static  int __init  fbmem_init(void)
{create_proc_read_entry("fb", 0, NULL, fbmem_read_proc, NULL);if (register_chrdev(FB_MAJOR,"fb",&fb_fops))           //(1)创建字符设备printk("unable to get major %d for fb devs\n", FB_MAJOR);fb_class = class_create(THIS_MODULE, "graphics");       //创建类if (IS_ERR(fb_class)) {printk(KERN_WARNING "Unable to create fb class; errno = %ld\n", PTR_ERR(fb_class));fb_class = NULL;}return 0;
}

static int fb_open(struct inode *inode, struct file *file)
{int fbidx = iminor(inode);      //获取设备节点的次设备号struct fb_info *info;                //定义fb_info结构体int res = 0;... ...if (!(info = registered_fb[fbidx]))   //(1) info= registered_fb[fbidx],获取此设备号的lcd驱动信息try_to_load(fbidx);... ... if (info->fbops->fb_open) {          res = info->fbops->fb_open(info,1);  //调用registered_fb[fbidx]->fbops->fb_openif (res)module_put(info->fbops->owner);}return res;
}

static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{unsigned long p = *ppos;struct inode *inode = file->f_path.dentry->d_inode; int fbidx = iminor(inode);                       //获取次设备号struct fb_info *info = registered_fb[fbidx];     //获取次设备号的lcd驱动的信息u32 *buffer, *dst;u32 __iomem *src;int c, i, cnt = 0, err = 0;unsigned long total_size;... ...if (info->fbops->fb_read)return info->fbops->fb_read(info, buf, count, ppos);total_size = info->screen_size;     //获取屏幕长度       ... ...buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,GFP_KERNEL);    //分配缓冲区       if (!buffer)return -ENOMEM;src = (u32 __iomem *) (info->screen_base + p);         //获取显存物理基地址if (info->fbops->fb_sync)info->fbops->fb_sync(info); while (count) {c  = (count > PAGE_SIZE) ? PAGE_SIZE : count;   //获取页地址dst = buffer;         /*因为src是32位,一个src等于4个字节,所以页地址c >> 2*/for (i = c >> 2; i--; )                     *dst++ = fb_readl(src++);    //读取显存每个像素点数据,放到dst地址上if (c & 3) {u8 *dst8 = (u8 *) dst;u8 __iomem *src8 = (u8 __iomem *) src;for (i = c & 3; i--;)*dst8++ = fb_readb(src8++);src = (u32 __iomem *) src8;}if (copy_to_user(buf, buffer, c)) {  //上传数据,长度等于页地址大小err = -EFAULT;break;}*ppos += c;buf += c;cnt += c;count -= c;}kfree(buffer); return (err) ? err : cnt;
}

int register_framebuffer(struct fb_info *fb_info)
{... ...
for (i = 0 ; i < FB_MAX; i++)    //查找空的数组if (!registered_fb[i])break;fb_info->node = i;           ... .../*创建设备节点,名称为fdi,主设备号为29,次设备号为i   */
fb_info->dev = device_create(fb_class, fb_info->device,MKDEV(FB_MAJOR, i), "fb%d", i);... ...registered_fb[i] = fb_info;... ...
}

int __devinit s3c2410fb_init(void)
{return platform_driver_register(&s3c2410fb_driver);
}static void __exit s3c2410fb_cleanup(void)
{platform_driver_unregister(&s3c2410fb_driver);
}

static struct platform_driver s3c2410fb_driver = {.probe           = s3c2410fb_probe,        //检测函数,注册设备.remove         = s3c2410fb_remove,    //删除设备.suspend = s3c2410fb_suspend,          //休眠.resume          = s3c2410fb_resume,    //唤醒.driver            = {.name     = "s3c2410-lcd",           //drv名字.owner    = THIS_MODULE,},
};

static int __init s3c2410fb_probe(struct platform_device *pdev)
{struct s3c2410fb_info *info;struct fb_info     *fbinfo;struct s3c2410fb_hw *mregs;int ret;int irq;int i;u32 lcdcon1;mach_info = pdev->dev.platform_data;     //获取LCD设备信息(长宽、类型等)if (mach_info == NULL) {dev_err(&pdev->dev,"no platform data for lcd, cannot attach\n");return -EINVAL;}mregs = &mach_info->regs;irq = platform_get_irq(pdev, 0);if (irq < 0) {dev_err(&pdev->dev, "no irq for device\n");return -ENOENT;}fbinfo = framebuffer_alloc(sizeof(struct s3c2410fb_info), &pdev->dev); //1.分配一个fb_info结构体if (!fbinfo) {return -ENOMEM;}/*2.设置fb_info*/info = fbinfo->par;info->fb = fbinfo;info->dev = &pdev->dev;... ...    /*3.硬件相关的操作,设置中断,LCD时钟频率,显存地址, 配置引脚... ...*/ret = request_irq(irq, s3c2410fb_irq, IRQF_DISABLED, pdev->name, info); //设置中断info->clk = clk_get(NULL, "lcd");                    //获取时钟clk_enable(info->clk);                                  //使能时钟ret = s3c2410fb_map_video_memory(info);               //显存地址  ret = s3c2410fb_init_registers(info);                //设置寄存器,配置引脚... ...ret = register_framebuffer(fbinfo);        //4.注册一个fb_info结构体if (ret < 0) {printk(KERN_ERR "Failed to register framebuffer device: %d\n", ret);goto free_video_memory;}
... ...
return ret;
}