Linux驱动开发2——字符设备驱动

1、申请设备号

#include <linux/fs.h>

int register_chrdev_region(dev_t first, unsigned int count, char *name);
静态分配字符设备号，从fist开始的count个，name为设备名称(name会出现在/proc/devices和sysfs中)，成功返回0，失败返回一个负的错误码

int alloc_chrdev_region(dev_t *dev, unsigned int firstminor, unsigned int count, char *name);
动态分配字符设备号，主设备号动态分配，次设备号从firstminor开始的count个，name为设备名称(动态分配的主设备号可以在/proc/devices中获取)

void unregister_chrdev_region(dev_t first, unsigned int count);
注销字符设备号，从first开始的count个

2、初始化字符设备

#include <linux/cdev.h>

动态创建
struct cdev *my_cdev = cdev_alloc();
my_cdev->ops = &my_fops;

静态创建
void cdev_init(struct cdev *cdev, struct file_operations *fops);

3、添加和删除字符设备

#include <linux/cdev.h>

添加字符设备
int cdev_add(struct cdev *dev, dev_t num, unsigned int count);

删除字符设备
void cdev_del(struct cdev *dev);

 4、file_operations