)) 184 return -EINVAL; 185 if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg)) 186 return -EBUSY; 187 client->addr = arg; 188 return 0; 189 case I2C_TENBIT: 190 if (arg) 191 client->flags |= I2C_M_TEN; 192 else 193 client->flags &= ~I2C_M_TEN; 194 return 0; 195 case I2C_PEC: 196 if (arg) 197 client->flags |= I2C_CLIENT_PEC; 198 else 199 client->flags &= ~I2C_CLIENT_PEC; 200 return 0; 201 case I2C_FUNCS: 202 funcs = i2c_get_functionality(client->adapter); 203 return (copy_to_user((unsigned long __user *)arg, &funcs, 204 sizeof(unsigned long)))?-EFAULT:0; 205 206 case I2C_RDWR: 207 if (copy_from_user(&rdwr_arg, 208 (struct i2c_rdwr_ioctl_data __user *)arg, 209 sizeof(rdwr_arg))) 210 return -EFAULT; 211 212 /* Put an arbitrary limit on the number of messages that can 213 * be sent at once */ 214 if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS) 215 return -EINVAL; 216 217 rdwr_pa = (struct i2c_msg *) 218 kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), 219 GFP_KERNEL); 220 221 if (rdwr_pa == NULL) return -ENOMEM; 222 223 if (copy_from_user(rdwr_pa, rdwr_arg.msgs, 224 rdwr_arg.nmsgs * sizeof(struct i2c_msg))) { 225 kfree(rdwr_pa); 226 return -EFAULT; 227 } 228 229 data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL); 230 if (data_ptrs == NULL) { 231 kfree(rdwr_pa); 232 return -ENOMEM; 233 } 234 235 res = 0; 236 for( i=0; i<rdwr_arg.nmsgs; i++ ) { 237 /* Limit the size of the message to a sane amount */ 238 if (rdwr_pa[i].len > 8192) { 239 res = -EINVAL; 240 break; 241 } 242 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf; 243 rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL); 244 if(rdwr_pa[i].buf == NULL) { 245 res = -ENOMEM; 246 break; 247 } 248 if(copy_from_user(rdwr_pa[i].buf, 249 data_ptrs[i], 250 rdwr_pa[i].len)) { 251 ++i; /* Needs to be kfreed too */ 252 res = -EFAULT; 253 break; 254 } 255 } 256 if (res < 0) { 257 int j; 258 for (j = 0; j < i; ++j) 259 kfree(rdwr_pa[j].buf); 260 kfree(data_ptrs); 261 kfree(rdwr_pa); 262 return res; 263 } 264 265 res = i2c_transfer(client->adapter, 266 rdwr_pa, 267 rdwr_arg.nmsgs); 268 while(i-- > 0) { 269 if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) { 270 if(copy_to_user( 271 data_ptrs[i], 272 rdwr_pa[i].buf, 273 rdwr_pa[i].len)) { 274 res = -EFAULT; 275 } 276 } 277 kfree(rdwr_pa[i].buf); 278 } 279 kfree(data_ptrs); 280 kfree(rdwr_pa); 281 return res; 282 283 case I2C_SMBUS: 284 if (copy_from_user(&data_arg, 285 (struct i2c_smbus_ioctl_data __user *) arg, 286 sizeof(struct i2c_smbus_ioctl_data))) 287 return -EFAULT; 288 if ((data_arg.size != I2C_SMBUS_BYTE) && 289 (data_arg.size != I2C_SMBUS_QUICK) && 290 (data_arg.size != I2C_SMBUS_BYTE_DATA) && 291 (data_arg.size != I2C_SMBUS_WORD_DATA) && 292 (data_arg.size != I2C_SMBUS_PROC_CALL) && 293 (data_arg.size != I2C_SMBUS_BLOCK_DATA) && 294 (data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) && 295 (data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) { 296 dev_dbg(&client->adapter->dev, 297 "size out of range (%x) in ioctl I2C_SMBUS.\n", 298 data_arg.size); 299 return -EINVAL; 300 } 301 /* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1, 302 so the check is valid if size==I2C_SMBUS_QUICK too. */ 303 if ((data_arg.read_write != I2C_SMBUS_READ) && 304 (data_arg.read_write != I2C_SMBUS_WRITE)) { 305 dev_dbg(&client->adapter->dev, 306 "read_write out of range (%x) in ioctl I2C_SMBUS.