imx6ull看门狗使用_内部看门狗输出-优快云博客

一、内部看门狗

1、内部看门狗使用说明

内部看门狗使用WDOG1，

复位输出控制选择WDOG1_B —— MX6UL_PAD_GPIO1_IO08__WDOG1_WDOG_B

注：该引脚正常使用时为高电平，当看门狗超时或系统重启后输出低电平，仅设备重新上电才能够恢复为高电平。

【IMX6ULL参考手册(11/2017 )——59.5.6.2 WDOG_B generation （P4087）】

2、设备树配置

2.1配置输出引脚电器属性

&iomuxc {

pinctrl-names = "default";

……

pinctrl_gpio1_wdg1: gpio1_wdg1_grp {

fsl,pins = <

MX6UL_PAD_GPIO1_IO08__WDOG1_WDOG_B 0x30b0

};

……

};

2.2配置看门狗参数

&wdog1 {

pinctrl-names = "default";

pinctrl-0 = <&pinctrl_gpio1_wdg1>;

fsl,ext-reset-output;

timeout-sec = <5>;

status = "okay";

};

fsl,ext-reset-output 开启复位输出

timeout-sec 设置看门狗超时复位时间，上述配置为5S

3、内核配置

Device Drivers --->

[*] Watchdog Timer Support --->

[*] Update boot-enabled watchdog until userspace takes over

<*> IMX2+ Watchdog

4、验证

4.1烧写内核与设备树，重启系统

4.2查看设备

其中/dev/watchdog0便是内部看门狗WDOG1

4.3编写应用测试

#include <stdio.h>  
#include <stdlib.h>  
#include <string.h>  
#include <unistd.h>  
#include <fcntl.h>  
#include <sys/ioctl.h>  
#include <linux/types.h>  
#include <linux/watchdog.h>  

#define cst_str2(c1, c2) (((unsigned int)0 | \
                                    (char)c2) << 8 | \
                                    (char)c1)

  
int main(int argc, char *argv[])  
{  
	int fd;
	int flags;  
	int timeout = 10;
	int dummy = 0;

	fd = open("/dev/watchdog0", O_WRONLY);

	if (fd == -1) {
		printf("Watchdog open fail.\n");
		exit(-1);
	}

	if (argc > 1) {
		switch (cst_str2(argv[1][0], argv[1][1])) 
		{
		case cst_str2('-','s'):
			if(argc > 2)
				timeout = atoi(argv[2]);
			ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
			printf("set timeout : %d\n", timeout);
			break;
		case cst_str2('-', 'g'):
			ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
			printf("get timeout : %d\n", timeout);
			break;
		case cst_str2('-', 'e'):	//使能看门狗
			flags = WDIOS_ENABLECARD;
			ioctl(fd, WDIOC_SETOPTIONS, &flags);
			printf("Watchdog card enabled.\n");
			break;
		case cst_str2('-', 'd'):	//禁用看门狗
			flags = WDIOS_DISABLECARD;
			ioctl(fd, WDIOC_SETOPTIONS, &flags);
			printf("Watchdog card disabled.\n");
close(fd);
			return 0;
			break;
		
		default:
			printf("\
\t-s set timeout.\n\
\t-g get timeout.\n\
\t-d to disable.\n\
\t-e to enable.\n\
");
			break;
		}
	}

	while (1) {  
		ioctl(fd, WDIOC_KEEPALIVE, &dummy);		//喂狗
		sleep(1);  
	}  
}