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-rw-r--r--tools/iio/generic_buffer.c359
1 files changed, 359 insertions, 0 deletions
diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c
new file mode 100644
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+++ b/tools/iio/generic_buffer.c
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+/* Industrialio buffer test code.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * Command line parameters
+ * generic_buffer -n <device_name> -t <trigger_name>
+ * If trigger name is not specified the program assumes you want a dataready
+ * trigger associated with the device and goes looking for it.
+ *
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/dir.h>
+#include <linux/types.h>
+#include <string.h>
+#include <poll.h>
+#include <endian.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include "iio_utils.h"
+
+/**
+ * size_from_channelarray() - calculate the storage size of a scan
+ * @channels: the channel info array
+ * @num_channels: number of channels
+ *
+ * Has the side effect of filling the channels[i].location values used
+ * in processing the buffer output.
+ **/
+int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
+{
+ int bytes = 0;
+ int i = 0;
+
+ while (i < num_channels) {
+ if (bytes % channels[i].bytes == 0)
+ channels[i].location = bytes;
+ else
+ channels[i].location = bytes - bytes%channels[i].bytes
+ + channels[i].bytes;
+ bytes = channels[i].location + channels[i].bytes;
+ i++;
+ }
+ return bytes;
+}
+
+void print2byte(int input, struct iio_channel_info *info)
+{
+ /* First swap if incorrect endian */
+ if (info->be)
+ input = be16toh((uint16_t)input);
+ else
+ input = le16toh((uint16_t)input);
+
+ /*
+ * Shift before conversion to avoid sign extension
+ * of left aligned data
+ */
+ input >>= info->shift;
+ if (info->is_signed) {
+ int16_t val = input;
+
+ val &= (1 << info->bits_used) - 1;
+ val = (int16_t)(val << (16 - info->bits_used)) >>
+ (16 - info->bits_used);
+ printf("%05f ", ((float)val + info->offset)*info->scale);
+ } else {
+ uint16_t val = input;
+
+ val &= (1 << info->bits_used) - 1;
+ printf("%05f ", ((float)val + info->offset)*info->scale);
+ }
+}
+/**
+ * process_scan() - print out the values in SI units
+ * @data: pointer to the start of the scan
+ * @channels: information about the channels. Note
+ * size_from_channelarray must have been called first to fill the
+ * location offsets.
+ * @num_channels: number of channels
+ **/
+void process_scan(char *data,
+ struct iio_channel_info *channels,
+ int num_channels)
+{
+ int k;
+
+ for (k = 0; k < num_channels; k++)
+ switch (channels[k].bytes) {
+ /* only a few cases implemented so far */
+ case 2:
+ print2byte(*(uint16_t *)(data + channels[k].location),
+ &channels[k]);
+ break;
+ case 4:
+ if (!channels[k].is_signed) {
+ uint32_t val = *(uint32_t *)
+ (data + channels[k].location);
+ printf("%05f ", ((float)val +
+ channels[k].offset)*
+ channels[k].scale);
+
+ }
+ break;
+ case 8:
+ if (channels[k].is_signed) {
+ int64_t val = *(int64_t *)
+ (data +
+ channels[k].location);
+ if ((val >> channels[k].bits_used) & 1)
+ val = (val & channels[k].mask) |
+ ~channels[k].mask;
+ /* special case for timestamp */
+ if (channels[k].scale == 1.0f &&
+ channels[k].offset == 0.0f)
+ printf("%" PRId64 " ", val);
+ else
+ printf("%05f ", ((float)val +
+ channels[k].offset)*
+ channels[k].scale);
+ }
+ break;
+ default:
+ break;
+ }
+ printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+ unsigned long num_loops = 2;
+ unsigned long timedelay = 1000000;
+ unsigned long buf_len = 128;
+
+ int ret, c, i, j, toread;
+ int fp;
+
+ int num_channels;
+ char *trigger_name = NULL, *device_name = NULL;
+ char *dev_dir_name, *buf_dir_name;
+
+ int datardytrigger = 1;
+ char *data;
+ ssize_t read_size;
+ int dev_num, trig_num;
+ char *buffer_access;
+ int scan_size;
+ int noevents = 0;
+ int notrigger = 0;
+ char *dummy;
+
+ struct iio_channel_info *channels;
+
+ while ((c = getopt(argc, argv, "l:w:c:et:n:g")) != -1) {
+ switch (c) {
+ case 'n':
+ device_name = optarg;
+ break;
+ case 't':
+ trigger_name = optarg;
+ datardytrigger = 0;
+ break;
+ case 'e':
+ noevents = 1;
+ break;
+ case 'c':
+ num_loops = strtoul(optarg, &dummy, 10);
+ break;
+ case 'w':
+ timedelay = strtoul(optarg, &dummy, 10);
+ break;
+ case 'l':
+ buf_len = strtoul(optarg, &dummy, 10);
+ break;
+ case 'g':
+ notrigger = 1;
+ break;
+ case '?':
+ return -1;
+ }
+ }
+
+ if (device_name == NULL)
+ return -1;
+
+ /* Find the device requested */
+ dev_num = find_type_by_name(device_name, "iio:device");
+ if (dev_num < 0) {
+ printf("Failed to find the %s\n", device_name);
+ ret = -ENODEV;
+ goto error_ret;
+ }
+ printf("iio device number being used is %d\n", dev_num);
+
+ asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
+
+ if (!notrigger) {
+ if (trigger_name == NULL) {
+ /*
+ * Build the trigger name. If it is device associated
+ * its name is <device_name>_dev[n] where n matches
+ * the device number found above.
