linux-imx

/* 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/idr.h>

#include <linux/err.h>

#include <linux/device.h>

#include <linux/interrupt.h>

#include <linux/list.h>

#include <linux/slab.h>

​

#include <linux/iio/iio.h>

#include <linux/iio/trigger.h>

#include "iio_core.h"

#include "iio_core_trigger.h"

#include <linux/iio/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_IDA(iio_trigger_ida);

​

/* Single list of all available triggers */

static LIST_HEAD(iio_trigger_list);

static DEFINE_MUTEX(iio_trigger_list_lock);

​

/**

 * iio_trigger_read_name() - retrieve useful identifying name

 * @dev:    device associated with the iio_trigger

 * @attr:   pointer to the device_attribute structure that is

 *      being processed

 * @buf:    buffer to print the name into

 *

 * Return: a negative number on failure or the number of written

 *     characters on success.

 */

static ssize_t iio_trigger_read_name(struct device *dev,

                     struct device_attribute *attr,

                     char *buf)

{

    struct iio_trigger *trig = to_iio_trigger(dev);

    return sprintf(buf, "%s\n", trig->name);

}

​

static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);

​

static struct attribute *iio_trig_dev_attrs[] = {

    &dev_attr_name.attr,

    NULL,

};

ATTRIBUTE_GROUPS(iio_trig_dev);

​

static struct iio_trigger *__iio_trigger_find_by_name(const char *name);

​

int __iio_trigger_register(struct iio_trigger *trig_info,

               struct module *this_mod)

{

    int ret;

​

    trig_info->owner = this_mod;

​

    trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);

    if (trig_info->id < 0)

        return trig_info->id;

​

    /* 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;

​

    /* Add to list of available triggers held by the IIO core */

    mutex_lock(&iio_trigger_list_lock);

    if (__iio_trigger_find_by_name(trig_info->name)) {

        pr_err("Duplicate trigger name '%s'\n", trig_info->name);

        ret = -EEXIST;