字符驱动之操作LED灯（一）：大体框架

头文件：
#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 <asm/arch/regs-gpio.h>
#include <asm/hardware.h>

定义变量
int major;
static struct class *firstdrv_class;
static struct class_device    *firstdrv_class_dev;




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

    return 0;
}


static ssize_t first_drv_write(struct file *file,const char __user *buf,size_t count,loff_t *ppos)
{
    printk("");
    return 0;
}

static int first_drv_init(void)
{
    major = register_chrdev(0,"first_drv",&first_drv_fops);
    //告诉内核，并填充驱动，把数组填充进去。但是系统信息未生成
    
    firstdrv_class = class_create(THIS_MODULE,"firstdrv");
    //在sys下新建class，名叫firstdrv_class。
    
    firstdrv_class_dev = class_device(firstdrv_class,NULL,MKDEV(major,0),NULL,"xyz");
    //在此类下面新建设备节点，设备号为major，节点叫做xyz。(/dev/xyz)
}

在入口中新建，需要在出口中删除。
static void first_drv_exit(void)
{
    unregister_chrdev(major,"first_drv");
    class_device_unregister(firstdrv_class_dev);
    class_destroy(firstdrv_class);
}

结尾：
module_init(first_drv_init);
module_exit(first_drv_exit);
module_license("GPL");