drivers/staging/iio/industrialio-core.c

   1 /* The industrial I/O core
   2  *
   3  * Copyright (c) 2008 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * Based on elements of hwmon and input subsystems.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/idr.h>
  15 #include <linux/kdev_t.h>
  16 #include <linux/err.h>
  17 #include <linux/device.h>
  18 #include <linux/fs.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/poll.h>
  21 #include <linux/sched.h>
  22 #include <linux/wait.h>
  23 #include <linux/cdev.h>
  24 #include <linux/slab.h>
  25 #include "iio.h"
  26 #include "trigger_consumer.h"
  27
  28 #define IIO_ID_PREFIX "device"
  29 #define IIO_ID_FORMAT IIO_ID_PREFIX "%d"
  30
  31 /* IDR to assign each registered device a unique id*/
  32 static DEFINE_IDR(iio_idr);
  33 /* IDR to allocate character device minor numbers */
  34 static DEFINE_IDR(iio_chrdev_idr);
  35 /* Lock used to protect both of the above */
  36 static DEFINE_SPINLOCK(iio_idr_lock);
  37
  38 dev_t iio_devt;
  39 EXPORT_SYMBOL(iio_devt);
  40
  41 #define IIO_DEV_MAX 256
  42 struct bus_type iio_bus_type = {
  43         .name = "iio",
  44 };
  45 EXPORT_SYMBOL(iio_bus_type);
  46
  47 void __iio_change_event(struct iio_detected_event_list *ev,
  48                         int ev_code,
  49                         s64 timestamp)
  50 {
  51         ev->ev.id = ev_code;
  52         ev->ev.timestamp = timestamp;
  53 }
  54 EXPORT_SYMBOL(__iio_change_event);
  55
  56 /* Used both in the interrupt line put events and the ring buffer ones */
  57
  58 /* Note that in it's current form someone has to be listening before events
  59  * are queued. Hence a client MUST open the chrdev before the ring buffer is
  60  * switched on.
  61  */
  62  int __iio_push_event(struct iio_event_interface *ev_int,
  63                      int ev_code,
  64                      s64 timestamp,
  65                      struct iio_shared_ev_pointer *
  66                      shared_pointer_p)
  67 {
  68         struct iio_detected_event_list *ev;
  69         int ret = 0;
  70
  71         /* Does anyone care? */
  72         mutex_lock(&ev_int->event_list_lock);
  73         if (test_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags)) {
  74                 if (ev_int->current_events == ev_int->max_events) {
  75                         mutex_unlock(&ev_int->event_list_lock);
  76                         return 0;
  77                 }
  78                 ev = kmalloc(sizeof(*ev), GFP_KERNEL);
  79                 if (ev == NULL) {
  80                         ret = -ENOMEM;
  81                         mutex_unlock(&ev_int->event_list_lock);
  82                         goto error_ret;
  83                 }
  84                 ev->ev.id = ev_code;
  85                 ev->ev.timestamp = timestamp;
  86                 ev->shared_pointer = shared_pointer_p;
  87                 if (ev->shared_pointer)
  88                         shared_pointer_p->ev_p = ev;
  89
  90                 list_add_tail(&ev->list, &ev_int->det_events.list);
  91                 ev_int->current_events++;
  92                 mutex_unlock(&ev_int->event_list_lock);
  93                 wake_up_interruptible(&ev_int->wait);
  94         } else
  95                 mutex_unlock(&ev_int->event_list_lock);
  96
  97 error_ret:
  98         return ret;
  99 }
 100 EXPORT_SYMBOL(__iio_push_event);
 101
 102 int iio_push_event(struct iio_dev *dev_info,
 103                    int ev_line,
 104                    int ev_code,
 105                    s64 timestamp)
 106 {
 107         return __iio_push_event(&dev_info->event_interfaces[ev_line],
 108                                 ev_code, timestamp, NULL);
 109 }
 110 EXPORT_SYMBOL(iio_push_event);
 111
 112 /* Generic interrupt line interrupt handler */
 113 static irqreturn_t iio_interrupt_handler(int irq, void *_int_info)
 114 {
 115         struct iio_interrupt *int_info = _int_info;
 116         struct iio_dev *dev_info = int_info->dev_info;
 117         struct iio_event_handler_list *p;
 118         s64 time_ns;
 119         unsigned long flags;
 120
 121         spin_lock_irqsave(&int_info->ev_list_lock, flags);
