/*********************************************************************************
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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: test_led.c
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* Description: This file is imx6ull LED test program
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*
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* Version: 1.0.0(2021年11月17日)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "2021年11月17日 22时59分31秒"
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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 <errno.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#define CLASS_LED "/sys/class/leds"
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int turn_led(char *which, unsigned char brightness);
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int main (int argc, char **argv)
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{
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while(1)
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{
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turn_led("sysled", 255);
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sleep(1);
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turn_led("sysled", 0);
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sleep(1);
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}
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return 0;
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}
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int turn_led(char *which, unsigned char brightness)
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{
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char led_path[64] = {0x0};
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char buf[5] = {0x0};
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int fd = -1;
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int rv = 0;
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if( !which )
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{
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printf("%s() Invalid input arguments\n", __func__);
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return -1;
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}
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snprintf(led_path, sizeof(led_path), "%s/%s/brightness", CLASS_LED, which);
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if( (fd=open(led_path, O_WRONLY)) < 0 )
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{
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printf("Open led file '%s' failure: %s\n", strerror(errno));
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return -2;
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}
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snprintf(buf, sizeof(buf), "%d", brightness);
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if( write(fd, buf, strlen(buf)) < 0 )
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{
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printf("Open led file '%s' failure: %s\n", strerror(errno));
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rv = -3;
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}
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close(fd);
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return rv;
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}
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