linux下字元裝置有哪些

struct tty_struct {
struct termios termios;
int pgrp;
int stopped;
void (*write)(struct tty_struct * tty);
struct tty_queue read_q;               //讀佇列
struct tty_queue write_q;              //寫佇列
struct tty_queue secondary;            //tty輔助佇列(存放規格化後的字元)
};

//include/linux/cdev.h
struct cdev {
        struct kobject kobj;
        struct module *owner;
        const struct file_operations *ops;
        struct list_head list;
        dev_t dev;
        unsigned int count;
};

//include/linux/fs.h
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 (*read_iter) (struct kiocb *, struct iov_iter *);
        ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
        int (*iterate) (struct file *, struct dir_context *);
        unsigned int (*poll) (struct file *, struct poll_table_struct *);
        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 (*mremap)(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 *, loff_t, loff_t, 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 **, void **);
        long (*fallocate)(struct file *file, int mode, loff_t offset,
                          loff_t len);
        void (*show_fdinfo)(struct seq_file *m, struct file *f);
#ifndef CONFIG_MMU
        unsigned (*mmap_capabilities)(struct file *);
#endif
};

extern struct class * __must_check __class_create(struct module *owner,
                                                  const char *name,
                                                  struct lock_class_key *key);

#define class_create(owner, name)               \
({                                              \
        static struct lock_class_key __key;     \
        __class_create(owner, name, &__key);    \
})

struct class {
        const char              *name;
        struct module           *owner;

        struct class_attribute          *class_attrs;
        const struct attribute_group    **dev_groups;
        struct kobject                  *dev_kobj;

        int (*dev_uevent)(struct device *dev, struct kobj_uevent_env *env);
        char *(*devnode)(struct device *dev, umode_t *mode);

        void (*class_release)(struct class *class);
        void (*dev_release)(struct device *dev);

        int (*suspend)(struct device *dev, pm_message_t state);
        int (*resume)(struct device *dev);

        const struct kobj_ns_type_operations *ns_type;
        const void *(*namespace)(struct device *dev);

        const struct dev_pm_ops *pm;

        struct subsys_private *p;
};

static inline long __must_check PTR_ERR(const void *ptr)
{
	return (long) ptr;
}

static inline long __must_check IS_ERR(const void *ptr)
{
	return IS_ERR_VALUE((unsigned long)ptr);
}

#include <linux/fs.h>		 //file_operations宣告
#include <linux/module.h>    //module_init  module_exit宣告
#include <linux/init.h>      //__init  __exit 宏定義宣告
#include <linux/device.h>	 //class  devise宣告
#include <linux/uaccess.h>   //copy_from_user 的標頭檔案
#include <linux/types.h>     //裝置號  dev_t 型別宣告
#include <asm/io.h>          //ioremap iounmap的標頭檔案

#define DEVICE_CNT 0	//裝置號個數

struct led_device{
	dev_t devid;	//裝置號
	int major;	//主裝置號
	int minor;	//次裝置號
	char* name = "led";	//驅動名
	struct cdev led_dev;	//cdev 結構體
	struct class *class;	/* 類 	*/
	struct device* device;	//裝置
};

struct led_device led;


static int led_open(struct inode *inode, struct file *filp)
{
	return 0;
}

static ssize_t led_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offt)
{
	return 0;
}


static ssize_t led_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{
	return 0;
}



/* 裝置操作函數 */
static struct file_operations led_fo = {
	.owner = THIS_MODULE,
	.open = led_open,
	.read = led_read,
	.write = led_write,
};

static int _init led_init()
{
	/*註冊字元裝置驅動*/
	
	/*1.註冊裝置號*/
	led.major = 0;	//由核心自動分配主裝置號
	if(led.major)	//如果分配了的話就註冊
	{
		led.devid = MKDEV(led.major,0);	
		register_chrdev_region(led.devid,DEVICE_CNT,led.name);	//將驅動註冊到核心中
	}
	else{		//如果沒有分配的話
					//從0號（次裝置號）開始申請
		alloc_chrdev_region(&led.devid,0,DEVICE_CNT,led.name);		//申請裝置號
		led.major = MAJOR(led.devid);	//獲取主裝置號
		led.minor = MANOR(led.devid);	//獲取次裝置號
	}
	printk("newcheled major=%d,minor=%d\r\n",newchrled.major, newchrled.minor);	

	/*2.初始化 cdev 結構體*/
	led.led_dev.woner = THIS_MODULE;
	cdev_init(&led.led_dev,&led_fo);	//將操作函數初始化到cdev結構體

	/*3.應該是向連結串列中添cdev*/
	cdev_add(&led.led_dev,led.devid,DEVICE_CNT);	

	/*4.建立節點*/
	led.class = class_create(THIS_MODULE,led.name);		//先建立一個類
	led.device = device_create(led.class,NULL,led.devid,NULL);	//建立裝置

	return 0;
		
}

static void _exit led_exit()
{
	/* 登出字元裝置驅動 */
	cdev_del(&newchrled.cdev);/*  刪除cdev */
	unregister_chrdev_region(newchrled.devid, NEWCHRLED_CNT); /* 登出裝置號 */

	device_destroy(newchrled.class, newchrled.devid);
	class_destroy(newchrled.class);
}



/*註冊字元裝置入口與解除安裝入口*/
module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("zhoujianghong");