+ */
+ ret = asprintf(&trigger_name,
+ "%s-dev%d", device_name, dev_num);
+ if (ret < 0) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ }
+
+ /* Verify the trigger exists */
+ trig_num = find_type_by_name(trigger_name, "trigger");
+ if (trig_num < 0) {
+ printf("Failed to find the trigger %s\n", trigger_name);
+ ret = -ENODEV;
+ goto error_free_triggername;
+ }
+ printf("iio trigger number being used is %d\n", trig_num);
+ } else
+ printf("trigger-less mode selected\n");
+
+ /*
+ * Parse the files in scan_elements to identify what channels are
+ * present
+ */
+ ret = build_channel_array(dev_dir_name, &channels, &num_channels);
+ if (ret) {
+ printf("Problem reading scan element information\n");
+ printf("diag %s\n", dev_dir_name);
+ goto error_free_triggername;
+ }
+
+ /*
+ * Construct the directory name for the associated buffer.
+ * As we know that the lis3l02dq has only one buffer this may
+ * be built rather than found.
+ */
+ ret = asprintf(&buf_dir_name,
+ "%siio:device%d/buffer", iio_dir, dev_num);
+ if (ret < 0) {
+ ret = -ENOMEM;
+ goto error_free_triggername;
+ }
+
+ if (!notrigger) {
+ printf("%s %s\n", dev_dir_name, trigger_name);
+ /* Set the device trigger to be the data ready trigger found
+ * above */
+ ret = write_sysfs_string_and_verify("trigger/current_trigger",
+ dev_dir_name,
+ trigger_name);
+ if (ret < 0) {
+ printf("Failed to write current_trigger file\n");
+ goto error_free_buf_dir_name;
+ }
+ }
+
+ /* Setup ring buffer parameters */
+ ret = write_sysfs_int("length", buf_dir_name, buf_len);
+ if (ret < 0)
+ goto error_free_buf_dir_name;
+
+ /* Enable the buffer */
+ ret = write_sysfs_int("enable", buf_dir_name, 1);
+ if (ret < 0)
+ goto error_free_buf_dir_name;
+ scan_size = size_from_channelarray(channels, num_channels);
+ data = malloc(scan_size*buf_len);
+ if (!data) {
+ ret = -ENOMEM;
+ goto error_free_buf_dir_name;
+ }
+
+ ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
+ if (ret < 0) {
+ ret = -ENOMEM;
+ goto error_free_data;
+ }
+
+ /* Attempt to open non blocking the access dev */
+ fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
+ if (fp == -1) { /* If it isn't there make the node */
+ printf("Failed to open %s\n", buffer_access);
+ ret = -errno;
+ goto error_free_buffer_access;
+ }
+
+ /* Wait for events 10 times */
+ for (j = 0; j < num_loops; j++) {
+ if (!noevents) {
+ struct pollfd pfd = {
+ .fd = fp,
+ .events = POLLIN,
+ };
+
+ poll(&pfd, 1, -1);
+ toread = buf_len;
+
+ } else {
+ usleep(timedelay);
+ toread = 64;
+ }
+
+ read_size = read(fp,
+ data,
+ toread*scan_size);
+ if (read_size < 0) {
+ if (errno == -EAGAIN) {
+ printf("nothing available\n");
+ continue;
+ } else
+ break;
+ }
+ for (i = 0; i < read_size/scan_size; i++)
+ process_scan(data + scan_size*i,
+ channels,
+ num_channels);
+ }
+
+ /* Stop the buffer */
+ ret = write_sysfs_int("enable", buf_dir_name, 0);
+ if (ret < 0)
+ goto error_close_buffer_access;
+
+ if (!notrigger)
+ /* Disconnect the trigger - just write a dummy name. */
+ write_sysfs_string("trigger/current_trigger",
+ dev_dir_name, "NULL");
+
+error_close_buffer_access:
+ close(fp);
+error_free_data:
+ free(data);
+error_free_buffer_access:
+ free(buffer_access);
+error_free_buf_dir_name:
+ free(buf_dir_name);
+error_free_triggername:
+ if (datardytrigger)
+ free(trigger_name);
+error_ret:
+ return ret;
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.