Linux驱动之利用ioctl函数和字符设备驱动对象分布注册点亮小灯-编程知识

实验结果

头文件代码

#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#define LED_ON _IOW('l',1,int)//开灯
#define LED_OFF _IOW('l',0,int)//关灯#endif

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "head2.h"struct cdev *cdev;      // 定义接收字符设备驱动对象的指针
unsigned int major = 0; // 定义主设备号
unsigned int minor = 0; // 定义次设备号
dev_t devno;            // 定义第一个设备号，动态申请设备号时要用到
struct class *cls;      // 向上传递目录的指针
struct device *dev;     // 向上传递设备节点的指针char kbuf[128] = {0}; // 定义内核中用来接收数据的一块空间gpio_t *vir_led1;      // 定义用来接收LED1地址映射的指针变量
gpio_t *vir_led2;      // 定义用来接收LED2地址映射的指针变量
gpio_t *vir_led3;      // 定义用来接收LED3地址映射的指针变量
unsigned int *vir_rcc; // 定义用来接收RCC地址映射的指针变量// 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;
}
// 通过ioctl进行io功能的控制
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{int which; // 因为传递过来的是用户空间的地址，在驱动中定义一个which将用户空间地址中的内容// 拷贝下来，实现指针的传递int ret = copy_from_user(&which, (unsigned int *)arg, 4);if (ret){printk("copy_from_user err\n");return ret;}// 根据用户空间功能码cmd的不同实现硬件不同的控制switch (cmd){case LED_ON:       // 开灯switch (which) // 根据传递的参数来决定哪一盏灯开{case 1:vir_led1->ODR |= (0X1 << 10); // LED1亮break;case 2:vir_led2->ODR |= (0X1 << 10); // LED亮break;case 3:vir_led3->ODR |= (0X1 << 8); // LED3亮break;default:break;}break;case LED_OFF: // 关灯switch (which){case 1:vir_led1->ODR &= (~(0X1 << 10));break;case 2:vir_led2->ODR &= (~(0X1 << 10));break;case 3:vir_led3->ODR &= (~(0X1 << 8));break;default:break;}break;}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__);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__);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遍历并且初始化
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,.unlocked_ioctl = mycdev_ioctl,
};//灯的初始化
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 &= (~(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)
{int ret;// 1、分配字符设备的驱动对象cdev = cdev_alloc();if (cdev == NULL){printk("申请字符设备驱动对象失败\n");ret = -EFAULT;goto OUT1;}printk("申请字符设备驱动对象成功\n");// 2、初始化字符设备驱动对象cdev_init(cdev, &fops);// 3、申请设备号if (major > 0) // 静态指定设备号{ret = register_chrdev_region(MKDEV(major, minor), 3, "mycdev");if (ret){printk("静态指定设备号失败\n");goto OUT2;}}else{ret = alloc_chrdev_region(&devno, minor, 3, "mycdev");if (ret){printk("静态指定设备号失败\n");goto OUT2;}major = MINOR(devno); // 根据设备号获取次设备号major = MAJOR(devno); // 根据设备号获取主设备号}printk("申请设备号成功\n");// 3、注册字符设备驱动对象ret = cdev_add(cdev, MKDEV(major, minor), 3);if (ret){printk("注册字符设备驱动失败\n");goto OUT3;}// 4、向上提供目录cls = class_create(THIS_MODULE, "mycdev");if (IS_ERR(cls)){printk("向上提供目录失败\n");ret = -PTR_ERR(cls);goto OUT4;}printk("向上提供目录信息成功\n");// 5、向上提供设备信息节点int i;for (i = 0; i < 3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mycdev%d", i);if (IS_ERR(dev)){printk("向上提供设备节点失败\n");ret = -PTR_ERR(dev);goto OUT5;}}printk("向上提交设备节点成功\n");// 寄存器映射以及初始化all_led_init();return 0;OUT5:for (--i; i >= 0; i--){device_destroy(cls, MKDEV(major, i)); // 释放提交成功的设备信息}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);// 销毁设备节点信息int i;for (i = 0; i < 3; i++){device_destroy(cls, MKDEV(major, i));}// 销毁目录class_destroy(cls);// 注销字符设备驱动对象cdev_del(cdev);// 释放设备号unregister_chrdev_region(MKDEV(major, minor), 3);// 释放 对象空间kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

用户空间代码

#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include<unistd.h>
#include<string.h>
#include<sys/ioctl.h>
#include"head.h"int main(int argc, char const *argv[])
{char buf[128]={0};int a,b;int fd=open("/dev/mycdev0",O_RDWR);if(fd<0){printf("打开设备文件失败\n");exit(-1);}while(1){printf("请输入要实现的功能：1（开灯）0（关灯>）");scanf("%d",&a);printf("请输入要控制的灯：1(LED1) 2(LED2) 3(LED3)>");scanf("%d",&b);switch(a){case 1:ioctl(fd,LED_ON,&b);break;case 0:ioctl(fd,LED_OFF,&b);break;}}close(fd);return 0;
}