1 /* Industrialio buffer test code.
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
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.
8 *
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
12 * conversion.
13 *
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.
18 *
19 */
20
21 #include <unistd.h>
22 #include <stdlib.h>
23 #include <dirent.h>
24 #include <fcntl.h>
25 #include <stdio.h>
26 #include <errno.h>
27 #include <sys/stat.h>
28 #include <sys/dir.h>
29 #include <linux/types.h>
30 #include <string.h>
31 #include <poll.h>
32 #include <endian.h>
33 #include <getopt.h>
34 #include <inttypes.h>
35 #include "iio_utils.h"
36
37 /**
38 * size_from_channelarray() - calculate the storage size of a scan
39 * @channels: the channel info array
40 * @num_channels: number of channels
41 *
42 * Has the side effect of filling the channels[i].location values used
43 * in processing the buffer output.
44 **/
size_from_channelarray(struct iio_channel_info * channels,int num_channels)45 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
46 {
47 int bytes = 0;
48 int i = 0;
49
50 while (i < num_channels) {
51 if (bytes % channels[i].bytes == 0)
52 channels[i].location = bytes;
53 else
54 channels[i].location = bytes - bytes % channels[i].bytes
55 + channels[i].bytes;
56
57 bytes = channels[i].location + channels[i].bytes;
58 i++;
59 }
60
61 return bytes;
62 }
63
print1byte(uint8_t input,struct iio_channel_info * info)64 void print1byte(uint8_t input, struct iio_channel_info *info)
65 {
66 /*
67 * Shift before conversion to avoid sign extension
68 * of left aligned data
69 */
70 input >>= info->shift;
71 input &= info->mask;
72 if (info->is_signed) {
73 int8_t val = (int8_t)(input << (8 - info->bits_used)) >>
74 (8 - info->bits_used);
75 printf("%05f ", ((float)val + info->offset) * info->scale);
76 } else {
77 printf("%05f ", ((float)input + info->offset) * info->scale);
78 }
79 }
80
print2byte(uint16_t input,struct iio_channel_info * info)81 void print2byte(uint16_t input, struct iio_channel_info *info)
82 {
83 /* First swap if incorrect endian */
84 if (info->be)
85 input = be16toh(input);
86 else
87 input = le16toh(input);
88
89 /*
90 * Shift before conversion to avoid sign extension
91 * of left aligned data
92 */
93 input >>= info->shift;
94 input &= info->mask;
95 if (info->is_signed) {
96 int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
97 (16 - info->bits_used);
98 printf("%05f ", ((float)val + info->offset) * info->scale);
99 } else {
100 printf("%05f ", ((float)input + info->offset) * info->scale);
101 }
102 }
103
print4byte(uint32_t input,struct iio_channel_info * info)104 void print4byte(uint32_t input, struct iio_channel_info *info)
105 {
106 /* First swap if incorrect endian */
107 if (info->be)
108 input = be32toh(input);
109 else
110 input = le32toh(input);
111
112 /*
113 * Shift before conversion to avoid sign extension
114 * of left aligned data
115 */
116 input >>= info->shift;
117 input &= info->mask;
118 if (info->is_signed) {
119 int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
120 (32 - info->bits_used);
121 printf("%05f ", ((float)val + info->offset) * info->scale);
122 } else {
123 printf("%05f ", ((float)input + info->offset) * info->scale);
124 }
125 }
126
print8byte(uint64_t input,struct iio_channel_info * info)127 void print8byte(uint64_t input, struct iio_channel_info *info)
128 {
129 /* First swap if incorrect endian */
130 if (info->be)
131 input = be64toh(input);
132 else
133 input = le64toh(input);
134
135 /*
136 * Shift before conversion to avoid sign extension
137 * of left aligned data
138 */
139 input >>= info->shift;
140 input &= info->mask;
141 if (info->is_signed) {
142 int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
143 (64 - info->bits_used);
144 /* special case for timestamp */
145 if (info->scale == 1.0f && info->offset == 0.0f)
146 printf("%" PRId64 " ", val);
147 else
148 printf("%05f ",
149 ((float)val + info->offset) * info->scale);
150 } else {
151 printf("%05f ", ((float)input + info->offset) * info->scale);
152 }
153 }
154
155 /**
156 * process_scan() - print out the values in SI units
157 * @data: pointer to the start of the scan
158 * @channels: information about the channels.
159 * Note: size_from_channelarray must have been called first
160 * to fill the location offsets.
