1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Industrialio buffer test code.
4 * Copyright (c) 2008 Jonathan Cameron
6 * This program is primarily intended as an example application.
7 * Reads the current buffer setup from sysfs and starts a short capture
8 * from the specified device, pretty printing the result after appropriate
11 * Command line parameters
12 * generic_buffer -n <device_name> -t <trigger_name>
13 * If trigger name is not specified the program assumes you want a dataready
14 * trigger associated with the device and goes looking for it.
25 #include <linux/types.h>
33 #include <sys/ioctl.h>
34 #include <linux/iio/buffer.h>
35 #include "iio_utils.h"
38 * enum autochan - state for the automatic channel enabling mechanism
41 AUTOCHANNELS_DISABLED,
47 * size_from_channelarray() - calculate the storage size of a scan
48 * @channels: the channel info array
49 * @num_channels: number of channels
51 * Has the side effect of filling the channels[i].location values used
52 * in processing the buffer output.
54 static unsigned int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
56 unsigned int bytes = 0;
58 unsigned int misalignment;
60 while (i < num_channels) {
61 if (channels[i].bytes > max)
62 max = channels[i].bytes;
63 if (bytes % channels[i].bytes == 0)
64 channels[i].location = bytes;
66 channels[i].location = bytes - bytes % channels[i].bytes
69 bytes = channels[i].location + channels[i].bytes;
73 * We want the data in next sample to also be properly aligned so
74 * we'll add padding at the end if needed. Adding padding only
75 * works for channel data which size is 2^n bytes.
77 misalignment = bytes % max;
79 bytes += max - misalignment;
84 static void print1byte(uint8_t input, struct iio_channel_info *info)
87 * Shift before conversion to avoid sign extension
88 * of left aligned data
90 input >>= info->shift;
92 if (info->is_signed) {
93 int8_t val = (int8_t)(input << (8 - info->bits_used)) >>
94 (8 - info->bits_used);
95 printf("%05f ", ((float)val + info->offset) * info->scale);
97 printf("%05f ", ((float)input + info->offset) * info->scale);
101 static void print2byte(uint16_t input, struct iio_channel_info *info)
103 /* First swap if incorrect endian */
105 input = be16toh(input);
107 input = le16toh(input);
110 * Shift before conversion to avoid sign extension
111 * of left aligned data
113 input >>= info->shift;
115 if (info->is_signed) {
116 int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
117 (16 - info->bits_used);
118 printf("%05f ", ((float)val + info->offset) * info->scale);
120 printf("%05f ", ((float)input + info->offset) * info->scale);
124 static void print4byte(uint32_t input, struct iio_channel_info *info)
126 /* First swap if incorrect endian */
128 input = be32toh(input);
130 input = le32toh(input);
133 * Shift before conversion to avoid sign extension
134 * of left aligned data
136 input >>= info->shift;
138 if (info->is_signed) {
139 int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
140 (32 - info->bits_used);
141 printf("%05f ", ((float)val + info->offset) * info->scale);
143 printf("%05f ", ((float)input + info->offset) * info->scale);
147 static void print8byte(uint64_t input, struct iio_channel_info *info)
149 /* First swap if incorrect endian */
151 input = be64toh(input);
153 input = le64toh(input);
156 * Shift before conversion to avoid sign extension
157 * of left aligned data
159 input >>= info->shift;
161 if (info->is_signed) {
162 int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
163 (64 - info->bits_used);
164 /* special case for timestamp */
165 if (info->scale == 1.0f && info->offset == 0.0f)
166 printf("%" PRId64 " ", val);
169 ((float)val + info->offset) * info->scale);
171 printf("%05f ", ((float)input + info->offset) * info->scale);
176 * process_scan() - print out the values in SI units
177 * @data: pointer to the start of the scan
178 * @channels: information about the channels.
179 * Note: size_from_channelarray must have been called first
180 * to fill the location offsets.
