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.
28 #include <linux/types.h>
31 #include "iio_utils.h"
34 * size_from_channelarray() - calculate the storage size of a scan
35 * @channels: the channel info array
36 * @num_channels: size of the channel info array
38 * Has the side effect of filling the channels[i].location values used
39 * in processing the buffer output.
41 int size_from_channelarray(struct iio_channel_info
*channels
, int num_channels
)
45 while (i
< num_channels
) {
46 if (bytes
% channels
[i
].bytes
== 0)
47 channels
[i
].location
= bytes
;
49 channels
[i
].location
= bytes
- bytes
%channels
[i
].bytes
51 bytes
= channels
[i
].location
+ channels
[i
].bytes
;
57 void print2byte(int input
, struct iio_channel_info
*info
)
59 /* shift before conversion to avoid sign extension
60 of left aligned data */
61 input
= input
>> info
->shift
;
62 if (info
->is_signed
) {
64 val
&= (1 << info
->bits_used
) - 1;
65 val
= (int16_t)(val
<< (16 - info
->bits_used
)) >>
66 (16 - info
->bits_used
);
68 (float)(val
+ info
->offset
)*info
->scale
);
71 val
&= (1 << info
->bits_used
) - 1;
72 printf("%05f ", ((float)val
+ info
->offset
)*info
->scale
);
76 * process_scan() - print out the values in SI units
77 * @data: pointer to the start of the scan
78 * @infoarray: information about the channels. Note
79 * size_from_channelarray must have been called first to fill the
81 * @num_channels: the number of active channels
83 void process_scan(char *data
,
84 struct iio_channel_info
*infoarray
,
88 for (k
= 0; k
< num_channels
; k
++)
89 switch (infoarray
[k
].bytes
) {
90 /* only a few cases implemented so far */
92 print2byte(*(uint16_t *)(data
+ infoarray
[k
].location
),
96 if (infoarray
[k
].is_signed
) {
97 int64_t val
= *(int64_t *)
99 infoarray
[k
].location
);
100 if ((val
>> infoarray
[k
].bits_used
) & 1)
101 val
= (val
& infoarray
[k
].mask
) |
103 /* special case for timestamp */
104 if (infoarray
[k
].scale
== 1.0f
&&
105 infoarray
[k
].offset
== 0.0f
)
106 printf(" %lld", val
);
108 printf("%05f ", ((float)val
+
109 infoarray
[k
].offset
)*
119 int main(int argc
, char **argv
)
121 unsigned long num_loops
= 2;
122 unsigned long timedelay
= 1000000;
123 unsigned long buf_len
= 128;
126 int ret
, c
, i
, j
, toread
;
132 char *trigger_name
= NULL
, *device_name
= NULL
;
133 char *dev_dir_name
, *buf_dir_name
;
135 int datardytrigger
= 1;
138 int dev_num
, trig_num
;
144 struct iio_channel_info
*infoarray
;
146 while ((c
= getopt(argc
, argv
, "l:w:c:et:n:")) != -1) {
149 device_name
= optarg
;
152 trigger_name
= optarg
;
159 num_loops
= strtoul(optarg
, &dummy
, 10);
162 timedelay
= strtoul(optarg
, &dummy
, 10);
165 buf_len
= strtoul(optarg
, &dummy
, 10);
172 if (device_name
== NULL
)
175 /* Find the device requested */
176 dev_num
= find_type_by_name(device_name
, "iio:device");
178 printf("Failed to find the %s\n", device_name
);
182 printf("iio device number being used is %d\n", dev_num
);
184 asprintf(&dev_dir_name
, "%siio:device%d", iio_dir
, dev_num
);
185 if (trigger_name
== NULL
) {
187 * Build the trigger name. If it is device associated it's
188 * name is <device_name>_dev[n] where n matches the device
191 ret
= asprintf(&trigger_name
,
192 "%s-dev%d", device_name
, dev_num
);
199 /* Verify the trigger exists */
200 trig_num
= find_type_by_name(trigger_name
, "trigger");
202 printf("Failed to find the trigger %s\n", trigger_name
);
204 goto error_free_triggername
;
206 printf("iio trigger number being used is %d\n", trig_num
);
209 * Parse the files in scan_elements to identify what channels are
212 ret
= build_channel_array(dev_dir_name
, &infoarray
, &num_channels
);
214 printf("Problem reading scan element information\n");
215 printf("diag %s\n", dev_dir_name
);
216 goto error_free_triggername
;
220 * Construct the directory name for the associated buffer.
221 * As we know that the lis3l02dq has only one buffer this may
222 * be built rather than found.
224 ret
= asprintf(&buf_dir_name
,
225 "%siio:device%d/buffer", iio_dir
, dev_num
);
228 goto error_free_triggername
;
230 printf("%s %s\n", dev_dir_name
, trigger_name
);
231 /* Set the device trigger to be the data rdy trigger found above */
232 ret
= write_sysfs_string_and_verify("trigger/current_trigger",
236 printf("Failed to write current_trigger file\n");
237 goto error_free_buf_dir_name
;
240 /* Setup ring buffer parameters */
241 ret
= write_sysfs_int("length", buf_dir_name
, buf_len
);
243 goto error_free_buf_dir_name
;
245 /* Enable the buffer */
246 ret
= write_sysfs_int("enable", buf_dir_name
, 1);
248 goto error_free_buf_dir_name
;
249 scan_size
= size_from_channelarray(infoarray
, num_channels
);
250 data
= malloc(scan_size
*buf_len
);
253 goto error_free_buf_dir_name
;
256 ret
= asprintf(&buffer_access
, "/dev/iio:device%d", dev_num
);
259 goto error_free_data
;
262 /* Attempt to open non blocking the access dev */
263 fp
= open(buffer_access
, O_RDONLY
| O_NONBLOCK
);
264 if (fp
== -1) { /*If it isn't there make the node */
265 printf("Failed to open %s\n", buffer_access
);
267 goto error_free_buffer_access
;
270 /* Wait for events 10 times */
271 for (j
= 0; j
< num_loops
; j
++) {
273 struct pollfd pfd
= {
289 if (read_size
== -EAGAIN
) {
290 printf("nothing available\n");
293 for (i
= 0; i
< read_size
/scan_size
; i
++)
294 process_scan(data
+ scan_size
*i
,
299 /* Stop the ring buffer */
300 ret
= write_sysfs_int("enable", buf_dir_name
, 0);
302 goto error_close_buffer_access
;
304 /* Disconnect from the trigger - just write a dummy name.*/
305 write_sysfs_string("trigger/current_trigger",
306 dev_dir_name
, "NULL");
308 error_close_buffer_access
:
312 error_free_buffer_access
:
314 error_free_buf_dir_name
:
316 error_free_triggername
: