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/cdev.h>
  22 #include "iio.h"
  23 #include "trigger_consumer.h"
  24
  25 #define IIO_ID_PREFIX "device"
  26 #define IIO_ID_FORMAT IIO_ID_PREFIX "%d"
  27
  28 /* IDR to assign each registered device a unique id*/
  29 static DEFINE_IDR(iio_idr);
  30
  31 /* IDR for general event identifiers */
  32 static DEFINE_IDR(iio_event_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 static char *iio_devnode(struct device *dev, mode_t *mode)
  43 {
  44         return kasprintf(GFP_KERNEL, "iio/%s", dev_name(dev));
  45 }
  46
  47 struct class iio_class = {
  48         .name = "iio",
  49         .devnode = iio_devnode,
  50 };
  51 EXPORT_SYMBOL(iio_class);
  52
  53 void __iio_change_event(struct iio_detected_event_list *ev,
  54                         int ev_code,
  55                         s64 timestamp)
  56 {
  57         ev->ev.id = ev_code;
  58         ev->ev.timestamp = timestamp;
  59 }
  60 EXPORT_SYMBOL(__iio_change_event);
  61
  62 /* Used both in the interrupt line put events and the ring buffer ones */
  63
  64 /* Note that in it's current form someone has to be listening before events
  65  * are queued. Hence a client MUST open the chrdev before the ring buffer is
  66  * switched on.
  67  */
  68  int __iio_push_event(struct iio_event_interface *ev_int,
  69                      int ev_code,
  70                      s64 timestamp,
  71                      struct iio_shared_ev_pointer *
  72                      shared_pointer_p)
  73 {
  74         struct iio_detected_event_list *ev;
  75         int ret = 0;
  76
  77         /* Does anyone care? */
  78         mutex_lock(&ev_int->event_list_lock);
  79         if (test_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags)) {
  80                 if (ev_int->current_events == ev_int->max_events)
  81                         return 0;
  82                 ev = kmalloc(sizeof(*ev), GFP_KERNEL);
  83                 if (ev == NULL) {
  84                         ret = -ENOMEM;
  85                         goto error_ret;
  86                 }
  87                 ev->ev.id = ev_code;
  88                 ev->ev.timestamp = timestamp;
  89                 ev->shared_pointer = shared_pointer_p;
  90                 if (ev->shared_pointer)
  91                         shared_pointer_p->ev_p = ev;
  92
  93                 list_add_tail(&ev->list, &ev_int->det_events.list);
  94                 ev_int->current_events++;
  95                 mutex_unlock(&ev_int->event_list_lock);
  96                 wake_up_interruptible(&ev_int->wait);
  97         } else
  98                 mutex_unlock(&ev_int->event_list_lock);
  99
 100 error_ret:
 101         return ret;
 102 }
 103 EXPORT_SYMBOL(__iio_push_event);
 104
 105 int iio_push_event(struct iio_dev *dev_info,
 106                    int ev_line,
 107                    int ev_code,
 108                    s64 timestamp)
 109 {
 110         return __iio_push_event(&dev_info->event_interfaces[ev_line],
 111                                 ev_code, timestamp, NULL);
 112 }
 113 EXPORT_SYMBOL(iio_push_event);
 114
 115 /* Generic interrupt line interrupt handler */
 116 irqreturn_t iio_interrupt_handler(int irq, void *_int_info)
 117 {
 118         struct iio_interrupt *int_info = _int_info;
 119         struct iio_dev *dev_info = int_info->dev_info;
 120         struct iio_event_handler_list *p;
 121         s64 time_ns;
 122         unsigned long flags;
 123
 124         spin_lock_irqsave(&int_info->ev_list_lock, flags);
 125         if (list_empty(&int_info->ev_list)) {
 126                 spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
 127                 return IRQ_NONE;
 128         }
 129
 130         time_ns = iio_get_time_ns();
 131         /* detect single element list*/
 132         if (list_is_singular(&int_info->ev_list)) {
 133                 disable_irq_nosync(irq);
 134                 p = list_first_entry(&int_info->ev_list,
 135                                      struct iio_event_handler_list,
 136                                      list);
 137                 /* single event handler - maybe shared */
 138                 p->handler(dev_info, 1, time_ns, !(p->refcount > 1));
 139         } else
 140                 list_for_each_entry(p, &int_info->ev_list, list) {