181 * @num_channels: number of channels
183 static void process_scan(char *data, struct iio_channel_info *channels,
188 for (k = 0; k < num_channels; k++)
189 switch (channels[k].bytes) {
190 /* only a few cases implemented so far */
192 print1byte(*(uint8_t *)(data + channels[k].location),
196 print2byte(*(uint16_t *)(data + channels[k].location),
200 print4byte(*(uint32_t *)(data + channels[k].location),
204 print8byte(*(uint64_t *)(data + channels[k].location),
213 static int enable_disable_all_channels(char *dev_dir_name, int buffer_idx, int enable)
215 const struct dirent *ent;
216 char scanelemdir[256];
220 snprintf(scanelemdir, sizeof(scanelemdir),
221 FORMAT_SCAN_ELEMENTS_DIR, dev_dir_name, buffer_idx);
222 scanelemdir[sizeof(scanelemdir)-1] = '\0';
224 dp = opendir(scanelemdir);
226 fprintf(stderr, "Enabling/disabling channels: can't open %s\n",
232 while (ent = readdir(dp), ent) {
233 if (iioutils_check_suffix(ent->d_name, "_en")) {
234 printf("%sabling: %s\n",
235 enable ? "En" : "Dis",
237 ret = write_sysfs_int(ent->d_name, scanelemdir,
240 fprintf(stderr, "Failed to enable/disable %s\n",
245 if (closedir(dp) == -1) {
246 perror("Enabling/disabling channels: "
247 "Failed to close directory");
253 static void print_usage(void)
255 fprintf(stderr, "Usage: generic_buffer [options]...\n"
256 "Capture, convert and output data from IIO device buffer\n"
257 " -a Auto-activate all available channels\n"
258 " -A Force-activate ALL channels\n"
259 " -b <n> The buffer which to open (by index), default 0\n"
260 " -c <n> Do n conversions, or loop forever if n < 0\n"
261 " -e Disable wait for event (new data)\n"
262 " -g Use trigger-less mode\n"
263 " -l <n> Set buffer length to n samples\n"
264 " --device-name -n <name>\n"
265 " --device-num -N <num>\n"
266 " Set device by name or number (mandatory)\n"
267 " --trigger-name -t <name>\n"
268 " --trigger-num -T <num>\n"
269 " Set trigger by name or number\n"
270 " -w <n> Set delay between reads in us (event-less mode)\n");
273 static enum autochan autochannels = AUTOCHANNELS_DISABLED;
274 static char *dev_dir_name = NULL;
275 static char *buf_dir_name = NULL;
276 static int buffer_idx = 0;
277 static bool current_trigger_set = false;
279 static void cleanup(void)
283 /* Disable trigger */
284 if (dev_dir_name && current_trigger_set) {
285 /* Disconnect the trigger - just write a dummy name. */
286 ret = write_sysfs_string("trigger/current_trigger",
287 dev_dir_name, "NULL");
289 fprintf(stderr, "Failed to disable trigger: %s\n",
291 current_trigger_set = false;
296 ret = write_sysfs_int("enable", buf_dir_name, 0);
298 fprintf(stderr, "Failed to disable buffer: %s\n",
302 /* Disable channels if auto-enabled */
303 if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) {
304 ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 0);
306 fprintf(stderr, "Failed to disable all channels\n");
307 autochannels = AUTOCHANNELS_DISABLED;
311 static void sig_handler(int signum)
313 fprintf(stderr, "Caught signal %d\n", signum);
318 static void register_cleanup(void)
320 struct sigaction sa = { .sa_handler = sig_handler };
321 const int signums[] = { SIGINT, SIGTERM, SIGABRT };
324 for (i = 0; i < ARRAY_SIZE(signums); ++i) {
325 ret = sigaction(signums[i], &sa, NULL);
327 perror("Failed to register signal handler");
333 static const struct option longopts[] = {
334 { "device-name", 1, 0, 'n' },
335 { "device-num", 1, 0, 'N' },
336 { "trigger-name", 1, 0, 't' },
337 { "trigger-num", 1, 0, 'T' },
341 int main(int argc, char **argv)
343 long long num_loops = 2;
344 unsigned long timedelay = 1000000;
345 unsigned long buf_len = 128;
348 unsigned long long j;
349 unsigned long toread;
355 int num_channels = 0;
356 char *trigger_name = NULL, *device_name = NULL;
360 int dev_num = -1, trig_num = -1;
361 char *buffer_access = NULL;
362 unsigned int scan_size;