 122         if (list_empty(&int_info->ev_list)) {
 123                 spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
 124                 return IRQ_NONE;
 125         }
 126
 127         time_ns = iio_get_time_ns();
 128         /* detect single element list*/
 129         if (list_is_singular(&int_info->ev_list)) {
 130                 disable_irq_nosync(irq);
 131                 p = list_first_entry(&int_info->ev_list,
 132                                      struct iio_event_handler_list,
 133                                      list);
 134                 /* single event handler - maybe shared */
 135                 p->handler(dev_info, 1, time_ns, !(p->refcount > 1));
 136         } else
 137                 list_for_each_entry(p, &int_info->ev_list, list) {
 138                         disable_irq_nosync(irq);
 139                         p->handler(dev_info, 1, time_ns, 0);
 140                 }
 141         spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
 142
 143         return IRQ_HANDLED;
 144 }
 145
 146 static struct iio_interrupt *iio_allocate_interrupt(void)
 147 {
 148         struct iio_interrupt *i = kmalloc(sizeof *i, GFP_KERNEL);
 149         if (i) {
 150                 spin_lock_init(&i->ev_list_lock);
 151                 INIT_LIST_HEAD(&i->ev_list);
 152         }
 153         return i;
 154 }
 155
 156 /* Confirming the validity of supplied irq is left to drivers.*/
 157 int iio_register_interrupt_line(unsigned int irq,
 158                                 struct iio_dev *dev_info,
 159                                 int line_number,
 160                                 unsigned long type,
 161                                 const char *name)
 162 {
 163         int ret;
 164
 165         dev_info->interrupts[line_number] = iio_allocate_interrupt();
 166         if (dev_info->interrupts[line_number] == NULL) {
 167                 ret = -ENOMEM;
 168                 goto error_ret;
 169         }
 170         dev_info->interrupts[line_number]->line_number = line_number;
 171         dev_info->interrupts[line_number]->irq = irq;
 172         dev_info->interrupts[line_number]->dev_info = dev_info;
 173
 174         /* Possibly only request on demand?
 175          * Can see this may complicate the handling of interrupts.
 176          * However, with this approach we might end up handling lots of
 177          * events no-one cares about.*/
 178         ret = request_irq(irq,
 179                           &iio_interrupt_handler,
 180                           type,
 181                           name,
 182                           dev_info->interrupts[line_number]);
 183
 184 error_ret:
 185         return ret;
 186 }
 187 EXPORT_SYMBOL(iio_register_interrupt_line);
 188
 189 /* This turns up an awful lot */
 190 ssize_t iio_read_const_attr(struct device *dev,
 191                             struct device_attribute *attr,
 192                             char *buf)
 193 {
 194         return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
 195 }
 196 EXPORT_SYMBOL(iio_read_const_attr);
 197
 198 /* Before this runs the interrupt generator must have been disabled */
 199 void iio_unregister_interrupt_line(struct iio_dev *dev_info, int line_number)
 200 {
 201         /* make sure the interrupt handlers are all done */
 202         flush_scheduled_work();
 203         free_irq(dev_info->interrupts[line_number]->irq,
 204                  dev_info->interrupts[line_number]);
 205         kfree(dev_info->interrupts[line_number]);
 206 }
 207 EXPORT_SYMBOL(iio_unregister_interrupt_line);
 208
 209 /* Reference counted add and remove */
 210 void iio_add_event_to_list(struct iio_event_handler_list *el,
 211                           struct list_head *head)
 212 {
 213         unsigned long flags;
 214         struct iio_interrupt *inter = to_iio_interrupt(head);
 215
 216         /* take mutex to protect this element */
 217         mutex_lock(&el->exist_lock);
 218         if (el->refcount == 0) {
 219                 /* Take the event list spin lock */
 220                 spin_lock_irqsave(&inter->ev_list_lock, flags);
 221                 list_add(&el->list, head);
