android下调试3G之gpio控制3G上电

た入场券 2022-08-13 14:40 204阅读 0赞

如果是自己开发的板子，需要用GPIO引脚控制3G模块开机/关机时，下面的文章会对你有所帮助，是以处理器IMX6和中兴MG3732模块为例介绍。

一、引脚连接

处理器的gpio3\_GPIO\[9\]连接3G模块的ON/OFF（29）引脚来控制3G的开机/关机。

二、开关机条件

给ON/OFF引脚连续2500~3500毫秒低电平则开机，给再ON/OFF引脚连续2500~3500毫秒低电平则关机。

三、gpio驱动程序

gpio\_3g.c

#include<linux/module.h>
    #include<linux/kernel.h>
    #include<linux/init.h>
    #include<linux/fs.h>
    #include<linux/cdev.h>
    #include<linux/device.h>
    #include<asm/io.h>
    #include<linux/mm.h>
    #include<asm/uaccess.h>
    #include<linux/gpio.h>
    
    #define GPIO_IOF_MAGIC 0xd0
    #define 3G_INPUT	    _IO(GPIO_IOF_MAGIC,8)
    #define 3G_OUTPUT   	_IO(GPIO_IOF_MAGIC,9)
    #define 3G_ON_OFF		IMX_GPIO_NR(3,9)    //控制引脚为：gpio3[9]
    
    MODULE_LICENSE ("GPL");
    int gpio_major=2555;
    int gpio_minor=0;
    int number_devices=1;
    struct cdev gpiocdev;
    struct class *my_class;
    
    static int gpio_open(struct inode *inode,struct file *file)
    {
    	printk (KERN_INFO "GPIO device opened\n");
    	
    	if(gpio_direction_output(3G_ON_OFF,0x00)<0){
    		printk("3G_ON_OFF set direction failed\n");
    	}  
    	return 0;
    }
    
    static long gpio_ioctl(struct file *file,unsigned int cmd,unsigned long arg)
    {
    	int val;
    	printk("GPIO:ioctl running....\n");
    	
    	switch(cmd){
    		case 3G_INPUT:
    			if(gpio_direction_input(3G_ON_OFF)<0){
    				printk("3G_ON_OFF set input failed\n");
    			}
    			if(arg>0){
    				gpio_set_value(3G_ON_OFF,0x01);
    			}else{
    				gpio_set_value(3G_ON_OFF,0x00);
    			}
    			val=gpio_get_value(3G_ON_OFF);
    			printk("3G_ON_OFF ioctl val=%d\n",val);
    		break;
    		case 3G_OUTPUT:
    			if(gpio_direction_output(3G_ON_OFF,0x00)<0){
    				printk("3G_ON_OFF set direction failed\n");
    			}
    			if(arg>0){
    				gpio_set_value(3G_ON_OFF,0x01);
    			}else{
    				gpio_set_value(3G_ON_OFF,0x00);
    			}
    			val=gpio_get_value(3G_ON_OFF);
    			printk("3G_ON_OFF ioctl val=%d\n",val);
    		break;		
    		default:
    			printk("cmd is not exist\n");
    			return -1;
    	}
    	return val;
    }
    
    
    static int gpio_release (struct inode *inode, struct file *file)
    {
    	printk (KERN_INFO "GPIO device closed\n");  
    	return 0;
    }
    
    struct file_operations gpio_fops = {
    	.owner=THIS_MODULE,
    	.open=gpio_open,
    	.release=gpio_release,
    	.unlocked_ioctl=gpio_ioctl,
    };
    
    static void char_reg_setup_cdev (void)
    {
    	int error;
    	dev_t devno;
    	devno=MKDEV(gpio_major,gpio_minor);
    	cdev_init(&gpiocdev,&gpio_fops);
    	gpiocdev.owner=THIS_MODULE;
    	error=cdev_add(&gpiocdev,devno,1);
    	if (error)
    		printk(KERN_NOTICE "Error %d adding char device GPIO",error);
    }
    
    static int __init gpio_init (void)
    {
    	int result;
    	dev_t devno;
    
    	devno=MKDEV(gpio_major,gpio_minor);
    
    	if(gpio_major){
    		result=register_chrdev_region(devno,number_devices,"gpio_3g");
    	}else{
    		result=alloc_chrdev_region(&devno,0,number_devices,"gpio_3g");
    		gpio_major=MAJOR(devno);
    	}
    	if (result<0){
    		printk(KERN_WARNING "GPIO:can't get major number %d\n", gpio_major);
    		return result;
    	}
    	char_reg_setup_cdev ();	
    	my_class=class_create(THIS_MODULE,"GPIOCLASS");
    	device_create(my_class,NULL,MKDEV(gpio_major,gpio_minor),NULL,"gpio_3g");
    
