1.在串口工具进行输入：

echo 1 > /dev/myled0 ---->led1灯点亮

echo 0 > /dev/myled0 ---->led1灯熄灭

echo 1 > /dev/myled1 ---->led1灯点亮

echo 0 > /dev/myled1 ---->led1灯熄灭

echo 1 > /dev/myled2 ---->led1灯点亮

echo 0 > /dev/myled2 ---->led1灯熄灭

linux@ubuntu:/sys/class/myled$ ls /dev/myled* -ll

crw------- 1 root root 236, 0 Nov 18 14:55 /dev/myled0 ----->控制PE10（LED1）

crw------- 1 root root 236, 1 Nov 18 14:55 /dev/myled1----->控制PF10（LED2）

crw------- 1 root root 236, 2 Nov 18 14:55 /dev/myled2----->控制PE8（LED3）

2.驱动：

open:在open函数中获取到次设备号，用私有数据传参，传递给write函数

write：在write函数，判断次设备号，就知道操作的是哪盏灯

3.要求：

1）分部实现注册字符设备驱动

2）自动创建设备节点

3）通过结构体对led灯地址进行映射

4）次设备号完成私有数据传参

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include
#include "demo2.h"#define CNAME "myled" //宏定义设备名//定义设备号
#if 1
unsigned int major = 0; //动态设备号
#else
unsigned int major = 500; //动态设备号
#endif//int all_led_init();
const int count = 3;int mnior = 0;      //次设备号
struct cdev *cdev;  //
struct class *cls;  //目录句柄
struct device *dev; //gpio_t *led1;
unsigned int *RCC;
gpio_t *led2;
gpio_t *led3;//打开
int mydemo_open(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);file->private_data = (void*)(MINOR(inode->i_rdev));return 0;
}//读
ssize_t mydemo_read(struct file *file, char __user *ubuf, size_t size, loff_t *loff)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}
//写
ssize_t mydemo_write(struct file *file, const char __user *ubuf, size_t size, loff_t *loff)
{char kbuf[10]={0};int ret;int a;if(size>sizeof(kbuf))size=sizeof(kbuf);a=(int)file->private_data;printk("myled%d open\n",a);printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);ret = copy_from_user(kbuf, ubuf, size);if (ret){printk("copy from user is error\n");return -EIO;}//接收第一个灯信息if (kbuf[0] == '1') //开灯{if (a == 0)led1->ODR |= (1 << 10);else if (a == 1)led2->ODR |= (1 << 10);else if (a == 2)led3->ODR |= (1 << 8);}else if (kbuf[0] == '0') //关灯{if (a == 0)led1->ODR &= ~(1 << 10);else if (a == 1)led2->ODR &= ~(1 << 10);else if (a == 2)led3->ODR &= ~(1 << 8);}return size;
}
//关闭int mydemo_close(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}//操作方法结构体初始化
const struct file_operations fops =
{.open = mydemo_open,.read = mydemo_read,.write = mydemo_write,.release = mydemo_close,
};int all_led_init(void)
{//映射地址//映射物理地址为虚拟地址RCC = ioremap(0x50000A28, 4);  // GPLOE使能led1 = ioremap(0x50006000, 4); // PE引脚设置为输出模式led2 = ioremap(0x50007000, 4);led3 = ioremap(0x50006000, 4);(*RCC) |= (0x3 << 4);// led1led1->MODER &= ~(0x3 << 20);led1->MODER |= (0x1 << 20);led1->ODR &= ~(0x1 << 10);// led2led2->MODER &= ~(0x3 << 20);led2->MODER |= (0x1 << 20);led2->ODR &= ~(0x1 << 10);// led3led3->MODER &= ~(0x3 << 16);led3->MODER |= (0x1 << 16);led3->ODR &= ~(0x1 << 8);return 0;
}//入口函数
static int __init demo_init(void)
{int ret, i;dev_t devno;printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);// 1.分配结构体对象cdev = cdev_alloc();if (NULL == cdev){printk("cdev alloc is error\n");ret = -ENOMEM;goto ERR1;}printk("cdev 分配成功\n");// 2.设备对象初始化cdev_init(cdev, &fops);// 3.设备号申请if (major == 0){ret = alloc_chrdev_region(&devno, mnior, count, CNAME); //动态申请设备号if (ret){printk("alloc_chrdev_register is error \n");goto ERR2;}major = MAJOR(devno);mnior = MINOR(devno);printk("动态申请设备号成功\n");}else{ret = register_chrdev_region(MKDEV(major, mnior), count, CNAME); //静态申请设备号if (ret){printk("静安申请设备号失败\n");goto ERR2;}printk("静态申请设备号成功\n");}// 4.注册字符设备驱动ret = cdev_add(cdev,MKDEV(major, mnior), count);if (ret){printk("字符设备驱动注册失败\n");goto ERR3;}printk("字符设备注册成功\n");// 5.自动创建设备结点cls = class_create(THIS_MODULE, "led");if (IS_ERR(cls)){printk("创建设备目录失败\n");ret = PTR_ERR(cls);goto ERR4;}//向上提交设备结点信息for (i = 0; i < 3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);if (IS_ERR(dev)){printk("创建逻辑结点失败\n");ret = PTR_ERR(dev);goto ERR5;}}printk("创建逻辑节点成功\n");//寄存器的初始化all_led_init();return 0;ERR5:for (--i; i >= 0; i--){device_destroy(cls, MKDEV(major, i));}class_destroy(cls);
ERR4:cdev_del(cdev);
ERR3:unregister_chrdev_region(MKDEV(major, mnior), count);
ERR2:kfree(cdev);
ERR1:return ret;
}//出口函数
static void __exit demo_exit(void)
{// 1.销毁设备节点int i;for (i = 0; i < count; i++){device_destroy(cls, MKDEV(major, i));}class_destroy(cls);// 2.注销字符设备驱动cdev_del(cdev);// 3.释放设备号unregister_chrdev_region(MKDEV(major, mnior), count);// 4.释放动态申请的空间kfree(cdev);printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
}//内核寻找入口出口宏封装
module_init(demo_init);
module_exit(demo_exit);//许可证
MODULE_LICENSE("GPL");