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_IDA(iio_ida
);
33 /* IDR to allocate character device minor numbers */
34 static DEFINE_IDA(iio_chrdev_ida
);
35 /* Lock used to protect both of the above */
36 static DEFINE_SPINLOCK(iio_ida_lock
);
39 EXPORT_SYMBOL(iio_devt
);
41 #define IIO_DEV_MAX 256
42 struct bus_type iio_bus_type
= {
45 EXPORT_SYMBOL(iio_bus_type
);
47 void __iio_change_event(struct iio_detected_event_list
*ev
,
52 ev
->ev
.timestamp
= timestamp
;
54 EXPORT_SYMBOL(__iio_change_event
);
56 /* Used both in the interrupt line put events and the ring buffer ones */
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
62 int __iio_push_event(struct iio_event_interface
*ev_int
,
65 struct iio_shared_ev_pointer
*
68 struct iio_detected_event_list
*ev
;
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
);
78 ev
= kmalloc(sizeof(*ev
), GFP_KERNEL
);
81 mutex_unlock(&ev_int
->event_list_lock
);
85 ev
->ev
.timestamp
= timestamp
;
86 ev
->shared_pointer
= shared_pointer_p
;
87 if (ev
->shared_pointer
)
88 shared_pointer_p
->ev_p
= ev
;
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
);
95 mutex_unlock(&ev_int
->event_list_lock
);
100 EXPORT_SYMBOL(__iio_push_event
);
102 int iio_push_event(struct iio_dev
*dev_info
,
107 return __iio_push_event(&dev_info
->event_interfaces
[ev_line
],
108 ev_code
, timestamp
, NULL
);
110 EXPORT_SYMBOL(iio_push_event
);
112 /* Generic interrupt line interrupt handler */
113 static irqreturn_t
iio_interrupt_handler(int irq
, void *_int_info
)
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
;
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
);
127 time_ns
= iio_get_time_ns();
128 list_for_each_entry(p
, &int_info
->ev_list
, list
) {
129 disable_irq_nosync(irq
);
130 p
->handler(dev_info
, 1, time_ns
, !(p
->refcount
> 1));
132 spin_unlock_irqrestore(&int_info
->ev_list_lock
, flags
);
137 static struct iio_interrupt
*iio_allocate_interrupt(void)
139 struct iio_interrupt
*i
= kmalloc(sizeof *i
, GFP_KERNEL
);
141 spin_lock_init(&i
->ev_list_lock
);
142 INIT_LIST_HEAD(&i
->ev_list
);
147 /* Confirming the validity of supplied irq is left to drivers.*/
148 int iio_register_interrupt_line(unsigned int irq
,
149 struct iio_dev
*dev_info
,
156 dev_info
->interrupts
[line_number
] = iio_allocate_interrupt();
157 if (dev_info
->interrupts
[line_number
] == NULL
) {
161 dev_info
->interrupts
[line_number
]->line_number
= line_number
;
162 dev_info
->interrupts
[line_number
]->irq
= irq
;
163 dev_info
->interrupts
[line_number
]->dev_info
= dev_info
;
165 /* Possibly only request on demand?
166 * Can see this may complicate the handling of interrupts.