 141                         disable_irq_nosync(irq);
 142                         p->handler(dev_info, 1, time_ns, 0);
 143                 }
 144         spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
 145
 146         return IRQ_HANDLED;
 147 }
 148
 149 static struct iio_interrupt *iio_allocate_interrupt(void)
 150 {
 151         struct iio_interrupt *i = kmalloc(sizeof *i, GFP_KERNEL);
 152         if (i) {
 153                 spin_lock_init(&i->ev_list_lock);
 154                 INIT_LIST_HEAD(&i->ev_list);
 155         }
 156         return i;
 157 }
 158
 159 /* Confirming the validity of supplied irq is left to drivers.*/
 160 int iio_register_interrupt_line(unsigned int irq,
 161                                 struct iio_dev *dev_info,
 162                                 int line_number,
 163                                 unsigned long type,
 164                                 const char *name)
 165 {
 166         int ret;
 167
 168         dev_info->interrupts[line_number] = iio_allocate_interrupt();
 169         if (dev_info->interrupts[line_number] == NULL) {
 170                 ret = -ENOMEM;
 171                 goto error_ret;
 172         }
 173         dev_info->interrupts[line_number]->line_number = line_number;
 174         dev_info->interrupts[line_number]->irq = irq;
 175         dev_info->interrupts[line_number]->dev_info = dev_info;
 176
 177         /* Possibly only request on demand?
 178          * Can see this may complicate the handling of interrupts.
 179          * However, with this approach we might end up handling lots of
 180          * events no-one cares about.*/
 181         ret = request_irq(irq,
 182                           &iio_interrupt_handler,
 183                           type,
 184                           name,
 185                           dev_info->interrupts[line_number]);
 186
 187 error_ret:
 188         return ret;
 189 }
 190 EXPORT_SYMBOL(iio_register_interrupt_line);
 191
 192 /* This turns up an awful lot */
 193 ssize_t iio_read_const_attr(struct device *dev,
 194                             struct device_attribute *attr,
 195                             char *buf)
 196 {
 197         return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
 198 }
 199 EXPORT_SYMBOL(iio_read_const_attr);
 200
 201 /* Before this runs the interrupt generator must have been disabled */
 202 void iio_unregister_interrupt_line(struct iio_dev *dev_info, int line_number)
 203 {
 204         /* make sure the interrupt handlers are all done */
 205         flush_scheduled_work();
 206         free_irq(dev_info->interrupts[line_number]->irq,
 207                  dev_info->interrupts[line_number]);
 208         kfree(dev_info->interrupts[line_number]);
 209 }
 210 EXPORT_SYMBOL(iio_unregister_interrupt_line);
 211
 212 /* Reference counted add and remove */
 213 void iio_add_event_to_list(struct iio_event_handler_list *el,
 214                           struct list_head *head)
 215 {
 216         unsigned long flags;
 217         struct iio_interrupt *inter = to_iio_interrupt(head);
 218
 219         /* take mutex to protect this element */
 220         mutex_lock(&el->exist_lock);
 221         if (el->refcount == 0) {
 222                 /* Take the event list spin lock */
 223                 spin_lock_irqsave(&inter->ev_list_lock, flags);
 224                 list_add(&el->list, head);
 225                 spin_unlock_irqrestore(&inter->ev_list_lock, flags);
 226         }
 227         el->refcount++;
 228         mutex_unlock(&el->exist_lock);
 229 }
 230 EXPORT_SYMBOL(iio_add_event_to_list);
 231
 232 void iio_remove_event_from_list(struct iio_event_handler_list *el,
 233                                struct list_head *head)
 234 {
 235         unsigned long flags;
 236         struct iio_interrupt *inter = to_iio_interrupt(head);
 237
 238         mutex_lock(&el->exist_lock);
 239         el->refcount--;
 240         if (el->refcount == 0) {
 241                 /* Take the event list spin lock */
 242                 spin_lock_irqsave(&inter->ev_list_lock, flags);
 243                 list_del_init(&el->list);
 244                 spin_unlock_irqrestore(&inter->ev_list_lock, flags);
 245         }
 246         mutex_unlock(&el->exist_lock);
 247 }
 248 EXPORT_SYMBOL(iio_remove_event_from_list);
 249
