1 /* The industrial I/O core
3 * Copyright (c) 2008 Jonathan Cameron
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.
9 * Based on elements of hwmon and input subsystems.
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>
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>
26 #include "trigger_consumer.h"
28 #define IIO_ID_PREFIX "device"
29 #define IIO_ID_FORMAT IIO_ID_PREFIX "%d"
31 /* IDR to assign each registered device a unique id*/
32 static DEFINE_IDR(iio_idr);
34 /* IDR for general event identifiers */
35 static DEFINE_IDR(iio_event_idr);
36 /* IDR to allocate character device minor numbers */
37 static DEFINE_IDR(iio_chrdev_idr);
38 /* Lock used to protect both of the above */
39 static DEFINE_SPINLOCK(iio_idr_lock);
42 EXPORT_SYMBOL(iio_devt);
44 #define IIO_DEV_MAX 256
45 static char *iio_devnode(struct device *dev, mode_t *mode)
47 return kasprintf(GFP_KERNEL, "iio/%s", dev_name(dev));
50 struct class iio_class = {
52 .devnode = iio_devnode,
54 EXPORT_SYMBOL(iio_class);
56 void __iio_change_event(struct iio_detected_event_list *ev,
61 ev->ev.timestamp = timestamp;
63 EXPORT_SYMBOL(__iio_change_event);
65 /* Used both in the interrupt line put events and the ring buffer ones */
67 /* Note that in it's current form someone has to be listening before events
68 * are queued. Hence a client MUST open the chrdev before the ring buffer is
71 int __iio_push_event(struct iio_event_interface *ev_int,
74 struct iio_shared_ev_pointer *
77 struct iio_detected_event_list *ev;
80 /* Does anyone care? */
81 mutex_lock(&ev_int->event_list_lock);
82 if (test_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags)) {
83 if (ev_int->current_events == ev_int->max_events) {
84 mutex_unlock(&ev_int->event_list_lock);
87 ev = kmalloc(sizeof(*ev), GFP_KERNEL);
90 mutex_unlock(&ev_int->event_list_lock);
94 ev->ev.timestamp = timestamp;
95 ev->shared_pointer = shared_pointer_p;
96 if (ev->shared_pointer)
97 shared_pointer_p->ev_p = ev;
99 list_add_tail(&ev->list, &ev_int->det_events.list);
100 ev_int->current_events++;
101 mutex_unlock(&ev_int->event_list_lock);
102 wake_up_interruptible(&ev_int->wait);
104 mutex_unlock(&ev_int->event_list_lock);
109 EXPORT_SYMBOL(__iio_push_event);
111 int iio_push_event(struct iio_dev *dev_info,
116 return __iio_push_event(&dev_info->event_interfaces[ev_line],
117 ev_code, timestamp, NULL);
119 EXPORT_SYMBOL(iio_push_event);
121 /* Generic interrupt line interrupt handler */
122 static irqreturn_t iio_interrupt_handler(int irq, void *_int_info)
124 struct iio_interrupt *int_info = _int_info;
125 struct iio_dev *dev_info = int_info->dev_info;
126 struct iio_event_handler_list *p;
130 spin_lock_irqsave(&int_info->ev_list_lock, flags);
131 if (list_empty(&int_info->ev_list)) {
132 spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
136 time_ns = iio_get_time_ns();
137 /* detect single element list*/
138 if (list_is_singular(&int_info->ev_list)) {
139 disable_irq_nosync(irq);
140 p = list_first_entry(&int_info->ev_list,
141 struct iio_event_handler_list,
143 /* single event handler - maybe shared */
144 p->handler(dev_info, 1, time_ns, !(p->refcount > 1));
146 list_for_each_entry(p, &int_info->ev_list, list) {
147 disable_irq_nosync(irq);
148 p->handler(dev_info, 1, time_ns, 0);
150 spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
155 static struct iio_interrupt *iio_allocate_interrupt(void)
157 struct iio_interrupt *i = kmalloc(sizeof *i, GFP_KERNEL);
159 spin_lock_init(&i->ev_list_lock);
160 INIT_LIST_HEAD(&i->ev_list);
165 /* Confirming the validity of supplied irq is left to drivers.*/
166 int iio_register_interrupt_line(unsigned int irq,
167 struct iio_dev *dev_info,
174 dev_info->interrupts[line_number] = iio_allocate_interrupt();
175 if (dev_info->interrupts[line_number] == NULL) {
179 dev_info->interrupts[line_number]->line_number = line_number;
180 dev_info->interrupts[line_number]->irq = irq;
181 dev_info->interrupts[line_number]->dev_info = dev_info;
183 /* Possibly only request on demand?
