head.h
#ifndef __HEAD_H__
#define __HEAD_H__
#define PHY_LED13_MODER 0x50006000 //[20 21]/[16 17] >01
#define PHY_LED13_ODR 0x50006014 // [10]/[8]
#define PHY_LED2_MODER 0x50007000 //[20 21] >01
#define PHY_LED2_ODR 0x50007014 //10
#define PHY_RCC 0x50000A28 //4 5 bits
#define LED_ON _IOW('l',1,int *)
#define LED_OFF _IOW('l',0,int *)
#endif
text.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include "head.h"
int main(int argc,const char * argv[])
{
int a;
int b;
while(1)
{
int fd;
//Get the function we want to implement from the interrupt
printf("Please select the lights to be controlled: 0-LED1, 1-LED2, 2-LED3\
");
scanf("%d", & amp;a);
switch(a)
{
case 1:
fd = open("/dev/mycdev0",O_RDWR);
break;
case 2:
fd = open("/dev/mycdev1",O_RDWR);
break;
case 3:
fd = open("/dev/mycdev2",O_RDWR);
break;
}
if(fd<0)
{
printf("Failed to open device file\
");
return -1;
}
printf("Open device file successfully\
");
printf("Please enter the function you want to implement");
printf("0(lights off)1(lights on)\
");
printf("Please enter:");
scanf("%d", & amp;b);
switch (b)
{
case 1:
ioctl(fd,LED_ON, & amp;b);
break;
case 0:
ioctl(fd,LED_OFF, & amp;b);
break;
}
close(fd);
}
return 0;
}
demo.c
#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/cdev.h>
#include <linux/slab.h>
#include <linux/kdev_t.h>
#include "head.h"
struct class *cls;
struct device *dev;
unsigned int *vir_moder13;
unsigned int *vir_moder2;
unsigned int *vir_odr13;
unsigned int *vir_odr2;
unsigned int *vir_rcc;
char kbuf[128]={};
//Encapsulation operation method
int mycdev_open(struct inode * inode,struct file* file)
{
unsigned int min=MINOR(inode->i_rdev);//Get the minor device number of the opened file
file->private_data=(void *)min;
printk("%s:%s:%d\
",__FILE__,__func__,__LINE__);
return 0;
}
/*
ssize_t mycdev_read(struct file * file,char *ubuf,size_t size,loff_t *lof)
{
printk("%s:%s:%d\
",__FILE__,__func__,__LINE__);
unsigned long ret;
ret=copy_to_user(ubuf,kbuf,size);
if(ret)
{
printk("copy to user filed\
");
return -EIO;
}
return 0;
}
ssize_t mycdev_write(struct file * file,const char *ubuf,size_t size,loff_t *lof)
{
printk("%s:%s:%d\
",__FILE__,__func__,__LINE__);
unsigned long ret;
ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
printk("copy from user filed\
");
return -EIO;
}
//Control LED lights
if(kbuf[0]=='0')//Turn off the light
{
(*vir_odr13) & amp;=~(0x1<<10);
(*vir_odr13) & amp;=~(0x1<<8);
(*vir_odr2) & amp;=~(0x1<<10);
}
else if(kbuf[0]=='1')//Turn on LED1
{
(*vir_odr13)|=(0x1<<10);
}
else if(kbuf[0]=='2')//Turn on LED2
{
(*vir_odr2)|=(0x1<<10);
}
else if(kbuf[0]=='3')//Turn on LED3
{
(*vir_odr13)|=(0x1<<8);
}
return 0;
}
*/
int mycdev_close(struct inode * indode,struct file* file)
{
printk("%s:%s:%d\
",__FILE__,__func__,__LINE__);
return 0;
}
long mycdev_ioctl(struct file *file,unsigned int cmd,unsigned long arg)
{
int min=(int)file->private_data;//Get the minor device number of the file
switch(min)
{
case 0://LED1
switch(cmd)
{
case LED_ON://turn on the light
(*vir_odr13) |=(0x1<<10);
break;
case LED_OFF://turn off the light
(*vir_odr13) & amp;=~(0x1<<10);
break;
}
break;
case 1://LED2
switch(cmd)
{
case LED_ON://turn on the light
(*vir_odr2) |=(0x1<<10);
break;
case LED_OFF://turn off the light
(*vir_odr2) & amp;=~(0x1<<10);
break;
}
break;
case 2://LED3
switch(cmd)
{
case LED_ON://turn on the light
(*vir_odr13) |=(0x1<<8);
break;
case LED_OFF://turn off the light
(*vir_odr13) & amp;=~(0x1<<8);
break;
}
break;
}
return 0;
}
struct file_operations fops = {
.open=mycdev_open,
//.read=mycdev_read,
//.write=mycdev_write,
.unlocked_ioctl = mycdev_ioctl,
.release=mycdev_close,
};
struct cdev* cdev;
unsigned int major=0;
unsigned int minor=0;
dev_t devno;
static int __init mycdev_init(void)
{
int i;
//Register character device driver
//1. Apply for an object space cdev_alloc
int ret;
