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)
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 = input >> info->shift;
75 if (info->is_signed) {
77 val &= (1 << info->bits_used) - 1;
78 val = (int16_t)(val << (16 - info->bits_used)) >>
79 (16 - info->bits_used);
80 printf("%05f ", ((float)val + info->offset)*info->scale);
83 val &= (1 << info->bits_used) - 1;
84 printf("%05f ", ((float)val + info->offset)*info->scale);
88 * process_scan() - print out the values in SI units
89 * @data: pointer to the start of the scan
90 * @channels: information about the channels. Note
91 * size_from_channelarray must have been called first to fill the
93 * @num_channels: number of channels
95 void process_scan(char *data,
96 struct iio_channel_info *channels,
100 for (k = 0; k < num_channels; k++)
101 switch (channels[k].bytes) {
102 /* only a few cases implemented so far */
104 print2byte(*(uint16_t *)(data + channels[k].location),
108 if (!channels[k].is_signed) {
109 uint32_t val = *(uint32_t *)
110 (data + channels[k].location);
111 printf("%05f ", ((float)val +
118 if (channels[k].is_signed) {
119 int64_t val = *(int64_t *)
121 channels[k].location);
122 if ((val >> channels[k].bits_used) & 1)
123 val = (val & channels[k].mask) |
125 /* special case for timestamp */
126 if (channels[k].scale == 1.0f &&
127 channels[k].offset == 0.0f)
128 printf("%" PRId64 " ", val);
130 printf("%05f ", ((float)val +
141 int main(int argc, char **argv)
143 unsigned long num_loops = 2;
144 unsigned long timedelay = 1000000;
145 unsigned long buf_len = 128;
147 int ret, c, i, j, toread;
151 char *trigger_name = NULL, *device_name = NULL;
152 char *dev_dir_name, *buf_dir_name;
154 int datardytrigger = 1;
157 int dev_num, trig_num;
163 struct iio_channel_info *channels;
165 while ((c = getopt(argc, argv, "l:w:c:et:n:")) != -1) {
168 device_name = optarg;
171 trigger_name = optarg;
178 num_loops = strtoul(optarg, &dummy, 10);
181 timedelay = strtoul(optarg, &dummy, 10);
184 buf_len = strtoul(optarg, &dummy, 10);
191 if (device_name == NULL)
194 /* Find the device requested */
195 dev_num = find_type_by_name(device_name, "iio:device");
197 printf("Failed to find the %s\n", device_name);
201 printf("iio device number being used is %d\n", dev_num);
203 asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
204 if (trigger_name == NULL) {
206 * Build the trigger name. If it is device associated its
207 * name is <device_name>_dev[n] where n matches the device
210 ret = asprintf(&trigger_name,
211 "%s-dev%d", device_name, dev_num);
218 /* Verify the trigger exists */
219 trig_num = find_type_by_name(trigger_name, "trigger");
221 printf("Failed to find the trigger %s\n", trigger_name);
223 goto error_free_triggername;
225 printf("iio trigger number being used is %d\n", trig_num);
228 * Parse the files in scan_elements to identify what channels are
231 ret = build_channel_array(dev_dir_name, &channels, &num_channels);
233 printf("Problem reading scan element information\n");
234 printf("diag %s\n", dev_dir_name);
235 goto error_free_triggername;
239 * Construct the directory name for the associated buffer.
240 * As we know that the lis3l02dq has only one buffer this may
241 * be built rather than found.
243 ret = asprintf(&buf_dir_name,
244 "%siio:device%d/buffer", iio_dir, dev_num);
247 goto error_free_triggername;
249 printf("%s %s\n", dev_dir_name, trigger_name);
250 /* Set the device trigger to be the data ready trigger found above */
251 ret = write_sysfs_string_and_verify("trigger/current_trigger",
255 printf("Failed to write current_trigger file\n");
256 goto error_free_buf_dir_name;
259 /* Setup ring buffer parameters */
260 ret = write_sysfs_int("length", buf_dir_name, buf_len);
262 goto error_free_buf_dir_name;
264 /* Enable the buffer */
265 ret = write_sysfs_int("enable", buf_dir_name, 1);
267 goto error_free_buf_dir_name;
268 scan_size = size_from_channelarray(channels, num_channels);
269 data = malloc(scan_size*buf_len);
272 goto error_free_buf_dir_name;
275 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
278 goto error_free_data;
281 /* Attempt to open non blocking the access dev */
282 fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
283 if (fp == -1) { /* If it isn't there make the node */
284 printf("Failed to open %s\n", buffer_access);
286 goto error_free_buffer_access;
289 /* Wait for events 10 times */
290 for (j = 0; j < num_loops; j++) {
292 struct pollfd pfd = {
308 if (read_size == -EAGAIN) {
309 printf("nothing available\n");
312 for (i = 0; i < read_size/scan_size; i++)
313 process_scan(data + scan_size*i,
318 /* Stop the buffer */
319 ret = write_sysfs_int("enable", buf_dir_name, 0);
321 goto error_close_buffer_access;
323 /* Disconnect the trigger - just write a dummy name. */
324 write_sysfs_string("trigger/current_trigger",
325 dev_dir_name, "NULL");
327 error_close_buffer_access:
331 error_free_buffer_access:
333 error_free_buf_dir_name:
335 error_free_triggername: