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 struct bus_type iio_bus_type
= {
48 EXPORT_SYMBOL(iio_bus_type
);
50 void __iio_change_event(struct iio_detected_event_list
*ev
,
55 ev
->ev
.timestamp
= timestamp
;
57 EXPORT_SYMBOL(__iio_change_event
);
59 /* Used both in the interrupt line put events and the ring buffer ones */
61 /* Note that in it's current form someone has to be listening before events
62 * are queued. Hence a client MUST open the chrdev before the ring buffer is
65 int __iio_push_event(struct iio_event_interface
*ev_int
,
68 struct iio_shared_ev_pointer
*
71 struct iio_detected_event_list
*ev
;
74 /* Does anyone care? */
75 mutex_lock(&ev_int
->event_list_lock
);
76 if (test_bit(IIO_BUSY_BIT_POS
, &ev_int
->handler
.flags
)) {
77 if (ev_int
->current_events
== ev_int
->max_events
) {
78 mutex_unlock(&ev_int
->event_list_lock
);
81 ev
= kmalloc(sizeof(*ev
), GFP_KERNEL
);
84 mutex_unlock(&ev_int
->event_list_lock
);
88 ev
->ev
.timestamp
= timestamp
;
89 ev
->shared_pointer
= shared_pointer_p
;
90 if (ev
->shared_pointer
)
91 shared_pointer_p
->ev_p
= ev
;
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
);
98 mutex_unlock(&ev_int
->event_list_lock
);
103 EXPORT_SYMBOL(__iio_push_event
);
105 int iio_push_event(struct iio_dev
*dev_info
,
110 return __iio_push_event(&dev_info
->event_interfaces
[ev_line
],
111 ev_code
, timestamp
, NULL
);
113 EXPORT_SYMBOL(iio_push_event
);
115 /* Generic interrupt line interrupt handler */
116 static irqreturn_t
iio_interrupt_handler(int irq
, void *_int_info
)
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
;
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
);
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
,
137 /* single event handler - maybe shared */
138 p
->handler(dev_info
, 1, time_ns
, !(p
->refcount
> 1));
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);
144 spin_unlock_irqrestore(&int_info
->ev_list_lock
, flags
);
149 static struct iio_interrupt
*iio_allocate_interrupt(void)
151 struct iio_interrupt
*i
= kmalloc(sizeof *i
, GFP_KERNEL
);
153 spin_lock_init(&i
->ev_list_lock
);
154 INIT_LIST_HEAD(&i
->ev_list
);
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
,
168 dev_info
->interrupts
[line_number
] = iio_allocate_interrupt();
169 if (dev_info
->interrupts
[line_number
] == NULL
) {
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
;
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
,
185 dev_info
->interrupts
[line_number
]);
190 EXPORT_SYMBOL(iio_register_interrupt_line
);
192 /* This turns up an awful lot */
193 ssize_t
iio_read_const_attr(struct device
*dev
,
194 struct device_attribute
*attr
,
197 return sprintf(buf
, "%s\n", to_iio_const_attr(attr
)->string
);
199 EXPORT_SYMBOL(iio_read_const_attr
);
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
)
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
]);
210 EXPORT_SYMBOL(iio_unregister_interrupt_line
);
212 /* Reference counted add and remove */
213 void iio_add_event_to_list(struct iio_event_handler_list
*el
,
214 struct list_head
*head
)
217 struct iio_interrupt
*inter
= to_iio_interrupt(head
);
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
);
228 mutex_unlock(&el
->exist_lock
);
230 EXPORT_SYMBOL(iio_add_event_to_list
);
232 void iio_remove_event_from_list(struct iio_event_handler_list
*el
,
233 struct list_head
*head
)
236 struct iio_interrupt
*inter
= to_iio_interrupt(head
);
238 mutex_lock(&el
->exist_lock
);
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
);
246 mutex_unlock(&el
->exist_lock
);
248 EXPORT_SYMBOL(iio_remove_event_from_list
);
250 static ssize_t
iio_event_chrdev_read(struct file
*filep
,
255 struct iio_event_interface
*ev_int
= filep
->private_data
;
256 struct iio_detected_event_list
*el
;
260 mutex_lock(&ev_int
->event_list_lock
);
261 if (list_empty(&ev_int
->det_events
.list
)) {
262 if (filep
->f_flags
& O_NONBLOCK
) {
264 goto error_mutex_unlock
;
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
,
273 /* Single access device so noone else can get the data */
274 mutex_lock(&ev_int
->event_list_lock
);
277 el
= list_first_entry(&ev_int
->det_events
.list
,
278 struct iio_detected_event_list
,
281 if (copy_to_user(buf
, &(el
->ev
), len
)) {
283 goto error_mutex_unlock
;
286 ev_int
->current_events
--;
287 mutex_unlock(&ev_int
->event_list_lock
);
289 * Possible concurency issue if an update of this event is on its way
290 * through. May lead to new event being removed whilst the reported
291 * event was the unescalated event. In typical use case this is not a
292 * problem as userspace will say read half the buffer due to a 50%
293 * full event which would make the correct 100% full incorrect anyway.
