1 /* Industrialio buffer test code.
3 * Copyright (c) 2008 Jonathan Cameron
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
9 * This program is primarily intended as an example application.
10 * Reads the current buffer setup from sysfs and starts a short capture
11 * from the specified device, pretty printing the result after appropriate
14 * Command line parameters
15 * generic_buffer -n <device_name> -t <trigger_name>
16 * If trigger name is not specified the program assumes you want a dataready
17 * trigger associated with the device and goes looking for it.
30 #include <linux/types.h>
36 #include "iio_utils.h"
39 * size_from_channelarray() - calculate the storage size of a scan
40 * @channels: the channel info array
41 * @num_channels: number of channels
43 * Has the side effect of filling the channels[i].location values used
44 * in processing the buffer output.
46 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
51 while (i < num_channels) {
52 if (bytes % channels[i].bytes == 0)
53 channels[i].location = bytes;
55 channels[i].location = bytes - bytes%channels[i].bytes
57 bytes = channels[i].location + channels[i].bytes;
63 void print2byte(int input, struct iio_channel_info *info)
65 /* First swap if incorrect endian */
67 input = be16toh((uint16_t)input);
69 input = le16toh((uint16_t)input);
72 * Shift before conversion to avoid sign extension
73 * of left aligned data
75 input = input >> info->shift;
76 if (info->is_signed) {
79 val &= (1 << info->bits_used) - 1;
80 val = (int16_t)(val << (16 - info->bits_used)) >>
81 (16 - info->bits_used);
82 printf("%05f ", ((float)val + info->offset)*info->scale);
86 val &= (1 << info->bits_used) - 1;
87 printf("%05f ", ((float)val + info->offset)*info->scale);
91 * process_scan() - print out the values in SI units
92 * @data: pointer to the start of the scan
93 * @channels: information about the channels. Note
94 * size_from_channelarray must have been called first to fill the
96 * @num_channels: number of channels
98 void process_scan(char *data,
99 struct iio_channel_info *channels,
104 for (k = 0; k < num_channels; k++)
105 switch (channels[k].bytes) {
106 /* only a few cases implemented so far */
108 print2byte(*(uint16_t *)(data + channels[k].location),
112 if (!channels[k].is_signed) {
113 uint32_t val = *(uint32_t *)
114 (data + channels[k].location);
115 printf("%05f ", ((float)val +
122 if (channels[k].is_signed) {
123 int64_t val = *(int64_t *)
125 channels[k].location);
126 if ((val >> channels[k].bits_used) & 1)
127 val = (val & channels[k].mask) |
129 /* special case for timestamp */
130 if (channels[k].scale == 1.0f &&
131 channels[k].offset == 0.0f)
132 printf("%" PRId64 " ", val);
134 printf("%05f ", ((float)val +
145 int main(int argc, char **argv)
147 unsigned long num_loops = 2;
148 unsigned long timedelay = 1000000;
149 unsigned long buf_len = 128;
151 int ret, c, i, j, toread;
155 char *trigger_name = NULL, *device_name = NULL;
156 char *dev_dir_name, *buf_dir_name;
158 int datardytrigger = 1;
161 int dev_num, trig_num;
168 struct iio_channel_info *channels;
170 while ((c = getopt(argc, argv, "l:w:c:et:n:g")) != -1) {
173 device_name = optarg;
176 trigger_name = optarg;
183 num_loops = strtoul(optarg, &dummy, 10);
186 timedelay = strtoul(optarg, &dummy, 10);
189 buf_len = strtoul(optarg, &dummy, 10);
199 if (device_name == NULL)
202 /* Find the device requested */
203 dev_num = find_type_by_name(device_name, "iio:device");
205 printf("Failed to find the %s\n", device_name);
209 printf("iio device number being used is %d\n", dev_num);
211 asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
214 if (trigger_name == NULL) {
216 * Build the trigger name. If it is device associated
217 * its name is <device_name>_dev[n] where n matches
218 * the device number found above.
220 ret = asprintf(&trigger_name,
221 "%s-dev%d", device_name, dev_num);
228 /* Verify the trigger exists */
229 trig_num = find_type_by_name(trigger_name, "trigger");
231 printf("Failed to find the trigger %s\n", trigger_name);
233 goto error_free_triggername;
235 printf("iio trigger number being used is %d\n", trig_num);
237 printf("trigger-less mode selected\n");
240 * Parse the files in scan_elements to identify what channels are
243 ret = build_channel_array(dev_dir_name, &channels, &num_channels);
245 printf("Problem reading scan element information\n");
246 printf("diag %s\n", dev_dir_name);
247 goto error_free_triggername;
251 * Construct the directory name for the associated buffer.
252 * As we know that the lis3l02dq has only one buffer this may
253 * be built rather than found.
255 ret = asprintf(&buf_dir_name,
256 "%siio:device%d/buffer", iio_dir, dev_num);
259 goto error_free_triggername;
263 printf("%s %s\n", dev_dir_name, trigger_name);
264 /* Set the device trigger to be the data ready trigger found
266 ret = write_sysfs_string_and_verify("trigger/current_trigger",
270 printf("Failed to write current_trigger file\n");
271 goto error_free_buf_dir_name;
275 /* Setup ring buffer parameters */
276 ret = write_sysfs_int("length", buf_dir_name, buf_len);
278 goto error_free_buf_dir_name;
280 /* Enable the buffer */
281 ret = write_sysfs_int("enable", buf_dir_name, 1);
283 goto error_free_buf_dir_name;
284 scan_size = size_from_channelarray(channels, num_channels);
285 data = malloc(scan_size*buf_len);
288 goto error_free_buf_dir_name;
291 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
294 goto error_free_data;
297 /* Attempt to open non blocking the access dev */
298 fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
299 if (fp == -1) { /* If it isn't there make the node */
300 printf("Failed to open %s\n", buffer_access);
302 goto error_free_buffer_access;
305 /* Wait for events 10 times */
306 for (j = 0; j < num_loops; j++) {
308 struct pollfd pfd = {
325 if (errno == -EAGAIN) {
326 printf("nothing available\n");
331 for (i = 0; i < read_size/scan_size; i++)
332 process_scan(data + scan_size*i,
337 /* Stop the buffer */
338 ret = write_sysfs_int("enable", buf_dir_name, 0);
340 goto error_close_buffer_access;
343 /* Disconnect the trigger - just write a dummy name. */
344 write_sysfs_string("trigger/current_trigger",
345 dev_dir_name, "NULL");
347 error_close_buffer_access:
351 error_free_buffer_access:
353 error_free_buf_dir_name:
355 error_free_triggername: