360 lines
8.4 KiB
C
360 lines
8.4 KiB
C
/* Industrialio buffer test code.
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*
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* Copyright (c) 2008 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is primarily intended as an example application.
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* Reads the current buffer setup from sysfs and starts a short capture
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* from the specified device, pretty printing the result after appropriate
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* conversion.
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*
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* Command line parameters
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* generic_buffer -n <device_name> -t <trigger_name>
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* If trigger name is not specified the program assumes you want a dataready
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* trigger associated with the device and goes looking for it.
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*
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <sys/dir.h>
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#include <linux/types.h>
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#include <string.h>
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#include <poll.h>
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#include <endian.h>
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#include <getopt.h>
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#include <inttypes.h>
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#include "iio_utils.h"
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/**
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* size_from_channelarray() - calculate the storage size of a scan
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* @channels: the channel info array
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* @num_channels: number of channels
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*
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* Has the side effect of filling the channels[i].location values used
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* in processing the buffer output.
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**/
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int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
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{
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int bytes = 0;
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int i = 0;
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while (i < num_channels) {
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if (bytes % channels[i].bytes == 0)
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channels[i].location = bytes;
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else
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channels[i].location = bytes - bytes%channels[i].bytes
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+ channels[i].bytes;
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bytes = channels[i].location + channels[i].bytes;
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i++;
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}
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return bytes;
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}
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void print2byte(int input, struct iio_channel_info *info)
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{
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/* First swap if incorrect endian */
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if (info->be)
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input = be16toh((uint16_t)input);
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else
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input = le16toh((uint16_t)input);
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/*
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* Shift before conversion to avoid sign extension
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* of left aligned data
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*/
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input >>= info->shift;
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if (info->is_signed) {
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int16_t val = input;
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val &= (1 << info->bits_used) - 1;
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val = (int16_t)(val << (16 - info->bits_used)) >>
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(16 - info->bits_used);
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printf("%05f ", ((float)val + info->offset)*info->scale);
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} else {
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uint16_t val = input;
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val &= (1 << info->bits_used) - 1;
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printf("%05f ", ((float)val + info->offset)*info->scale);
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}
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}
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/**
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* process_scan() - print out the values in SI units
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* @data: pointer to the start of the scan
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* @channels: information about the channels. Note
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* size_from_channelarray must have been called first to fill the
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* location offsets.
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* @num_channels: number of channels
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**/
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void process_scan(char *data,
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struct iio_channel_info *channels,
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int num_channels)
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{
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int k;
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for (k = 0; k < num_channels; k++)
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switch (channels[k].bytes) {
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/* only a few cases implemented so far */
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case 2:
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print2byte(*(uint16_t *)(data + channels[k].location),
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&channels[k]);
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break;
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case 4:
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if (!channels[k].is_signed) {
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uint32_t val = *(uint32_t *)
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(data + channels[k].location);
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printf("%05f ", ((float)val +
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channels[k].offset)*
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channels[k].scale);
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}
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break;
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case 8:
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if (channels[k].is_signed) {
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int64_t val = *(int64_t *)
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(data +
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channels[k].location);
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if ((val >> channels[k].bits_used) & 1)
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val = (val & channels[k].mask) |
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~channels[k].mask;
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/* special case for timestamp */
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if (channels[k].scale == 1.0f &&
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channels[k].offset == 0.0f)
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printf("%" PRId64 " ", val);
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else
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printf("%05f ", ((float)val +
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channels[k].offset)*
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channels[k].scale);
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}
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break;
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default:
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break;
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}
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printf("\n");
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}
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int main(int argc, char **argv)
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{
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unsigned long num_loops = 2;
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unsigned long timedelay = 1000000;
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unsigned long buf_len = 128;
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int ret, c, i, j, toread;
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int fp;
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int num_channels;
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char *trigger_name = NULL, *device_name = NULL;
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char *dev_dir_name, *buf_dir_name;
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int datardytrigger = 1;
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char *data;
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ssize_t read_size;
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int dev_num, trig_num;
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char *buffer_access;
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int scan_size;
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int noevents = 0;
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int notrigger = 0;
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char *dummy;
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struct iio_channel_info *channels;
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while ((c = getopt(argc, argv, "l:w:c:et:n:g")) != -1) {
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switch (c) {
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case 'n':
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device_name = optarg;
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break;
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case 't':
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trigger_name = optarg;
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datardytrigger = 0;
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break;
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case 'e':
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noevents = 1;
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break;
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case 'c':
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num_loops = strtoul(optarg, &dummy, 10);
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break;
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case 'w':
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timedelay = strtoul(optarg, &dummy, 10);
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break;
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case 'l':
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buf_len = strtoul(optarg, &dummy, 10);
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break;
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case 'g':
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notrigger = 1;
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break;
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case '?':
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return -1;
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}
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}
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if (device_name == NULL)
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return -1;
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/* Find the device requested */
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dev_num = find_type_by_name(device_name, "iio:device");
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if (dev_num < 0) {
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printf("Failed to find the %s\n", device_name);
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ret = -ENODEV;
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goto error_ret;
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}
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printf("iio device number being used is %d\n", dev_num);
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asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
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if (!notrigger) {
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if (trigger_name == NULL) {
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/*
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* Build the trigger name. If it is device associated
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* its name is <device_name>_dev[n] where n matches
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* the device number found above.
