华清11.16

首先在头函数led.h中声明gpio结构体和gpioe，gpiof，rcc的物理地址。

#ifndef __LED_H__
#define __LED_H__
typedef struct 
{
    volatile unsigned int MODER;
    volatile unsigned int OTYPER;  
    volatile unsigned int OSPEEDR;
    volatile unsigned int PUPDR;
    volatile unsigned int IDR;
    volatile unsigned int ODR;
}gpio_t;
 
#define WL_GPIOE 0x50006000
#define WL_GPIOF 0x50007000
#define WL_RCC   0x50000a28
#endif

 在驱动程序中，定义gpio结构体类型的两个指针接受物理地址映射的虚拟地址，然后通过结构体来寻找对应的寄存器，而不用手动添加偏移量。

在init函数中申请驱动设备号，映射地址，使能并初始化灯。在write函数中接受来自用户程序的值，存入kbuf中。kbuf[0]中的值用以确定指定操作的小灯编号，kbud[1]中的值确定亮灭操作。

最后在exit函数中接触映射并注销字符设备驱动。

#include 
#include
#include
#include
#include
#include"led.h"
#define CNAME "myled"
int major;
volatile int* RCC=NULL;
volatile gpio_t* GPIOE=NULL;
volatile gpio_t* GPIOF=NULL;
char kbuf[128]={0};
int mydev_open (struct inode *inode, struct file *file)
{
    return 0;
}
ssize_t mydev_read (struct file *file, char __user *ubuf, size_t size, loff_t *loffs)
{
    int res;
    if(size>sizeof(kbuf))
        size=sizeof(kbuf);
    res=copy_to_user(ubuf,kbuf,size);
    if(res)
    {
        printk("copy to user error");
        return EIO;
    }
    return size;
}
ssize_t mydev_write (struct file *file, const char __user *ubuf, size_t size, loff_t *loffs)
{
    int res;
    if(size > sizeof(kbuf)) 
        size=sizeof(kbuf);
    res=copy_from_user(kbuf,ubuf,size);
    if(res)
    {
        printk("copy from user error\n");
        return EIO;
    }
    printk("copy over , kbuf=%s\n",kbuf);
//接收后亮灯逻辑，kbuf[0]表示灯，kbuf[1]表示亮灭
    if(kbuf[0]=='1')
    {
        if(kbuf[1]=='1')
        {
            GPIOE->ODR|=(0x1<<10);
        }
        else if(kbuf[1]=='0')
        {
             GPIOE->ODR&=(~(0x1<<10));
        } 
    } 
    if(kbuf[0]=='2')
    {
        if(kbuf[1]=='1')
        {
            GPIOF->ODR|=(0x1<<10);
        }
        else if(kbuf[1]=='0')
        {
             GPIOF->ODR&=(~(0x1<<10));
        } 
    } 
    if(kbuf[0]=='3')
    {
        if(kbuf[1]=='1')
        {
            GPIOE->ODR|=(0x1<<8);
        }
        else if(kbuf[1]=='0')
        {
             GPIOE->ODR&=(~(0x1<<8));
        } 
    }  
    return size;
}
int mydev_close (struct inode *inode, struct file *file)
{
    return 0;
}
const struct file_operations fops= {
    .open=mydev_open,
    .read=mydev_read,
    .write=mydev_write,
    .release=mydev_close,
};
static int __init demo_init(void)
{
    major=register_chrdev(major,CNAME,&fops);
    if(major<0)
    {
        printk("register_chrdev error\n");
        return major;
    }
    printk("major=%d\n",major);
    //RCC映射
    RCC=ioremap(WL_RCC,4);
    if(NULL==RCC)
    {
        printk("rcc ioremap error\n");
        return ENOMEM;
    }
    //GPIOE映射
    GPIOE=ioremap(WL_GPIOE,sizeof(gpio_t));
    if(NULL==GPIOE)
    {
        printk("gpioE ioremap error\n");
        return ENOMEM;
    }
    //GPIOF映射
    GPIOF=ioremap(WL_GPIOF,sizeof(gpio_t));
    if(NULL==GPIOF)
    {
        printk("gpioF ioremap error\n");
        return ENOMEM;
    }
    //初始化灯
    *RCC|=(0x1<<4);
    *RCC|=(0x1<<5);
    GPIOE->MODER&=(~(0x3<<20));
    GPIOE->MODER|=(0x1<<20);
    GPIOF->MODER&=(~(0x3<<20));
    GPIOF->MODER|=(0x1<<20);
    GPIOE->MODER&=(~(0x3<<16));
    GPIOE->MODER|=(0x1<<16);
    return 0;
}
static void __exit demo_exit(void)
{
    //解除映射
    iounmap(GPIOE);
    iounmap(GPIOF); 
    iounmap(RCC);
    unregister_chrdev(major,CNAME);
}
module_init(demo_init);
module_exit(demo_exit);
MODULE_LICENSE("GPL");

 在用户程序启动前先下载（insmod）驱动程序（.ko文件）并在/dev/下添加申请的驱动。

在调用open，write，read，等函数时会调用驱动代码中对应的函数。

通过在死循环中写入1灯亮，1灯灭，2灯亮，2灯灭，3灯亮，3灯灭的循环，并在每步操作后sleep休眠来观察现象。

#include
#include
#include
#include
#include
#include
#include
char buf[128]={""};
int main(int argc, char const *argv[])
{
    int fd=-1;
    fd=open("/dev/myled",O_RDWR);
    if(-1==fd)
    {
        perror("open error");
        return -1;
    }
    while (1)
    {
        buf[0]='1';
        buf[1]='1';
        write(fd,buf,sizeof(buf));
        sleep(1);
        buf[0]='1';
        buf[1]='0';
        write(fd,buf,sizeof(buf));
        sleep(1);
        buf[0]='2';
        buf[1]='1';
        write(fd,buf,sizeof(buf));
        sleep(1);
        buf[0]='2';
        buf[1]='0';
        write(fd,buf,sizeof(buf));
        sleep(1);
        buf[0]='3';
        buf[1]='1';
        write(fd,buf,sizeof(buf));
        sleep(1);
        buf[0]='3';
        buf[1]='0';
        write(fd,buf,sizeof(buf));
        sleep(1);
    }
    
    close(fd);
    return 0;
}