linux-imx

/**

 * 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 const 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;