 250 ssize_t iio_event_chrdev_read(struct file *filep,
 251                               char *buf,
 252                               size_t count,
 253                               loff_t *f_ps)
 254 {
 255         struct iio_event_interface *ev_int = filep->private_data;
 256         struct iio_detected_event_list *el;
 257         int ret;
 258         size_t len;
 259
 260         mutex_lock(&ev_int->event_list_lock);
 261         if (list_empty(&ev_int->det_events.list)) {
 262                 if (filep->f_flags & O_NONBLOCK) {
 263                         ret = -EAGAIN;
 264                         goto error_mutex_unlock;
 265                 }
 266                 mutex_unlock(&ev_int->event_list_lock);
 267                 /* Blocking on device; waiting for something to be there */
 268                 ret = wait_event_interruptible(ev_int->wait,
 269                                                !list_empty(&ev_int
 270                                                            ->det_events.list));
 271                 if (ret)
 272                         goto error_ret;
 273                 /* Single access device so noone else can get the data */
 274                 mutex_lock(&ev_int->event_list_lock);
 275         }
 276
 277         el = list_first_entry(&ev_int->det_events.list,
 278                               struct iio_detected_event_list,
 279                               list);
 280         len = sizeof el->ev;
 281         if (copy_to_user(buf, &(el->ev), len)) {
 282                 ret = -EFAULT;
 283                 goto error_mutex_unlock;
 284         }
 285         list_del(&el->list);
 286         ev_int->current_events--;
 287         mutex_unlock(&ev_int->event_list_lock);
 288         /*
 289          * Possible concurency issue if an update of this event is on its way
 290          * through. May lead to new even being removed whilst the reported event
 291          * was the unescalated event. In typical use case this is not a problem
 292          * as userspace will say read half the buffer due to a 50% full event
 293          * which would make the correct 100% full incorrect anyway.
 294          */
 295         spin_lock(&el->shared_pointer->lock);
 296         if (el->shared_pointer)
 297                 (el->shared_pointer->ev_p) = NULL;
 298         spin_unlock(&el->shared_pointer->lock);
 299
 300         kfree(el);
 301
 302         return len;
 303
 304 error_mutex_unlock:
 305         mutex_unlock(&ev_int->event_list_lock);
 306 error_ret:
 307
 308         return ret;
 309 }
 310
 311 int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 312 {
 313         struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
 314         struct iio_event_interface *ev_int = hand->private;
 315         struct iio_detected_event_list *el, *t;
 316
 317         mutex_lock(&ev_int->event_list_lock);
 318         clear_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags);
 319         /*
 320          * In order to maintain a clean state for reopening,
 321          * clear out any awaiting events. The mask will prevent
 322          * any new __iio_push_event calls running.
 323          */
 324         list_for_each_entry_safe(el, t, &ev_int->det_events.list, list) {
 325                 list_del(&el->list);
 326                 kfree(el);
 327         }
 328         mutex_unlock(&ev_int->event_list_lock);
 329
 330         return 0;
 331 }
 332
 333 int iio_event_chrdev_open(struct inode *inode, struct file *filep)
 334 {
 335         struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
 336         struct iio_event_interface *ev_int = hand->private;
 337
 338         mutex_lock(&ev_int->event_list_lock);
 339         if (test_and_set_bit(IIO_BUSY_BIT_POS, &hand->flags)) {
 340                 fops_put(filep->f_op);
 341                 mutex_unlock(&ev_int->event_list_lock);
 342                 return -EBUSY;
 343         }
 344         filep->private_data = hand->private;
 345         mutex_unlock(&ev_int->event_list_lock);
 346
 347         return 0;
 348 }
 349
 350 static const struct file_operations iio_event_chrdev_fileops = {
 351         .read =  iio_event_chrdev_read,
 352         .release = iio_event_chrdev_release,
 353         .open = iio_event_chrdev_open,
 354         .owner = THIS_MODULE,
 355 };