 222                 spin_unlock_irqrestore(&inter->ev_list_lock, flags);
 223         }
 224         el->refcount++;
 225         mutex_unlock(&el->exist_lock);
 226 }
 227 EXPORT_SYMBOL(iio_add_event_to_list);
 228
 229 void iio_remove_event_from_list(struct iio_event_handler_list *el,
 230                                struct list_head *head)
 231 {
 232         unsigned long flags;
 233         struct iio_interrupt *inter = to_iio_interrupt(head);
 234
 235         mutex_lock(&el->exist_lock);
 236         el->refcount--;
 237         if (el->refcount == 0) {
 238                 /* Take the event list spin lock */
 239                 spin_lock_irqsave(&inter->ev_list_lock, flags);
 240                 list_del_init(&el->list);
 241                 spin_unlock_irqrestore(&inter->ev_list_lock, flags);
 242         }
 243         mutex_unlock(&el->exist_lock);
 244 }
 245 EXPORT_SYMBOL(iio_remove_event_from_list);
 246
 247 static ssize_t iio_event_chrdev_read(struct file *filep,
 248                                      char __user *buf,
 249                                      size_t count,
 250                                      loff_t *f_ps)
 251 {
 252         struct iio_event_interface *ev_int = filep->private_data;
 253         struct iio_detected_event_list *el;
 254         int ret;
 255         size_t len;
 256
 257         mutex_lock(&ev_int->event_list_lock);
 258         if (list_empty(&ev_int->det_events.list)) {
 259                 if (filep->f_flags & O_NONBLOCK) {
 260                         ret = -EAGAIN;
 261                         goto error_mutex_unlock;
 262                 }
 263                 mutex_unlock(&ev_int->event_list_lock);
 264                 /* Blocking on device; waiting for something to be there */
 265                 ret = wait_event_interruptible(ev_int->wait,
 266                                                !list_empty(&ev_int
 267                                                            ->det_events.list));
 268                 if (ret)
 269                         goto error_ret;
 270                 /* Single access device so noone else can get the data */
 271                 mutex_lock(&ev_int->event_list_lock);
 272         }
 273
 274         el = list_first_entry(&ev_int->det_events.list,
 275                               struct iio_detected_event_list,
 276                               list);
 277         len = sizeof el->ev;
 278         if (copy_to_user(buf, &(el->ev), len)) {
 279                 ret = -EFAULT;
 280                 goto error_mutex_unlock;
 281         }
 282         list_del(&el->list);
 283         ev_int->current_events--;
 284         mutex_unlock(&ev_int->event_list_lock);
 285         /*
 286          * Possible concurency issue if an update of this event is on its way
 287          * through. May lead to new event being removed whilst the reported
 288          * event was the unescalated event. In typical use case this is not a
 289          * problem as userspace will say read half the buffer due to a 50%
 290          * full event which would make the correct 100% full incorrect anyway.
 291          */
 292         if (el->shared_pointer) {
 293                 spin_lock(&el->shared_pointer->lock);
 294                 (el->shared_pointer->ev_p) = NULL;
 295                 spin_unlock(&el->shared_pointer->lock);
 296         }
 297         kfree(el);
 298
 299         return len;
 300
 301 error_mutex_unlock:
 302         mutex_unlock(&ev_int->event_list_lock);
 303 error_ret:
 304
 305         return ret;
 306 }
 307
 308 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 309 {
 310         struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
 311         struct iio_event_interface *ev_int = hand->private;
 312         struct iio_detected_event_list *el, *t;
 313
 314         mutex_lock(&ev_int->event_list_lock);
 315         clear_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags);
 316         /*
 317          * In order to maintain a clean state for reopening,
 318          * clear out any awaiting events. The mask will prevent
 319          * any new __iio_push_event calls running.
