编写驱动代码(字符设备驱动注册与注销,用户空间与内核空间进行数据传递,映射地址,断开映射地址)
编译驱动代码(编写相关Makefile)
安装(insmod)
手动创建设备文件(mknod 设备文件路径及名字 c 主设备号 次设备号)
编写应用程序测试
#ifndef __HEAD_H__
#define __HEAD_H__
typedef struct{
unsigned int moder;
unsigned int otyper;
unsigned int ospeedr;
unsigned int pupdr;
unsigned int idr;
unsigned int odr;
}gpio;
#define GPIOE 0x50006000
#define GPIOF 0x50007000
#define RCC 0x50000A28
#endif
#include
#include
#include
#include
#include
#include "head.h"
char kbuf[128] = {0};
// 虚拟地址
gpio *vir_gpioe;
gpio *vir_gpiof;
int *vir_rcc;
// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
int ret;
if (sizeof(kbuf) < size)
size = sizeof(kbuf);
ret = copy_to_user(ubuf, kbuf, size);
if (ret)
{
printk("copy_to_user failed\n");
return -EIO;
}
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
int ret;
if (sizeof(kbuf) < size)
size = sizeof(kbuf);
ret = copy_from_user(kbuf, ubuf, size);
if (ret)
{
printk("copy_from_user failed\n");
return -EIO;
}
switch (kbuf[0])
{
case '1': // 第一盏灯
if (kbuf[1] == '0') // 灭灯
{
vir_gpioe->odr &= (~(0x1 << 10));
}
else if (kbuf[1] == '1') // 亮灯
{
vir_gpioe->odr |= (0x1 << 10);
}
break;
case '2': // 第二盏灯
if (kbuf[1] == '0') // 灭灯
{
vir_gpiof->odr &= (~(0x1 << 10));
}
else if (kbuf[1] == '1') // 亮灯
{
vir_gpiof->odr |= (0x1 << 10);
}
break;
case '3': // 第三盏灯
if (kbuf[1] == '0') // 灭灯
{
vir_gpioe->odr &= (~(0x1 << 8));
}
else if (kbuf[1] == '1') // 亮灯
{
vir_gpioe->odr |= (0x1 << 8);
}
break;
default:
break;
}
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
// 存放主设备号
int major;
// 定义操作方法结构体变量并初始化
struct file_operations fops =
{
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_close,
};
static int __init mycdev_init(void)
{
// 注册字符设备驱动
major = register_chrdev(major, "mychrdev", &fops);
if (major < 0)
{
printk("字符设备驱动注册失败\n");
return -1;
}
printk("字符设备驱动注册成功,major=%d\n", major);
// 地址映射
vir_gpioe = ioremap(GPIOE, sizeof(gpio));
if (vir_gpioe == NULL)
{
printk("gpioe寄存器映射失败\n");
return -EFAULT;
}
vir_gpiof = ioremap(GPIOF, sizeof(gpio));
if (vir_gpiof == NULL)
{
printk("gpiof寄存器映射失败\n");
return -EFAULT;
}
vir_rcc = ioremap(RCC, 4);
if (vir_rcc == NULL)
{
printk("rcc寄存器映射失败\n");
return -EFAULT;
}
printk("寄存器映射成功\n");
// 寄存器初始化
// rcc寄存器使能
(*vir_rcc) |= (0x3 << 4);
// 设置为输出
// led1
vir_gpioe->moder &= (~(0x3 << 20));
vir_gpioe->moder |= (0x1 << 20);
// led2
vir_gpiof->moder &= (~(0x3 << 20));
vir_gpiof->moder |= (0x1 << 20);
// led3
vir_gpioe->moder &= (~(0x3 << 16));
vir_gpioe->moder |= (0x1 << 16);
// 默认为灯灭
vir_gpioe->odr &= (~(0x1 << 10));//led1
vir_gpiof->odr &= (~(0x1 << 10));//led2
vir_gpioe->odr &= (~(0x1 << 8));//led3
printk("寄存器初始化成功\n");
return 0;
}
static void __exit mycdev_exit(void)
{
unregister_chrdev(major, "mychrdev");
//断开映射
iounmap(vir_gpioe);
iounmap(vir_gpiof);
iounmap(vir_rcc);
printk("断开映射成功\n");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");
#include
#include
#include
#include
#include
#include
#include
int main(int argc, const char *argv[])
{
char buf[128] = {0};
int fd = open("/dev/mychrdev", O_RDWR);
if (fd < 0)
{
printf("打开设备文件失败\n");
exit(-1);
}
while (1)
{
printf("控制第几盏LED灯(一共三盏灯),亮1,灭0 ex:11>");
fgets(buf, sizeof(buf), stdin);
buf[strlen(buf) - 1] = '\0';
write(fd, buf, sizeof(buf));
}
close(fd);
return 0;
}