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 <linux/init.h>
#include <linux/module.h>
#include<linux/fs.h>
#include<linux/uaccess.h>
#include<linux/io.h>
#include<linux/device.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <uapi/linux/kdev_t.h>
#include "myled.h"
#define CNAME "myled"
char kbuf[128] = {0};
struct class *cls;
struct device *dev;
//虚拟地址
gpio_t *virt_gpioe; //PE
gpio_t *virt_gpiof; //PF
volatile unsigned int *virt_rcc; //RCC
//cdev结构体指针
struct cdev *cdev;
#if 1
unsigned int major=0; //动态申请设备号
#else
unsigned int major=500; //静态申请设备号
#endif
int minor = 0;
const int count=3;
int mycdev_open(struct inode *inode, struct file *file)
{
int minor;
minor=MINOR(inode->i_rdev);
file->private_data=(void*)minor;
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
return 0;
}
ssize_t mycdev_read(struct file *file, char __user *ubuf, size_t size, loff_t *loff)
{
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
return size;
}
ssize_t mycdev_write (struct file *file, const char __user *ubuf, size_t size, loff_t *loff)
{
int minor;
int ret;
minor=(int)file->private_data;
switch(minor)
{
case 0: //LED1---->PE10
if(size > sizeof(kbuf))
{
size=sizeof(kbuf);
}
ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
printk("传递数据失败\n");
return -EIO;
}
if('0'==kbuf[0])
{
virt_gpioe->ODR &= (~(0x1<<10));
}
else
{
virt_gpioe->ODR |=(0x1<<10);
}
break;
case 1: //LED2---->PF10
if(size > sizeof(kbuf))
{
size=sizeof(kbuf);
}
ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
printk("传递数据失败\n");
return -EIO;
}
if('0'==kbuf[0])
{
virt_gpiof->ODR &= (~(0x1<<10));
}
else
{
virt_gpiof->ODR |=(0x1<<10);
}
break;
case 2: //LED3---->PE8
if(size > sizeof(kbuf))
{
size=sizeof(kbuf);
}
ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
printk("传递数据失败\n");
return -EIO;
}
if('0'==kbuf[0])
{
virt_gpioe->ODR &= (~(0x1<<8));
}
else
{
virt_gpioe->ODR |=(0x1<<8);
}
break;
}
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
return size;
}
long mycdev_ioctl(struct file *file,unsigned int cmd,unsigned long arg)
{
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;
}
//操作方法结构体
const struct file_operations fops =
{
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.unlocked_ioctl = mycdev_ioctl,
.release = mycdev_close,
};
//入口
static int __init mycdev_init(void)
{
int i;
int ret;
dev_t devno; //动态分配的设备号
//1.分配cdev结构体
cdev=cdev_alloc();
if(NULL==cdev)
{
printk("cdev_alloc fail\n");
goto ERR1;
return -EIO;
}
//2.初始化结构体
cdev_init(cdev,&fops);
//3.申请设备号
if(major>0)
{
//静态
ret=register_chrdev_region(MKDEV(major,minor),count,CNAME);
if(ret)
{
printk("静态申请设备号失败\n");
ret=-ENOMEM;
goto ERR2;
}
}
else
{
//动态申请设备号
ret=alloc_chrdev_region(&devno,0,count,CNAME);
if(ret)
{
printk("动态申请设备失败\n");
ret=-ENOMEM;
goto ERR2;
}
major=MAJOR(devno);
minor=MINOR(devno);
}
//4.驱动的注册
ret=cdev_add(cdev,MKDEV(major,minor),count);
if(ret)
{
printk("驱动注册失败\n");
return -EIO;
goto ERR3;
}
//5.自动创建设备节点
cls=class_create(THIS_MODULE,CNAME);
if(IS_ERR(cls))
{
printk("向上层提交目录信息失败\n");
ret=PTR_ERR(cls);
goto ERR4;
}
//提交设备结点信息
for(i=0;i<count;i++)
{
dev=device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);
if(IS_ERR(dev))
{
printk("提交设备结点信息失败\n");
ret=PTR_ERR(dev);
goto ERR5;
}
}
//对灯地址进行映射
virt_rcc=ioremap(PHY_RCC,4);
if(NULL==virt_rcc)
{
printk("RCC映射失败\n");
return -ENOMEM;
}
virt_gpioe=ioremap(PHY_GPIOE,sizeof(gpio_t));
if(NULL==virt_gpioe)
{
printk("GPIOE映射失败");
return -ENOMEM;
}
virt_gpiof=ioremap(PHY_GPIOF,sizeof(gpio_t));
if(NULL==virt_gpiof)
{
printk("GPIOF映射失败\n");
return -ENOMEM;
}
//对灯进行初始化
//RCC使能
*virt_rcc |= (0x3 << 4);
//1.对LED1--->PE10初始化
//设置PE10引脚为输出模式
virt_gpioe->MODER &= (~(0x3 << 20));
virt_gpioe->MODER |= (0x1 << 20);
//设置PE10引脚默认为低电平
virt_gpioe->ODR &= (~(0x1 << 10));
//2.对LED2--->PF10初始化
//设置PF10引脚为输出模式
virt_gpiof->MODER &= (~(0x3 << 20));
virt_gpiof->MODER |= (0x1 << 20);
//设置PF10引脚默认为低电平
virt_gpiof->ODR &= (~(0x1 << 10));
//3.对LED3--->PE8初始化
//设置PE8引脚为输出模式
virt_gpioe->MODER &= (~(0x3 << 16));
virt_gpioe->MODER |= (0x1 << 16);
//设置PE8引脚默认为低电平
virt_gpioe->ODR &= (~(0x1 << 8));
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,minor),count);
ERR2:
kfree(cdev);
ERR1:
//返回错误码
return -EIO;
}
//出口
static void __exit mycdev_exit(void)
{
int i;
//1。销毁设备节点信息
for(i=0;i<count;i++)
{
device_destroy(cls,MKDEV(major,i));
}
//2.销毁目录信息
class_destroy(cls);
//3.驱动的注销
cdev_del(cdev);
//4.销毁设备号
unregister_chrdev_region(MKDEV(major,minor),count);
//5.释放cdev结构体
kfree(cdev);
}
//指定入口地址
module_init(mycdev_init);
module_exit(mycdev_exit);
//指定出口地址
//许可证
MODULE_LICENSE("GPL");
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