 320          */
 321         list_for_each_entry_safe(el, t, &ev_int->det_events.list, list) {
 322                 list_del(&el->list);
 323                 kfree(el);
 324         }
 325         mutex_unlock(&ev_int->event_list_lock);
 326
 327         return 0;
 328 }
 329
 330 static int iio_event_chrdev_open(struct inode *inode, struct file *filep)
 331 {
 332         struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
 333         struct iio_event_interface *ev_int = hand->private;
 334
 335         mutex_lock(&ev_int->event_list_lock);
 336         if (test_and_set_bit(IIO_BUSY_BIT_POS, &hand->flags)) {
 337                 fops_put(filep->f_op);
 338                 mutex_unlock(&ev_int->event_list_lock);
 339                 return -EBUSY;
 340         }
 341         filep->private_data = hand->private;
 342         mutex_unlock(&ev_int->event_list_lock);
 343
 344         return 0;
 345 }
 346
 347 static const struct file_operations iio_event_chrdev_fileops = {
 348         .read =  iio_event_chrdev_read,
 349         .release = iio_event_chrdev_release,
 350         .open = iio_event_chrdev_open,
 351         .owner = THIS_MODULE,
 352         .llseek = noop_llseek,
 353 };
 354
 355 static void iio_event_dev_release(struct device *dev)
 356 {
 357         struct iio_event_interface *ev_int
 358                 = container_of(dev, struct iio_event_interface, dev);
 359         cdev_del(&ev_int->handler.chrdev);
 360         iio_device_free_chrdev_minor(MINOR(dev->devt));
 361 };
 362
 363 static struct device_type iio_event_type = {
 364         .release = iio_event_dev_release,
 365 };
 366
 367 int iio_device_get_chrdev_minor(void)
 368 {
 369         int ret, val;
 370
 371 idr_again:
 372         if (unlikely(idr_pre_get(&iio_chrdev_idr, GFP_KERNEL) == 0))
 373                 return -ENOMEM;
 374         spin_lock(&iio_idr_lock);
 375         ret = idr_get_new(&iio_chrdev_idr, NULL, &val);
 376         spin_unlock(&iio_idr_lock);
 377         if (unlikely(ret == -EAGAIN))
 378                 goto idr_again;
 379         else if (unlikely(ret))
 380                 return ret;
 381         if (val > IIO_DEV_MAX)
 382                 return -ENOMEM;
 383         return val;
 384 }
 385
 386 void iio_device_free_chrdev_minor(int val)
 387 {
 388         spin_lock(&iio_idr_lock);
 389         idr_remove(&iio_chrdev_idr, val);
 390         spin_unlock(&iio_idr_lock);
 391 }
 392
 393 int iio_setup_ev_int(struct iio_event_interface *ev_int,
 394                      const char *name,
 395                      struct module *owner,
 396                      struct device *dev)
 397 {
 398         int ret, minor;
 399
 400         ev_int->dev.bus = &iio_bus_type;
 401         ev_int->dev.parent = dev;
 402         ev_int->dev.type = &iio_event_type;
 403         device_initialize(&ev_int->dev);
 404
 405         minor = iio_device_get_chrdev_minor();
 406         if (minor < 0) {
 407                 ret = minor;
 408                 goto error_device_put;
 409         }
 410         ev_int->dev.devt = MKDEV(MAJOR(iio_devt), minor);
 411         dev_set_name(&ev_int->dev, "%s", name);
 412
 413         ret = device_add(&ev_int->dev);
 414         if (ret)
 415                 goto error_free_minor;
 416
 417         cdev_init(&ev_int->handler.chrdev, &iio_event_chrdev_fileops);
 418         ev_int->handler.chrdev.owner = owner;
 419
 420         mutex_init(&ev_int->event_list_lock);
 421         /* discussion point - make this variable? */
 422         ev_int->max_events = 10;
 423         ev_int->current_events = 0;
 424         INIT_LIST_HEAD(&ev_int->det_events.list);
 425         init_waitqueue_head(&ev_int->wait);
 426         ev_int->handler.private = ev_int;
 427         ev_int->handler.flags = 0;
 428
 429         ret = cdev_add(&ev_int->handler.chrdev, ev_int->dev.devt, 1);
 430         if (ret)
 431                 goto error_unreg_device;
 432
 433         return 0;
 434
 435 error_unreg_device:
 436         device_unregister(&ev_int->dev);
 437 error_free_minor:
 438         iio_device_free_chrdev_minor(minor);
 439 error_device_put:
 440         put_device(&ev_int->dev);
 441
 442         return ret;
 443 }
 444
 445 void iio_free_ev_int(struct iio_event_interface *ev_int)
 446 {
 447         device_unregister(&ev_int->dev);
 448         put_device(&ev_int->dev);
 449 }
 450
 451 static int __init iio_dev_init(void)
 452 {
 453         int err;
 454