167 * However, with this approach we might end up handling lots of
168 * events no-one cares about.*/
169 ret
= request_irq(irq
,
170 &iio_interrupt_handler
,
173 dev_info
->interrupts
[line_number
]);
178 EXPORT_SYMBOL(iio_register_interrupt_line
);
180 /* This turns up an awful lot */
181 ssize_t
iio_read_const_attr(struct device
*dev
,
182 struct device_attribute
*attr
,
185 return sprintf(buf
, "%s\n", to_iio_const_attr(attr
)->string
);
187 EXPORT_SYMBOL(iio_read_const_attr
);
189 /* Before this runs the interrupt generator must have been disabled */
190 void iio_unregister_interrupt_line(struct iio_dev
*dev_info
, int line_number
)
192 /* make sure the interrupt handlers are all done */
193 flush_scheduled_work();
194 free_irq(dev_info
->interrupts
[line_number
]->irq
,
195 dev_info
->interrupts
[line_number
]);
196 kfree(dev_info
->interrupts
[line_number
]);
198 EXPORT_SYMBOL(iio_unregister_interrupt_line
);
200 /* Reference counted add and remove */
201 void iio_add_event_to_list(struct iio_event_handler_list
*el
,
202 struct list_head
*head
)
205 struct iio_interrupt
*inter
= to_iio_interrupt(head
);
207 /* take mutex to protect this element */
208 mutex_lock(&el
->exist_lock
);
209 if (el
->refcount
== 0) {
210 /* Take the event list spin lock */
211 spin_lock_irqsave(&inter
->ev_list_lock
, flags
);
212 list_add(&el
->list
, head
);
213 spin_unlock_irqrestore(&inter
->ev_list_lock
, flags
);
216 mutex_unlock(&el
->exist_lock
);
218 EXPORT_SYMBOL(iio_add_event_to_list
);
220 void iio_remove_event_from_list(struct iio_event_handler_list
*el
,
221 struct list_head
*head
)
224 struct iio_interrupt
*inter
= to_iio_interrupt(head
);
226 mutex_lock(&el
->exist_lock
);
228 if (el
->refcount
== 0) {
229 /* Take the event list spin lock */
230 spin_lock_irqsave(&inter
->ev_list_lock
, flags
);
231 list_del_init(&el
->list
);
232 spin_unlock_irqrestore(&inter
->ev_list_lock
, flags
);
234 mutex_unlock(&el
->exist_lock
);
236 EXPORT_SYMBOL(iio_remove_event_from_list
);
238 static ssize_t
iio_event_chrdev_read(struct file
*filep
,
243 struct iio_event_interface
*ev_int
= filep
->private_data
;
244 struct iio_detected_event_list
*el
;
248 mutex_lock(&ev_int
->event_list_lock
);
249 if (list_empty(&ev_int
->det_events
.list
)) {
250 if (filep
->f_flags
& O_NONBLOCK
) {
252 goto error_mutex_unlock
;
254 mutex_unlock(&ev_int
->event_list_lock
);
255 /* Blocking on device; waiting for something to be there */
256 ret
= wait_event_interruptible(ev_int
->wait
,
261 /* Single access device so noone else can get the data */
262 mutex_lock(&ev_int
->event_list_lock
);
265 el
= list_first_entry(&ev_int
->det_events
.list
,
266 struct iio_detected_event_list
,
269 if (copy_to_user(buf
, &(el
->ev
), len
)) {
271 goto error_mutex_unlock
;
274 ev_int
->current_events
--;
275 mutex_unlock(&ev_int
->event_list_lock
);
277 * Possible concurency issue if an update of this event is on its way
278 * through. May lead to new event being removed whilst the reported
279 * event was the unescalated event. In typical use case this is not a
280 * problem as userspace will say read half the buffer due to a 50%
281 * full event which would make the correct 100% full incorrect anyway.
283 if (el
->shared_pointer
) {
284 spin_lock(&el
->shared_pointer
->lock
);
285 (el
->shared_pointer
->ev_p
) = NULL
;
286 spin_unlock(&el
->shared_pointer
->lock
);
293 mutex_unlock(&ev_int
->event_list_lock
);
299 static int iio_event_chrdev_release(struct inode
*inode
, struct file
*filep
)
301 struct iio_handler
*hand
= iio_cdev_to_handler(inode
->i_cdev
);
302 struct iio_event_interface
*ev_int
= hand
->private;
303 struct iio_detected_event_list
*el
, *t
;
305 mutex_lock(&ev_int
->event_list_lock
);
306 clear_bit(IIO_BUSY_BIT_POS
, &ev_int
->handler
.flags
);
308 * In order to maintain a clean state for reopening,
309 * clear out any awaiting events. The mask will prevent
310 * any new __iio_push_event calls running.
