一、单独映射寄存器实现
可参考arm点灯 C语言 cortex-A7核 点LED灯 （附 汇编实现、使用C语言 循环实现、使用C语言 封装函数实现【重要、常用】）-CSDN博客
1 应用程序 test.c
cs
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
int main(int argc, char const *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("打开设备文件成功\n");
while(1)
{
printf("请输入要进行的操作：0(关灯) 1(开灯) >>> ");
fgets(buf,sizeof(buf),stdin);//在终端读一个字符串
buf[strlen(buf) - 1] = '\0';
write(fd, buf, sizeof(buf));//将数据传递给内核
}
close(fd);
return 0;
}2 头文件head.h
cs
#ifndef __HEAD_H__
#define __HEAD_H__
//GPIOE
#define PHY_LED1_MODER 0X50006000
#define PHY_LED1_ODR 0x50006014
//GPIOF
#define PHY_LED2_MODER 0X50007000
#define PHY_LED2_ODR 0x50007014
//RCC
#define PHY_RCC 0x50000A28
#endif3 驱动程序 demo.c
cs
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "head.h"
unsigned int major;
char kbuf[128] = {};
//定义三个指针指向映射后的虚拟内存
unsigned int *vir_moder_E;
unsigned int *vir_odr_E;
unsigned int *vir_moder_F;
unsigned int *vir_odr_F;
unsigned 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)
{
printk("%s:%s:%d\n",__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\n",__FILE__,__func__,__LINE__);
int ret;
ret = copy_from_user(kbuf,ubuf,size);
if (ret)
{
printk("copy_from_user filed\n");
return -EIO;
}
if(kbuf[0] == '0') //关灯
{
//关灯逻辑
(*vir_odr_E) &= (~(0x1 << 10)); //LED1默认关灯
(*vir_odr_F) &= (~(0x1 << 10)); //LED2默认关灯
(*vir_odr_E) &= (~(0x1 << 8)); //LED3默认关灯
}
else if(kbuf[0] == '1') //开灯
{
//开灯逻辑
(*vir_odr_E) |= (0x1 << 10); //LED1
(*vir_odr_F) |= (0x1 << 10); //LED2
(*vir_odr_E) |= (0x1 << 8); //LED3
}
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
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_close,
};
static int __init mycdev_init(void)
{
//注册字符设备驱动
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);
//进行寄存器的地址映射
//GPIOE
vir_moder_E = ioremap(PHY_LED1_MODER,4);
if(vir_moder_E == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_odr_E = ioremap(PHY_LED1_ODR,4);
if(vir_odr_E == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
//GPIOF
vir_moder_F = ioremap(PHY_LED2_MODER,4);
if(vir_moder_F == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_odr_F = ioremap(PHY_LED2_ODR,4);
if(vir_odr_F == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
//RCC
vir_rcc = ioremap(PHY_RCC,4);
if(vir_rcc == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
printk("寄存器内存映射成功\n");
//LED1寄存器初始化
(*vir_rcc) |= (0x1 << 4); //GPIOE控制器时钟使能
(*vir_moder_E) &= (~(0x3 << 20)); //MODER[21:20]->00
(*vir_moder_E) |= (0x1 << 20); //MODER[21:20]->01
(*vir_odr_E) &= (~(0x1 << 10)); //默认关灯
//LED2寄存器初始化
(*vir_rcc) |= (0x1 << 5); //GPIOF控制器时钟使能
(*vir_moder_F) &= (~(0x3 << 20)); //MODER[21:20]->00
(*vir_moder_F) |= (0x1 << 20); //MODER[21:20]->01
(*vir_odr_F) &= (~(0x1 << 10)); //默认关灯
//LED3寄存器初始化
(*vir_rcc) |= (0x1 << 4); //GPIOE控制器时钟使能
(*vir_moder_E) &= (~(0x3 << 16)); //MODER[17:16]->00
(*vir_moder_E) |= (0x1 << 16); //MODER[17:16]->01
(*vir_odr_E) &= (~(0x1 << 8)); //默认关灯
return 0;
}
static void __exit mycdev_exit(void)
{
//取消内存映射
iounmap(vir_moder_E);
iounmap(vir_odr_E);
iounmap(vir_moder_F);
iounmap(vir_odr_F);
iounmap(vir_rcc);
//注册字符设备驱动
unregister_chrdev(major,"mychrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");编写好代码后，make成arm架构
