通过字符设备驱动的分步实现编写LED驱动，另外实现特备文件和设备的绑定

设备驱动的分步实现编写LED驱动，另外实现特备文件和设备的绑定"/>

通过字符设备驱动的分步实现编写LED驱动，另外实现特备文件和设备的绑定

头文件.h文件

#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
// 构建开灯关灯的功能码
#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)
#endif

驱动文件

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "head.h"
unsigned int major = 0;
struct cdev *cdev;
unsigned int minor = 0;
dev_t devno;
struct class *cls;
struct device *dev;
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;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);switch (cmd){case 1: // myled1switch (arg){case 0: // LED1灭vir_led1->ODR &= (~(0x1 << 10));break;case 1: // LED1亮vir_led1->ODR |= (0x1 << 10);break;default:break;}break;case 2: // myled3switch (arg){case 0:vir_led2->ODR &= (~(0X1 << 10));break;case 1:vir_led2->ODR |= (0X1 << 10);break;default:break;}break;case 3: // myled3switch (arg){case 0:vir_led3->ODR &= (~(0X1 << 8));break;case 1:vir_led3->ODR |= (0X1 << 8);break;default:break;}break;default: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,.unlocked_ioctl = mycdev_ioctl,.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);// led1vir_led1->MODER &= (~(3 << 20));vir_led1->MODER |= (1 << 20);vir_led1->ODR &= (~(1 << 10));// led2vir_led2->MODER &= (~(3 << 20));vir_led2->MODER |= (1 << 20);//vir_led2->ODR |= (0X1 << 10);vir_led2->ODR &= (~(1 << 10));// led3vir_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)
{// 1.申请一个对象空间cdev_allocint ret;cdev = cdev_alloc();if (NULL == cdev){printk("申请对象空间失败\n");ret = -EFAULT;goto out1;}printk("字符设备驱动对象申请成功\n");// 2.初始化对象cdev_initcdev_init(cdev, &fops);// 3.申请设备号 register_chrdev_region()/alloc_chrdev_region()if (major == 0){ret = alloc_chrdev_region(&devno, minor, 3, "mychrdev");if (ret){printk("动态申请设备号失败\n");goto out2;}major = MAJOR(devno); // 根据设备号获取主设备号minor = MINOR(devno); // 根据设备号获取次设备号}else{ret = register_chrdev_region(MKDEV(major, minor), 3, "mychrdev");if (ret){printk("静态指定设备号失败\n");goto out2;}}printk("设备申请成功\n");// 4.注册驱动对象 cdev_addret = cdev_add(cdev, MKDEV(major, minor), 3);if (ret){printk("注册字符设备驱动对象失败\n");goto out3;}printk("注册字符设备驱动对象成功\n");// 5.向上提交目录 class_createcls = class_create(THIS_MODULE, "mychrdev");if (IS_ERR(cls)){printk("向上提交目录失败\n");goto out4;}printk("向上提交目录成功\n");// 6.向上提交设备节点信息 device_creatint i;for (i = 0; i < 3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);if (IS_ERR(dev)){printk("向上提交设备节点失败\n");goto out5;}}printk("向上提交设备节点信息成功\n");// 寄存器映射以及初始化all_led_init();return 0;
out5:// 将提交成功的节点信息释放for (--i; i >= 0; i--){device_destroy(cls, MKDEV(major, i));}// 销毁目录class_destroy(cls);
out4:cdev_del(cdev);
out3:unregister_chrdev_region(MKDEV(major, minor), 3);
out2:kfree(cdev);
out1:return ret;
}static void __exit mycdev_exit(void)
{// 取消地址映射iounmap(vir_led1);iounmap(vir_led2);iounmap(vir_rcc);// 1.销毁设备节点信息int i;for (i = 0; i < 3; i++){device_destroy(cls, MKDEV(major, i));}// 2.销毁目录class_destroy(cls);// 3.注销字符设备驱动对象cdev_del(cdev);// 4.释放设备号unregister_chrdev_region(MKDEV(major, minor), 3);// 5.释放申请到的字符设备驱动对象空间kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用程序

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include "head.h"
int fd1=0, fd2=0, fd3=0;
int main(int argc, char const *argv[])
{char buf[128] = {0};int a, b;while (1){// 从终端读取printf("myled0控制led1,myled0控制led1,myled0控制led1\n");printf("请选择要控制的灯：1 2 3\n");printf("请输入>");scanf("%d", &a);printf("请输入要实现的功能 ");printf("0(关灯) 1(开灯)\n");printf("请输入>");scanf("%d", &b);switch (a){case 1:if (fd2 > 0)close(fd2);if (fd3 > 0)close(fd3);fd1 = open("/dev/myled0", O_RDWR);if (fd1 < 0){printf("打开设备文件失败\n");exit(-1);}ioctl(fd1, 1, b);break;case 2:if (fd2 > 0)close(fd2);if (fd2 > 0)close(fd2);fd1 = open("/dev/myled1", O_RDWR);if (fd1 < 0){printf("打开设备文件失败\n");exit(-1);}ioctl(fd1, 2, b);break;case 3:if (fd1 > 0)close(fd1);if (fd2 > 0)close(fd2);fd3 = open("/dev/myled2", O_RDWR);if (fd3 < 0){printf("打开设备文件失败\n");exit(-1);}ioctl(fd3, 3, b);break;default:break;}}if (fd1 > 0)close(fd1);if (fd2 > 0)close(fd2);if (fd3 > 0)close(fd3);return 0;
}