366 bool force_autochannels = false;
368 struct iio_channel_info *channels = NULL;
372 while ((c = getopt_long(argc, argv, "aAb:c:egl:n:N:t:T:w:?", longopts,
376 autochannels = AUTOCHANNELS_ENABLED;
379 autochannels = AUTOCHANNELS_ENABLED;
380 force_autochannels = true;
384 buffer_idx = strtoll(optarg, &dummy, 10);
389 if (buffer_idx < 0) {
397 num_loops = strtoll(optarg, &dummy, 10);
412 buf_len = strtoul(optarg, &dummy, 10);
420 device_name = strdup(optarg);
424 dev_num = strtoul(optarg, &dummy, 10);
431 trigger_name = strdup(optarg);
435 trig_num = strtoul(optarg, &dummy, 10);
441 timedelay = strtoul(optarg, &dummy, 10);
454 /* Find the device requested */
455 if (dev_num < 0 && !device_name) {
456 fprintf(stderr, "Device not set\n");
460 } else if (dev_num >= 0 && device_name) {
461 fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n");
465 } else if (dev_num < 0) {
466 dev_num = find_type_by_name(device_name, "iio:device");
468 fprintf(stderr, "Failed to find the %s\n", device_name);
473 printf("iio device number being used is %d\n", dev_num);
475 ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
478 /* Fetch device_name if specified by number */
480 device_name = malloc(IIO_MAX_NAME_LENGTH);
485 ret = read_sysfs_string("name", dev_dir_name, device_name);
487 fprintf(stderr, "Failed to read name of device %d\n", dev_num);
493 printf("trigger-less mode selected\n");
494 } else if (trig_num >= 0) {
496 ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
500 trigger_name = malloc(IIO_MAX_NAME_LENGTH);
501 ret = read_sysfs_string("name", trig_dev_name, trigger_name);
504 fprintf(stderr, "Failed to read trigger%d name from\n", trig_num);
507 printf("iio trigger number being used is %d\n", trig_num);
511 * Build the trigger name. If it is device associated
512 * its name is <device_name>_dev[n] where n matches
513 * the device number found above.
515 ret = asprintf(&trigger_name,
516 "%s-dev%d", device_name, dev_num);
523 /* Look for this "-devN" trigger */
524 trig_num = find_type_by_name(trigger_name, "trigger");
526 /* OK try the simpler "-trigger" suffix instead */
528 ret = asprintf(&trigger_name,
529 "%s-trigger", device_name);
536 trig_num = find_type_by_name(trigger_name, "trigger");
538 fprintf(stderr, "Failed to find the trigger %s\n",
544 printf("iio trigger number being used is %d\n", trig_num);
548 * Parse the files in scan_elements to identify what channels are
551 ret = build_channel_array(dev_dir_name, buffer_idx, &channels, &num_channels);
553 fprintf(stderr, "Problem reading scan element information\n"
554 "diag %s\n", dev_dir_name);
557 if (num_channels && autochannels == AUTOCHANNELS_ENABLED &&
558 !force_autochannels) {
559 fprintf(stderr, "Auto-channels selected but some channels "
560 "are already activated in sysfs\n");
561 fprintf(stderr, "Proceeding without activating any channels\n");
564 if ((!num_channels && autochannels == AUTOCHANNELS_ENABLED) ||
565 (autochannels == AUTOCHANNELS_ENABLED && force_autochannels)) {
566 fprintf(stderr, "Enabling all channels\n");
568 ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 1);
570 fprintf(stderr, "Failed to enable all channels\n");
574 /* This flags that we need to disable the channels again */
575 autochannels = AUTOCHANNELS_ACTIVE;
577 ret = build_channel_array(dev_dir_name, buffer_idx, &channels,
580 fprintf(stderr, "Problem reading scan element "
582 "diag %s\n", dev_dir_name);
586 fprintf(stderr, "Still no channels after "
587 "auto-enabling, giving up\n");
592 if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) {
594 "No channels are enabled, we have nothing to scan.\n");
595 fprintf(stderr, "Enable channels manually in "
596 FORMAT_SCAN_ELEMENTS_DIR
597 "/*_en or pass -a to autoenable channels and "
598 "try again.\n", dev_dir_name, buffer_idx);
604 * Construct the directory name for the associated buffer.
