/*********************************************************************************
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* Copyright: (C) 2021 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: gpiod.c
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* Description: This file is used to control a pin GPIO output by libgpiod
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*
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* pi@raspberrypi:~ $ gpio readall show BCM and wPi pinmap
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*
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*
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* Version: 1.0.0(2021/01/23)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "2021/01/23 12:13:26"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <string.h>
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#include <time.h>
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#include <errno.h>
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#include <gpiod.h>
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void gpiod_ctxless_cb(void *data)
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{
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sleep(1);
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}
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int main(int argc, char *argv[])
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{
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struct gpiod_chip *chip;
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struct gpiod_line *line;
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int bcm_pin;
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int level;
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if( argc != 3 )
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{
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printf(" Usage: sudo %s [BCM Pin number] [1/0]\n", argv[0]);
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printf("example, turn BCM Pin #19 lowlevel : sudo %s 19 0\n", argv[0]);
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printf("example, turn BCM Pin #19 highlevel: sudo %s 19 1\n", argv[0]);
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return 0;
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}
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bcm_pin = atoi(argv[1]);
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level = atoi(argv[2]);
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#if 0
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if( level )
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gpiod_ctxless_set_value("gpiochip0", bcm_pin, 1, false, "led", gpiod_ctxless_cb, NULL);
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else
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gpiod_ctxless_set_value("gpiochip0", bcm_pin, 0, false, "led", gpiod_ctxless_cb, NULL);
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#else
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chip = gpiod_chip_open_by_name("gpiochip0");
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if( !chip )
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{
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printf("gpiod open chip failure, maybe you need running as root\n");
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exit(1);
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}
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line = gpiod_chip_get_line(chip, bcm_pin);
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if( !line )
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{
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printf("gpiod get line for BCM pin [#%d] failure\n", bcm_pin);
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exit(1);
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}
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gpiod_line_request_output(line, "led", 1);
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printf("set BCM pin #%d as %s level\n", bcm_pin, level?"high":"low");
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if( level )
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{
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gpiod_line_set_value(line, 1);
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}
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else
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{
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gpiod_line_set_value(line, 0);
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}
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sleep(1); /* must add sleep here, or it will not take effect */
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gpiod_line_release(line);
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gpiod_chip_close(chip);
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#endif
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return 0;
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}
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