drivers/staging/iio/Documentation/iio_event_monitor.c

/* Industrialio event test code.
 *
 * Copyright (c) 2011-2012 Lars-Peter Clausen <lars@metafoo.de>
 *
 * 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.
 *
 * This program is primarily intended as an example application.
 * Reads the current buffer setup from sysfs and starts a short capture
 * from the specified device, pretty printing the result after appropriate
 * conversion.
 *
 * Usage:
 *	iio_event_monitor <device_name>
 *
 */

#define _GNU_SOURCE

#include <unistd.h>
#include <stdbool.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <poll.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include "iio_utils.h"
#include <linux/iio/events.h>

static const char * const iio_chan_type_name_spec[] = {
	[IIO_VOLTAGE] = "voltage",
	[IIO_CURRENT] = "current",
	[IIO_POWER] = "power",
	[IIO_ACCEL] = "accel",
	[IIO_ANGL_VEL] = "anglvel",
	[IIO_MAGN] = "magn",
	[IIO_LIGHT] = "illuminance",
	[IIO_INTENSITY] = "intensity",
	[IIO_PROXIMITY] = "proximity",
	[IIO_TEMP] = "temp",
	[IIO_INCLI] = "incli",
	[IIO_ROT] = "rot",
	[IIO_ANGL] = "angl",
	[IIO_TIMESTAMP] = "timestamp",
	[IIO_CAPACITANCE] = "capacitance",
	[IIO_ALTVOLTAGE] = "altvoltage",
};

static const char * const iio_ev_type_text[] = {
	[IIO_EV_TYPE_THRESH] = "thresh",
	[IIO_EV_TYPE_MAG] = "mag",
	[IIO_EV_TYPE_ROC] = "roc",
	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
};

static const char * const iio_ev_dir_text[] = {
	[IIO_EV_DIR_EITHER] = "either",
	[IIO_EV_DIR_RISING] = "rising",
	[IIO_EV_DIR_FALLING] = "falling"
};

static const char * const iio_modifier_names[] = {
	[IIO_MOD_X] = "x",
	[IIO_MOD_Y] = "y",
	[IIO_MOD_Z] = "z",
	[IIO_MOD_LIGHT_BOTH] = "both",
	[IIO_MOD_LIGHT_IR] = "ir",
};

static bool event_is_known(struct iio_event_data *event)
{
	enum iio_chan_type type = IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event->id);
	enum iio_modifier mod = IIO_EVENT_CODE_EXTRACT_MODIFIER(event->id);
	enum iio_event_type ev_type = IIO_EVENT_CODE_EXTRACT_TYPE(event->id);
	enum iio_event_direction dir = IIO_EVENT_CODE_EXTRACT_DIR(event->id);

	switch (type) {
	case IIO_VOLTAGE:
	case IIO_CURRENT:
	case IIO_POWER:
	case IIO_ACCEL:
	case IIO_ANGL_VEL:
	case IIO_MAGN:
	case IIO_LIGHT:
	case IIO_INTENSITY:
	case IIO_PROXIMITY:
	case IIO_TEMP:
	case IIO_INCLI:
	case IIO_ROT:
	case IIO_ANGL:
	case IIO_TIMESTAMP:
	case IIO_CAPACITANCE:
	case IIO_ALTVOLTAGE:
		break;
	default:
		return false;
	}

	switch (mod) {
	case IIO_NO_MOD:
	case IIO_MOD_X:
	case IIO_MOD_Y:
	case IIO_MOD_Z:
	case IIO_MOD_LIGHT_BOTH:
	case IIO_MOD_LIGHT_IR:
		break;
	default:
		return false;
	}

	switch (ev_type) {
	case IIO_EV_TYPE_THRESH:
	case IIO_EV_TYPE_MAG:
	case IIO_EV_TYPE_ROC:
	case IIO_EV_TYPE_THRESH_ADAPTIVE:
	case IIO_EV_TYPE_MAG_ADAPTIVE:
		break;
	default:
		return false;
	}

	switch (dir) {
	case IIO_EV_DIR_EITHER:
	case IIO_EV_DIR_RISING:
	case IIO_EV_DIR_FALLING:
		break;
	default:
		return false;
	}

	return true;
}

static void print_event(struct iio_event_data *event)
{
	enum iio_chan_type type = IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event->id);
	enum iio_modifier mod = IIO_EVENT_CODE_EXTRACT_MODIFIER(event->id);
	enum iio_event_type ev_type = IIO_EVENT_CODE_EXTRACT_TYPE(event->id);
	enum iio_event_direction dir = IIO_EVENT_CODE_EXTRACT_DIR(event->id);
	int chan = IIO_EVENT_CODE_EXTRACT_CHAN(event->id);
	int chan2 = IIO_EVENT_CODE_EXTRACT_CHAN2(event->id);
	bool diff = IIO_EVENT_CODE_EXTRACT_DIFF(event->id);

	if (!event_is_known(event)) {
		printf("Unknown event: time: %lld, id: %llx\n",
				event->timestamp, event->id);
		return;
	}

	printf("Event: time: %lld, ", event->timestamp);

	if (mod != IIO_NO_MOD) {
		printf("type: %s(%s), ",
			iio_chan_type_name_spec[type],
			iio_modifier_names[mod]);
	} else {
		printf("type: %s, ",
			iio_chan_type_name_spec[type]);
	}

	if (diff && chan >= 0 && chan2 >= 0)
		printf("channel: %d-%d, ", chan, chan2);
	else if (chan >= 0)
		printf("channel: %d, ", chan);

	printf("evtype: %s, direction: %s\n",
		iio_ev_type_text[ev_type],
		iio_ev_dir_text[dir]);
}

int main(int argc, char **argv)
{
	struct iio_event_data event;
	const char *device_name;
	char *chrdev_name;
	int ret;
	int dev_num;
	int fd, event_fd;

	if (argc <= 1) {
		printf("Usage: %s <device_name>\n", argv[0]);
		return -1;
	}

	device_name = argv[1];

	dev_num = find_type_by_name(device_name, "iio:device");
	if (dev_num >= 0) {
		printf("Found IIO device with name %s with device number %d\n",
			device_name, dev_num);
		ret = asprintf(&chrdev_name, "/dev/iio:device%d", dev_num);
		if (ret < 0) {
			ret = -ENOMEM;
			goto error_ret;
		}
	} else {
		/* If we can't find a IIO device by name assume device_name is a
		   IIO chrdev */
		chrdev_name = strdup(device_name);
	}

	fd = open(chrdev_name, 0);
	if (fd == -1) {
		fprintf(stdout, "Failed to open %s\n", chrdev_name);
		ret = -errno;
		goto error_free_chrdev_name;
	}

	ret = ioctl(fd, IIO_GET_EVENT_FD_IOCTL, &event_fd);

	close(fd);

	if (ret == -1 || event_fd == -1) {
		fprintf(stdout, "Failed to retrieve event fd\n");
		ret = -errno;
		goto error_free_chrdev_name;
	}

	while (true) {
		ret = read(event_fd, &event, sizeof(event));
		if (ret == -1) {
			if (errno == EAGAIN) {
				printf("nothing available\n");
				continue;
			} else {
				perror("Failed to read event from device");
				ret = -errno;
				break;
			}
		}

		print_event(&event);
	}

	close(event_fd);
error_free_chrdev_name:
	free(chrdev_name);
error_ret:
	return ret;
}