239 lines
6.0 KiB
C
239 lines
6.0 KiB
C
/* Industrialio ring buffer with a lis3l02dq accelerometer
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*
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* Copyright (c) 2008 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is primarily intended as an example application.
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*/
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#include <dirent.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <sys/dir.h>
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#include <linux/types.h>
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#include "iio_utils.h"
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const char *device_name = "lis3l02dq";
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const char *trigger_name_base = "lis3l02dq-dev";
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const int num_vals = 3;
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const int scan_ts = 1;
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const int buf_len = 128;
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const int num_loops = 10;
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/*
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* Could get this from ring bps, but only after starting the ring
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* which is a bit late for it to be useful.
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*
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* Todo: replace with much more generic version based on scan_elements
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* directory.
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*/
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int size_from_scanmode(int num_vals, int timestamp)
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{
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if (num_vals && timestamp)
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return 16;
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else if (timestamp)
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return 8;
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else
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return num_vals*2;
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}
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int main(int argc, char **argv)
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{
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int ret;
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int i, j, k, toread;
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FILE *fp_ev;
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int fp;
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char *trigger_name, *dev_dir_name, *buf_dir_name;
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char *data;
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size_t read_size;
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struct iio_event_data dat;
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int dev_num, trig_num;
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char *buffer_access, *buffer_event;
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const char *iio_dir = "/sys/bus/iio/devices/";
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int scan_size;
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float gain = 1;
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/* Find out which iio device is the accelerometer. */
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dev_num = find_type_by_name(device_name, "device");
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if (dev_num < 0) {
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printf("Failed to find the %s\n", device_name);
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ret = -ENODEV;
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goto error_ret;
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}
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printf("iio device number being used is %d\n", dev_num);
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asprintf(&dev_dir_name, "%sdevice%d", iio_dir, dev_num);
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/*
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* Build the trigger name.
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* In this case we want the lis3l02dq's data ready trigger
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* for this lis3l02dq. The naming is lis3l02dq_dev[n], where
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* n matches the device number found above.
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*/
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ret = asprintf(&trigger_name, "%s%d", trigger_name_base, dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_free_dev_dir_name;
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}
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/*
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* Find the trigger by name.
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* This is techically unecessary here as we only need to
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* refer to the trigger by name and that name is already
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* known.
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*/
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trig_num = find_type_by_name(trigger_name, "trigger");
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if (trig_num < 0) {
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printf("Failed to find the %s\n", trigger_name);
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ret = -ENODEV;
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goto error_free_triggername;
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}
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printf("iio trigger number being used is %d\n", trig_num);
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/*
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* Read in the scale value - in a more generic case, first
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* check for accel_scale, then the indivual channel scales
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*/
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ret = read_sysfs_float("accel_scale", dev_dir_name, &gain);
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if (ret)
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goto error_free_triggername;;
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/*
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* Construct the directory name for the associated buffer.
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* As we know that the lis3l02dq has only one buffer this may
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* be built rather than found.
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*/
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ret = asprintf(&buf_dir_name, "%sdevice%d:buffer0", iio_dir, dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_free_triggername;
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}
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/* Set the device trigger to be the data rdy trigger found above */
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ret = write_sysfs_string_and_verify("trigger/current_trigger",
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dev_dir_name,
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trigger_name);
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if (ret < 0) {
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printf("Failed to write current_trigger file\n");
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goto error_free_buf_dir_name;
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}
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/* Setup ring buffer parameters */
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ret = write_sysfs_int("length", buf_dir_name, buf_len);
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if (ret < 0)
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goto error_free_buf_dir_name;
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/* Enable the buffer */
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ret = write_sysfs_int("ring_enable", buf_dir_name, 1);
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if (ret < 0)
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goto error_free_buf_dir_name;
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data = malloc(size_from_scanmode(num_vals, scan_ts)*buf_len);
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if (!data) {
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ret = -ENOMEM;
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goto error_free_buf_dir_name;
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}
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ret = asprintf(&buffer_access,
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"/dev/device%d:buffer0:access0",
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dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_free_data;
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}
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ret = asprintf(&buffer_event, "/dev/device%d:buffer0:event0", dev_num);
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if (ret < 0) {
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ret = -ENOMEM;
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goto error_free_data;
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}
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/* Attempt to open non blocking the access dev */
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fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
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if (fp == -1) { /*If it isn't there make the node */
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printf("Failed to open %s\n", buffer_access);
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ret = -errno;
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goto error_free_buffer_event;
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}
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/* Attempt to open the event access dev (blocking this time) */
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fp_ev = fopen(buffer_event, "rb");
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if (fp_ev == NULL) {
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printf("Failed to open %s\n", buffer_event);
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ret = -errno;
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goto error_close_buffer_access;
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}
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/* Wait for events 10 times */
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for (j = 0; j < num_loops; j++) {
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read_size = fread(&dat, 1, sizeof(struct iio_event_data),
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fp_ev);
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switch (dat.id) {
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case IIO_EVENT_CODE_RING_100_FULL:
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toread = buf_len;
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break;
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case IIO_EVENT_CODE_RING_75_FULL:
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toread = buf_len*3/4;
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break;
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case IIO_EVENT_CODE_RING_50_FULL:
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toread = buf_len/2;
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break;
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default:
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printf("Unexpecteded event code\n");
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continue;
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}
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read_size = read(fp,
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data,
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toread*size_from_scanmode(num_vals, scan_ts));
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if (read_size == -EAGAIN) {
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printf("nothing available\n");
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continue;
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}
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scan_size = size_from_scanmode(num_vals, scan_ts);
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for (i = 0; i < read_size/scan_size; i++) {
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for (k = 0; k < num_vals; k++) {
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__s16 val = *(__s16 *)(&data[i*scan_size
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+ (k)*2]);
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printf("%05f ", (float)val*gain);
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}
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printf(" %lld\n",
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*(__s64 *)(&data[(i + 1)
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*size_from_scanmode(num_vals,
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scan_ts)
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- sizeof(__s64)]));
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}
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}
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/* Stop the ring buffer */
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ret = write_sysfs_int("ring_enable", buf_dir_name, 0);
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if (ret < 0)
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goto error_close_buffer_event;
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/* Disconnect from the trigger - just write a dummy name.*/
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write_sysfs_string("trigger/current_trigger",
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dev_dir_name, "NULL");
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error_close_buffer_event:
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fclose(fp_ev);
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error_close_buffer_access:
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close(fp);
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error_free_data:
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free(data);
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error_free_buffer_access:
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free(buffer_access);
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error_free_buffer_event:
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free(buffer_event);
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error_free_buf_dir_name:
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free(buf_dir_name);
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error_free_triggername:
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free(trigger_name);
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error_free_dev_dir_name:
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free(dev_dir_name);
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error_ret:
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return ret;
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}
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