blob: 5682e61600f697539bded7a723dbc4aed84ede3f [file] [log] [blame]
/* The industrial I/O core, trigger handling functions
*
* Copyright (c) 2008 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/slab.h>
#include "iio.h"
#include "trigger.h"
#include "trigger_consumer.h"
/* RFC - Question of approach
* Make the common case (single sensor single trigger)
* simple by starting trigger capture from when first sensors
* is added.
*
* Complex simultaneous start requires use of 'hold' functionality
* of the trigger. (not implemented)
*
* Any other suggestions?
*/
static DEFINE_IDR(iio_trigger_idr);
static DEFINE_SPINLOCK(iio_trigger_idr_lock);
/* Single list of all available triggers */
static LIST_HEAD(iio_trigger_list);
static DEFINE_MUTEX(iio_trigger_list_lock);
/**
* iio_trigger_register_sysfs() - create a device for this trigger
* @trig_info: the trigger
*
* Also adds any control attribute registered by the trigger driver
**/
static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
{
int ret = 0;
if (trig_info->control_attrs)
ret = sysfs_create_group(&trig_info->dev.kobj,
trig_info->control_attrs);
return ret;
}
static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
{
if (trig_info->control_attrs)
sysfs_remove_group(&trig_info->dev.kobj,
trig_info->control_attrs);
}
/**
* iio_trigger_register_id() - get a unique id for this trigger
* @trig_info: the trigger
**/
static int iio_trigger_register_id(struct iio_trigger *trig_info)
{
int ret = 0;
idr_again:
if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0))
return -ENOMEM;
spin_lock(&iio_trigger_idr_lock);
ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id);
spin_unlock(&iio_trigger_idr_lock);
if (unlikely(ret == -EAGAIN))
goto idr_again;
else if (likely(!ret))
trig_info->id = trig_info->id & MAX_ID_MASK;
return ret;
}
/**
* iio_trigger_unregister_id() - free up unique id for use by another trigger
* @trig_info: the trigger
**/
static void iio_trigger_unregister_id(struct iio_trigger *trig_info)
{
spin_lock(&iio_trigger_idr_lock);
idr_remove(&iio_trigger_idr, trig_info->id);
spin_unlock(&iio_trigger_idr_lock);
}
int iio_trigger_register(struct iio_trigger *trig_info)
{
int ret;
ret = iio_trigger_register_id(trig_info);
if (ret)
goto error_ret;
/* Set the name used for the sysfs directory etc */
dev_set_name(&trig_info->dev, "trigger%ld",
(unsigned long) trig_info->id);
ret = device_add(&trig_info->dev);
if (ret)
goto error_unregister_id;
ret = iio_trigger_register_sysfs(trig_info);
if (ret)
goto error_device_del;
/* Add to list of available triggers held by the IIO core */
mutex_lock(&iio_trigger_list_lock);
list_add_tail(&trig_info->list, &iio_trigger_list);
mutex_unlock(&iio_trigger_list_lock);
return 0;
error_device_del:
device_del(&trig_info->dev);
error_unregister_id:
iio_trigger_unregister_id(trig_info);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_trigger_register);
void iio_trigger_unregister(struct iio_trigger *trig_info)
{
struct iio_trigger *cursor;
mutex_lock(&iio_trigger_list_lock);
list_for_each_entry(cursor, &iio_trigger_list, list)
if (cursor == trig_info) {
list_del(&cursor->list);
break;
}
mutex_unlock(&iio_trigger_list_lock);
iio_trigger_unregister_sysfs(trig_info);
iio_trigger_unregister_id(trig_info);
/* Possible issue in here */
device_unregister(&trig_info->dev);
}
EXPORT_SYMBOL(iio_trigger_unregister);
struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len)
{
struct iio_trigger *trig;
bool found = false;
if (len && name[len - 1] == '\n')
len--;
mutex_lock(&iio_trigger_list_lock);
list_for_each_entry(trig, &iio_trigger_list, list) {
if (strncmp(trig->name, name, len) == 0) {
found = true;
break;
}
}
mutex_unlock(&iio_trigger_list_lock);
return found ? trig : NULL;
}
EXPORT_SYMBOL(iio_trigger_find_by_name);
void iio_trigger_poll(struct iio_trigger *trig)
{
struct iio_poll_func *pf_cursor;
list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) {
if (pf_cursor->poll_func_immediate) {
pf_cursor->poll_func_immediate(pf_cursor->private_data);
trig->use_count++;
}
}
list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) {
if (pf_cursor->poll_func_main) {
pf_cursor->poll_func_main(pf_cursor->private_data);
trig->use_count++;
}
}
}
EXPORT_SYMBOL(iio_trigger_poll);
void iio_trigger_notify_done(struct iio_trigger *trig)
{
trig->use_count--;
if (trig->use_count == 0 && trig->try_reenable)
if (trig->try_reenable(trig)) {
/* Missed and interrupt so launch new poll now */
trig->timestamp = 0;
iio_trigger_poll(trig);
}
}
EXPORT_SYMBOL(iio_trigger_notify_done);
/**
* iio_trigger_read_name() - retrieve useful identifying name
**/
ssize_t iio_trigger_read_name(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_trigger *trig = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", trig->name);
}
EXPORT_SYMBOL(iio_trigger_read_name);
/* Trigger Consumer related functions */
/* Complexity in here. With certain triggers (datardy) an acknowledgement
* may be needed if the pollfuncs do not include the data read for the
* triggering device.
