staging:iio: Add event monitor example application

Add a small evtest like application to monitor events generated by an IIO
device. The application can be used as an example on how to listen for IIO
events and also is usful for testing and debugging device drivers which
generate IIO events.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 "../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",
+};
+
+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:
+		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;
+}