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本文将介绍在EXYNOS4412平台上实现对LED灯开关的控制

首先定义命令在led.h文件中

#define LED_MAGIC 'L'#define LED_ON _IO(LED_MAGIC,1)#define LED_OFF _IO(LED_MAGIC,0)

LED2对应控制寄存器为GPL2

LED3对应控制寄存器为GPK1 接下来编写led控制驱动程序

#include 
   
    #include 
    
     #include 
     
      #include 
      
       #include 
       
        #include "led.h"#define GPL2CON 0x11000100 //GPL2CON寄存器的物理地址#define GPL2DAT 0x11000104         //GPL2DAT寄存器的物理地址#define GPK1CON 0x11000060//GPK1CON寄存器的物理地址#define GPK1DAT 0x11000064//GPK1DAT寄存器的物理地址static int *pgpl2con;static int *pgpl2dat;static int *pgpk1con;static int *pgpk1dat;struct cdev cdev;dev_t devno;int led_open(struct inode *node, struct file *filp){    pgpl2con = ioremap(GPL2CON,4);//将物理地址转化为虚拟地址    pgpl2dat = ioremap(GPL2DAT,4);    pgpk1con = ioremap(GPK1CON,4);    pgpk1dat = ioremap(GPK1DAT,4);    writel((readl(pgpl2con)& ~(0xf<<0)) |(0x1<<0),pgpl2con);   //led2对应GPL2寄存器的第0位，将其写0x1配置为输出模式    writel((readl(pgpk1con)& ~(0xf<<4)) |(0x1<<4),pgpk1con);     // led3对应GPK1寄存器的第0位，将其写0x1配置为输出模式    return 0;}long led_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){    switch (cmd)    {        case LED_ON:             writel(readl(pgpl2dat) |(0x1<<0), pgpl2dat);               //led2对应GPL2寄存器的第0位，将其写0x1配置为高电平             writel(readl(pgpk1dat) |(0x1<<1), pgpk1dat);             //led2对应GPk1寄存器的第0位，将其写0x1配置为高电平            printk("OPEN is success\n");            break;        case LED_OFF:            writel(readl(pgpl2dat) &(~(0x1<<0)), pgpl2dat);             //led2对应GPL2寄存器的第0位，将其0x1取反为0配置为低电平            writel(readl(pgpk1dat) &(~(0x1<<1)), pgpk1dat);             //led2对应GPK1寄存器的第0位，将其0x1取反为0配置为低电平            printk("close is success\n");            break;        default:            return -EINVAL;    }}/*文件操作结构体*/static struct file_operations led_fops ={    .open = led_open,    .unlocked_ioctl = led_ioctl,};/*设备驱动模块加载函数*/static int led_init(){    cdev_init(&cdev,&led_fops);*初始化cdev结构*/    alloc_chrdev_region(&devno, 0 , 1 , "myled"); /* 注册字符设备 */    cdev_add(&cdev, devno, 1);    return 0;}static void led_exit(){    cdev_del(&cdev); /*注销设备*/    unregister_chrdev_region(devno,1);/*释放设备号*/}module_init(led_init);module_exit(led_exit);
       
      
     
    
   

应用程序

led_app.c#include
   
    #include
    
     #include
     
      #include
      
       #include "led.h"#include
       
        int main(int argc,char *argv[]){    int fd;    int cmd;    if(argc<2)    {        printf("please input second para\n");        return 0;    }    cmd = atoi(argv[1]);    fd = open("/dev/myled0",O_RDWR);    if(cmd ==1)    ioctl(fd,LED_ON);    if(cmd==0)    ioctl(fd,LED_OFF);    return 0;}
       
      
     
    
   

编写Makefile，通过make编译该驱动程序生成led.ko文件。

使用arm-none-linux-gnueabi-gcc led_app.c -o led_app -static编译应用程序文件，使用 tftp将led.ko ,led_app下载到开发板中 [root@iTOP-4412]# insmod led.ko [root@iTOP-4412]# mknod /dev/myled0 c 249 0 [root@iTOP-4412]# ./led_app 0 [ 26.834348] close is success [root@iTOP-4412]# ./led_app 1 [ 31.561757] OPEN is success