This example libiio program is meant to exercise the features of IIO present in the sample dummy IIO device in the linux kernel.
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <stdio.h>
#include <errno.h>
#include <getopt.h>
#include <inttypes.h>
#include <iio/iio.h>
#include <iio/iio-debug.h>
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
#define IIO_ENSURE(expr) { \
if (!(expr)) { \
(void) fprintf(stderr, "assertion failed (%s:%d)\n", __FILE__, __LINE__); \
(void) abort(); \
} \
}
static char *name = "iio_dummy_part_no";
static char *trigger_str = "instance1";
static int buffer_length = 1;
static int count = -1;
enum {
BUFFER_POINTER,
SAMPLE_CALLBACK,
CHANNEL_READ_RAW,
CHANNEL_READ,
MAX_READ_METHOD,
};
static int buffer_read_method = BUFFER_POINTER;
static struct iio_device *dev;
static struct iio_context *ctx;
static struct iio_buffer *rxbuf;
static struct iio_channel **channels;
static unsigned int channel_count;
static struct iio_channels_mask *rxmask;
static struct iio_stream *rxstream;
static bool stop;
static bool has_repeat;
static void shutdown(void)
{
int ret;
if (channels) { free(channels); }
printf("* Destroying stream\n");
if (rxstream) { iio_stream_destroy(rxstream); }
printf("* Destroying buffers\n");
if (rxbuf) { iio_buffer_destroy(rxbuf); }
printf("* Disassociate trigger\n");
if (dev) {
ret = iio_device_set_trigger(dev, NULL);
if (ret < 0) {
char buf[256];
iio_strerror(-ret, buf, sizeof(buf));
fprintf(stderr, "%s while Disassociate trigger\n", buf);
}
}
printf("* Destroying channel masks\n");
if (rxmask)
iio_channels_mask_destroy(rxmask);
printf("* Destroying context\n");
if (ctx) { iio_context_destroy(ctx); }
exit(0);
}
static void handle_sig(int sig)
{
printf("Waiting for process to finish... got signal : %d\n", sig);
stop = true;
}
static ssize_t sample_cb(const struct iio_channel *chn, void *src, size_t bytes, __notused void *d)
{
const struct iio_data_format *fmt = iio_channel_get_data_format(chn);
unsigned int j, repeat = has_repeat ? fmt->repeat : 1;
printf("%s ", iio_channel_get_id(chn));
for (j = 0; j < repeat; ++j) {
if (bytes == sizeof(int16_t))
printf("%" PRIi16 " ", ((int16_t *)src)[j]);
else if (bytes == sizeof(int64_t))
printf("%" PRId64 " ", ((int64_t *)src)[j]);
}
return bytes * repeat;
}
static void usage(__notused int argc, char *argv[])
{
printf("Usage: %s [OPTION]\n", argv[0]);
printf(" -d\tdevice name (default \"iio_dummy_part_no\")\n");
printf(" -t\ttrigger name (default \"instance1\")\n");
printf(" -b\tbuffer length (default 1)\n");
printf(" -r\tread method (default 0 pointer, 1 callback, 2 read raw, 3 read)\n");
printf(" -c\tread count (default no limit)\n");
}
static void parse_options(int argc, char *argv[])
{
int c;
while ((c = getopt(argc, argv, "d:t:b:r:c:h")) != -1) {
switch (c)
{
case 'd':
name = optarg;
break;
case 't':
trigger_str = optarg;
break;
case 'b':
buffer_length = atoi(optarg);
break;
case 'r':
if (atoi(optarg) >= 0 && atoi(optarg) < MAX_READ_METHOD) {
buffer_read_method = atoi(optarg);
} else {
usage(argc, argv);
exit(1);
}
break;
case 'c':
if (atoi(optarg) > 0) {
count = atoi(optarg);
} else {
usage(argc, argv);
exit(1);
}
break;
case 'h':
default:
usage(argc, argv);
exit(1);
}
}
}
int main (int argc, char **argv)
{
unsigned int i, j,
major = iio_context_get_version_major(NULL),
minor = iio_context_get_version_minor(NULL);
int err;
struct iio_device *trigger;
parse_options(argc, argv);
signal(SIGINT, handle_sig);
printf("Library version: %u.%u (git tag: %s)\n", major, minor,
iio_context_get_version_tag(NULL));
has_repeat = ((major * 10000) + minor) >= 8 ? true : false;
printf("* Acquiring IIO context\n");
IIO_ENSURE((ctx = iio_create_context(NULL, NULL)) && "No context");
IIO_ENSURE(iio_context_get_devices_count(ctx) > 0 && "No devices");
printf("* Acquiring device %s\n", name);
dev = iio_context_find_device(ctx, name);
if (!dev) {
fprintf(stderr, "No device found");
shutdown();
}
printf("* Initializing IIO streaming channels:\n");
rxmask = iio_create_channels_mask(iio_device_get_channels_count(dev));
if (!rxmask) {
fprintf(stderr, "Unable to allocate channels mask\n");
shutdown();
