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.
29 #include <linux/types.h>
35 #include "iio_utils.h"
38 * size_from_channelarray() - calculate the storage size of a scan
39 * @channels: the channel info array
40 * @num_channels: number of channels
42 * Has the side effect of filling the channels[i].location values used
43 * in processing the buffer output.
45 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
50 while (i < num_channels) {
51 if (bytes % channels[i].bytes == 0)
52 channels[i].location = bytes;
54 channels[i].location = bytes - bytes%channels[i].bytes
56 bytes = channels[i].location + channels[i].bytes;
62 void print2byte(int input, struct iio_channel_info *info)
64 /* First swap if incorrect endian */
66 input = be16toh((uint16_t)input);
68 input = le16toh((uint16_t)input);
71 * Shift before conversion to avoid sign extension
72 * of left aligned data
74 input >>= info->shift;
75 if (info->is_signed) {
78 val &= (1 << info->bits_used) - 1;
79 val = (int16_t)(val << (16 - info->bits_used)) >>
80 (16 - info->bits_used);
81 printf("%05f ", ((float)val + info->offset)*info->scale);
85 val &= (1 << info->bits_used) - 1;
86 printf("%05f ", ((float)val + info->offset)*info->scale);
90 * process_scan() - print out the values in SI units
91 * @data: pointer to the start of the scan
92 * @channels: information about the channels. Note
93 * size_from_channelarray must have been called first to fill the
95 * @num_channels: number of channels
97 void process_scan(char *data,
98 struct iio_channel_info *channels,
103 for (k = 0; k < num_channels; k++)
104 switch (channels[k].bytes) {
105 /* only a few cases implemented so far */
107 print2byte(*(uint16_t *)(data + channels[k].location),
111 if (!channels[k].is_signed) {
112 uint32_t val = *(uint32_t *)
113 (data + channels[k].location);
114 printf("%05f ", ((float)val +
121 if (channels[k].is_signed) {
122 int64_t val = *(int64_t *)
124 channels[k].location);
125 if ((val >> channels[k].bits_used) & 1)
126 val = (val & channels[k].mask) |
128 /* special case for timestamp */
129 if (channels[k].scale == 1.0f &&
130 channels[k].offset == 0.0f)
131 printf("%" PRId64 " ", val);
133 printf("%05f ", ((float)val +
144 int main(int argc, char **argv)
146 unsigned long num_loops = 2;
147 unsigned long timedelay = 1000000;
148 unsigned long buf_len = 128;
150 int ret, c, i, j, toread;
154 char *trigger_name = NULL, *device_name = NULL;
155 char *dev_dir_name, *buf_dir_name;
157 int datardytrigger = 1;
160 int dev_num, trig_num;
167 struct iio_channel_info *channels;
169 while ((c = getopt(argc, argv, "l:w:c:et:n:g")) != -1) {
172 device_name = optarg;
175 trigger_name = optarg;
182 num_loops = strtoul(optarg, &dummy, 10);
185 timedelay = strtoul(optarg, &dummy, 10);
188 buf_len = strtoul(optarg, &dummy, 10);
198 if (device_name == NULL)
201 /* Find the device requested */
202 dev_num = find_type_by_name(device_name, "iio:device");
204 printf("Failed to find the %s\n", device_name);
208 printf("iio device number being used is %d\n", dev_num);
210 asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
213 if (trigger_name == NULL) {
215 * Build the trigger name. If it is device associated
216 * its name is <device_name>_dev[n] where n matches
217 * the device number found above.
219 ret = asprintf(&trigger_name,
220 "%s-dev%d", device_name, dev_num);
227 /* Verify the trigger exists */
228 trig_num = find_type_by_name(trigger_name, "trigger");
230 printf("Failed to find the trigger %s\n", trigger_name);
232 goto error_free_triggername;
234 printf("iio trigger number being used is %d\n", trig_num);
236 printf("trigger-less mode selected\n");
239 * Parse the files in scan_elements to identify what channels are
242 ret = build_channel_array(dev_dir_name, &channels, &num_channels);
244 printf("Problem reading scan element information\n");
245 printf("diag %s\n", dev_dir_name);
246 goto error_free_triggername;
250 * Construct the directory name for the associated buffer.
251 * As we know that the lis3l02dq has only one buffer this may
252 * be built rather than found.
254 ret = asprintf(&buf_dir_name,
255 "%siio:device%d/buffer", iio_dir, dev_num);
258 goto error_free_triggername;
262 printf("%s %s\n", dev_dir_name, trigger_name);
263 /* Set the device trigger to be the data ready trigger found
265 ret = write_sysfs_string_and_verify("trigger/current_trigger",
269 printf("Failed to write current_trigger file\n");
270 goto error_free_buf_dir_name;
274 /* Setup ring buffer parameters */
275 ret = write_sysfs_int("length", buf_dir_name, buf_len);
277 goto error_free_buf_dir_name;
279 /* Enable the buffer */
280 ret = write_sysfs_int("enable", buf_dir_name, 1);
282 goto error_free_buf_dir_name;
283 scan_size = size_from_channelarray(channels, num_channels);
284 data = malloc(scan_size*buf_len);
287 goto error_free_buf_dir_name;
290 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
293 goto error_free_data;
296 /* Attempt to open non blocking the access dev */
297 fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
298 if (fp == -1) { /* If it isn't there make the node */
299 printf("Failed to open %s\n", buffer_access);
301 goto error_free_buffer_access;
304 /* Wait for events 10 times */
305 for (j = 0; j < num_loops; j++) {
307 struct pollfd pfd = {
324 if (errno == -EAGAIN) {
325 printf("nothing available\n");
330 for (i = 0; i < read_size/scan_size; i++)
331 process_scan(data + scan_size*i,
336 /* Stop the buffer */
337 ret = write_sysfs_int("enable", buf_dir_name, 0);
339 goto error_close_buffer_access;
342 /* Disconnect the trigger - just write a dummy name. */
343 write_sysfs_string("trigger/current_trigger",
344 dev_dir_name, "NULL");
346 error_close_buffer_access:
350 error_free_buffer_access:
352 error_free_buf_dir_name:
354 error_free_triggername: