/*********************************************************************************
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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: led.c
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* Description: This file is used to control RGB 3-colors LED
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*
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* pi@raspberrypi:~ $ gpio readall #show RPi pin map
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*
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* LED #PIN BCM
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* I ---- 39 ---- GND
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* G ---- 37 ---- 26
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* R ---- 35 ---- 19
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* B ---- 33 ---- 13
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*
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* Version: 1.0.0(2012/11/03)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "2021/11/03 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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#define msleep(x) usleep( 1000*(x) )
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#define DELAY 500
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#define ON 1
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#define OFF 0
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/* Three LEDs code */
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enum
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{
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LED_R = 0,
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LED_G,
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LED_B,
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LED_MAX,
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};
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/* RGB 3-color LED BCM pin number */
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static int led_gpio[LED_MAX]= { 19, 26, 13 };
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void init_led(void);
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int turn_led(int which, int cmd);
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int main(int argc, char *argv[])
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{
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init_led();
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while(1)
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{
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turn_led(LED_R, ON);
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turn_led(LED_R, OFF);
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turn_led(LED_G, ON);
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turn_led(LED_G, OFF);
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turn_led(LED_B, ON);
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turn_led(LED_B, OFF);
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}
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return 0;
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}
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#if 1 /* Use libgpiod lowlevel API */
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struct gpiod_chip* chip;
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void init_led(void)
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{
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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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}
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int turn_led(int which, int cmd)
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{
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int rv = 0;
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struct gpiod_line* line;
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line = gpiod_chip_get_line(chip, led_gpio[which]);
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if( !line )
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{
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rv = -2;
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}
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gpiod_line_request_output(line, "led", 0);
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if( OFF == cmd )
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{
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gpiod_line_set_value(line, 0);
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}
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else
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{
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gpiod_line_set_value(line, 1);
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}
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msleep(DELAY);
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}
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#else /* use libgpiod ctxless high level API */
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void init_led(void)
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{
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}
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static 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 turn_led(int which, int cmd)
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{
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if( OFF == cmd )
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gpiod_ctxless_set_value("gpiochip0", led_gpio[which], 0, false, "led", gpiod_ctxless_cb, NULL);
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else
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gpiod_ctxless_set_value("gpiochip0", led_gpio[which], 1, false, "led", gpiod_ctxless_cb, NULL);
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}
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#endif
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