184 * Can see this may complicate the handling of interrupts.
185 * However, with this approach we might end up handling lots of
186 * events no-one cares about.*/
187 ret = request_irq(irq,
188 &iio_interrupt_handler,
191 dev_info->interrupts[line_number]);
196 EXPORT_SYMBOL(iio_register_interrupt_line);
198 /* This turns up an awful lot */
199 ssize_t iio_read_const_attr(struct device *dev,
200 struct device_attribute *attr,
203 return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
205 EXPORT_SYMBOL(iio_read_const_attr);
207 /* Before this runs the interrupt generator must have been disabled */
208 void iio_unregister_interrupt_line(struct iio_dev *dev_info, int line_number)
210 /* make sure the interrupt handlers are all done */
211 flush_scheduled_work();
212 free_irq(dev_info->interrupts[line_number]->irq,
213 dev_info->interrupts[line_number]);
214 kfree(dev_info->interrupts[line_number]);
216 EXPORT_SYMBOL(iio_unregister_interrupt_line);
218 /* Reference counted add and remove */
219 void iio_add_event_to_list(struct iio_event_handler_list *el,
220 struct list_head *head)
223 struct iio_interrupt *inter = to_iio_interrupt(head);
225 /* take mutex to protect this element */
226 mutex_lock(&el->exist_lock);
227 if (el->refcount == 0) {
228 /* Take the event list spin lock */
229 spin_lock_irqsave(&inter->ev_list_lock, flags);
230 list_add(&el->list, head);
231 spin_unlock_irqrestore(&inter->ev_list_lock, flags);
234 mutex_unlock(&el->exist_lock);
236 EXPORT_SYMBOL(iio_add_event_to_list);
238 void iio_remove_event_from_list(struct iio_event_handler_list *el,
239 struct list_head *head)
242 struct iio_interrupt *inter = to_iio_interrupt(head);
244 mutex_lock(&el->exist_lock);
246 if (el->refcount == 0) {
247 /* Take the event list spin lock */
248 spin_lock_irqsave(&inter->ev_list_lock, flags);
249 list_del_init(&el->list);
250 spin_unlock_irqrestore(&inter->ev_list_lock, flags);
252 mutex_unlock(&el->exist_lock);
254 EXPORT_SYMBOL(iio_remove_event_from_list);
256 static ssize_t iio_event_chrdev_read(struct file *filep,
261 struct iio_event_interface *ev_int = filep->private_data;
262 struct iio_detected_event_list *el;
266 mutex_lock(&ev_int->event_list_lock);
267 if (list_empty(&ev_int->det_events.list)) {
268 if (filep->f_flags & O_NONBLOCK) {
270 goto error_mutex_unlock;
272 mutex_unlock(&ev_int->event_list_lock);
273 /* Blocking on device; waiting for something to be there */
274 ret = wait_event_interruptible(ev_int->wait,
279 /* Single access device so noone else can get the data */
280 mutex_lock(&ev_int->event_list_lock);
283 el = list_first_entry(&ev_int->det_events.list,
284 struct iio_detected_event_list,
287 if (copy_to_user(buf, &(el->ev), len)) {
289 goto error_mutex_unlock;
292 ev_int->current_events--;
293 mutex_unlock(&ev_int->event_list_lock);
295 * Possible concurency issue if an update of this event is on its way
296 * through. May lead to new event being removed whilst the reported
297 * event was the unescalated event. In typical use case this is not a
298 * problem as userspace will say read half the buffer due to a 50%
299 * full event which would make the correct 100% full incorrect anyway.
301 if (el->shared_pointer) {
302 spin_lock(&el->shared_pointer->lock);
303 (el->shared_pointer->ev_p) = NULL;
304 spin_unlock(&el->shared_pointer->lock);
311 mutex_unlock(&ev_int->event_list_lock);
317 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
319 struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
320 struct iio_event_interface *ev_int = hand->private;
321 struct iio_detected_event_list *el, *t;
323 mutex_lock(&ev_int->event_list_lock);
324 clear_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags);
326 * In order to maintain a clean state for reopening,
327 * clear out any awaiting events. The mask will prevent
328 * any new __iio_push_event calls running.