295 if (el
->shared_pointer
) {
296 spin_lock(&el
->shared_pointer
->lock
);
297 (el
->shared_pointer
->ev_p
) = NULL
;
298 spin_unlock(&el
->shared_pointer
->lock
);
305 mutex_unlock(&ev_int
->event_list_lock
);
311 static int iio_event_chrdev_release(struct inode
*inode
, struct file
*filep
)
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
;
317 mutex_lock(&ev_int
->event_list_lock
);
318 clear_bit(IIO_BUSY_BIT_POS
, &ev_int
->handler
.flags
);
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.
324 list_for_each_entry_safe(el
, t
, &ev_int
->det_events
.list
, list
) {
328 mutex_unlock(&ev_int
->event_list_lock
);
333 static int iio_event_chrdev_open(struct inode
*inode
, struct file
*filep
)
335 struct iio_handler
*hand
= iio_cdev_to_handler(inode
->i_cdev
);
336 struct iio_event_interface
*ev_int
= hand
->private;
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
);
344 filep
->private_data
= hand
->private;
345 mutex_unlock(&ev_int
->event_list_lock
);
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
,
357 static void iio_event_dev_release(struct device
*dev
)
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
));
365 static struct device_type iio_event_type
= {
366 .release
= iio_event_dev_release
,
369 int iio_device_get_chrdev_minor(void)
374 if (unlikely(idr_pre_get(&iio_chrdev_idr
, GFP_KERNEL
) == 0))
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
))
381 else if (unlikely(ret
))
383 if (val
> IIO_DEV_MAX
)
388 void iio_device_free_chrdev_minor(int val
)
390 spin_lock(&iio_idr_lock
);
391 idr_remove(&iio_chrdev_idr
, val
);
392 spin_unlock(&iio_idr_lock
);
395 int iio_setup_ev_int(struct iio_event_interface
*ev_int
,
397 struct module
*owner
,
402 ev_int
->dev
.bus
= &iio_bus_type
;
403 ev_int
->dev
.parent
= dev
;
404 ev_int
->dev
.type
= &iio_event_type
;
405 device_initialize(&ev_int
->dev
);
407 minor
= iio_device_get_chrdev_minor();
410 goto error_device_put
;
412 ev_int
->dev
.devt
= MKDEV(MAJOR(iio_devt
), minor
);
413 dev_set_name(&ev_int
->dev
, "%s", name
);
415 ret
= device_add(&ev_int
->dev
);
417 goto error_free_minor
;
419 cdev_init(&ev_int
->handler
.chrdev
, &iio_event_chrdev_fileops
);
420 ev_int
->handler
.chrdev
.owner
= owner
;
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;
431 ret
= cdev_add(&ev_int
->handler
.chrdev
, ev_int
->dev
.devt
, 1);
433 goto error_unreg_device
;
438 device_unregister(&ev_int
->dev
);
440 iio_device_free_chrdev_minor(minor
);
442 put_device(&ev_int
->dev
);
447 void iio_free_ev_int(struct iio_event_interface
*ev_int
)
449 device_unregister(&ev_int
->dev
);
450 put_device(&ev_int
->dev
);
453 static int __init
iio_dev_init(void)
457 err
= alloc_chrdev_region(&iio_devt
, 0, IIO_DEV_MAX
, "iio");
459 printk(KERN_ERR
"%s: failed to allocate char dev region\n",
465 static void __exit
iio_dev_exit(void)
468 unregister_chrdev_region(iio_devt
, IIO_DEV_MAX
);
471 static int __init
iio_init(void)
475 /* Register sysfs bus */
476 ret
= bus_register(&iio_bus_type
);
479 "%s could not register bus type\n",
484 ret
= iio_dev_init();
486 goto error_unregister_bus_type
;
490 error_unregister_bus_type
:
491 bus_unregister(&iio_bus_type
);
496 static void __exit
iio_exit(void)
499 bus_unregister(&iio_bus_type
);
502 static int iio_device_register_sysfs(struct iio_dev
*dev_info
)
506 ret
= sysfs_create_group(&dev_info
->dev
.kobj
, dev_info
->attrs
);
508 dev_err(dev_info
->dev
.parent
,
509 "Failed to register sysfs hooks\n");
