head.h
#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 GPIOE 0x50006000
#define GPIOF 0x50007000
#define GPIOB 0x50003000
#define RCC 0X50000A28
#define LED_ON_IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)
#endif
test.c
#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[])
{
int a, s;
char buf[128] = {0};
int fd1,fd2,fd;
while (1)
{
printf("Please input operating device 0(led1) 1(led2) 2(led3)\
");
scanf("%d", &s);
printf("execute function>");
printf("0(closed) 1(opened)\
");
printf("Please input>");
scanf("%d", &a);
switch (s)
{
case 0:
fd = open("/dev/myled0", O_RDWR);
if (0 == a)
ioctl(fd, LED_OFF, s);
else if (1 == a)
ioctl(fd, LED_ON, s);
break;
case 1:
fd1 = open("/dev/myled1", O_RDWR);
if (0 == a)
ioctl(fd, LED_OFF, s);
else if (1 == a)
ioctl(fd, LED_ON, s);
break;
case 2:
fd2 = open("/dev/myled2", O_RDWR);
if (0 == a)
ioctl(fd, LED_OFF, s);
else if (1 == a)
ioctl(fd, LED_ON, s);
break;
default:
printf("Input error, re-enter\
");
break;
}
if (!(0 == s || 1 == s || 2 == s))
{
continue;
}
if (fd < 0 || fd1 < 0 || fd2 < 0)
{
printf("Failed to open device file\
");
exit(-1);
}
}
close(fd);
close(fd1);
close(fd2);
return 0;
}
mychrdev_led.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/cdev.h>
#include "head.h"
char kbuf[128] = {0};
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
struct class *cls;
struct device *dev;
struct cdev* cdev;
dev_t devno;
unsigned int minor = 0;
unsigned int major;
int mycdev_open(struct inode *inode, struct file *file)
{
int a=inode->i_rdev;//Get the device number corresponding to the current device file
file->private_data=(void *)MINOR(a);//Save the minor device number to the file structure of the current file
printk("%s:%s:%d\
", __FILE__, __func__, __LINE__);
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\
", __FILE__, __func__, __LINE__);
return 0;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch(cmd)
{
case LED_ON:
switch(arg)
{
case 1:
vir_led1->ODR|=(0x1 << 10);
break;
case 2:
vir_led2->ODR|=(0x1 << 10);
break;
case 3:
vir_led3->ODR|=(0x1 << 8);
break;
}
break;
case LED_OFF:
switch(arg)
{
case 1:
vir_led1->ODR|=(~(0x1 << 10));
break;
case 2:
vir_led2->ODR|=(~(0x1 << 10));
break;
case 3:
vir_led3->ODR|=(~(0x1 << 8));
break;
}
break;
}
return 0;
}
// Define the operation method structure variable and assign it
struct file_operations fops = {
.open = mycdev_open,
.unlocked_ioctl=mycdev_ioctl,
.release = mycdev_close,
};
int led_init(void)
{
// Mapping of register addresses
vir_led1 = ioremap(GPIOE, sizeof(gpio_t));
if (vir_led1 == NULL)
{
printk("ioremap filed:%d\
", __LINE__);
return -ENOMEM;
}
vir_led2 = ioremap(GPIOF, sizeof(gpio_t));
if (vir_led2 == NULL)
{
printk("ioremap filed:%d\
", __LINE__);
return -ENOMEM;
}
vir_led3 = ioremap(GPIOE, sizeof(gpio_t));
if (vir_led3 == NULL)
{
printk("ioremap filed:%d\
", __LINE__);
return -ENOMEM;
}
vir_rcc = ioremap(RCC, 4);
if (vir_rcc == NULL)
{
printk("ioremap filed:%d\
", __LINE__);
return -ENOMEM;
}
printk("Physical address mapping successful\
");
// register initialization
// rcc
(*vir_rcc) |= (0x3 << 4);
// led
vir_led1->MODER & amp;= (~(0x3 << 20));
vir_led1->MODER |= (0x1 << 20);
vir_led1->ODR &= (~(0x1 << 10));
vir_led2->MODER & amp;= (~(0x3 << 20));
vir_led2->MODER |= (0x1 << 20);
vir_led2->ODR & amp;= (~(0x1 << 10));
vir_led3->MODER & amp;= (~(0x3 << 16));
vir_led3->MODER |= (0x1 << 16);
vir_led3->ODR & amp;= (~(0x1 << 8));
printk("Register initialized successfully\
");
return 0;
}
static int __init mycdev_init(void)
{
int i;
//1. Apply for object space cdev_alloc
int ret;
cdev = cdev_alloc();
if(NULL == cdev)
{
printk("Drive space application failed\
");
ret = -EFAULT;
goto OUT1;
}
printk("Successful drive space application\
");
//2. Initialize the object cdev_init
cdev_init(cdev, &fops);
//3. Apply for device number register_chrdev_region()/alloc_chrdev_region()
if(0 == major)
{
ret = alloc_chrdev_region( & devno,minor,3,"myled");
if(ret)
{
printk("Dynamic application for device number failed\
");
goto OUT2;
}
major = MAJOR(devno);
minor = MINOR(devno);
}
else
{
ret = register_chrdev_region(MKDEV(major,minor),3,"myled");
if(ret)
{
printk("Static application device number failed\
");
goto OUT2;
}
}
printk("Apply for device number successfully\
");
//4. Register the driver object cdev_add()
ret=cdev_add(cdev,MKDEV(major,minor),3);
if(ret)
{
printk("Failed to register device driver object\
");
goto OUT3;
}
printk("Device driver object registered successfully\
");
// Submit directory up
cls = class_create(THIS_MODULE, "myled");
if (IS_ERR(cls))
{
printk("Failed to submit directory up\
");
ret = -PTR_ERR(cls);
goto OUT4;
}
printk("submit directory information successfully\
");
// Submit device node information upward
for(i=0;i<3;i ++ )
{
dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
if (IS_ERR(dev))
{
printk("Failed to submit device node information up\
");
ret = -PTR_ERR(dev);
goto OUT5;
}
}
printk("submit the device node up successfully\
");
// register map and initialization
led_init();
return 0;
OUT5:
for (--i;i>=0;i--)
{
device_destroy(cls,MKDEV(major,i));
}
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)
{
// Cancel address mapping
iounmap(vir_led1);
iounmap(vir_led2);
iounmap(vir_led3);
iounmap(vir_rcc);
//Destroy node information
int i;
for (i=0;i<3;i + + )
{
device_destroy(cls,MKDEV(major,i));
}
//Destroy directory information
class_destroy(cls);
// Unregister the driver object
cdev_del(cdev);
//Release the device number
unregister_chrdev_region(MKDEV(major,minor),3);
// release object space
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");