    	if(gpio_request(3G_ON_OFF,"UnKnow")<0){
    		printk("3G_ON_OFF request failed\n");
    	}
    	printk (KERN_INFO "char device GPIO registered\n");
    
    	return 0;
    }
    
    static void __exit gpio_exit(void)
    {
    	dev_t devno=MKDEV(gpio_major,gpio_minor);
    	gpio_free(3G_ON_OFF);
    
    	cdev_del(&gpiocdev);
    	unregister_chrdev_region(devno,number_devices);
    	device_destroy(my_class,devno);
    	class_destroy(my_class);
    	printk(KERN_INFO"char device GPIO  unregister\n");
    }
    
    module_init (gpio_init);
    module_exit (gpio_exit);

四、内核添加gpio驱动步骤（android4.3源码）

1、把gpio\_3g.c放到~/myandroid/kernel\_imx/drivers/char目录下（假设源码在~/myandroid下）。

2、~/myandroid/kernel\_imx/drivers/char/Konfig中最后添加红色框部分语句。

![Center][]

3、在~/myandroid/kernel\_imx/drivers/char/Makefile中添加红色框部分语句。

![Center 1][]

4、在~/myandroid/kernel\_imx下 make  menuconfig 来配置内核，配置完成后退出并保存。如下图：

![Center 2][]

![Center 3][]

![Center 4][]

![Center 5][]

5、在进入~/myandroid/kernel\_imx目录执行：

cp  .config   arch/arm/configs/imx6\_android\_defconfig

到此后，行以下命令编译：

source build/enevsetup.sh

lunch sabresb\_6dq-user

make

五、编译3G模块开关机程序

1、程序代码

3g\_on\_off.c

#include<stdio.h>
    #include<unistd.h>
    #include<fcntl.h>
    #include<errno.h>
    #include<sys/ioctl.h>
    #include<sys/types.h>
    
    #define 3G_INPUT     _IO(GPIO_IOF_MAGIC,8)
    #define 3G_OUTPUT    _IO(GPIO_IOF_MAGIC,9)
    
    #define SET_ON           0x01
    #define SET_OFF          0x00
    
    int main(int argc, char *argv[])
    {
    	int fd;
    	fd=open("/dev/gpio_3g",O_RDWR); //打开gpio_3g设备文件
    	if(fd<0){
    		perror("open:");
    	}
    	if(ioctl(fd,3G_OUTPUT,SET_ON)<0){ //设置该引脚为输出高
    		perror("3G_OUTPUT ioctl:");
    	}
    	sleep(3);
    	if(ioctl(fd,3G_OUTPUT,SET_OFF)<0){ //设置该引脚为输出低
    		perror("3G_OUTPUT ioctl:");
    	}
    	
    	if(ioctl(fd,3G_INPUT,SET_OFF)<0){ //设置该引脚为输入，防止被意外篡改
    		perror("3G_INPUT ioctl:");
    	}
    	close(fd);
    	return 0;
    }

Android.mk

LOCAL_PATH	:=$(call my-dir)
    include	$(CLEAR_VARS)
    LOCAL_MODULE_TAGES	:=optional
    LOCAL_MODULE	:=3g_on_off
    LOCAL_SRC_FILES	:=3g_on_off.c
    include	$(BUILD_EXECUTABLE)

2、在~/myandroid/external下创建 3g\_on\_off文件夹

3、把 3g\_on\_off.c 和 Android.mk 文件放到新建文件夹下。

4、执行以下命令编译：

source  build/enevsetup.sh

lunch  sabresb\_6dq-user

mmm  external/3g\_on\_off

5、把生成的可执行程序：

~/myandroid/out/target/product/sabresd\_6dq/obj/EXECUTABLES/3g\_on\_off\_intermediates/3g\_on\_off放到

~/myandroid/out/target/product/sabresd\_6dq/system里面

执行：make  snod   打包

六、烧写镜像到开发板，执行3g\_on\_off程序对3G模块进行开关机操作。

3G上电后，连接板子的调试串口终端会输出以下红色框的信息，此时表明已识别USB串口设备

![Center 6][]

[Center]: /images/20220810/c0faf1d9058a4f688a239cfb532213e4.png
[Center 1]: /images/20220810/464f4a76a8384ce1b403558cb8e60413.png
[Center 2]: /images/20220810/3a7e116ccb5c464e9379870fb6c7a614.png
[Center 3]: /images/20220810/e0f23e4af1d34cd2a369eec669612f27.png
[Center 4]: /images/20220810/ec25698924954e7d9804d4b247b27ef3.png
[Center 5]: /images/20220810/a39ae9e71baf4cbea66f801ef7c7649f.png
[Center 6]: /images/20220810/5e199fd1083c48de82605e326a6b8503.png