 356
 357 static void iio_event_dev_release(struct device *dev)
 358 {
 359         struct iio_event_interface *ev_int
 360                 = container_of(dev, struct iio_event_interface, dev);
 361         cdev_del(&ev_int->handler.chrdev);
 362         iio_device_free_chrdev_minor(MINOR(dev->devt));
 363 };
 364
 365 static struct device_type iio_event_type = {
 366         .release = iio_event_dev_release,
 367 };
 368
 369 int iio_device_get_chrdev_minor(void)
 370 {
 371         int ret, val;
 372
 373 idr_again:
 374         if (unlikely(idr_pre_get(&iio_chrdev_idr, GFP_KERNEL) == 0))
 375                 return -ENOMEM;
 376         spin_lock(&iio_idr_lock);
 377         ret = idr_get_new(&iio_chrdev_idr, NULL, &val);
 378         spin_unlock(&iio_idr_lock);
 379         if (unlikely(ret == -EAGAIN))
 380                 goto idr_again;
 381         else if (unlikely(ret))
 382                 return ret;
 383         if (val > IIO_DEV_MAX)
 384                 return -ENOMEM;
 385         return val;
 386 }
 387
 388 void iio_device_free_chrdev_minor(int val)
 389 {
 390         spin_lock(&iio_idr_lock);
 391         idr_remove(&iio_chrdev_idr, val);
 392         spin_unlock(&iio_idr_lock);
 393 }
 394
 395 int iio_setup_ev_int(struct iio_event_interface *ev_int,
 396                      const char *name,
 397                      struct module *owner,
 398                      struct device *dev)
 399 {
 400         int ret, minor;
 401
 402         ev_int->dev.class = &iio_class;
 403         ev_int->dev.parent = dev;
 404         ev_int->dev.type = &iio_event_type;
 405         device_initialize(&ev_int->dev);
 406
 407         minor = iio_device_get_chrdev_minor();
 408         if (minor < 0) {
 409                 ret = minor;
 410                 goto error_device_put;
 411         }
 412         ev_int->dev.devt = MKDEV(MAJOR(iio_devt), minor);
 413         dev_set_name(&ev_int->dev, "%s", name);
 414
 415         ret = device_add(&ev_int->dev);
 416         if (ret)
 417                 goto error_free_minor;
 418
 419         cdev_init(&ev_int->handler.chrdev, &iio_event_chrdev_fileops);
 420         ev_int->handler.chrdev.owner = owner;
 421
 422         mutex_init(&ev_int->event_list_lock);
 423         /* discussion point - make this variable? */
 424         ev_int->max_events = 10;
 425         ev_int->current_events = 0;
 426         INIT_LIST_HEAD(&ev_int->det_events.list);
 427         init_waitqueue_head(&ev_int->wait);
 428         ev_int->handler.private = ev_int;
 429         ev_int->handler.flags = 0;
 430
 431         ret = cdev_add(&ev_int->handler.chrdev, ev_int->dev.devt, 1);
 432         if (ret)
 433                 goto error_unreg_device;
 434
 435         return 0;
 436
 437 error_unreg_device:
 438         device_unregister(&ev_int->dev);
 439 error_free_minor:
 440         iio_device_free_chrdev_minor(minor);
 441 error_device_put:
 442         put_device(&ev_int->dev);
 443
 444         return ret;
 445 }
 446
 447 void iio_free_ev_int(struct iio_event_interface *ev_int)
 448 {
 449         device_unregister(&ev_int->dev);
 450         put_device(&ev_int->dev);
 451 }
 452
 453 static int __init iio_dev_init(void)
 454 {
 455         int err;
 456
 457         err = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
 458         if (err < 0)
 459                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
 460                        __FILE__);
 461
 462         return err;
 463 }
 464
 465 static void __exit iio_dev_exit(void)
 466 {
 467         if (iio_devt)
 468                 unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
 469 }
 470
 471 static int __init iio_init(void)
 472 {
 473         int ret;
 474
 475         /* Create sysfs class */
 476         ret  = class_register(&iio_class);
 477         if (ret < 0) {
 478                 printk(KERN_ERR
 479                        "%s could not create sysfs class\n",
 480                         __FILE__);
 481                 goto error_nothing;
 482         }
 483
 484         ret = iio_dev_init();
 485         if (ret < 0)
 486                 goto error_unregister_class;
 487
 488         return 0;
 489
 490 error_unregister_class:
 491         class_unregister(&iio_class);
 492 error_nothing:
 493         return ret;
 494 }
 495
 496 static void __exit iio_exit(void)
