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/**
* The industrial I/O periodic hrtimer trigger driver
*
* Copyright (C) Intuitive Aerial AB
* Written by Marten Svanfeldt, marten@intuitiveaerial.com
* Copyright (C) 2012, Analog Device Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
* Copyright (C) 2015, Intel Corporation
*
* 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/slab.h>
#include <linux/hrtimer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/sw_trigger.h>
/* default sampling frequency - 100Hz */
#define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100
struct iio_hrtimer_info {
struct iio_sw_trigger swt;
struct hrtimer timer;
unsigned long sampling_frequency;
ktime_t period;
};
static struct config_item_type iio_hrtimer_type = {
.ct_owner = THIS_MODULE,
};
static
ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
return snprintf(buf, PAGE_SIZE, "%lu\n", info->sampling_frequency);
}
static
ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
unsigned long val;
int ret;
ret = kstrtoul(buf, 10, &val);
if (ret)
return ret;
if (!val || val > NSEC_PER_SEC)
return -EINVAL;
info->sampling_frequency = val;
info->period = ktime_set(0, NSEC_PER_SEC / val);
return len;
}
static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,
iio_hrtimer_show_sampling_frequency,
iio_hrtimer_store_sampling_frequency);
static struct attribute *iio_hrtimer_attrs[] = {
&dev_attr_sampling_frequency.attr,
NULL
};
static const struct attribute_group iio_hrtimer_attr_group = {
.attrs = iio_hrtimer_attrs,
};
static const struct attribute_group *iio_hrtimer_attr_groups[] = {
&iio_hrtimer_attr_group,
NULL
};
static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer)
{
struct iio_hrtimer_info *info;
info = container_of(timer, struct iio_hrtimer_info, timer);
hrtimer_forward_now(timer, info->period);
iio_trigger_poll(info->swt.trigger);
return HRTIMER_RESTART;
}
static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
{
struct iio_hrtimer_info *trig_info;
trig_info = iio_trigger_get_drvdata(trig);
if (state)
hrtimer_start(&trig_info->timer, trig_info->period,
HRTIMER_MODE_REL);
else
hrtimer_cancel(&trig_info->timer);
return 0;
}
static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
.owner = THIS_MODULE,
.set_trigger_state = iio_trig_hrtimer_set_state,
};
static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name)
{
struct iio_hrtimer_info *trig_info;
int ret;
trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
if (!trig_info)
return ERR_PTR(-ENOMEM);
trig_info->swt.trigger = iio_trigger_alloc("%s", name);
if (!trig_info->swt.trigger) {
ret = -ENOMEM;
goto err_free_trig_info;
}
iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info);
trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops;
trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups;
hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
trig_info->timer.function = iio_hrtimer_trig_handler;
trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;
trig_info->period = ktime_set(0, NSEC_PER_SEC /
trig_info->sampling_frequency);
ret = iio_trigger_register(trig_info->swt.trigger);
if (ret)
goto err_free_trigger;
iio_swt_group_init_type_name(&trig_info->swt, name, &iio_hrtimer_type);
return &trig_info->swt;
err_free_trigger:
iio_trigger_free(trig_info->swt.trigger);
err_free_trig_info:
kfree(trig_info);
return ERR_PTR(ret);
}
static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt)
{
struct iio_hrtimer_info *trig_info;
trig_info = iio_trigger_get_drvdata(swt->trigger);
iio_trigger_unregister(swt->trigger);
/* cancel the timer after unreg to make sure no one rearms it */
hrtimer_cancel(&trig_info->timer);
iio_trigger_free(swt->trigger);
kfree(trig_info);
return 0;
}
static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = {
.probe = iio_trig_hrtimer_probe,
.remove = iio_trig_hrtimer_remove,
};
static struct iio_sw_trigger_type iio_trig_hrtimer = {
.name = "hrtimer",
.owner = THIS_MODULE,
.ops = &iio_trig_hrtimer_ops,
};
module_iio_sw_trigger_driver(iio_trig_hrtimer);
MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>");
MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");
MODULE_LICENSE("GPL v2");
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