 455         err = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
 456         if (err < 0)
 457                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
 458                        __FILE__);
 459
 460         return err;
 461 }
 462
 463 static void __exit iio_dev_exit(void)
 464 {
 465         if (iio_devt)
 466                 unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
 467 }
 468
 469 static int __init iio_init(void)
 470 {
 471         int ret;
 472
 473         /* Register sysfs bus */
 474         ret  = bus_register(&iio_bus_type);
 475         if (ret < 0) {
 476                 printk(KERN_ERR
 477                        "%s could not register bus type\n",
 478                         __FILE__);
 479                 goto error_nothing;
 480         }
 481
 482         ret = iio_dev_init();
 483         if (ret < 0)
 484                 goto error_unregister_bus_type;
 485
 486         return 0;
 487
 488 error_unregister_bus_type:
 489         bus_unregister(&iio_bus_type);
 490 error_nothing:
 491         return ret;
 492 }
 493
 494 static void __exit iio_exit(void)
 495 {
 496         iio_dev_exit();
 497         bus_unregister(&iio_bus_type);
 498 }
 499
 500 static int iio_device_register_sysfs(struct iio_dev *dev_info)
 501 {
 502         int ret = 0;
 503
 504         ret = sysfs_create_group(&dev_info->dev.kobj, dev_info->attrs);
 505         if (ret) {
 506                 dev_err(dev_info->dev.parent,
 507                         "Failed to register sysfs hooks\n");
 508                 goto error_ret;
 509         }
 510
 511         if (dev_info->scan_el_attrs) {
 512                 ret = sysfs_create_group(&dev_info->dev.kobj,
 513                                          dev_info->scan_el_attrs);
 514                 if (ret)
 515                         dev_err(&dev_info->dev,
 516                                 "Failed to add sysfs scan els\n");
 517         }
 518
 519 error_ret:
 520         return ret;
 521 }
 522
 523 static void iio_device_unregister_sysfs(struct iio_dev *dev_info)
 524 {
 525         if (dev_info->scan_el_attrs)
 526                 sysfs_remove_group(&dev_info->dev.kobj,
 527                                    dev_info->scan_el_attrs);
 528
 529         sysfs_remove_group(&dev_info->dev.kobj, dev_info->attrs);
 530 }
 531
 532 /* Return a negative errno on failure */
 533 int iio_get_new_idr_val(struct idr *this_idr)
 534 {
 535         int ret;
 536         int val;
 537
 538 idr_again:
 539         if (unlikely(idr_pre_get(this_idr, GFP_KERNEL) == 0))
 540                 return -ENOMEM;
 541
 542         spin_lock(&iio_idr_lock);
 543         ret = idr_get_new(this_idr, NULL, &val);
 544         spin_unlock(&iio_idr_lock);
 545         if (unlikely(ret == -EAGAIN))
 546                 goto idr_again;
 547         else if (unlikely(ret))
 548                 return ret;
 549
 550         return val;
 551 }
 552 EXPORT_SYMBOL(iio_get_new_idr_val);
 553
 554 void iio_free_idr_val(struct idr *this_idr, int id)
 555 {
 556         spin_lock(&iio_idr_lock);
 557         idr_remove(this_idr, id);
 558         spin_unlock(&iio_idr_lock);
 559 }
 560 EXPORT_SYMBOL(iio_free_idr_val);
 561
 562 static int iio_device_register_id(struct iio_dev *dev_info,
 563                                   struct idr *this_idr)
 564 {
 565
 566         dev_info->id = iio_get_new_idr_val(&iio_idr);
 567         if (dev_info->id < 0)
 568                 return dev_info->id;
 569         return 0;
 570 }
 571
 572 static void iio_device_unregister_id(struct iio_dev *dev_info)
 573 {
 574         iio_free_idr_val(&iio_idr, dev_info->id);
 575 }
 576
 577 static inline int __iio_add_event_config_attrs(struct iio_dev *dev_info, int i)
 578 {
 579         int ret;
 580         /*p for adding, q for removing */
 581         struct attribute **attrp, **attrq;
 582
 583         if (dev_info->event_conf_attrs && dev_info->event_conf_attrs[i].attrs) {
 584                 attrp = dev_info->event_conf_attrs[i].attrs;
 585                 while (*attrp) {
 586                         ret =  sysfs_add_file_to_group(&dev_info->dev.kobj,
 587                                                        *attrp,
 588                                                        dev_info
 589                                                        ->event_attrs[i].name);
 590                         if (ret)
 591                                 goto error_ret;
 592                         attrp++;