513 if (dev_info
->scan_el_attrs
) {
514 ret
= sysfs_create_group(&dev_info
->dev
.kobj
,
515 dev_info
->scan_el_attrs
);
517 dev_err(&dev_info
->dev
,
518 "Failed to add sysfs scan els\n");
525 static void iio_device_unregister_sysfs(struct iio_dev
*dev_info
)
527 if (dev_info
->scan_el_attrs
)
528 sysfs_remove_group(&dev_info
->dev
.kobj
,
529 dev_info
->scan_el_attrs
);
531 sysfs_remove_group(&dev_info
->dev
.kobj
, dev_info
->attrs
);
534 /* Return a negative errno on failure */
535 int iio_get_new_idr_val(struct idr
*this_idr
)
541 if (unlikely(idr_pre_get(this_idr
, GFP_KERNEL
) == 0))
544 spin_lock(&iio_idr_lock
);
545 ret
= idr_get_new(this_idr
, NULL
, &val
);
546 spin_unlock(&iio_idr_lock
);
547 if (unlikely(ret
== -EAGAIN
))
549 else if (unlikely(ret
))
554 EXPORT_SYMBOL(iio_get_new_idr_val
);
556 void iio_free_idr_val(struct idr
*this_idr
, int id
)
558 spin_lock(&iio_idr_lock
);
559 idr_remove(this_idr
, id
);
560 spin_unlock(&iio_idr_lock
);
562 EXPORT_SYMBOL(iio_free_idr_val
);
564 static int iio_device_register_id(struct iio_dev
*dev_info
,
565 struct idr
*this_idr
)
568 dev_info
->id
= iio_get_new_idr_val(&iio_idr
);
569 if (dev_info
->id
< 0)
574 static void iio_device_unregister_id(struct iio_dev
*dev_info
)
576 iio_free_idr_val(&iio_idr
, dev_info
->id
);
579 static inline int __iio_add_event_config_attrs(struct iio_dev
*dev_info
, int i
)
582 /*p for adding, q for removing */
583 struct attribute
**attrp
, **attrq
;
585 if (dev_info
->event_conf_attrs
&& dev_info
->event_conf_attrs
[i
].attrs
) {
586 attrp
= dev_info
->event_conf_attrs
[i
].attrs
;
588 ret
= sysfs_add_file_to_group(&dev_info
->dev
.kobj
,
591 ->event_attrs
[i
].name
);
600 attrq
= dev_info
->event_conf_attrs
[i
].attrs
;
601 while (attrq
!= attrp
) {
602 sysfs_remove_file_from_group(&dev_info
->dev
.kobj
,
604 dev_info
->event_attrs
[i
].name
);
611 static inline int __iio_remove_event_config_attrs(struct iio_dev
*dev_info
,
614 struct attribute
**attrq
;
616 if (dev_info
->event_conf_attrs
617 && dev_info
->event_conf_attrs
[i
].attrs
) {
618 attrq
= dev_info
->event_conf_attrs
[i
].attrs
;
620 sysfs_remove_file_from_group(&dev_info
->dev
.kobj
,
623 ->event_attrs
[i
].name
);
631 static int iio_device_register_eventset(struct iio_dev
*dev_info
)
635 if (dev_info
->num_interrupt_lines
== 0)
638 dev_info
->event_interfaces
=
639 kzalloc(sizeof(struct iio_event_interface
)
640 *dev_info
->num_interrupt_lines
,
642 if (dev_info
->event_interfaces
== NULL
) {
647 dev_info
->interrupts
= kzalloc(sizeof(struct iio_interrupt
*)
648 *dev_info
->num_interrupt_lines
,
650 if (dev_info
->interrupts
== NULL
) {
652 goto error_free_event_interfaces
;
655 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++) {
656 dev_info
->event_interfaces
[i
].owner
= dev_info
->driver_module
;
657 ret
= iio_get_new_idr_val(&iio_event_idr
);
659 goto error_free_setup_ev_ints
;
661 dev_info
->event_interfaces
[i
].id
= ret
;
663 snprintf(dev_info
->event_interfaces
[i
]._name
, 20,
665 dev_name(&dev_info
->dev
),
666 dev_info
->event_interfaces
[i
].id
);
668 ret
= iio_setup_ev_int(&dev_info
->event_interfaces
[i
],
669 (const char *)(dev_info
670 ->event_interfaces
[i
]
672 dev_info
->driver_module
,
675 dev_err(&dev_info
->dev
,
676 "Could not get chrdev interface\n");
677 iio_free_idr_val(&iio_event_idr
,
678 dev_info
->event_interfaces
[i
].id
);
679 goto error_free_setup_ev_ints
;
682 dev_set_drvdata(&dev_info
