linux驱动中在/proc虚拟文件系统目录下自动创建设备【转】

来自：http://blog.csdn.net/smilefyx/article/details/40539885

一、简述

本文实例演示如何在Linux驱动编程中使驱动自动在/proc目录下穿件文件，用户可以直接操作/proc目录下的文件对设备进行操作。

二、编码

2.1、测试驱动源码

使用编辑工具编写如下驱动测试代码，如文件procbuffer.c内容如下：

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#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <asm/uaccess.h>

#include <asm/irq.h>

#include <asm/io.h>

#include <mach/gpio.h>

#include <mach/hardware.h>

#include <linux/device.h>

#include <linux/proc_fs.h>

#define PROC_DIR_NAME "ArvinFei"

#define PROC_FILE_NAME "wrbuffer"

struct proc_dir_entry *proc_wrbuff_dir;

static int proc_wrbuff_open(struct inode *inode,struct file *file);

static ssize_t proc_wrbuff_read(struct file *file, char __user *buf, size_t count, loff_t *offset);

static ssize_t proc_wrbuff_write(struct file *file, const char __user *buf, size_t count, loff_t *offset);

static struct file_operations fops_proc_wrbuffer = {

.owner = THIS_MODULE,

.open = proc_wrbuff_open,

.read = proc_wrbuff_read,

.write = proc_wrbuff_write,

};

static int proc_wrbuff_open(struct inode *inode,struct file *file) {

printk("open proc wrbuffer device!");

return 0;

}

static ssize_t proc_wrbuff_read(struct file *file, char __user *buf, size_t count, loff_t *offset) {

printk("read proc wrbuffer device!");

return 0;

}

static ssize_t proc_wrbuff_write(struct file *file, const char __user *buf, size_t count, loff_t *offset) {

printk("write proc wrbuffer device!");

return 0;

}

static int __init proc_wrbuff_init(void) {

int ret = 0;

struct proc_dir_entry *proc_file;

/*1 create parent dir in /porc */

proc_wrbuff_dir = proc_mkdir(PROC_DIR_NAME, NULL);

if(!proc_wrbuff_dir){

printk("create proc dir error!");

return -ENOMEM;

}

/*2 creata device file in /proc/parent dir*/

proc_file = create_proc_entry(PROC_FILE_NAME, 0666, proc_wrbuff_dir);

if (!proc_file) {

printk("create proc file error!");

ret = -ENOMEM;

goto no_proc_file;

}

/*3 set file operation point*/

proc_file->proc_fops = &fops_proc_wrbuffer;

return 0;

no_proc_file:

remove_proc_entry(PROC_FILE_NAME,proc_wrbuff_dir);

return ret;

}

static void __exit proc_wrbuff_exit(void) {

//

remove_proc_entry(PROC_FILE_NAME,proc_wrbuff_dir);

//

remove_proc_entry(PROC_DIR_NAME,NULL);

}

late_initcall(proc_wrbuff_init);

module_exit(proc_wrbuff_exit);

MODULE_AUTHOR("yxtouch520@yeah.net");

MODULE_DESCRIPTION("allwinner buffer read and write test driver,you can control this device use the interface in /proc dir.");

MODULE_LICENSE("GPL");

2.2、Makefile

Makefile中的内核源代码请按照自己源码存放的位置进行修改。

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obj-m := proc_wrbuffer.o

proc_wrbuffer-objs := procbuffer.o

KERNELDIR := /home/feiyinxian/workspace/A20/landsem/A20_Android4.4/lichee/linux-3.4

PWD := $(shell pwd)

modules:

$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

.PHONY:clean

clean:

rm *.ko *.o