 593                 }
 594         }
 595         return 0;
 596
 597 error_ret:
 598         attrq = dev_info->event_conf_attrs[i].attrs;
 599         while (attrq != attrp) {
 600                         sysfs_remove_file_from_group(&dev_info->dev.kobj,
 601                                              *attrq,
 602                                              dev_info->event_attrs[i].name);
 603                 attrq++;
 604         }
 605
 606         return ret;
 607 }
 608
 609 static inline int __iio_remove_event_config_attrs(struct iio_dev *dev_info,
 610                                                   int i)
 611 {
 612         struct attribute **attrq;
 613
 614         if (dev_info->event_conf_attrs
 615                 && dev_info->event_conf_attrs[i].attrs) {
 616                 attrq = dev_info->event_conf_attrs[i].attrs;
 617                 while (*attrq) {
 618                         sysfs_remove_file_from_group(&dev_info->dev.kobj,
 619                                                      *attrq,
 620                                                      dev_info
 621                                                      ->event_attrs[i].name);
 622                         attrq++;
 623                 }
 624         }
 625
 626         return 0;
 627 }
 628
 629 static int iio_device_register_eventset(struct iio_dev *dev_info)
 630 {
 631         int ret = 0, i, j;
 632
 633         if (dev_info->num_interrupt_lines == 0)
 634                 return 0;
 635
 636         dev_info->event_interfaces =
 637                 kzalloc(sizeof(struct iio_event_interface)
 638                         *dev_info->num_interrupt_lines,
 639                         GFP_KERNEL);
 640         if (dev_info->event_interfaces == NULL) {
 641                 ret = -ENOMEM;
 642                 goto error_ret;
 643         }
 644
 645         dev_info->interrupts = kzalloc(sizeof(struct iio_interrupt *)
 646                                        *dev_info->num_interrupt_lines,
 647                                        GFP_KERNEL);
 648         if (dev_info->interrupts == NULL) {
 649                 ret = -ENOMEM;
 650                 goto error_free_event_interfaces;
 651         }
 652
 653         for (i = 0; i < dev_info->num_interrupt_lines; i++) {
 654                 dev_info->event_interfaces[i].owner = dev_info->driver_module;
 655
 656                 snprintf(dev_info->event_interfaces[i]._name, 20,
 657                          "%s:event%d",
 658                          dev_name(&dev_info->dev),
 659                          i);
 660
 661                 ret = iio_setup_ev_int(&dev_info->event_interfaces[i],
 662                                        (const char *)(dev_info
 663                                                       ->event_interfaces[i]
 664                                                       ._name),
 665                                        dev_info->driver_module,
 666                                        &dev_info->dev);
 667                 if (ret) {
 668                         dev_err(&dev_info->dev,
 669                                 "Could not get chrdev interface\n");
 670                         goto error_free_setup_ev_ints;
 671                 }
 672
 673                 dev_set_drvdata(&dev_info->event_interfaces[i].dev,
 674                                 (void *)dev_info);
 675                 ret = sysfs_create_group(&dev_info
 676                                         ->event_interfaces[i]
 677                                         .dev.kobj,
 678                                         &dev_info->event_attrs[i]);
 679
 680                 if (ret) {
 681                         dev_err(&dev_info->dev,
 682                                 "Failed to register sysfs for event attrs");
 683                         goto error_remove_sysfs_interfaces;
 684                 }
 685         }
 686
 687         for (i = 0; i < dev_info->num_interrupt_lines; i++) {
 688                 ret = __iio_add_event_config_attrs(dev_info, i);
 689                 if (ret)
 690                         goto error_unregister_config_attrs;
 691         }
 692
 693         return 0;
 694
 695 error_unregister_config_attrs:
 696         for (j = 0; j < i; j++)
 697                 __iio_remove_event_config_attrs(dev_info, i);
 698         i = dev_info->num_interrupt_lines - 1;
 699 error_remove_sysfs_interfaces:
 700         for (j = 0; j < i; j++)