\n", 307 data_arg.read_write); 308 return -EINVAL; 309 } 310 311 /* Note that command values are always valid! */ 312 313 if ((data_arg.size == I2C_SMBUS_QUICK) || 314 ((data_arg.size == I2C_SMBUS_BYTE) && 315 (data_arg.read_write == I2C_SMBUS_WRITE))) 316 /* These are special: we do not use data */ 317 return i2c_smbus_xfer(client->adapter, client->addr, 318 client->flags, 319 data_arg.read_write, 320 data_arg.command, 321 data_arg.size, NULL); 322 323 if (data_arg.data == NULL) { 324 dev_dbg(&client->adapter->dev, 325 "data is NULL pointer in ioctl I2C_SMBUS.\n"); 326 return -EINVAL; 327 } 328 329 if ((data_arg.size == I2C_SMBUS_BYTE_DATA) || 330 (data_arg.size == I2C_SMBUS_BYTE)) 331 datasize = sizeof(data_arg.data->byte); 332 else if ((data_arg.size == I2C_SMBUS_WORD_DATA) || 333 (data_arg.size == I2C_SMBUS_PROC_CALL)) 334 datasize = sizeof(data_arg.data->word); 335 else /* size == smbus block, i2c block, or block proc. call */ 336 datasize = sizeof(data_arg.data->block); 337 338 if ((data_arg.size == I2C_SMBUS_PROC_CALL) || 339 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 340 (data_arg.read_write == I2C_SMBUS_WRITE)) { 341 if (copy_from_user(&temp, data_arg.data, datasize)) 342 return -EFAULT; 343 } 344 res = i2c_smbus_xfer(client->adapter,client->addr,client->flags, 345 data_arg.read_write, 346 data_arg.command,data_arg.size,&temp); 347 if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) || 348 (data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) || 349 (data_arg.read_write == I2C_SMBUS_READ))) { 350 if (copy_to_user(data_arg.data, &temp, datasize)) 351 return -EFAULT; 352 } 353 return res; 354 355 default: 356 return i2c_control(client,cmd,arg); 357 } 358 return 0; 359 } 360 361 static int i2cdev_open(struct inode *inode, struct file *file) 362 { 363 unsigned int minor = iminor(inode); 364 struct i2c_client *client; 365 struct i2c_adapter *adap; 366 struct i2c_dev *i2c_dev; 367 368 i2c_dev = i2c_dev_get_by_minor(minor); 369 if (!i2c_dev) 370 return -ENODEV; 371 372 adap = i2c_get_adapter(i2c_dev->adap->nr); 373 if (!adap) 374 return -ENODEV; 375 376 client = kmalloc(sizeof(*client), GFP_KERNEL); 377 if (!client) { 378 i2c_put_adapter(adap); 379 return -ENOMEM; 380 } 381 memcpy(client, &i2cdev_client_template, sizeof(*client)); 382 383 /* registered with adapter, passed as client to user */ 384 client->adapter = adap; 385 file->private_data = client; 386 387 return 0; 388 } 389 390 static int i2cdev_release(struct inode *inode, struct file *file) 391 { 392 struct i2c_client *client = file->private_data; 393 394 i2c_put_adapter(client->adapter); 395 kfree(client); 396 file->private_data = NULL; 397 398 return 0; 399 } 400 401 static struct file_operations i2cdev_fops = { 402 .owner = THIS_MODULE, 403 .llseek = no_llseek, 404 .read = i2cdev_read, 405 .write = i2cdev_write, 406 .ioctl = i2cdev_ioctl, 407 .open = i2cdev_open, 408 .release = i2cdev_release, 409 }; 410 411 static void release_i2c_dev(struct class_device *dev) 412 { 413 struct i2c_dev *i2c_dev = to_i2c_dev(dev); 414 complete(&i2c_dev->released); 415 } 416 417 static struct class i2c_dev_class = { 418 .name = "i2c-dev", 419 .release = &release_i2c_dev, 420 }; 421 422 static int i2cdev_attach_adapter(struct i2c_adapter *adap) 423 { 424 struct i2c_dev *i2c_dev; 425 int retval; 426 427 i2c_dev = get_free_i2c_dev(adap); 428 if (IS_ERR(i2c_dev)) 429 return PTR_ERR(i2c_dev); 430 431 pr_debug("i2c-dev: adapter [%s] registered as minor %d\n", 432 adap->name, i2c_dev->minor); 433 434 /* register this i2c device with the driver core */ 435 i2c_dev->adap = adap; 436 if (adap->dev.parent == &platform_bus) 437 i2c_dev->class_dev.dev = &adap->dev; 438 else 439 i2c_dev->class_dev.dev = adap->dev.parent; 440 i2c_dev->class_dev.class = &i2c_dev_class; 441 i2c_dev->class_dev.devt = MKDEV(I2C_MAJOR, i2c_dev->minor); 442 snprintf(i2c_dev->class_dev.class_id, BUS_ID_SIZE, "i2c-%d", i2c_dev->minor); 443 retval = class_device_register(&i2c_dev->class_dev); 444 if (retval) 445 goto error; 446 class_device_create_file(&i2c_dev->class_dev, &class_device_attr_name); 447 return 0; 448 error: 449 return_i2c_dev(i2c_dev); 450 kfree(i2c_dev); 451 return retval; 452 } 453 454 static int i2cdev_detach_adapter(struct i2c_adapter *adap) 455 { 456 struct i2c_dev *i2c_dev; 457 458 i2c_dev = i2c_dev_get_by_adapter(adap); 459 if (!i2c_dev) 460 return -ENODEV; 461 462 init_completion(&i2c_dev->released); 463 return_i2c_dev(i2c_dev); 464 class_device_unregister(&i2c_dev->class_dev); 465 wait_for_completion(&i2c_dev->released); 466 kfree(i2c_dev); 467 468 pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name); 469 return 0; 470 } 471 472 static int i2cdev_detach_client(struct i2c_client *client) 473 { 474 return 0; 475 } 476 477 static int i2cdev_command(struct i2c_client *client, unsigned int cmd, 478 void *arg) 479 { 480 return -1; 481 } 482 483 static struct i2c_driver i2cdev_driver = { 484 .owner = THIS_MODULE, 485 .name = "dev_driver", 486 .id = I2C_DRIVERID_I2CDEV, 487 .flags = I2C_DF_NOTIFY, 488 .attach_adapter = i2cdev_attach_adapter, 489 .detach_adapter = i2cdev_detach_adapter, 490 .detach_client = i2cdev_detach_client, 491 .command = i2cdev_command, 492 }; 493 494 static struct i2c_client i2cdev_client_template = { 495 .name = "I2C /dev entry", 496 .addr = -1, 497 .driver = &i2cdev_driver, 498 }; 499 500 static int __init i2c_dev_init(void) 501 { 502 int res; 503 504 printk(KERN_INFO "i2c /dev entries driver\n"); 505 506 res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops); 507 if (res) 508 goto out; 509 510 res = class_register(&i2c_dev_class); 511 if (res) 512 goto out_unreg_chrdev; 513 514 res = i2c_add_driver(&i2cdev_driver); 515 if (res) 516 goto out_unreg_class; 517 518 return 0; 519 520 out_unreg_class: 521 class_unregister(&i2c_dev_class); 522 out_unreg_chrdev: 523 unregister_chrdev(I2C_MAJOR, "i2c"); 524 out: 525 printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__); 526 return res; 527 } 528 529 static void __exit i2c_dev_exit(void) 530 { 531 i2c_del_driver(&i2cdev_driver); 532 class_unregister(&i2c_dev_class); 533 unregister_chrdev(I2C_MAJOR,"i2c"); 534 } 535 536 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and " 537 "Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 538 MODULE_DESCRIPTION("I2C /dev entries driver"); 539 MODULE_LICENSE("GPL"); 540 541 module_init(i2c_dev_init); 542 module_exit(i2c_dev_exit); 543