312 list_for_each_entry_safe(el
, t
, &ev_int
->det_events
.list
, list
) {
316 mutex_unlock(&ev_int
->event_list_lock
);
321 static int iio_event_chrdev_open(struct inode
*inode
, struct file
*filep
)
323 struct iio_handler
*hand
= iio_cdev_to_handler(inode
->i_cdev
);
324 struct iio_event_interface
*ev_int
= hand
->private;
326 mutex_lock(&ev_int
->event_list_lock
);
327 if (test_and_set_bit(IIO_BUSY_BIT_POS
, &hand
->flags
)) {
328 fops_put(filep
->f_op
);
329 mutex_unlock(&ev_int
->event_list_lock
);
332 filep
->private_data
= hand
->private;
333 mutex_unlock(&ev_int
->event_list_lock
);
338 static const struct file_operations iio_event_chrdev_fileops
= {
339 .read
= iio_event_chrdev_read
,
340 .release
= iio_event_chrdev_release
,
341 .open
= iio_event_chrdev_open
,
342 .owner
= THIS_MODULE
,
343 .llseek
= noop_llseek
,
346 static void iio_event_dev_release(struct device
*dev
)
348 struct iio_event_interface
*ev_int
349 = container_of(dev
, struct iio_event_interface
, dev
);
350 cdev_del(&ev_int
->handler
.chrdev
);
351 iio_device_free_chrdev_minor(MINOR(dev
->devt
));
354 static struct device_type iio_event_type
= {
355 .release
= iio_event_dev_release
,
358 int iio_device_get_chrdev_minor(void)
363 if (unlikely(ida_pre_get(&iio_chrdev_ida
, GFP_KERNEL
) == 0))
365 spin_lock(&iio_ida_lock
);
366 ret
= ida_get_new(&iio_chrdev_ida
, &val
);
367 spin_unlock(&iio_ida_lock
);
368 if (unlikely(ret
== -EAGAIN
))
370 else if (unlikely(ret
))
372 if (val
> IIO_DEV_MAX
)
377 void iio_device_free_chrdev_minor(int val
)
379 spin_lock(&iio_ida_lock
);
380 ida_remove(&iio_chrdev_ida
, val
);
381 spin_unlock(&iio_ida_lock
);
384 int iio_setup_ev_int(struct iio_event_interface
*ev_int
,
386 struct module
*owner
,
391 ev_int
->dev
.bus
= &iio_bus_type
;
392 ev_int
->dev
.parent
= dev
;
393 ev_int
->dev
.type
= &iio_event_type
;
394 device_initialize(&ev_int
->dev
);
396 minor
= iio_device_get_chrdev_minor();
399 goto error_device_put
;
401 ev_int
->dev
.devt
= MKDEV(MAJOR(iio_devt
), minor
);
402 dev_set_name(&ev_int
->dev
, "%s", name
);
404 ret
= device_add(&ev_int
->dev
);
406 goto error_free_minor
;
408 cdev_init(&ev_int
->handler
.chrdev
, &iio_event_chrdev_fileops
);
409 ev_int
->handler
.chrdev
.owner
= owner
;
411 mutex_init(&ev_int
->event_list_lock
);
412 /* discussion point - make this variable? */
413 ev_int
->max_events
= 10;
414 ev_int
->current_events
= 0;
415 INIT_LIST_HEAD(&ev_int
->det_events
.list
);
416 init_waitqueue_head(&ev_int
->wait
);
417 ev_int
->handler
.private = ev_int
;
418 ev_int
->handler
.flags
= 0;
420 ret
= cdev_add(&ev_int
->handler
.chrdev
, ev_int
->dev
.devt
, 1);
422 goto error_unreg_device
;
427 device_unregister(&ev_int
->dev
);
429 iio_device_free_chrdev_minor(minor
);
431 put_device(&ev_int
->dev
);
436 void iio_free_ev_int(struct iio_event_interface
*ev_int
)
438 device_unregister(&ev_int
->dev
);
439 put_device(&ev_int
->dev
);
442 static int __init
iio_dev_init(void)
446 err
= alloc_chrdev_region(&iio_devt
, 0, IIO_DEV_MAX
, "iio");
448 printk(KERN_ERR
"%s: failed to allocate char dev region\n",
454 static void __exit
iio_dev_exit(void)
457 unregister_chrdev_region(iio_devt
, IIO_DEV_MAX
);
460 static int __init
iio_init(void)
464 /* Register sysfs bus */
465 ret
= bus_register(&iio_bus_type
);
468 "%s could not register bus type\n",
473 ret
= iio_dev_init();
475 goto error_unregister_bus_type
;