->event_interfaces
[i
].dev
,
684 ret
= sysfs_create_group(&dev_info
685 ->event_interfaces
[i
]
687 &dev_info
->event_attrs
[i
]);
690 dev_err(&dev_info
->dev
,
691 "Failed to register sysfs for event attrs");
692 goto error_remove_sysfs_interfaces
;
696 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++) {
697 ret
= __iio_add_event_config_attrs(dev_info
, i
);
699 goto error_unregister_config_attrs
;
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
711 ->event_interfaces
[j
].dev
.kobj
,
712 &dev_info
->event_attrs
[j
]);
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
[j
].id
);
717 iio_free_ev_int(&dev_info
->event_interfaces
[j
]);
719 kfree(dev_info
->interrupts
);
720 error_free_event_interfaces
:
721 kfree(dev_info
->event_interfaces
);
727 static void iio_device_unregister_eventset(struct iio_dev
*dev_info
)
731 if (dev_info
->num_interrupt_lines
== 0)
733 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++)
734 sysfs_remove_group(&dev_info
735 ->event_interfaces
[i
].dev
.kobj
,
736 &dev_info
->event_attrs
[i
]);
738 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++) {
739 iio_free_idr_val(&iio_event_idr
,
740 dev_info
->event_interfaces
[i
].id
);
741 iio_free_ev_int(&dev_info
->event_interfaces
[i
]);
743 kfree(dev_info
->interrupts
);
744 kfree(dev_info
->event_interfaces
);
747 static void iio_dev_release(struct device
*device
)
749 struct iio_dev
*dev
= to_iio_dev(device
);
755 static struct device_type iio_dev_type
= {
756 .name
= "iio_device",
757 .release
= iio_dev_release
,
760 struct iio_dev
*iio_allocate_device(void)
762 struct iio_dev
*dev
= kzalloc(sizeof *dev
, GFP_KERNEL
);
765 dev
->dev
.type
= &iio_dev_type
;
766 dev
->dev
.bus
= &iio_bus_type
;
767 device_initialize(&dev
->dev
);
768 dev_set_drvdata(&dev
->dev
, (void *)dev
);
769 mutex_init(&dev
->mlock
);
775 EXPORT_SYMBOL(iio_allocate_device
);
777 void iio_free_device(struct iio_dev
*dev
)
782 EXPORT_SYMBOL(iio_free_device
);
784 int iio_device_register(struct iio_dev
*dev_info
)
788 ret
= iio_device_register_id(dev_info
, &iio_idr
);
790 dev_err(&dev_info
->dev
, "Failed to get id\n");
793 dev_set_name(&dev_info
->dev
, "device%d", dev_info
->id
);
795 ret
= device_add(&dev_info
->dev
);
798 ret
= iio_device_register_sysfs(dev_info
);
800 dev_err(dev_info
->dev
.parent
,
801 "Failed to register sysfs interfaces\n");
802 goto error_del_device
;
804 ret
= iio_device_register_eventset(dev_info
);
806 dev_err(dev_info
->dev
.parent
,
807 "Failed to register event set\n");
808 goto error_free_sysfs
;
810 if (dev_info
->modes
& INDIO_RING_TRIGGERED
)
811 iio_device_register_trigger_consumer(dev_info
);
816 iio_device_unregister_sysfs(dev_info
);
818 device_del(&dev_info
->dev
);
820 iio_device_unregister_id(dev_info
);
824 EXPORT_SYMBOL(iio_device_register
);
826 void iio_device_unregister(struct iio_dev
*dev_info
)
828 if (dev_info
->modes
& INDIO_RING_TRIGGERED
)
829 iio_device_unregister_trigger_consumer(dev_info
);
830 iio_device_unregister_eventset(dev_info
);
831 iio_device_unregister_sysfs(dev_info
);
832 iio_device_unregister_id(dev_info
);
833 device_unregister(&dev_info
->dev
);
835 EXPORT_SYMBOL(iio_device_unregister
);
839 module_put(THIS_MODULE
);
844 __module_get(THIS_MODULE
);
847 subsys_initcall(iio_init
);
848 module_exit(iio_exit
);
850 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
851 MODULE_DESCRIPTION("Industrial I/O core");
852 MODULE_LICENSE("GPL");