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*/
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ret = asprintf(&trigger_name,
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"%s-dev%d", device_name, dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_ret;
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}
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}
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/* Verify the trigger exists */
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trig_num = find_type_by_name(trigger_name, "trigger");
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if (trig_num < 0) {
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printf("Failed to find the trigger %s\n", trigger_name);
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ret = -ENODEV;
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goto error_free_triggername;
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}
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printf("iio trigger number being used is %d\n", trig_num);
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} else
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printf("trigger-less mode selected\n");
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/*
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* Parse the files in scan_elements to identify what channels are
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* present
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*/
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ret = build_channel_array(dev_dir_name, &channels, &num_channels);
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if (ret) {
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printf("Problem reading scan element information\n");
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printf("diag %s\n", dev_dir_name);
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goto error_free_triggername;
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}
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/*
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* Construct the directory name for the associated buffer.
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* As we know that the lis3l02dq has only one buffer this may
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* be built rather than found.
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*/
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ret = asprintf(&buf_dir_name,
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"%siio:device%d/buffer", iio_dir, dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_free_triggername;
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}
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if (!notrigger) {
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printf("%s %s\n", dev_dir_name, trigger_name);
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/* Set the device trigger to be the data ready trigger found
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* above */
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ret = write_sysfs_string_and_verify("trigger/current_trigger",
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dev_dir_name,
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trigger_name);
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if (ret < 0) {
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printf("Failed to write current_trigger file\n");
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goto error_free_buf_dir_name;
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}
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}
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/* Setup ring buffer parameters */
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ret = write_sysfs_int("length", buf_dir_name, buf_len);
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if (ret < 0)
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goto error_free_buf_dir_name;
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/* Enable the buffer */
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ret = write_sysfs_int("enable", buf_dir_name, 1);
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if (ret < 0)
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goto error_free_buf_dir_name;
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scan_size = size_from_channelarray(channels, num_channels);
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data = malloc(scan_size*buf_len);
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if (!data) {
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ret = -ENOMEM;
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goto error_free_buf_dir_name;
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}
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ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_free_data;
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}
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/* Attempt to open non blocking the access dev */
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fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
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if (fp == -1) { /* If it isn't there make the node */
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printf("Failed to open %s\n", buffer_access);
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ret = -errno;
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goto error_free_buffer_access;
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}
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/* Wait for events 10 times */
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for (j = 0; j < num_loops; j++) {
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if (!noevents) {
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struct pollfd pfd = {
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.fd = fp,
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.events = POLLIN,
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};
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poll(&pfd, 1, -1);
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toread = buf_len;
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} else {
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usleep(timedelay);
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toread = 64;
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}
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read_size = read(fp,
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data,
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toread*scan_size);
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if (read_size < 0) {
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if (errno == -EAGAIN) {
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printf("nothing available\n");
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continue;
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} else
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break;
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}
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for (i = 0; i < read_size/scan_size; i++)
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process_scan(data + scan_size*i,
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channels,
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num_channels);
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}
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/* Stop the buffer */
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ret = write_sysfs_int("enable", buf_dir_name, 0);
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if (ret < 0)
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goto error_close_buffer_access;
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if (!notrigger)
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/* Disconnect the trigger - just write a dummy name. */
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write_sysfs_string("trigger/current_trigger",
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dev_dir_name, "NULL");
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error_close_buffer_access:
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close(fp);
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error_free_data:
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free(data);
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error_free_buffer_access:
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free(buffer_access);
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error_free_buf_dir_name:
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free(buf_dir_name);
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error_free_triggername:
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if (datardytrigger)
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free(trigger_name);
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error_ret:
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return ret;
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}
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