479 error_unregister_bus_type
:
480 bus_unregister(&iio_bus_type
);
485 static void __exit
iio_exit(void)
488 bus_unregister(&iio_bus_type
);
491 static int iio_device_register_sysfs(struct iio_dev
*dev_info
)
495 ret
= sysfs_create_group(&dev_info
->dev
.kobj
, dev_info
->attrs
);
497 dev_err(dev_info
->dev
.parent
,
498 "Failed to register sysfs hooks\n");
506 static void iio_device_unregister_sysfs(struct iio_dev
*dev_info
)
508 sysfs_remove_group(&dev_info
->dev
.kobj
, dev_info
->attrs
);
511 /* Return a negative errno on failure */
512 int iio_get_new_ida_val(struct ida
*this_ida
)
518 if (unlikely(ida_pre_get(this_ida
, GFP_KERNEL
) == 0))
521 spin_lock(&iio_ida_lock
);
522 ret
= ida_get_new(this_ida
, &val
);
523 spin_unlock(&iio_ida_lock
);
524 if (unlikely(ret
== -EAGAIN
))
526 else if (unlikely(ret
))
531 EXPORT_SYMBOL(iio_get_new_ida_val
);
533 void iio_free_ida_val(struct ida
*this_ida
, int id
)
535 spin_lock(&iio_ida_lock
);
536 ida_remove(this_ida
, id
);
537 spin_unlock(&iio_ida_lock
);
539 EXPORT_SYMBOL(iio_free_ida_val
);
541 static int iio_device_register_id(struct iio_dev
*dev_info
,
542 struct ida
*this_ida
)
544 dev_info
->id
= iio_get_new_ida_val(&iio_ida
);
545 if (dev_info
->id
< 0)
550 static void iio_device_unregister_id(struct iio_dev
*dev_info
)
552 iio_free_ida_val(&iio_ida
, dev_info
->id
);
555 static inline int __iio_add_event_config_attrs(struct iio_dev
*dev_info
, int i
)
558 /*p for adding, q for removing */
559 struct attribute
**attrp
, **attrq
;
561 if (dev_info
->event_conf_attrs
&& dev_info
->event_conf_attrs
[i
].attrs
) {
562 attrp
= dev_info
->event_conf_attrs
[i
].attrs
;
564 ret
= sysfs_add_file_to_group(&dev_info
->dev
.kobj
,
567 ->event_attrs
[i
].name
);
576 attrq
= dev_info
->event_conf_attrs
[i
].attrs
;
577 while (attrq
!= attrp
) {
578 sysfs_remove_file_from_group(&dev_info
->dev
.kobj
,
580 dev_info
->event_attrs
[i
].name
);
587 static inline int __iio_remove_event_config_attrs(struct iio_dev
*dev_info
,
590 struct attribute
**attrq
;
592 if (dev_info
->event_conf_attrs
593 && dev_info
->event_conf_attrs
[i
].attrs
) {
594 attrq
= dev_info
->event_conf_attrs
[i
].attrs
;
596 sysfs_remove_file_from_group(&dev_info
->dev
.kobj
,
599 ->event_attrs
[i
].name
);
607 static int iio_device_register_eventset(struct iio_dev
*dev_info
)
611 if (dev_info
->num_interrupt_lines
== 0)
614 dev_info
->event_interfaces
=
615 kzalloc(sizeof(struct iio_event_interface
)
616 *dev_info
->num_interrupt_lines
,
618 if (dev_info
->event_interfaces
== NULL
) {
623 dev_info
->interrupts
= kzalloc(sizeof(struct iio_interrupt
*)
624 *dev_info
->num_interrupt_lines
,
626 if (dev_info
->interrupts
== NULL
) {
628 goto error_free_event_interfaces
;
631 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++) {
632 dev_info
->event_interfaces
[i
].owner
= dev_info
->driver_module
;
634 snprintf(dev_info
->event_interfaces
[i
]._name
, 20,
636 dev_name(&dev_info
->dev
),
639 ret
= iio_setup_ev_int(&dev_info
->event_interfaces
[i
],
640 (const char *)(dev_info
641 ->event_interfaces
[i
]
643 dev_info
->driver_module
,
646 dev_err(&dev_info
->dev
,
647 "Could not get chrdev interface\n");
648 goto error_free_setup_ev_ints
;
651 dev_set_drvdata(&dev_info
->event_interfaces
[i
].dev
,
653 ret
= sysfs_create_group(&dev_info
654 ->event_interfaces
[i
]
656 &dev_info
->event_attrs
[i
]);
659 dev_err(&dev_info
->dev
,