 497 {
 498         iio_dev_exit();
 499         class_unregister(&iio_class);
 500 }
 501
 502 static int iio_device_register_sysfs(struct iio_dev *dev_info)
 503 {
 504         int ret = 0;
 505
 506         ret = sysfs_create_group(&dev_info->dev.kobj, dev_info->attrs);
 507         if (ret) {
 508                 dev_err(dev_info->dev.parent,
 509                         "Failed to register sysfs hooks\n");
 510                 goto error_ret;
 511         }
 512
 513         if (dev_info->scan_el_attrs) {
 514                 ret = sysfs_create_group(&dev_info->dev.kobj,
 515                                          dev_info->scan_el_attrs);
 516                 if (ret)
 517                         dev_err(&dev_info->dev,
 518                                 "Failed to add sysfs scan els\n");
 519         }
 520
 521 error_ret:
 522         return ret;
 523 }
 524
 525 static void iio_device_unregister_sysfs(struct iio_dev *dev_info)
 526 {
 527         if (dev_info->scan_el_attrs)
 528                 sysfs_remove_group(&dev_info->dev.kobj,
 529                                    dev_info->scan_el_attrs);
 530
 531         sysfs_remove_group(&dev_info->dev.kobj, dev_info->attrs);
 532 }
 533
 534 int iio_get_new_idr_val(struct idr *this_idr)
 535 {
 536         int ret;
 537         int val;
 538
 539 idr_again:
 540         if (unlikely(idr_pre_get(this_idr, GFP_KERNEL) == 0))
 541                 return -ENOMEM;
 542
 543         spin_lock(&iio_idr_lock);
 544         ret = idr_get_new(this_idr, NULL, &val);
 545         spin_unlock(&iio_idr_lock);
 546         if (unlikely(ret == -EAGAIN))
 547                 goto idr_again;
 548         else if (unlikely(ret))
 549                 return ret;
 550
 551         return val;
 552 }
 553 EXPORT_SYMBOL(iio_get_new_idr_val);
 554
 555 void iio_free_idr_val(struct idr *this_idr, int id)
 556 {
 557         spin_lock(&iio_idr_lock);
 558         idr_remove(this_idr, id);
 559         spin_unlock(&iio_idr_lock);
 560 }
 561 EXPORT_SYMBOL(iio_free_idr_val);
 562
 563 static int iio_device_register_id(struct iio_dev *dev_info,
 564                                   struct idr *this_idr)
 565 {
 566
 567         dev_info->id = iio_get_new_idr_val(&iio_idr);
 568         if (dev_info->id < 0)
 569                 return dev_info->id;
 570         return 0;
 571 }
 572
 573 static void iio_device_unregister_id(struct iio_dev *dev_info)
 574 {
 575         iio_free_idr_val(&iio_idr, dev_info->id);
 576 }
 577
 578 static inline int __iio_add_event_config_attrs(struct iio_dev *dev_info, int i)
 579 {
 580         int ret;
 581         /*p for adding, q for removing */
 582         struct attribute **attrp, **attrq;
 583
 584         if (dev_info->event_conf_attrs && dev_info->event_conf_attrs[i].attrs) {
 585                 attrp = dev_info->event_conf_attrs[i].attrs;
 586                 while (*attrp) {
 587                         ret =  sysfs_add_file_to_group(&dev_info->dev.kobj,
 588                                                        *attrp,
 589                                                        dev_info
 590                                                        ->event_attrs[i].name);
 591                         if (ret)
 592                                 goto error_ret;
 593                         attrp++;
 594                 }
 595         }
 596         return 0;
 597
 598 error_ret:
 599         attrq = dev_info->event_conf_attrs[i].attrs;
 600         while (attrq != attrp) {
 601                         sysfs_remove_file_from_group(&dev_info->dev.kobj,
 602                                              *attrq,
 603                                              dev_info->event_attrs[i].name);
 604                 attrq++;
 605         }
 606
 607         return ret;
 608 }
 609
 610 static inline int __iio_remove_event_config_attrs(struct iio_dev *dev_info,
 611                                                   int i)
 612 {
 613         struct attribute **attrq;
 614
 615         if (dev_info->event_conf_attrs
 616                 && dev_info->event_conf_attrs[i].attrs) {
 617                 attrq = dev_info->event_conf_attrs[i].attrs;
 618                 while (*attrq) {
 619                         sysfs_remove_file_from_group(&dev_info->dev.kobj,
