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 #define _GNU_SOURCE
22
23 #include <unistd.h>
24 #include <dirent.h>
25 #include <fcntl.h>
26 #include <stdio.h>
27 #include <errno.h>
28 #include <sys/stat.h>
29 #include <sys/dir.h>
30 #include <linux/types.h>
31 #include <string.h>
32 #include <poll.h>
33 #include <endian.h>
34 #include <getopt.h>
35 #include <inttypes.h>
36 #include "iio_utils.h"
37
38 /**
39 * size_from_channelarray() - calculate the storage size of a scan
40 * @channels: the channel info array
41 * @num_channels: number of channels
42 *
43 * Has the side effect of filling the channels[i].location values used
44 * in processing the buffer output.
45 **/
size_from_channelarray(struct iio_channel_info * channels,int num_channels)46 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
47 {
48 int bytes = 0;
49 int i = 0;
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 = input >> info->shift;
75 if (info->is_signed) {
76 int16_t val = input;
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);
81 } else {
82 uint16_t val = input;
83 val &= (1 << info->bits_used) - 1;
84 printf("%05f ", ((float)val + info->offset)*info->scale);
85 }
86 }
87 /**
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
92 * location offsets.
93 * @num_channels: number of channels
94 **/
process_scan(char * data,struct iio_channel_info * channels,int num_channels)95 void process_scan(char *data,
96 struct iio_channel_info *channels,
97 int num_channels)
98 {
99 int k;
100 for (k = 0; k < num_channels; k++)
101 switch (channels[k].bytes) {
102 /* only a few cases implemented so far */
103 case 2:
104 print2byte(*(uint16_t *)(data + channels[k].location),
105 &channels[k]);
106 break;
107 case 4:
108 if (!channels[k].is_signed) {
109 uint32_t val = *(uint32_t *)
110 (data + channels[k].location);
111 printf("%05f ", ((float)val +
112 channels[k].offset)*
113 channels[k].scale);
114
115 }
116 break;
117 case 8:
118 if (channels[k].is_signed) {
119 int64_t val = *(int64_t *)
120 (data +
121 channels[k].location);
122 if ((val >> channels[k].bits_used) & 1)
123 val = (val & channels[k].mask) |
124 ~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);
129 else
130 printf("%05f ", ((float)val +
131 channels[k].offset)*
132 channels[k].scale);
133 }
134 break;
135 default:
136 break;
137 }
138 printf("\n");
139 }
140
main(int argc,char ** argv)141 int main(int argc, char **argv)
142 {
143 unsigned long num_loops = 2;
144 unsigned long timedelay = 1000000;
145 unsigned long buf_len = 128;
146
147 int ret, c, i, j, toread;
148 int fp;
149
150 int num_channels;
151 char *trigger_name = NULL, *device_name = NULL;
152 char *dev_dir_name, *buf_dir_name;
153
154 int datardytrigger = 1;
155 char *data;
156 ssize_t read_size;
157 int dev_num, trig_num;
158 char *buffer_access;
159 int scan_size;
160 int noevents = 0;
161 char *dummy;
162
163 struct iio_channel_info *channels;
164
165 while ((c = getopt(argc, argv, "l:w:c:et:n:")) != -1) {
166 switch (c) {
167 case 'n':
168 device_name = optarg;
169 break;
170 case 't':
171 trigger_name = optarg;
172 datardytrigger = 0;
173 break;
174 case 'e':
175 noevents = 1;
176 break;
177 case 'c':
178 num_loops = strtoul(optarg, &dummy, 10);
179 break;
180 case 'w':
181 timedelay = strtoul(optarg, &dummy, 10);
182 break;
183 case 'l':
184 buf_len = strtoul(optarg, &dummy, 10);
185 break;
186 case '?':
187 return -1;
188 }
189 }
190
191 if (device_name == NULL)
192 return -1;
193
194 /* Find the device requested */
195 dev_num = find_type_by_name(device_name, "iio:device");
196 if (dev_num < 0) {
197 printf("Failed to find the %s\n", device_name);
198 ret = -ENODEV;
199 goto error_ret;
200 }
201 printf("iio device number being used is %d\n", dev_num);
202
203 asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
204 if (trigger_name == NULL) {
205 /*
206 * Build the trigger name. If it is device associated its
207 * name is <device_name>_dev[n] where n matches the device
208 * number found above
209 */
210 ret = asprintf(&trigger_name,
211 "%s-dev%d", device_name, dev_num);
212 if (ret < 0) {
213 ret = -ENOMEM;
214 goto error_ret;
215 }
216 }
217
218 /* Verify the trigger exists */
219 trig_num = find_type_by_name(trigger_name, "trigger");
220 if (trig_num < 0) {
221 printf("Failed to find the trigger %s\n", trigger_name);
222 ret = -ENODEV;
223 goto error_free_triggername;
224 }
225 printf("iio trigger number being used is %d\n", trig_num);
226
227 /*
228 * Parse the files in scan_elements to identify what channels are
229 * present
230 */
231 ret = build_channel_array(dev_dir_name, &channels, &num_channels);
232 if (ret) {
233 printf("Problem reading scan element information\n");
234 printf("diag %s\n", dev_dir_name);
235 goto error_free_triggername;
236 }
237
238 /*
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.
242 */
243 ret = asprintf(&buf_dir_name,
244 "%siio:device%d/buffer", iio_dir, dev_num);
245 if (ret < 0) {
246 ret = -ENOMEM;
247 goto error_free_triggername;
248 }
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",
252 dev_dir_name,
253 trigger_name);
254 if (ret < 0) {
255 printf("Failed to write current_trigger file\n");
256 goto error_free_buf_dir_name;
257 }
258
259 /* Setup ring buffer parameters */
260 ret = write_sysfs_int("length", buf_dir_name, buf_len);
261 if (ret < 0)
262 goto error_free_buf_dir_name;
263
264 /* Enable the buffer */
265 ret = write_sysfs_int("enable", buf_dir_name, 1);
266 if (ret < 0)
267 goto error_free_buf_dir_name;
268 scan_size = size_from_channelarray(channels, num_channels);
269 data = malloc(scan_size*buf_len);
270 if (!data) {
271 ret = -ENOMEM;
272 goto error_free_buf_dir_name;
273 }
274
275 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
276 if (ret < 0) {
277 ret = -ENOMEM;
278 goto error_free_data;
279 }
280
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);
285 ret = -errno;
286 goto error_free_buffer_access;
287 }
288
289 /* Wait for events 10 times */
290 for (j = 0; j < num_loops; j++) {
291 if (!noevents) {
292 struct pollfd pfd = {
293 .fd = fp,
294 .events = POLLIN,
295 };
296
297 poll(&pfd, 1, -1);
298 toread = buf_len;
299
300 } else {
301 usleep(timedelay);
302 toread = 64;
303 }
304
305 read_size = read(fp,
306 data,
307 toread*scan_size);
308 if (read_size < 0) {
309 if (errno == -EAGAIN) {
310 printf("nothing available\n");
311 continue;
312 } else
313 break;
314 }
315 for (i = 0; i < read_size/scan_size; i++)
316 process_scan(data + scan_size*i,
317 channels,
318 num_channels);
319 }
320
321 /* Stop the buffer */
322 ret = write_sysfs_int("enable", buf_dir_name, 0);
323 if (ret < 0)
324 goto error_close_buffer_access;
325
326 /* Disconnect the trigger - just write a dummy name. */
327 write_sysfs_string("trigger/current_trigger",
328 dev_dir_name, "NULL");
329
330 error_close_buffer_access:
331 close(fp);
332 error_free_data:
333 free(data);
334 error_free_buffer_access:
335 free(buffer_access);
336 error_free_buf_dir_name:
337 free(buf_dir_name);
338 error_free_triggername:
339 if (datardytrigger)
340 free(trigger_name);
341 error_ret:
342 return ret;
343 }
344