驱动开发day8
head.h
#ifndef __HEAD_H__
#define __HEAD_H__
// 构建开灯关灯的功能码
#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)
#endif demo.c
#include
#include
#include
#include
#include
#include
#include
#include"head.h"
#include
#include
#include
#include
struct device_node *dnode;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
char kbuf[128]={0};
struct cdev *cdev;
unsigned int major=0;
unsigned int minor=0;
dev_t devno;
struct class *cls;
struct device *dev;
int mycdev_open(struct inode *inode, struct file *file)
{
int min=MINOR(inode->i_rdev);//获取打开的的文件的次设备号
file->private_data= (void *)min;
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int min=(int)file->private_data; //获取到文件的次设备号
switch(min)
{
case 0: //操作LED1
switch(cmd)
{
case LED_ON: //开灯
gpiod_set_value(gpiono1,1);
break;
case LED_OFF: //关灯
gpiod_set_value(gpiono1,0);
break;
}
break;
case 1: //操作LED2
switch(cmd)
{
case LED_ON: //开灯
gpiod_set_value(gpiono2,1);
break;
case LED_OFF: //关灯
gpiod_set_value(gpiono2,0);
break;
}
break;
case 2: //操作LED3
switch(cmd)
{
case LED_ON: //开灯
gpiod_set_value(gpiono3,1);
break;
case LED_OFF:
gpiod_set_value(gpiono3,0);
break;
}
break;
}
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变量并赋值
struct file_operations fops = {
.open = mycdev_open,
.unlocked_ioctl = mycdev_ioctl,
.release = mycdev_close,
};
static int __init mycdev_init(void)
{
//1.申请一个对象空间cdev_alloc
int ret;
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("字符设备驱动对象申请成功\n");
//2.初始化对象cdev_init
cdev_init(cdev,&fops);
//3.申请设备号 register_chrdev_region()/alloc_chrdev_region()
if(major==0)//动态申请
{
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("设备号申请成功\n");
//4.注册驱动对象 cdev_add
ret=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_create
cls=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_create
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("向上提交设备节点失败\n");
goto out5;
}
}
printk("向上提交设备节点信息成功\n");
//解析设备树节点信息
dnode = of_find_node_by_path("/myled");
if(dnode == NULL)
{
printk("解析设备树节点失败\n");
return -ENXIO;
}
//获取LED2 GPIO编号
gpiono2 = gpiod_get_from_of_node(dnode, "led2-gpio", 0, GPIOD_OUT_LOW, NULL);
if(IS_ERR(gpiono2))
{
printk("申请gpio信息失败\n");
return -PTR_ERR(gpiono2);
}
//获取LED1 GPIO编号
gpiono1 = gpiod_get_from_of_node(dnode, "led1-gpio", 0, GPIOD_OUT_LOW, NULL);
if(IS_ERR(gpiono1))
{
printk("申请gpio信息失败\n");
return -PTR_ERR(gpiono1);
}
//获取LED3 GPIO编号
gpiono3 = gpiod_get_from_of_node(dnode, "led3-gpio", 0, GPIOD_OUT_LOW, NULL);
if(IS_ERR(gpiono3))
{
printk("申请gpio信息失败\n");
return -PTR_ERR(gpiono3);
}
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)
{
gpiod_set_value(gpiono1,0);
gpiod_set_value(gpiono2,0);
gpiod_set_value(gpiono3,0);
//释放GPIO编号
gpiod_put(gpiono1);
gpiod_put(gpiono2);
gpiod_put(gpiono3);
//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"); test.c
#include
#include
#include
#include
#include
#include
#include
#include
#include "head.h"
int main(int argc, char const *argv[])
{
int a,b;
while(1)
{
char buf[128]="/dev/mycdev";
//从终端读取
printf("请输入要实现的LED灯:");
printf("0(LED1) 1(LED2) 2(LED3)\n");
printf("请输入>");
scanf("%d",&b);
sprintf(buf,"%s%d",buf,b);
int fd=open(buf,O_RDWR);
if(fd<0)
{
printf("打开设备文件失败\n");
exit(-1);
}
//从终端读取
printf("请输入要实现的功能 ");
printf("0(关灯) 1(开灯)\n");
printf("请输入>");
scanf("%d",&a);
switch(a)
{
case 1:
ioctl(fd,LED_ON);
break;
case 0:
ioctl(fd,LED_OFF);
break;
}
close(fd);
}
return 0; 计时器
#include
#include
#include
#include
#include
#include
struct timer_list hw;
void mytime_hello(struct timer_list *timer)
{
printk("hello world\n");
mod_timer(timer, jiffies + 5*HZ);
}
//入口函数，安装内核模块时执行
static int __init mycdev_init(void)
{
timer_setup(&hw, mytime_hello, 0);
hw.expires = jiffies + 5*HZ;
add_timer(&hw);
return 0;
}
//出口函数，卸载内核模块时执行
static void __exit mycdev_exit(void)
{
del_timer(&hw);
}
//用于声明入口函数
module_init(mycdev_init);
//用于声明出口函数
module_exit(mycdev_exit);
//声明当前内核模块遵循GPL协议
MODULE_LICENSE("GPL");