330 list_for_each_entry_safe(el, t, &ev_int->det_events.list, list) {
334 mutex_unlock(&ev_int->event_list_lock);
339 static int iio_event_chrdev_open(struct inode *inode, struct file *filep)
341 struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
342 struct iio_event_interface *ev_int = hand->private;
344 mutex_lock(&ev_int->event_list_lock);
345 if (test_and_set_bit(IIO_BUSY_BIT_POS, &hand->flags)) {
346 fops_put(filep->f_op);
347 mutex_unlock(&ev_int->event_list_lock);
350 filep->private_data = hand->private;
351 mutex_unlock(&ev_int->event_list_lock);
356 static const struct file_operations iio_event_chrdev_fileops = {
357 .read = iio_event_chrdev_read,
358 .release = iio_event_chrdev_release,
359 .open = iio_event_chrdev_open,
360 .owner = THIS_MODULE,
363 static void iio_event_dev_release(struct device *dev)
365 struct iio_event_interface *ev_int
366 = container_of(dev, struct iio_event_interface, dev);
367 cdev_del(&ev_int->handler.chrdev);
368 iio_device_free_chrdev_minor(MINOR(dev->devt));
371 static struct device_type iio_event_type = {
372 .release = iio_event_dev_release,
375 int iio_device_get_chrdev_minor(void)
380 if (unlikely(idr_pre_get(&iio_chrdev_idr, GFP_KERNEL) == 0))
382 spin_lock(&iio_idr_lock);
383 ret = idr_get_new(&iio_chrdev_idr, NULL, &val);
384 spin_unlock(&iio_idr_lock);
385 if (unlikely(ret == -EAGAIN))
387 else if (unlikely(ret))
389 if (val > IIO_DEV_MAX)
394 void iio_device_free_chrdev_minor(int val)
396 spin_lock(&iio_idr_lock);
397 idr_remove(&iio_chrdev_idr, val);
398 spin_unlock(&iio_idr_lock);
401 int iio_setup_ev_int(struct iio_event_interface *ev_int,
403 struct module *owner,
408 ev_int->dev.class = &iio_class;
409 ev_int->dev.parent = dev;
410 ev_int->dev.type = &iio_event_type;
411 device_initialize(&ev_int->dev);
413 minor = iio_device_get_chrdev_minor();
416 goto error_device_put;
418 ev_int->dev.devt = MKDEV(MAJOR(iio_devt), minor);
419 dev_set_name(&ev_int->dev, "%s", name);
421 ret = device_add(&ev_int->dev);
423 goto error_free_minor;
425 cdev_init(&ev_int->handler.chrdev, &iio_event_chrdev_fileops);
426 ev_int->handler.chrdev.owner = owner;
428 mutex_init(&ev_int->event_list_lock);
429 /* discussion point - make this variable? */
430 ev_int->max_events = 10;
431 ev_int->current_events = 0;
432 INIT_LIST_HEAD(&ev_int->det_events.list);
433 init_waitqueue_head(&ev_int->wait);
434 ev_int->handler.private = ev_int;
435 ev_int->handler.flags = 0;
437 ret = cdev_add(&ev_int->handler.chrdev, ev_int->dev.devt, 1);
439 goto error_unreg_device;
444 device_unregister(&ev_int->dev);
446 iio_device_free_chrdev_minor(minor);
448 put_device(&ev_int->dev);
453 void iio_free_ev_int(struct iio_event_interface *ev_int)
455 device_unregister(&ev_int->dev);
456 put_device(&ev_int->dev);
459 static int __init iio_dev_init(void)
463 err = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
465 printk(KERN_ERR "%s: failed to allocate char dev region\n",
471 static void __exit iio_dev_exit(void)
474 unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
477 static int __init iio_init(void)
481 /* Create sysfs class */
482 ret = class_register(&iio_class);
485 "%s could not create sysfs class\n",
490 ret = iio_dev_init();
492 goto error_unregister_class;
496 error_unregister_class:
497 class_unregister(&iio_class);
502 static void __exit iio_exit(void)
505 class_unregister(&iio_class);
508 static int iio_device_register_sysfs(struct iio_dev *dev_info)
512 ret = sysfs_create_group(&dev_info->dev.kobj, dev_info->attrs);