* This is not currently handled. Alternative of not enabling trigger unless
* the relevant function is in there may be the best option.
*/
/* Worth protecting against double additions?*/
int iio_trigger_attach_poll_func(struct iio_trigger *trig,
struct iio_poll_func *pf)
{
int ret = 0;
unsigned long flags;
spin_lock_irqsave(&trig->pollfunc_list_lock, flags);
list_add_tail(&pf->list, &trig->pollfunc_list);
spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags);
if (trig->set_trigger_state)
ret = trig->set_trigger_state(trig, true);
if (ret) {
printk(KERN_ERR "set trigger state failed\n");
list_del(&pf->list);
}
return ret;
}
EXPORT_SYMBOL(iio_trigger_attach_poll_func);
int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
struct iio_poll_func *pf)
{
struct iio_poll_func *pf_cursor;
unsigned long flags;
int ret = -EINVAL;
spin_lock_irqsave(&trig->pollfunc_list_lock, flags);
list_for_each_entry(pf_cursor, &trig->pollfunc_list, list)
if (pf_cursor == pf) {
ret = 0;
break;
}
if (!ret) {
if (list_is_singular(&trig->pollfunc_list)
&& trig->set_trigger_state) {
spin_unlock_irqrestore(&trig->pollfunc_list_lock,
flags);
/* May sleep hence cannot hold the spin lock */
ret = trig->set_trigger_state(trig, false);
if (ret)
goto error_ret;
spin_lock_irqsave(&trig->pollfunc_list_lock, flags);
}
/*
* Now we can delete safe in the knowledge that, if this is
* the last pollfunc then we have disabled the trigger anyway
* and so nothing should be able to call the pollfunc.
*/
list_del(&pf_cursor->list);
}
spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_trigger_dettach_poll_func);
/**
* iio_trigger_read_currrent() trigger consumer sysfs query which trigger
*
* For trigger consumers the current_trigger interface allows the trigger
* used by the device to be queried.
**/
static ssize_t iio_trigger_read_current(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *dev_info = dev_get_drvdata(dev);
int len = 0;
if (dev_info->trig)
len = snprintf(buf,
IIO_TRIGGER_NAME_LENGTH,
"%s\n",
dev_info->trig->name);
return len;
}
/**
* iio_trigger_write_current() trigger consumer sysfs set current trigger
*
* For trigger consumers the current_trigger interface allows the trigger
* used for this device to be specified at run time based on the triggers
* name.
**/
static ssize_t iio_trigger_write_current(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
struct iio_dev *dev_info = dev_get_drvdata(dev);
struct iio_trigger *oldtrig = dev_info->trig;
mutex_lock(&dev_info->mlock);
if (dev_info->currentmode == INDIO_RING_TRIGGERED) {
mutex_unlock(&dev_info->mlock);
return -EBUSY;
}
mutex_unlock(&dev_info->mlock);
len = len < IIO_TRIGGER_NAME_LENGTH ? len : IIO_TRIGGER_NAME_LENGTH;
dev_info->trig = iio_trigger_find_by_name(buf, len);
if (oldtrig && dev_info->trig != oldtrig)
iio_put_trigger(oldtrig);
if (dev_info->trig)
iio_get_trigger(dev_info->trig);
return len;
}
static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
iio_trigger_read_current,
iio_trigger_write_current);
static struct attribute *iio_trigger_consumer_attrs[] = {
&dev_attr_current_trigger.attr,
NULL,
};
static const struct attribute_group iio_trigger_consumer_attr_group = {
.name = "trigger",
.attrs = iio_trigger_consumer_attrs,
};
static void iio_trig_release(struct device *device)
{
struct iio_trigger *trig = to_iio_trigger(device);
kfree(trig);
iio_put();
}
static struct device_type iio_trig_type = {
.release = iio_trig_release,
};
struct iio_trigger *iio_allocate_trigger(void)
{
struct iio_trigger *trig;
trig = kzalloc(sizeof *trig, GFP_KERNEL);
if (trig) {
trig->dev.type = &iio_trig_type;
trig->dev.bus = &iio_bus_type;
device_initialize(&trig->dev);
dev_set_drvdata(&trig->dev, (void *)trig);
spin_lock_init(&trig->pollfunc_list_lock);
INIT_LIST_HEAD(&trig->list);
INIT_LIST_HEAD(&trig->pollfunc_list);
iio_get();
}
return trig;
}
EXPORT_SYMBOL(iio_allocate_trigger);
void iio_free_trigger(struct iio_trigger *trig)
{
if (trig)
put_device(&trig->dev);
}
EXPORT_SYMBOL(iio_free_trigger);
int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
{
int ret;
ret = sysfs_create_group(&dev_info->dev.kobj,
&iio_trigger_consumer_attr_group);
return ret;
}
EXPORT_SYMBOL(iio_device_register_trigger_consumer);
int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
{
sysfs_remove_group(&dev_info->dev.kobj,
&iio_trigger_consumer_attr_group);
return 0;
}
EXPORT_SYMBOL(iio_device_unregister_trigger_consumer);