161 * @num_channels: number of channels
162 **/
process_scan(char * data,struct iio_channel_info * channels,int num_channels)163 void process_scan(char *data,
164 struct iio_channel_info *channels,
165 int num_channels)
166 {
167 int k;
168
169 for (k = 0; k < num_channels; k++)
170 switch (channels[k].bytes) {
171 /* only a few cases implemented so far */
172 case 1:
173 print1byte(*(uint8_t *)(data + channels[k].location),
174 &channels[k]);
175 break;
176 case 2:
177 print2byte(*(uint16_t *)(data + channels[k].location),
178 &channels[k]);
179 break;
180 case 4:
181 print4byte(*(uint32_t *)(data + channels[k].location),
182 &channels[k]);
183 break;
184 case 8:
185 print8byte(*(uint64_t *)(data + channels[k].location),
186 &channels[k]);
187 break;
188 default:
189 break;
190 }
191 printf("\n");
192 }
193
print_usage(void)194 void print_usage(void)
195 {
196 fprintf(stderr, "Usage: generic_buffer [options]...\n"
197 "Capture, convert and output data from IIO device buffer\n"
198 " -c <n> Do n conversions\n"
199 " -e Disable wait for event (new data)\n"
200 " -g Use trigger-less mode\n"
201 " -l <n> Set buffer length to n samples\n"
202 " -n <name> Set device name (mandatory)\n"
203 " -t <name> Set trigger name\n"
204 " -w <n> Set delay between reads in us (event-less mode)\n");
205 }
206
main(int argc,char ** argv)207 int main(int argc, char **argv)
208 {
209 unsigned long num_loops = 2;
210 unsigned long timedelay = 1000000;
211 unsigned long buf_len = 128;
212
213 int ret, c, i, j, toread;
214 int fp;
215
216 int num_channels;
217 char *trigger_name = NULL, *device_name = NULL;
218 char *dev_dir_name, *buf_dir_name;
219
220 int datardytrigger = 1;
221 char *data;
222 ssize_t read_size;
223 int dev_num, trig_num;
224 char *buffer_access;
225 int scan_size;
226 int noevents = 0;
227 int notrigger = 0;
228 char *dummy;
229
230 struct iio_channel_info *channels;
231
232 while ((c = getopt(argc, argv, "c:egl:n:t:w:")) != -1) {
233 switch (c) {
234 case 'c':
235 errno = 0;
236 num_loops = strtoul(optarg, &dummy, 10);
237 if (errno)
238 return -errno;
239
240 break;
241 case 'e':
242 noevents = 1;
243 break;
244 case 'g':
245 notrigger = 1;
246 break;
247 case 'l':
248 errno = 0;
249 buf_len = strtoul(optarg, &dummy, 10);
250 if (errno)
251 return -errno;
252
253 break;
254 case 'n':
255 device_name = optarg;
256 break;
257 case 't':
258 trigger_name = optarg;
259 datardytrigger = 0;
260 break;
261 case 'w':
262 errno = 0;
263 timedelay = strtoul(optarg, &dummy, 10);
264 if (errno)
265 return -errno;
266 break;
267 case '?':
268 print_usage();
269 return -1;
270 }
271 }
272
273 if (!device_name) {
274 fprintf(stderr, "Device name not set\n");
275 print_usage();
276 return -1;
277 }
278
279 /* Find the device requested */
280 dev_num = find_type_by_name(device_name, "iio:device");
281 if (dev_num < 0) {
282 fprintf(stderr, "Failed to find the %s\n", device_name);
283 return dev_num;
284 }
285
286 printf("iio device number being used is %d\n", dev_num);
287
288 ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
289 if (ret < 0)
290 return -ENOMEM;
291
292 if (!notrigger) {
293 if (!trigger_name) {
294 /*
295 * Build the trigger name. If it is device associated
296 * its name is <device_name>_dev[n] where n matches
297 * the device number found above.
298 */
299 ret = asprintf(&trigger_name,
300 "%s-dev%d", device_name, dev_num);
301 if (ret < 0) {
302 ret = -ENOMEM;
303 goto error_free_dev_dir_name;
304 }
305 }
306
307 /* Verify the trigger exists */
308 trig_num = find_type_by_name(trigger_name, "trigger");
309 if (trig_num < 0) {
310 fprintf(stderr, "Failed to find the trigger %s\n",
311 trigger_name);
312 ret = trig_num;
313 goto error_free_triggername;
314 }
315
316 printf("iio trigger number being used is %d\n", trig_num);
317 } else {
318 printf("trigger-less mode selected\n");
319 }
320
321 /*
322 * Parse the files in scan_elements to identify what channels are
323 * present
324 */
325 ret = build_channel_array(dev_dir_name, &channels, &num_channels);
326 if (ret) {
327 fprintf(stderr, "Problem reading scan element information\n"
328 "diag %s\n", dev_dir_name);
329 goto error_free_triggername;
330 }
331 if (!num_channels) {
332 fprintf(stderr,
333 "No channels are enabled, we have nothing to scan.\n");
334 fprintf(stderr, "Enable channels manually in "
335 FORMAT_SCAN_ELEMENTS_DIR
336 "/*_en and try again.\n", dev_dir_name);
337 ret = -ENOENT;
338 goto error_free_triggername;
339 }
340
341 /*
342 * Construct the directory name for the associated buffer.