514 dev_err(dev_info->dev.parent,
515 "Failed to register sysfs hooks\n");
519 if (dev_info->scan_el_attrs) {
520 ret = sysfs_create_group(&dev_info->dev.kobj,
521 dev_info->scan_el_attrs);
523 dev_err(&dev_info->dev,
524 "Failed to add sysfs scan els\n");
531 static void iio_device_unregister_sysfs(struct iio_dev *dev_info)
533 if (dev_info->scan_el_attrs)
534 sysfs_remove_group(&dev_info->dev.kobj,
535 dev_info->scan_el_attrs);
537 sysfs_remove_group(&dev_info->dev.kobj, dev_info->attrs);
540 /* Return a negative errno on failure */
541 int iio_get_new_idr_val(struct idr *this_idr)
547 if (unlikely(idr_pre_get(this_idr, GFP_KERNEL) == 0))
550 spin_lock(&iio_idr_lock);
551 ret = idr_get_new(this_idr, NULL, &val);
552 spin_unlock(&iio_idr_lock);
553 if (unlikely(ret == -EAGAIN))
555 else if (unlikely(ret))
560 EXPORT_SYMBOL(iio_get_new_idr_val);
562 void iio_free_idr_val(struct idr *this_idr, int id)
564 spin_lock(&iio_idr_lock);
565 idr_remove(this_idr, id);
566 spin_unlock(&iio_idr_lock);
568 EXPORT_SYMBOL(iio_free_idr_val);
570 static int iio_device_register_id(struct iio_dev *dev_info,
571 struct idr *this_idr)
574 dev_info->id = iio_get_new_idr_val(&iio_idr);
575 if (dev_info->id < 0)
580 static void iio_device_unregister_id(struct iio_dev *dev_info)
582 iio_free_idr_val(&iio_idr, dev_info->id);
585 static inline int __iio_add_event_config_attrs(struct iio_dev *dev_info, int i)
588 /*p for adding, q for removing */
589 struct attribute **attrp, **attrq;
591 if (dev_info->event_conf_attrs && dev_info->event_conf_attrs[i].attrs) {
592 attrp = dev_info->event_conf_attrs[i].attrs;
594 ret = sysfs_add_file_to_group(&dev_info->dev.kobj,
597 ->event_attrs[i].name);
606 attrq = dev_info->event_conf_attrs[i].attrs;
607 while (attrq != attrp) {
608 sysfs_remove_file_from_group(&dev_info->dev.kobj,
610 dev_info->event_attrs[i].name);
617 static inline int __iio_remove_event_config_attrs(struct iio_dev *dev_info,
620 struct attribute **attrq;
622 if (dev_info->event_conf_attrs
623 && dev_info->event_conf_attrs[i].attrs) {
624 attrq = dev_info->event_conf_attrs[i].attrs;
626 sysfs_remove_file_from_group(&dev_info->dev.kobj,
629 ->event_attrs[i].name);
637 static int iio_device_register_eventset(struct iio_dev *dev_info)
641 if (dev_info->num_interrupt_lines == 0)
644 dev_info->event_interfaces =
645 kzalloc(sizeof(struct iio_event_interface)
646 *dev_info->num_interrupt_lines,
648 if (dev_info->event_interfaces == NULL) {
653 dev_info->interrupts = kzalloc(sizeof(struct iio_interrupt *)
654 *dev_info->num_interrupt_lines,
656 if (dev_info->interrupts == NULL) {
658 goto error_free_event_interfaces;
661 for (i = 0; i < dev_info->num_interrupt_lines; i++) {
662 dev_info->event_interfaces[i].owner = dev_info->driver_module;
663 ret = iio_get_new_idr_val(&iio_event_idr);
665 goto error_free_setup_ev_ints;
667 dev_info->event_interfaces[i].id = ret;
669 snprintf(dev_info->event_interfaces[i]._name, 20,
671 dev_info->event_interfaces[i].id);
673 ret = iio_setup_ev_int(&dev_info->event_interfaces[i],
674 (const char *)(dev_info
675 ->event_interfaces[i]
677 dev_info->driver_module,
680 dev_err(&dev_info->dev,
681 "Could not get chrdev interface\n");
682 iio_free_idr_val(&iio_event_idr,
683 dev_info->event_interfaces[i].id);
684 goto error_free_setup_ev_ints;
688 for (i = 0; i < dev_info->num_interrupt_lines; i++) {
689 snprintf(dev_info->event_interfaces[i]._attrname, 20,
690 "event_line%d_sources", i);
691 dev_info->event_attrs[i].name
693 (dev_info->event_interfaces[i]._attrname);
694 ret = sysfs_create_group(&dev_info->dev.kobj,
695 &dev_info->event_attrs[i]);
697 dev_err(&dev_info->dev,
698 "Failed to register sysfs for event attrs");
699 goto error_remove_sysfs_interfaces;
703 for (i = 0; i < dev_info->num_interrupt_lines; i++) {
704 ret = __iio_add_event_config_attrs(dev_info, i);
706 goto error_unregister_config_attrs;
711 error_unregister_config_attrs:
712 for (j = 0; j < i; j++)
713 __iio_remove_event_config_attrs(dev_info, i);
714 i = dev_info->num_interrupt_lines - 1;
715 error_remove_sysfs_interfaces:
716 for (j = 0; j < i; j++)
717 sysfs_remove_group(&dev_info->dev.kobj,
718 &dev_info->event_attrs[j]);
719 i = dev_info->num_interrupt_lines - 1;
720 error_free_setup_ev_ints:
721 for (j = 0; j < i; j++) {
722 iio_free_idr_val(&iio_event_idr,
723 dev_info->event_interfaces[i].id);
724 iio_free_ev_int(&dev_info->event_interfaces[j]);
726 kfree(dev_info->interrupts);
727 error_free_event_interfaces:
728 kfree(dev_info->event_interfaces);
734 static void iio_device_unregister_eventset(struct iio_dev *dev_info)
738 if (dev_info->num_interrupt_lines == 0)
740 for (i = 0; i < dev_info->num_interrupt_lines; i++)
741 sysfs_remove_group(&dev_info->dev.kobj,
742 &dev_info->event_attrs[i]);
744 for (i = 0; i < dev_info->num_interrupt_lines; i++) {
745 iio_free_idr_val(&iio_event_idr,
746 dev_info->event_interfaces[i].id);
747 iio_free_ev_int(&dev_info->event_interfaces[i]);
749 kfree(dev_info->interrupts);
750 kfree(dev_info->event_interfaces);
753 static void iio_dev_release(struct device *device)
755 struct iio_dev *dev = to_iio_dev(device);
761 static struct device_type iio_dev_type = {
762 .name = "iio_device",
763 .release = iio_dev_release,
766 struct iio_dev *iio_allocate_device(void)
768 struct iio_dev *dev = kzalloc(sizeof *dev, GFP_KERNEL);
771 dev->dev.type = &iio_dev_type;
772 dev->dev.class = &iio_class;
773 device_initialize(&dev->dev);
774 dev_set_drvdata(&dev->dev, (void *)dev);
775 mutex_init(&dev->mlock);
781 EXPORT_SYMBOL(iio_allocate_device);
783 void iio_free_device(struct iio_dev *dev)
788 EXPORT_SYMBOL(iio_free_device);
790 int iio_device_register(struct iio_dev *dev_info)
794 ret = iio_device_register_id(dev_info, &iio_idr);
796 dev_err(&dev_info->dev, "Failed to get id\n");
799 dev_set_name(&dev_info->dev, "device%d", dev_info->id);
801 ret = device_add(&dev_info->dev);
804 ret = iio_device_register_sysfs(dev_info);
806 dev_err(dev_info->dev.parent,
807 "Failed to register sysfs interfaces\n");
808 goto error_del_device;
810 ret = iio_device_register_eventset(dev_info);
812 dev_err(dev_info->dev.parent,
813 "Failed to register event set \n");
814 goto error_free_sysfs;
816 if (dev_info->modes & INDIO_RING_TRIGGERED)
817 iio_device_register_trigger_consumer(dev_info);
822 iio_device_unregister_sysfs(dev_info);
824 device_del(&dev_info->dev);
826 iio_device_unregister_id(dev_info);
830 EXPORT_SYMBOL(iio_device_register);
832 void iio_device_unregister(struct iio_dev *dev_info)
834 if (dev_info->modes & INDIO_RING_TRIGGERED)
835 iio_device_unregister_trigger_consumer(dev_info);
836 iio_device_unregister_eventset(dev_info);
837 iio_device_unregister_sysfs(dev_info);
838 iio_device_unregister_id(dev_info);
839 device_unregister(&dev_info->dev);
841 EXPORT_SYMBOL(iio_device_unregister);
845 module_put(THIS_MODULE);
850 __module_get(THIS_MODULE);
853 subsys_initcall(iio_init);
854 module_exit(iio_exit);
856 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
857 MODULE_DESCRIPTION("Industrial I/O core");
858 MODULE_LICENSE("GPL");