make arch=arm modname=demo
使用交叉编译工具链
arm-linux-gnueabihf-gcc test.c
将文件通过tftp传输到开发板中
cp demo.ko ~/nfs/rootfs/
cp a.out ~/nfs/rootfs/
4 效果呈现
二、封装结构体映射实现
kbuf[0] 控制灯
kbuf[1] 控制状态
1 头文件head.h
cs
#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_LED1_ADDR 0X50006000
#define PHY_LED2_ADDR 0X50007000
#define PHY_LED3_ADDR 0X50006000
#define PHY_RCC_ADDR 0X50000A28
#endif 2 驱动程序 demo.c
cs
#include <linux/init.h>
#include <linux/module.h>
#include<linux/fs.h>
#include<linux/io.h>
#include"head.h"
int major;
char kbuf[128]={0};
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
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)
{
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
unsigned long ret;
//向用户空间读取拷贝
if(size>sizeof(kbuf))//用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小
size=sizeof(kbuf);
ret=copy_to_user(ubuf,kbuf,size);
if(ret)//拷贝失败
{
printk("copy_to_user filed\n");
return ret;
}
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
unsigned long ret;
//从用户空间读取数据
if(size>sizeof(kbuf))//用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小
size=sizeof(kbuf);
ret=copy_from_user(kbuf,ubuf,size);
if(ret)//拷贝失败
{
printk("copy_to_user filed\n");
return ret;
}
switch(kbuf[0]){
case '1'://LED1
if(kbuf[1]=='0')//关灯
vir_led1->ODR &= (~(1<<10));
else//开灯
vir_led1->ODR |= 1<<10;
break;
case '2'://LED2
if(kbuf[1]=='0')//关灯
vir_led2->ODR &= (~(1<<10));
else//开灯
vir_led2->ODR |= 1<<10;
break;
case '3'://LED3
if(kbuf[1]=='0')//关灯
vir_led3->ODR &= (~(1<<8));
else//开灯
vir_led3->ODR |= 1<<8;
break;
}
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
return 0;
}
//定义操作方法结构体变量并赋值
struct file_operations fops={
.open=mycdev_open,
.read=mycdev_read,
.write=mycdev_write,
.release=mycdev_close,
};
int all_led_init(void)
{
//寄存器地址的映射
vir_led1=ioremap(PHY_LED1_ADDR,sizeof(gpio_t));
if(vir_led1==NULL)
{
printk("ioremap filed：%d\n",__LINE__);
return -ENOMEM;
}
vir_led2=ioremap(PHY_LED2_ADDR,sizeof(gpio_t));
if(vir_led2==NULL)
{
printk("ioremap filed：%d\n",__LINE__);
return -ENOMEM;
}
vir_led3=vir_led1;
vir_rcc=ioremap(PHY_RCC_ADDR,4);
if(vir_rcc==NULL)
{
printk("ioremap filed：%d\n",__LINE__);
return -ENOMEM;
}
printk("物理地址映射成功\n");
//寄存器的初始化
//rcc
(*vir_rcc) |= (3<<4);
//led1
vir_led1->MODER &= (~(3<<20));
vir_led1->MODER |= (1<<20);
vir_led1->ODR &= (~(1<<10));
//led2
vir_led2->MODER &= (~(3<<20));
vir_led2->MODER |= (1<<20);
vir_led2->ODR &= (~(1<<10));
//led3
vir_led3->MODER &= (~(3<<16));
vir_led1->MODER |= (1<<16);
vir_led1->ODR &= (~(1<<8));
printk("寄存器初始化成功\n");
return 0;
}
static int __init mycdev_init(void)
{
//字符设备驱动注册
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);
//寄存器映射以及初始化
all_led_init();
return 0;
}
static void __exit mycdev_exit(void)
{
//取消地址映射
iounmap(vir_led1);
iounmap(vir_led2);
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");3 应用程序 test.c
cs
#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include<unistd.h>
#include<string.h>
int main(int argc, char const *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)
{
//从终端读取
printf("请输入两个字符\n");
printf("第一个字符:1(LED1) 2(LED2) 3(LED3)\n");
printf("第二个字符:0(关灯) 1(开灯)\n");
printf("请输入>");
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;
}