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 bytes = channels[i].location + channels[i].bytes;
57 i++;
58 }
59 return bytes;
60 }
61
print2byte(int input,struct iio_channel_info * info)62 void print2byte(int input, struct iio_channel_info *info)
63 {
64 /* First swap if incorrect endian */
65 if (info->be)
66 input = be16toh((uint16_t)input);
67 else
68 input = le16toh((uint16_t)input);
69
70 /*
71 * Shift before conversion to avoid sign extension
72 * of left aligned data
73 */
74 input >>= info->shift;
75 if (info->is_signed) {
76 int16_t val = input;
77
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);
82 } else {
83 uint16_t val = input;
84
85 val &= (1 << info->bits_used) - 1;
86 printf("%05f ", ((float)val + info->offset)*info->scale);
87 }
88 }
89 /**
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
94 * location offsets.
95 * @num_channels: number of channels
96 **/
process_scan(char * data,struct iio_channel_info * channels,int num_channels)97 void process_scan(char *data,
98 struct iio_channel_info *channels,
99 int num_channels)
100 {
101 int k;
102
103 for (k = 0; k < num_channels; k++)
104 switch (channels[k].bytes) {
105 /* only a few cases implemented so far */
106 case 2:
107 print2byte(*(uint16_t *)(data + channels[k].location),
108 &channels[k]);
109 break;
110 case 4:
111 if (!channels[k].is_signed) {
112 uint32_t val = *(uint32_t *)
113 (data + channels[k].location);
114 printf("%05f ", ((float)val +
115 channels[k].offset)*
116 channels[k].scale);
117
118 }
119 break;
120 case 8:
121 if (channels[k].is_signed) {
122 int64_t val = *(int64_t *)
123 (data +
124 channels[k].location);
125 if ((val >> channels[k].bits_used) & 1)
126 val = (val & channels[k].mask) |
127 ~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);
132 else
133 printf("%05f ", ((float)val +
134 channels[k].offset)*
135 channels[k].scale);
136 }
137 break;
138 default:
139 break;
140 }
141 printf("\n");
142 }
143
main(int argc,char ** argv)144 int main(int argc, char **argv)
145 {
146 unsigned long num_loops = 2;
147 unsigned long timedelay = 1000000;
148 unsigned long buf_len = 128;
149
150 int ret, c, i, j, toread;
151 int fp;
152
153 int num_channels;
154 char *trigger_name = NULL, *device_name = NULL;
155 char *dev_dir_name, *buf_dir_name;
156
157 int datardytrigger = 1;
158 char *data;
159 ssize_t read_size;
160 int dev_num, trig_num;
161 char *buffer_access;
162 int scan_size;
163 int noevents = 0;
164 int notrigger = 0;
165 char *dummy;
166
167 struct iio_channel_info *channels;
168
169 while ((c = getopt(argc, argv, "l:w:c:et:n:g")) != -1) {
170 switch (c) {
171 case 'n':
172 device_name = optarg;
173 break;
174 case 't':
175 trigger_name = optarg;
176 datardytrigger = 0;
177 break;
178 case 'e':
179 noevents = 1;
180 break;
181 case 'c':
182 num_loops = strtoul(optarg, &dummy, 10);
183 break;
184 case 'w':
185 timedelay = strtoul(optarg, &dummy, 10);
186 break;
187 case 'l':
188 buf_len = strtoul(optarg, &dummy, 10);
189 break;
190 case 'g':
191 notrigger = 1;
192 break;
193 case '?':
194 return -1;
195 }
196 }
197
198 if (device_name == NULL)
199 return -1;
200
201 /* Find the device requested */
202 dev_num = find_type_by_name(device_name, "iio:device");
203 if (dev_num < 0) {
204 printf("Failed to find the %s\n", device_name);
205 ret = -ENODEV;
206 goto error_ret;
207 }
208 printf("iio device number being used is %d\n", dev_num);
209
210 asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
211
212 if (!notrigger) {
213 if (trigger_name == NULL) {
214 /*
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.