 701                 sysfs_remove_group(&dev_info
 702                                    ->event_interfaces[j].dev.kobj,
 703                                    &dev_info->event_attrs[j]);
 704 error_free_setup_ev_ints:
 705         for (j = 0; j < i; j++)
 706                 iio_free_ev_int(&dev_info->event_interfaces[j]);
 707         kfree(dev_info->interrupts);
 708 error_free_event_interfaces:
 709         kfree(dev_info->event_interfaces);
 710 error_ret:
 711
 712         return ret;
 713 }
 714
 715 static void iio_device_unregister_eventset(struct iio_dev *dev_info)
 716 {
 717         int i;
 718
 719         if (dev_info->num_interrupt_lines == 0)
 720                 return;
 721         for (i = 0; i < dev_info->num_interrupt_lines; i++)
 722                 sysfs_remove_group(&dev_info
 723                                    ->event_interfaces[i].dev.kobj,
 724                                    &dev_info->event_attrs[i]);
 725
 726         for (i = 0; i < dev_info->num_interrupt_lines; i++)
 727                 iio_free_ev_int(&dev_info->event_interfaces[i]);
 728         kfree(dev_info->interrupts);
 729         kfree(dev_info->event_interfaces);
 730 }
 731
 732 static void iio_dev_release(struct device *device)
 733 {
 734         struct iio_dev *dev = to_iio_dev(device);
 735
 736         iio_put();
 737         kfree(dev);
 738 }
 739
 740 static struct device_type iio_dev_type = {
 741         .name = "iio_device",
 742         .release = iio_dev_release,
 743 };
 744
 745 struct iio_dev *iio_allocate_device(void)
 746 {
 747         struct iio_dev *dev = kzalloc(sizeof *dev, GFP_KERNEL);
 748
 749         if (dev) {
 750                 dev->dev.type = &iio_dev_type;
 751                 dev->dev.bus = &iio_bus_type;
 752                 device_initialize(&dev->dev);
 753                 dev_set_drvdata(&dev->dev, (void *)dev);
 754                 mutex_init(&dev->mlock);
 755                 iio_get();
 756         }
 757
 758         return dev;
 759 }
 760 EXPORT_SYMBOL(iio_allocate_device);
 761
 762 void iio_free_device(struct iio_dev *dev)
 763 {
 764         if (dev)
 765                 iio_put_device(dev);
 766 }
 767 EXPORT_SYMBOL(iio_free_device);
 768
 769 int iio_device_register(struct iio_dev *dev_info)
 770 {
 771         int ret;
 772
 773         ret = iio_device_register_id(dev_info, &iio_idr);
 774         if (ret) {
 775                 dev_err(&dev_info->dev, "Failed to get id\n");
 776                 goto error_ret;
 777         }
 778         dev_set_name(&dev_info->dev, "device%d", dev_info->id);
 779
 780         ret = device_add(&dev_info->dev);
 781         if (ret)
 782                 goto error_free_idr;
 783         ret = iio_device_register_sysfs(dev_info);
 784         if (ret) {
 785                 dev_err(dev_info->dev.parent,
 786                         "Failed to register sysfs interfaces\n");
 787                 goto error_del_device;
 788         }
 789         ret = iio_device_register_eventset(dev_info);
 790         if (ret) {
 791                 dev_err(dev_info->dev.parent,
 792                         "Failed to register event set\n");
 793                 goto error_free_sysfs;
 794         }
 795         if (dev_info->modes & INDIO_RING_TRIGGERED)
 796                 iio_device_register_trigger_consumer(dev_info);
 797
 798         return 0;
 799
 800 error_free_sysfs:
 801         iio_device_unregister_sysfs(dev_info);
 802 error_del_device:
 803         device_del(&dev_info->dev);
 804 error_free_idr:
 805         iio_device_unregister_id(dev_info);
 806 error_ret:
 807         return ret;
 808 }
 809 EXPORT_SYMBOL(iio_device_register);
 810
 811 void iio_device_unregister(struct iio_dev *dev_info)
 812 {
 813         if (dev_info->modes & INDIO_RING_TRIGGERED)
 814                 iio_device_unregister_trigger_consumer(dev_info);
 815         iio_device_unregister_eventset(dev_info);
 816         iio_device_unregister_sysfs(dev_info);
 817         iio_device_unregister_id(dev_info);
 818         device_unregister(&dev_info->dev);
 819 }
 820 EXPORT_SYMBOL(iio_device_unregister);
 821
 822 void iio_put(void)
 823 {
 824         module_put(THIS_MODULE);
 825 }
 826
 827 void iio_get(void)
 828 {
 829         __module_get(THIS_MODULE);
 830 }
 831
 832 subsys_initcall(iio_init);
 833 module_exit(iio_exit);
 834
 835 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 836 MODULE_DESCRIPTION("Industrial I/O core");
 837 MODULE_LICENSE("GPL");