605 * As we know that the lis3l02dq has only one buffer this may
606 * be built rather than found.
608 ret = asprintf(&buf_dir_name,
609 "%siio:device%d/buffer%d", iio_dir, dev_num, buffer_idx);
615 if (stat(buf_dir_name, &st)) {
616 fprintf(stderr, "Could not stat() '%s', got error %d: %s\n",
617 buf_dir_name, errno, strerror(errno));
622 if (!S_ISDIR(st.st_mode)) {
623 fprintf(stderr, "File '%s' is not a directory\n", buf_dir_name);
629 printf("%s %s\n", dev_dir_name, trigger_name);
631 * Set the device trigger to be the data ready trigger found
634 ret = write_sysfs_string_and_verify("trigger/current_trigger",
639 "Failed to write current_trigger file\n");
644 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
650 /* Attempt to open non blocking the access dev */
651 fd = open(buffer_access, O_RDONLY | O_NONBLOCK);
652 if (fd == -1) { /* TODO: If it isn't there make the node */
654 fprintf(stderr, "Failed to open %s\n", buffer_access);
658 /* specify for which buffer index we want an FD */
661 ret = ioctl(fd, IIO_BUFFER_GET_FD_IOCTL, &buf_fd);
662 if (ret == -1 || buf_fd == -1) {
664 if (ret == -ENODEV || ret == -EINVAL)
666 "Device does not have this many buffers\n");
668 fprintf(stderr, "Failed to retrieve buffer fd\n");
673 /* Setup ring buffer parameters */
674 ret = write_sysfs_int("length", buf_dir_name, buf_len);
678 /* Enable the buffer */
679 ret = write_sysfs_int("enable", buf_dir_name, 1);
682 "Failed to enable buffer '%s': %s\n",
683 buf_dir_name, strerror(-ret));
687 scan_size = size_from_channelarray(channels, num_channels);
689 size_t total_buf_len = scan_size * buf_len;
691 if (scan_size > 0 && total_buf_len / scan_size != buf_len) {
693 perror("Integer overflow happened when calculate scan_size * buf_len");
697 data = malloc(total_buf_len);
704 * This check is being done here for sanity reasons, however it
705 * should be omitted under normal operation.
706 * If this is buffer0, we check that we get EBUSY after this point.
708 if (buffer_idx == 0) {
710 read_size = read(fd, data, 1);
711 if (read_size > -1 || errno != EBUSY) {
713 perror("Reading from '%s' should not be possible after ioctl()");
718 /* close now the main chardev FD and let the buffer FD work */
720 perror("Failed to close character device file");
723 for (j = 0; j < num_loops || num_loops < 0; j++) {
725 struct pollfd pfd = {
730 ret = poll(&pfd, 1, -1);
734 } else if (ret == 0) {
744 read_size = read(buf_fd, data, toread * scan_size);
746 if (errno == EAGAIN) {
747 fprintf(stderr, "nothing available\n");
753 for (i = 0; i < read_size / scan_size; i++)
754 process_scan(data + scan_size * i, channels,
761 if (fd >= 0 && close(fd) == -1)
762 perror("Failed to close character device");
763 if (buf_fd >= 0 && close(buf_fd) == -1)
764 perror("Failed to close buffer");
768 for (i = num_channels - 1; i >= 0; i--) {
769 free(channels[i].name);
770 free(channels[i].generic_name);