660 "Failed to register sysfs for event attrs");
661 goto error_remove_sysfs_interfaces
;
665 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++) {
666 ret
= __iio_add_event_config_attrs(dev_info
, i
);
668 goto error_unregister_config_attrs
;
673 error_unregister_config_attrs
:
674 for (j
= 0; j
< i
; j
++)
675 __iio_remove_event_config_attrs(dev_info
, i
);
676 i
= dev_info
->num_interrupt_lines
- 1;
677 error_remove_sysfs_interfaces
:
678 for (j
= 0; j
< i
; j
++)
679 sysfs_remove_group(&dev_info
680 ->event_interfaces
[j
].dev
.kobj
,
681 &dev_info
->event_attrs
[j
]);
682 error_free_setup_ev_ints
:
683 for (j
= 0; j
< i
; j
++)
684 iio_free_ev_int(&dev_info
->event_interfaces
[j
]);
685 kfree(dev_info
->interrupts
);
686 error_free_event_interfaces
:
687 kfree(dev_info
->event_interfaces
);
693 static void iio_device_unregister_eventset(struct iio_dev
*dev_info
)
697 if (dev_info
->num_interrupt_lines
== 0)
699 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++)
700 sysfs_remove_group(&dev_info
701 ->event_interfaces
[i
].dev
.kobj
,
702 &dev_info
->event_attrs
[i
]);
704 for (i
= 0; i
< dev_info
->num_interrupt_lines
; i
++)
705 iio_free_ev_int(&dev_info
->event_interfaces
[i
]);
706 kfree(dev_info
->interrupts
);
707 kfree(dev_info
->event_interfaces
);
710 static void iio_dev_release(struct device
*device
)
712 struct iio_dev
*dev
= to_iio_dev(device
);
718 static struct device_type iio_dev_type
= {
719 .name
= "iio_device",
720 .release
= iio_dev_release
,
723 struct iio_dev
*iio_allocate_device(void)
725 struct iio_dev
*dev
= kzalloc(sizeof *dev
, GFP_KERNEL
);
728 dev
->dev
.type
= &iio_dev_type
;
729 dev
->dev
.bus
= &iio_bus_type
;
730 device_initialize(&dev
->dev
);
731 dev_set_drvdata(&dev
->dev
, (void *)dev
);
732 mutex_init(&dev
->mlock
);
738 EXPORT_SYMBOL(iio_allocate_device
);
740 void iio_free_device(struct iio_dev
*dev
)
745 EXPORT_SYMBOL(iio_free_device
);
747 int iio_device_register(struct iio_dev
*dev_info
)
751 ret
= iio_device_register_id(dev_info
, &iio_ida
);
753 dev_err(&dev_info
->dev
, "Failed to get id\n");
756 dev_set_name(&dev_info
->dev
, "device%d", dev_info
->id
);
758 ret
= device_add(&dev_info
->dev
);
761 ret
= iio_device_register_sysfs(dev_info
);
763 dev_err(dev_info
->dev
.parent
,
764 "Failed to register sysfs interfaces\n");
765 goto error_del_device
;
767 ret
= iio_device_register_eventset(dev_info
);
769 dev_err(dev_info
->dev
.parent
,
770 "Failed to register event set\n");
771 goto error_free_sysfs
;
773 if (dev_info
->modes
& INDIO_RING_TRIGGERED
)
774 iio_device_register_trigger_consumer(dev_info
);
779 iio_device_unregister_sysfs(dev_info
);
781 device_del(&dev_info
->dev
);
783 iio_device_unregister_id(dev_info
);
787 EXPORT_SYMBOL(iio_device_register
);
789 void iio_device_unregister(struct iio_dev
*dev_info
)
791 if (dev_info
->modes
& INDIO_RING_TRIGGERED
)
792 iio_device_unregister_trigger_consumer(dev_info
);
793 iio_device_unregister_eventset(dev_info
);
794 iio_device_unregister_sysfs(dev_info
);
795 iio_device_unregister_id(dev_info
);
796 device_unregister(&dev_info
->dev
);
798 EXPORT_SYMBOL(iio_device_unregister
);
802 module_put(THIS_MODULE
);
807 __module_get(THIS_MODULE
);
810 subsys_initcall(iio_init
);
811 module_exit(iio_exit
);
813 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
814 MODULE_DESCRIPTION("Industrial I/O core");
815 MODULE_LICENSE("GPL");