一、head.h
#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_t;
#define PHY_RCC_ADDR 0X50000A28
#define PHY_LED1_ADDR 0X50006000
#define PHY_LED2_ADDR 0X50007000
#define PHY_LED3_ADDR 0X50006000
#endif
二、test.c
#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");
return -1;
}
printf("打开字符设备文件成功\n");
while (1)
{
printf("请输入需要控制的LED灯[1(LED1) 2(LED2) 3(LED3)]以及状态[0(关灯) 1(开灯)]>>>");
fgets(buf, sizeof(buf), stdin);
buf[strlen(buf) - 1] = '\0';
// 向设备文件中写
write(fd, buf, sizeof(buf));
}
close(fd);
return 0;
}
三、demo.c
#include
#include
#include
#include
#include
#include "head.h"
unsigned int major;
char kbuf[128] = {};
// 定义指针指向映射后的虚拟内存
unsigned int *vir_rcc;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
printk("%s:%s:%d", __FILE__, __func__, __LINE__);
return 0;
}
int mycdev_release(struct inode *inode, struct file *file)
{
printk("%s:%s:%d", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
printk("%s:%s:%d", __FILE__, __func__, __LINE__);
int ret;
ret = copy_to_user(ubuf, kbuf, size);
if (ret)
{
printk("copy_to_user filed\n");
return -EIO;
}
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
printk("%s:%s:%d", __FILE__, __func__, __LINE__);
int ret;
ret = copy_from_user(kbuf, ubuf, size);
if (ret)
{
printk("copy_from_user filed\n");
return -EIO;
}
switch (kbuf[0])
{
case '1':
if (kbuf[1] == '0')
vir_led1->ODR &= (~(0x1 << 10));
else
vir_led1->ODR |= (0x1 << 10);
break;
case '2':
if (kbuf[1] == '0')
vir_led2->ODR &= (~(0x1 << 10));
else
vir_led2->ODR |= (0x1 << 10);
break;
case '3':
if (kbuf[1] == '0')
vir_led3->ODR &= (~(0x1 << 8));
else
vir_led3->ODR |= (0x1 << 8);
break;
}
return 0;
}
// 定义操作方法结构体对象
struct file_operations fops = {
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_release};
// 入口函数,安装内核模块时执行
static int __init mycdev_init(void)
{
// static 修饰当前函数只能在本文件使用
// int 函数的返回值类型
// 注册字符设备驱动
// static inline int register_chrdev(unsigned int major, const char *name,
// const struct file_operations *fops)
major = register_chrdev(0, "mychrdev", &fops);
if (major < 0)
{
printk("字符设备驱动注册失败\n");
return major;
}
printk("字符设备驱动注册成功,major=%d\n", major);
// 寄存器地址映射
vir_rcc = ioremap(PHY_RCC_ADDR, 4);
if (vir_rcc == NULL)
{
printk("物理内存地址映射失败%d\n", __LINE__);
return -ENOMEM;
}
vir_led1 = ioremap(PHY_LED1_ADDR, 4);
if (vir_rcc == NULL)
{
printk("物理内存地址映射失败%d\n", __LINE__);
return -ENOMEM;
}
vir_led2 = ioremap(PHY_LED2_ADDR, 4);
if (vir_rcc == NULL)
{
printk("物理内存地址映射失败%d\n", __LINE__);
return -ENOMEM;
}
vir_led3 = ioremap(PHY_LED3_ADDR, 4);
if (vir_rcc == NULL)
{
printk("物理内存地址映射失败%d\n", __LINE__);
return -ENOMEM;
}
// 寄存器初始化
(*vir_rcc) |= (0x3 << 4);
vir_led1->MODER &= (~(0x3 << 20));
vir_led1->MODER |= (0x1 << 20);
vir_led1->ODR &= (~(0x1 << 10));
vir_led2->MODER &= (~(0x3 << 20));
vir_led2->MODER |= (0x1 << 20);
vir_led2->ODR &= (~(0x1 << 10));
vir_led3->MODER &= (~(0x3 << 16));
vir_led1->MODER |= (0x1 << 16);
vir_led1->ODR &= (~(0x1 << 8));
printk("寄存器初始化成功\n");
return 0;
}
static void __exit mycdev_exit(void)
{
iounmap(vir_led1);
iounmap(vir_led2);
iounmap(vir_led3);
iounmap(vir_rcc);
// 注销字符设备驱动
unregister_chrdev(major, "mychrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");