}
for (i = 0; i < iio_device_get_channels_count(dev); ++i) {
struct iio_channel *chn = iio_device_get_channel(dev, i);
if (iio_channel_is_scan_element(chn)) {
printf("%s\n", iio_channel_get_id(chn));
channel_count++;
}
}
if (channel_count == 0) {
printf("No scan elements found (make sure the driver built with 'CONFIG_IIO_SIMPLE_DUMMY_BUFFER=y')\n");
shutdown();
}
channels = calloc(channel_count, sizeof *channels);
if (!channels) {
fprintf(stderr, "Channel array allocation failed");
shutdown();
}
for (i = 0; i < channel_count; ++i) {
struct iio_channel *chn = iio_device_get_channel(dev, i);
if (iio_channel_is_scan_element(chn))
channels[i] = chn;
}
printf("* Acquiring trigger %s\n", trigger_str);
trigger = iio_context_find_device(ctx, trigger_str);
if (!trigger || !iio_device_is_trigger(trigger)) {
fprintf(stderr, "No trigger found (try setting up the iio-trig-hrtimer module)");
shutdown();
}
printf("* Enabling IIO streaming channels for buffered capture\n");
for (i = 0; i < channel_count; ++i)
iio_channel_enable(channels[i], rxmask);
printf("* Enabling IIO buffer trigger\n");
if (iio_device_set_trigger(dev, trigger)) {
fprintf(stderr, "Could not set trigger\n");
shutdown();
}
printf("* Creating non-cyclic RX IIO buffer\n");
rxbuf = iio_device_create_buffer(dev, 0, rxmask);
err = iio_err(rxbuf);
if (err) {
rxbuf = NULL;
ctx_perror(ctx, err, "Could not create buffer");
shutdown();
}
printf("* Creating IIO blocks of %u bytes\n", buffer_length);
rxstream = iio_buffer_create_stream(rxbuf, 4, buffer_length);
if (iio_err(rxstream)) {
rxstream = NULL;
ctx_perror(ctx, iio_err(rxstream), "Could not create RX stream");
shutdown();
}
printf("* Starting IO streaming (press CTRL+C to cancel)\n");
bool has_ts = strcmp(iio_channel_get_id(channels[channel_count-1]), "timestamp") == 0;
int64_t last_ts = 0;
while (!stop)
{
const struct iio_block *rxblock;
char *p_dat, *p_end;
ptrdiff_t p_inc;
int64_t now_ts;
rxblock = iio_stream_get_next_block(rxstream);
err = iio_err(rxblock);
if (err) {
ctx_perror(ctx, err, "Unable to receive block");
shutdown();
}
p_inc = iio_device_get_sample_size(dev, rxmask);
p_end = iio_block_end(rxblock);
if (has_ts)
for (p_dat = iio_block_first(rxblock, channels[channel_count-1]); p_dat < p_end; p_dat += p_inc) {
now_ts = (((int64_t *)p_dat)[0]);
printf("[%04" PRId64 "] ", last_ts > 0 ? (now_ts - last_ts)/1000/1000 : 0);
last_ts = now_ts;
}
switch (buffer_read_method)
{
case BUFFER_POINTER:
for (i = 0; i < channel_count; ++i) {
const struct iio_data_format *fmt = iio_channel_get_data_format(channels[i]);
unsigned int repeat = has_repeat ? fmt->repeat : 1;
printf("%s ", iio_channel_get_id(channels[i]));
for (p_dat = iio_block_first(rxblock, channels[i]); p_dat < p_end; p_dat += p_inc) {
for (j = 0; j < repeat; ++j) {
if (fmt->length/8 == sizeof(int16_t))
printf("%" PRIi16 " ", ((int16_t *)p_dat)[j]);
else if (fmt->length/8 == sizeof(int64_t))
printf("%" PRId64 " ", ((int64_t *)p_dat)[j]);
}
}
}
printf("\n");
break;
case SAMPLE_CALLBACK: {
int ret;
ret = iio_block_foreach_sample(rxblock, rxmask, sample_cb, NULL);
if (ret < 0)
dev_perror(dev, ret, "Unable to process buffer");
printf("\n");
break;
}
case CHANNEL_READ_RAW:
case CHANNEL_READ:
for (i = 0; i < channel_count; ++i) {
uint8_t *buf;
size_t sample, bytes;
const struct iio_data_format *fmt = iio_channel_get_data_format(channels[i]);
unsigned int repeat = has_repeat ? fmt->repeat : 1;
size_t sample_size = fmt->length / 8 * repeat;
buf = malloc(sample_size * buffer_length);
if (!buf) {
perror("trying to allocate memory for buffer\n");
shutdown();
}
bytes = iio_channel_read(channels[i], rxblock, buf,
sample_size * buffer_length,
buffer_read_method == CHANNEL_READ_RAW);
printf("%s ", iio_channel_get_id(channels[i]));
for (sample = 0; sample < bytes / sample_size; ++sample) {
for (j = 0; j < repeat; ++j) {
if (fmt->length / 8 == sizeof(int16_t))
printf("%" PRIi16 " ", ((int16_t *)buf)[sample+j]);
else if (fmt->length / 8 == sizeof(int64_t))
printf("%" PRId64 " ", ((int64_t *)buf)[sample+j]);
}
}
free(buf);
}
printf("\n");
break;
}
if (count != -1 && --count == 0)
break;
}
shutdown();
return 0;
}