1.生产设备节点
这里讲解的是杂项设备，杂项设备的主设备固定为10
misc源代码：“drivers/char/ misc.c，这个是在makefile中强制编译的
1.1杂项设备注册头文件
– include/linux/miscdevice.h
vim include/linux/miscdevice.h
struct miscdevice {
int minor;
const char *name;
const struct file_operations *fops;
struct list_head list;
struct device *parent;
struct device *this_device;
const char *nodename;
mode_t mode;
};
extern int misc_register(struct miscdevice * misc);
extern int misc_deregister(struct miscdevice *misc);
代码添加
#define MISC_NAME "hello_misc"//在/dev中显示的名字/
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("TOPEET");
struct miscdevice hello_misc= {
.minor=MISC_DYNAMIC_MINOR;//自动自动生产minor
.name=MISC_NAME;
.fops=;
};
int hello_probe(struct platform_device *pdev)
{
misc_register(&hello_misc);
printk(KERN_EMERG "hello_probe call \n");
return 0;
}
int hello_remove(struct platform_device *pdev)
{
misc_deregister(&hello_misc);
printk(KERN_EMERG"remove call \n");
return 0;
}
2 在misc中加入fs
include/linux/fs.h
vim include/linux/fs
/*
* NOTE:
* all file operations except setlease can be called without
* the big kernel lock held in all filesystems.
*/
struct file_operations {
struct module *owner;
loff_t (*llseek) (struct file *, loff_t, int);
ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
int (*readdir) (struct file *, void *, filldir_t);
unsigned int (*poll) (struct file *, struct poll_table_struct *);
/* remove by cym 20130408 support for MT660.ko */
#if 0
//#ifdef CONFIG_SMM6260_MODEM
#if 1// liang, Pixtree also need to use ioctl interface...
int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
#endif
#endif
/* end remove */
long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
int (*mmap) (struct file *, struct vm_area_struct *);
int (*open) (struct inode *, struct file *);
int (*flush) (struct file *, fl_owner_t id);
int (*release) (struct inode *, struct file *);
int (*fsync) (struct file *, int datasync);
int (*aio_fsync) (struct kiocb *, int datasync);
int (*fasync) (int, struct file *, int);
int (*lock) (struct file *, int, struct file_lock *);
ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
int (*check_flags)(int);
int (*flock) (struct file *, int, struct file_lock *);
ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
int (*setlease)(struct file *, long, struct file_lock **);
long (*fallocate)(struct file *file, int mode, loff_t offset,
loff_t len);
/* add by cym 20130408 support for MT6260 and Pixtree */
#if defined(CONFIG_SMM6260_MODEM) || defined(CONFIG_USE_GPIO_AS_I2C)
int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
#endif
/* end add */
};
#define IPERM_FLAG_RCU 0x0001
2.1填充fs
#include <linux/init.h>
#include <linux/module.h>
/*驱动注册的头文件，包含驱动的结构体和注册和卸载的函数*/
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#define DRIVER_NAME "hello" //必须和设备注册的一致
#define MISC_NAME "hello_misc"//在/dev中显示的名字/
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("TOPEET");
long hello_unlocked_ioctl(struct file *pfd, unsigned int cmd, unsigned long arg)
{
printk(KERN_EMERG "fs unlocked_ioctl call file:%s cmd:%d arg:%d \n",pfd,cmd,arg);
return 0;
}
int hello_release(struct inode *nd, struct file *pfd)
{
printk(KERN_EMERG "fs release call nd:%s file: \n",nd,pfd);
return 0;
}
int hello_open(struct inode *nd, struct file *pfd)
{
printk(KERN_EMERG "fs open call nd:%s file: \n",nd,pfd);
return 0;
}
struct file_operations hello_fs={
.owner=THIS_MODULE,
.open=hello_open,
.release=hello_release,
.unlocked_ioctl=hello_unlocked_ioctl,
};
struct miscdevice hello_misc={
.minor=MISC_DYNAMIC_MINOR,
.name=MISC_NAME,
.fops=&hello_fs,
};
int hello_probe(struct platform_device *pdev)
{
misc_register(&hello_misc);
printk(KERN_EMERG "hello_probe call \n");
return 0;
}
int hello_remove(struct platform_device *pdev)
{
misc_deregister(&hello_misc);
printk(KERN_EMERG"remove call \n");
return 0;
}
void hello_shutdown(struct platform_device *pdev)
{
printk(KERN_EMERG"shutdown call \n");
}
int hello_suspend(struct platform_device *pdev, pm_message_t state)
{
printk(KERN_EMERG"suspend call \n");
return 0;
}
int hello_resume(struct platform_device * pdev)
{
printk(KERN_EMERG"resume call \n");
return 0;
}
struct platform_driver stu_hello={
.probe=hello_probe,
.remove=hello_remove,
.shutdown=hello_shutdown,
.suspend=hello_suspend,
.resume=hello_resume,
.driver={
.name = DRIVER_NAME,
.owner = THIS_MODULE,
},
};
static int hello_init(void)
{
int err;
printk(KERN_EMERG "hello world enter\n");
err=platform_driver_register(&stu_hello);
printk(KERN_EMERG "register result:%d\n",err);
return 0;
}
static void hello_exit(void)
{
printk(KERN_EMERG "hello world exit\n");
platform_driver_unregister(&stu_hello);
}
module_init(hello_init);
module_exit(hello_exit);
2.2运行结果 insmode 和 rmmod
中间在dev中可以看到hello_misc
ls /dev/
image.png
[root@iTOP-4412]# insmod /mnt/udisk/hello_driver.ko
[ 3768.651034] hello world enter
[ 3768.660692] hello_probe call
[ 3768.670667] register result:0
hello_driver 2109 0 - Live 0xbf000000
[root@iTOP-4412]# rmmod hello_driver
[ 4077.111126] hello world exit
[ 4077.113711] remove call
2.3编写应用程序测试
打印头文件
– include <stdio.h>调用打印函数printf
• 应用中调用文件需要的头文件
– #include <sys/types.h>基本系统数据类型。系统的基本数据类型在 32 编译
环境中保持为 32 位值,并会在 64 编译环境中增长为 64 位值。
– #include <sys/stat.h>系统调用函数头文件。可以调用普通文件，目录，管
道，socket，字符，块的属性
– #include <fcntl.h>定义了open函数
– #include <unistd.h>定义了close函数
– #include <sys/ioctl.h>定义了ioctl函数
#include "stdio.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>//定义了open函数
#include <unistd.h>//定义了close函数
#include <sys/ioctl.h>//定义了ioctl函数
int main()
{
char *device="/dev/hello_misc";
int fd = open(device,O_RDWR|O_NDELAY);
if(fd<0)
{
printf("open file %s err \n",device);
}else
{
printf("open file %s seuccess \n",device);
ioctl(fd,123,678);
}
close(fd);
}
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