 620                                                      *attrq,
 621                                                      dev_info
 622                                                      ->event_attrs[i].name);
 623                         attrq++;
 624                 }
 625         }
 626
 627         return 0;
 628 }
 629
 630 static int iio_device_register_eventset(struct iio_dev *dev_info)
 631 {
 632         int ret = 0, i, j;
 633
 634         if (dev_info->num_interrupt_lines == 0)
 635                 return 0;
 636
 637         dev_info->event_interfaces =
 638                 kzalloc(sizeof(struct iio_event_interface)
 639                         *dev_info->num_interrupt_lines,
 640                         GFP_KERNEL);
 641         if (dev_info->event_interfaces == NULL) {
 642                 ret = -ENOMEM;
 643                 goto error_ret;
 644         }
 645
 646         dev_info->interrupts = kzalloc(sizeof(struct iio_interrupt *)
 647                                        *dev_info->num_interrupt_lines,
 648                                        GFP_KERNEL);
 649         if (dev_info->interrupts == NULL) {
 650                 ret = -ENOMEM;
 651                 goto error_free_event_interfaces;
 652         }
 653
 654         for (i = 0; i < dev_info->num_interrupt_lines; i++) {
 655                 dev_info->event_interfaces[i].owner = dev_info->driver_module;
 656                 ret = iio_get_new_idr_val(&iio_event_idr);
 657                 if (ret)
 658                         goto error_free_setup_ev_ints;
 659                 else
 660                         dev_info->event_interfaces[i].id = ret;
 661
 662                 snprintf(dev_info->event_interfaces[i]._name, 20,
 663                          "event_line%d",
 664                         dev_info->event_interfaces[i].id);
 665
 666                 ret = iio_setup_ev_int(&dev_info->event_interfaces[i],
 667                                        (const char *)(dev_info
 668                                                       ->event_interfaces[i]
 669                                                       ._name),
 670                                        dev_info->driver_module,
 671                                        &dev_info->dev);
 672                 if (ret) {
 673                         dev_err(&dev_info->dev,
 674                                 "Could not get chrdev interface\n");
 675                         iio_free_idr_val(&iio_event_idr,
 676                                          dev_info->event_interfaces[i].id);
 677                         goto error_free_setup_ev_ints;
 678                 }
 679         }
 680
 681         for (i = 0; i < dev_info->num_interrupt_lines; i++) {
 682                 snprintf(dev_info->event_interfaces[i]._attrname, 20,
 683                         "event_line%d_sources", i);
 684                 dev_info->event_attrs[i].name
 685                         = (const char *)
 686                         (dev_info->event_interfaces[i]._attrname);
 687                 ret = sysfs_create_group(&dev_info->dev.kobj,
 688                                          &dev_info->event_attrs[i]);
 689                 if (ret) {
 690                         dev_err(&dev_info->dev,
 691                                 "Failed to register sysfs for event attrs");
 692                         goto error_remove_sysfs_interfaces;
 693                 }
 694         }
 695
 696         for (i = 0; i < dev_info->num_interrupt_lines; i++) {
 697                 ret = __iio_add_event_config_attrs(dev_info, i);
 698                 if (ret)
 699                         goto error_unregister_config_attrs;
 700         }
 701
 702         return 0;
 703
 704 error_unregister_config_attrs:
 705         for (j = 0; j < i; j++)
 706                 __iio_remove_event_config_attrs(dev_info, i);
 707         i = dev_info->num_interrupt_lines - 1;
 708 error_remove_sysfs_interfaces:
 709         for (j = 0; j < i; j++)
 710                 sysfs_remove_group(&dev_info->dev.kobj,
 711                                    &dev_info->event_attrs[j]);
 712         i = dev_info->num_interrupt_lines - 1;
 713 error_free_setup_ev_ints:
 714         for (j = 0; j < i; j++) {
 715                 iio_free_idr_val(&iio_event_idr,
 716                                  dev_info->event_interfaces[i].id);