343 * As we know that the lis3l02dq has only one buffer this may
344 * be built rather than found.
345 */
346 ret = asprintf(&buf_dir_name,
347 "%siio:device%d/buffer", iio_dir, dev_num);
348 if (ret < 0) {
349 ret = -ENOMEM;
350 goto error_free_channels;
351 }
352
353 if (!notrigger) {
354 printf("%s %s\n", dev_dir_name, trigger_name);
355 /*
356 * Set the device trigger to be the data ready trigger found
357 * above
358 */
359 ret = write_sysfs_string_and_verify("trigger/current_trigger",
360 dev_dir_name,
361 trigger_name);
362 if (ret < 0) {
363 fprintf(stderr,
364 "Failed to write current_trigger file\n");
365 goto error_free_buf_dir_name;
366 }
367 }
368
369 /* Setup ring buffer parameters */
370 ret = write_sysfs_int("length", buf_dir_name, buf_len);
371 if (ret < 0)
372 goto error_free_buf_dir_name;
373
374 /* Enable the buffer */
375 ret = write_sysfs_int("enable", buf_dir_name, 1);
376 if (ret < 0) {
377 fprintf(stderr,
378 "Failed to enable buffer: %s\n", strerror(-ret));
379 goto error_free_buf_dir_name;
380 }
381
382 scan_size = size_from_channelarray(channels, num_channels);
383 data = malloc(scan_size * buf_len);
384 if (!data) {
385 ret = -ENOMEM;
386 goto error_free_buf_dir_name;
387 }
388
389 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
390 if (ret < 0) {
391 ret = -ENOMEM;
392 goto error_free_data;
393 }
394
395 /* Attempt to open non blocking the access dev */
396 fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
397 if (fp == -1) { /* TODO: If it isn't there make the node */
398 ret = -errno;
399 fprintf(stderr, "Failed to open %s\n", buffer_access);
400 goto error_free_buffer_access;
401 }
402
403 for (j = 0; j < num_loops; j++) {
404 if (!noevents) {
405 struct pollfd pfd = {
406 .fd = fp,
407 .events = POLLIN,
408 };
409
410 ret = poll(&pfd, 1, -1);
411 if (ret < 0) {
412 ret = -errno;
413 goto error_close_buffer_access;
414 } else if (ret == 0) {
415 continue;
416 }
417
418 toread = buf_len;
419 } else {
420 usleep(timedelay);
421 toread = 64;
422 }
423
424 read_size = read(fp, data, toread * scan_size);
425 if (read_size < 0) {
426 if (errno == EAGAIN) {
427 fprintf(stderr, "nothing available\n");
428 continue;
429 } else {
430 break;
431 }
432 }
433 for (i = 0; i < read_size / scan_size; i++)
434 process_scan(data + scan_size * i, channels,
435 num_channels);
436 }
437
438 /* Stop the buffer */
439 ret = write_sysfs_int("enable", buf_dir_name, 0);
440 if (ret < 0)
441 goto error_close_buffer_access;
442
443 if (!notrigger)
444 /* Disconnect the trigger - just write a dummy name. */
445 ret = write_sysfs_string("trigger/current_trigger",
446 dev_dir_name, "NULL");
447 if (ret < 0)
448 fprintf(stderr, "Failed to write to %s\n",
449 dev_dir_name);
450
451 error_close_buffer_access:
452 if (close(fp) == -1)
453 perror("Failed to close buffer");
454
455 error_free_buffer_access:
456 free(buffer_access);
457 error_free_data:
458 free(data);
459 error_free_buf_dir_name:
460 free(buf_dir_name);
461 error_free_channels:
462 for (i = num_channels - 1; i >= 0; i--) {
463 free(channels[i].name);
464 free(channels[i].generic_name);
465 }
466 free(channels);
467 error_free_triggername:
468 if (datardytrigger)
469 free(trigger_name);
470
471 error_free_dev_dir_name:
472 free(dev_dir_name);
473
474 return ret;
475 }
476