cdev=cdev_alloc();
if(cdev==NULL)
{
printk("Failed to apply for character device driver object space\
");
ret =-EFAULT;
goto out1;
}
printk("Application for character device driver object space successful\
");
//2.Initialize object cdev_init
cdev_init(cdev, & amp;fops);
//3. Apply for device number register_chrdev_region()/alloc_chrdev_region()
if(major==0)//Dynamic application
{
ret=alloc_chrdev_region( & amp;devno,minor,3,"mychrdev");
if(ret)
{
printk("Dynamic application for device number failed\
");
goto out2;
}
major=MAJOR(devno);//Get the major device number based on the device number
minor=MINOR(devno);//Get the minor device number based on the device number
}
else//static application
{
ret=register_chrdev_region(MKDEV(major,minor),3,"mychrdev");
if(ret)
{
printk("Static application for device number failed\
");
goto out2;
}
}
printk("Device number application successful\
");
//4. Register driver object cdev_add
ret=cdev_add(cdev,MKDEV(major,minor),3);
if(ret)
{
printk("Registration of character device driver object failed\
");
goto out3;
}
printk("Registration of character device driver object successful\
");
if(major<0)
{
printk("Character device driver registration failed\
");
return major;
}
printk("Character device driver successful major=%d\
",major);
//5. Submit the directory upward class_create
cls=class_create(THIS_MODULE,"mychrdev");
if(IS_ERR(cls))
{
printk("Failed to access the submission directory\
");
goto out4;
}
printk("I want to upload the submission directory successfully\
");
//6. Submit device node information upward device_create
for(i=0;i<3;i + + )
{
dev=device_create(cls,NULL,MKDEV(major,i),NULL,"mycdev%d",i);
if(IS_ERR(dev))
{
printk("Failed to submit device node\
");
goto out5;
}
}
printk("I want to submit the device node successfully\
");
//Perform register address mapping
vir_moder13 = ioremap(PHY_LED13_MODER,4);
if(vir_moder13 == NULL)
{
printk("Physical memory address mapping failed %d\
",__LINE__);
return -EFAULT;
}
vir_moder2 = ioremap(PHY_LED2_MODER,4);
if(vir_moder13 == NULL)
{
printk("Physical memory address mapping failed %d\
",__LINE__);
return -EFAULT;
}
vir_odr13 = ioremap(PHY_LED13_ODR,4);
if(vir_odr13 == NULL)
{
printk("Physical memory address mapping failed %d\
",__LINE__);
return -EFAULT;
}
vir_odr2 = ioremap(PHY_LED2_ODR,4);
if(vir_odr2 == NULL)
{
printk("Physical memory address mapping failed %d\
",__LINE__);
return -EFAULT;
}
vir_rcc = ioremap(PHY_RCC,4);
if(vir_rcc == NULL)
{
printk("Physical memory address mapping failed %d\
",__LINE__);
return -EFAULT;
}
printk("Register memory mapping successful\
");
//Register initialization
//rcc initialization
(*vir_rcc) |= (0x3<<4);//GPIOEF controller clock enable
(*vir_moder13) & amp;= ~(0x3<<20);
(*vir_moder13) |= (0x1<<20);//LED1
(*vir_moder13) & amp;= ~(0x3<<16);
(*vir_moder13) |= (0x1<<16);//LED3
(*vir_moder2) & amp;= ~(0x3<<20);
(*vir_moder2) |= (0x1<<20);//LED2
(*vir_odr13) & amp;=~(0x1<<10);//LED1
(*vir_odr13) & amp;=~(0x1<<8);//LED3
(*vir_odr2) & amp;=~(0x1<<10);//LED2
return 0;
printk("Initialization of LED successful");
out5:
//When submitting the device node fails, the successfully submitted node will be released.
for(i--;i>=0;i--)
{
device_destroy(cls,MKDEV(major,i));
}
//Destroy directory
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)
{
int i;
//Cancel memory mapping
iounmap(vir_moder13);
iounmap(vir_moder2);
iounmap(vir_odr13);
iounmap(vir_odr2);
iounmap(vir_rcc);
//1. Destroy device node information
for(i=0;i<3;i + + )
{
device_destroy(cls,MKDEV(major,i));
}
//2. Destroy the directory
class_destroy(cls);
//3. Unregister the character device driver object
cdev_del(cdev);
//4. Release the device number
unregister_chrdev_region(MKDEV(major,minor),3);
//5. Release the applied character device driver object space
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");