 717                 iio_free_ev_int(&dev_info->event_interfaces[j]);
 718         }
 719         kfree(dev_info->interrupts);
 720 error_free_event_interfaces:
 721         kfree(dev_info->event_interfaces);
 722 error_ret:
 723
 724         return ret;
 725 }
 726
 727 static void iio_device_unregister_eventset(struct iio_dev *dev_info)
 728 {
 729         int i;
 730
 731         if (dev_info->num_interrupt_lines == 0)
 732                 return;
 733         for (i = 0; i < dev_info->num_interrupt_lines; i++)
 734                 sysfs_remove_group(&dev_info->dev.kobj,
 735                                    &dev_info->event_attrs[i]);
 736
 737         for (i = 0; i < dev_info->num_interrupt_lines; i++) {
 738                 iio_free_idr_val(&iio_event_idr,
 739                                  dev_info->event_interfaces[i].id);
 740                 iio_free_ev_int(&dev_info->event_interfaces[i]);
 741         }
 742         kfree(dev_info->interrupts);
 743         kfree(dev_info->event_interfaces);
 744 }
 745
 746 static void iio_dev_release(struct device *device)
 747 {
 748         struct iio_dev *dev = to_iio_dev(device);
 749
 750         iio_put();
 751         kfree(dev);
 752 }
 753
 754 static struct device_type iio_dev_type = {
 755         .name = "iio_device",
 756         .release = iio_dev_release,
 757 };
 758
 759 struct iio_dev *iio_allocate_device(void)
 760 {
 761         struct iio_dev *dev = kzalloc(sizeof *dev, GFP_KERNEL);
 762
 763         if (dev) {
 764                 dev->dev.type = &iio_dev_type;
 765                 dev->dev.class = &iio_class;
 766                 device_initialize(&dev->dev);
 767                 dev_set_drvdata(&dev->dev, (void *)dev);
 768                 mutex_init(&dev->mlock);
 769                 iio_get();
 770         }
 771
 772         return dev;
 773 }
 774 EXPORT_SYMBOL(iio_allocate_device);
 775
 776 void iio_free_device(struct iio_dev *dev)
 777 {
 778         if (dev)
 779                 iio_put_device(dev);
 780 }
 781 EXPORT_SYMBOL(iio_free_device);
 782
 783 int iio_device_register(struct iio_dev *dev_info)
 784 {
 785         int ret;
 786
 787         ret = iio_device_register_id(dev_info, &iio_idr);
 788         if (ret) {
 789                 dev_err(&dev_info->dev, "Failed to get id\n");
 790                 goto error_ret;
 791         }
 792         dev_set_name(&dev_info->dev, "device%d", dev_info->id);
 793
 794         ret = device_add(&dev_info->dev);
 795         if (ret)
 796                 goto error_free_idr;
 797         ret = iio_device_register_sysfs(dev_info);
 798         if (ret) {
 799                 dev_err(dev_info->dev.parent,
 800                         "Failed to register sysfs interfaces\n");
 801                 goto error_del_device;
 802         }
 803         ret = iio_device_register_eventset(dev_info);
 804         if (ret) {
 805                 dev_err(dev_info->dev.parent,
 806                         "Failed to register event set \n");
 807                 goto error_free_sysfs;
 808         }
 809         if (dev_info->modes & INDIO_RING_TRIGGERED)
 810                 iio_device_register_trigger_consumer(dev_info);
 811
 812         return 0;
 813
 814 error_free_sysfs:
 815         iio_device_unregister_sysfs(dev_info);
 816 error_del_device:
 817         device_del(&dev_info->dev);
 818 error_free_idr:
 819         iio_device_unregister_id(dev_info);
 820 error_ret:
 821         return ret;
 822 }
 823 EXPORT_SYMBOL(iio_device_register);
 824
 825 void iio_device_unregister(struct iio_dev *dev_info)
 826 {
 827         if (dev_info->modes & INDIO_RING_TRIGGERED)
 828                 iio_device_unregister_trigger_consumer(dev_info);
 829         iio_device_unregister_eventset(dev_info);
 830         iio_device_unregister_sysfs(dev_info);
 831         iio_device_unregister_id(dev_info);
 832         device_unregister(&dev_info->dev);
 833 }
 834 EXPORT_SYMBOL(iio_device_unregister);
 835
 836 void iio_put(void)
 837 {
 838         module_put(THIS_MODULE);
 839 }
 840
 841 void iio_get(void)
 842 {
 843         __module_get(THIS_MODULE);
 844 }
 845
 846 subsys_initcall(iio_init);
 847 module_exit(iio_exit);
 848
 849 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 850 MODULE_DESCRIPTION("Industrial I/O core");
 851 MODULE_LICENSE("GPL");