218 */
219 ret = asprintf(&trigger_name,
220 "%s-dev%d", device_name, dev_num);
221 if (ret < 0) {
222 ret = -ENOMEM;
223 goto error_ret;
224 }
225 }
226
227 /* Verify the trigger exists */
228 trig_num = find_type_by_name(trigger_name, "trigger");
229 if (trig_num < 0) {
230 printf("Failed to find the trigger %s\n", trigger_name);
231 ret = -ENODEV;
232 goto error_free_triggername;
233 }
234 printf("iio trigger number being used is %d\n", trig_num);
235 } else
236 printf("trigger-less mode selected\n");
237
238 /*
239 * Parse the files in scan_elements to identify what channels are
240 * present
241 */
242 ret = build_channel_array(dev_dir_name, &channels, &num_channels);
243 if (ret) {
244 printf("Problem reading scan element information\n");
245 printf("diag %s\n", dev_dir_name);
246 goto error_free_triggername;
247 }
248
249 /*
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.
253 */
254 ret = asprintf(&buf_dir_name,
255 "%siio:device%d/buffer", iio_dir, dev_num);
256 if (ret < 0) {
257 ret = -ENOMEM;
258 goto error_free_triggername;
259 }
260
261 if (!notrigger) {
262 printf("%s %s\n", dev_dir_name, trigger_name);
263 /* Set the device trigger to be the data ready trigger found
264 * above */
265 ret = write_sysfs_string_and_verify("trigger/current_trigger",
266 dev_dir_name,
267 trigger_name);
268 if (ret < 0) {
269 printf("Failed to write current_trigger file\n");
270 goto error_free_buf_dir_name;
271 }
272 }
273
274 /* Setup ring buffer parameters */
275 ret = write_sysfs_int("length", buf_dir_name, buf_len);
276 if (ret < 0)
277 goto error_free_buf_dir_name;
278
279 /* Enable the buffer */
280 ret = write_sysfs_int("enable", buf_dir_name, 1);
281 if (ret < 0)
282 goto error_free_buf_dir_name;
283 scan_size = size_from_channelarray(channels, num_channels);
284 data = malloc(scan_size*buf_len);
285 if (!data) {
286 ret = -ENOMEM;
287 goto error_free_buf_dir_name;
288 }
289
290 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
291 if (ret < 0) {
292 ret = -ENOMEM;
293 goto error_free_data;
294 }
295
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);
300 ret = -errno;
301 goto error_free_buffer_access;
302 }
303
304 /* Wait for events 10 times */
305 for (j = 0; j < num_loops; j++) {
306 if (!noevents) {
307 struct pollfd pfd = {
308 .fd = fp,
309 .events = POLLIN,
310 };
311
312 poll(&pfd, 1, -1);
313 toread = buf_len;
314
315 } else {
316 usleep(timedelay);
317 toread = 64;
318 }
319
320 read_size = read(fp,
321 data,
322 toread*scan_size);
323 if (read_size < 0) {
324 if (errno == -EAGAIN) {
325 printf("nothing available\n");
326 continue;
327 } else
328 break;
329 }
330 for (i = 0; i < read_size/scan_size; i++)
331 process_scan(data + scan_size*i,
332 channels,
333 num_channels);
334 }
335
336 /* Stop the buffer */
337 ret = write_sysfs_int("enable", buf_dir_name, 0);
338 if (ret < 0)
339 goto error_close_buffer_access;
340
341 if (!notrigger)
342 /* Disconnect the trigger - just write a dummy name. */
343 write_sysfs_string("trigger/current_trigger",
344 dev_dir_name, "NULL");
345
346 error_close_buffer_access:
347 close(fp);
348 error_free_data:
349 free(data);
350 error_free_buffer_access:
351 free(buffer_access);
352 error_free_buf_dir_name:
353 free(buf_dir_name);
354 error_free_triggername:
355 if (datardytrigger)
356 free(trigger_name);
357 error_ret:
358 return ret;
359 }
360