1 fbmem_init(void)
 2 
 3     create_proc_read_entry("fb", 0, NULL, fbmem_read_proc, NULL);
 4 
 5     if (register_chrdev(FB_MAJOR,"fb",&fb_fops))  //创建字符设备
 6         printk("unable to get major %d for fb devs
", FB_MAJOR);
 7 
 8     fb_class = class_create(THIS_MODULE, "graphics");  //创建类
 9     if (IS_ERR(fb_class)) 
10         printk(KERN_WARNING "Unable to create fb class; errno = %ld
", PTR_ERR(fb_class));
11         fb_class = NULL;
12     
13     return 0;
14 

 1 static int fb_open(struct inode *inode, struct file *file)
 2 
 3        int fbidx = iminor(inode);      //获取设备节点的次设备号
 4        struct fb_info *info;           //定义fb_info结构体，其中包含帧缓冲相关信息
 5        int res = 0;
 6        ... ...
 7 
 8 if (!(info = registered_fb[fbidx]))   //(1) info= registered_fb[fbidx],获取此设备号的lcd驱动信息
 9               try_to_load(fbidx);
10        ... ... 
11 
12        if (info->fbops->fb_open)      ////判断此结构体中是否有fb_open     
13               res = info->fbops->fb_open(info,1);  //调用registered_fb[fbidx]->fbops->fb_open
14               if (res)
15                      module_put(info->fbops->owner);
16        
17 
18        return res;
19 

#define FB_MAX 32  //次设备号最大为32,最多支持32个fb设备
extern struct fb_info *registered_fb[FB_MAX];

 1 static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 2 
 3        unsigned long p = *ppos;
 4        struct inode *inode = file->f_path.dentry->d_inode; 
 5        int fbidx = iminor(inode);                       //获取次设备号
 6        struct fb_info *info = registered_fb[fbidx];     //获取次设备号的lcd驱动的信息
 7        u32 *buffer, *dst;
 8        u32 __iomem *src;
 9        int c, i, cnt = 0, err = 0;
10        unsigned long total_size;
11        ... ...
12        if (info->fbops->fb_read)　　//如果自定义了驱动层的read，则调用自定义的，否则调用默认的
13               return info->fbops->fb_read(info, buf, count, ppos);
14      
15        total_size = info->screen_size;     //获取屏幕长度
16     
17        ... ...
18 　　　　
19        buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,GFP_KERNEL); //分配缓冲区       
20        if (!buffer)
21               return -ENOMEM;
24 
25        src = (u32 __iomem *) (info->screen_base + p);         //获取显存物理基地址
26        if (info->fbops->fb_sync)
27               info->fbops->fb_sync(info); 
28 
29        while (count) 
30               c  = (count > PAGE_SIZE) ? PAGE_SIZE : count;   //获取页地址
31               dst = buffer;
32 
33          /*因为src是32位,一个src等于4个字节,所以页地址c >> 2*/
34               for (i = c >> 2; i--; )                     
35                      *dst++ = fb_readl(src++);    //读取显存每个像素点数据,放到dst地址上
36 
37               if (c & 3) 
38                      u8 *dst8 = (u8 *) dst;
39                      u8 __iomem *src8 = (u8 __iomem *) src;
40                      for (i = c & 3; i--;)
41                             *dst8++ = fb_readb(src8++);
42                      src = (u32 __iomem *) src8;
43               
44               if (copy_to_user(buf, buffer, c))   //上传数据,长度等于页地址大小
45                      err = -EFAULT;
46                      break;
47               
48               *ppos += c;
49               buf += c;
50               cnt += c;
51               count -= c;
52        
53        kfree(buffer); 
54        return (err) ? err : cnt;
55 

 1 int register_framebuffer(struct fb_info *fb_info)
 2 
 3  ... ...
 4 for (i = 0 ; i < FB_MAX; i++)    //查找空的数组
 5         if (!registered_fb[i])
 6          break;
 7 
 8 fb_info->node = i;           
 9  ... ...
10 
11 /*创建设备节点,名称为fdi,主设备号为29,次设备号为i   */
12 fb_info->dev = device_create(fb_class, fb_info->device,MKDEV(FB_MAJOR, i), "fb%d", i);
13  ... ...
14 
15 registered_fb[i] = fb_info;
16  ... ...
17 　　

1 int __devinit s3c2410fb_init(void)
2 
3      return platform_driver_register(&s3c2410fb_driver);
4 
5 
6 static void __exit s3c2410fb_cleanup(void)
7 
8      platform_driver_unregister(&s3c2410fb_driver);
9 

 1 static struct platform_driver s3c2410fb_driver = 
 2        .probe           = s3c2410fb_probe,    //检测函数,注册设备
 3        .remove         = s3c2410fb_remove,    //删除设备
 4        .suspend = s3c2410fb_suspend,          //休眠
 5        .resume          = s3c2410fb_resume,   //唤醒
 6        .driver            = 
 7               .name     = "s3c2410-lcd",       //drv名字
 8               .owner    = THIS_MODULE,
 9        ,
10 ;

 1 //archarmplat-s3c24xxdevs.c
 2 struct platform_device s3c_device_lcd = 
 3     .name          = "s3c2410-lcd", //设备名称
 4     .id            = -1,            //设备ID
 5     .num_resources = ARRAY_SIZE(s3c_lcd_resource),
 6     .resource      = s3c_lcd_resource,
 7     .dev           = 
 8        .dma_mask      = &s3c_device_lcd_dmamask,
 9        .coherent_dma_mask    = 0xffffffffUL
10     
11 ;

 1 static int __init s3c2410fb_probe(struct platform_device *pdev)
 2 
 3        struct s3c2410fb_info *info; //定义指向s3c2410fb_info的结构体指针
 4        struct fb_info     *fbinfo; //定义指向fb_info的结构体指针
 5        struct s3c2410fb_hw *mregs;
 6        int ret;
 7        int irq;
 8        int i;
 9        u32 lcdcon1;
10  
11        mach_info = pdev->dev.platform_data;     //获取LCD设备信息(长宽、类型等)
12 
13        if (mach_info == NULL) 
14               dev_err(&pdev->dev,"no platform data for lcd, cannot attach
");
15               return -EINVAL;
16        
17        mregs = &mach_info->regs;
18 
19 
20        irq = platform_get_irq(pdev, 0);
21        if (irq < 0) 
22               dev_err(&pdev->dev, "no irq for device
");
23               return -ENOENT;
24        
25 
27 　　　　/* 1. 分配一个s3c2410fb_info结构体给fbinfo*/
28        fbinfo = framebuffer_alloc(sizeof(struct s3c2410fb_info), &pdev->dev);
29        if (!fbinfo) 
30               return -ENOMEM;
31        
34 
35      /*2.设置fb_info*/
36        info = fbinfo->par; //par成员用来存放帧缓冲的私有数据，此处为LCD控制器
37        info->fb = fbinfo;
38        info->dev = &pdev->dev;
39        ... ...
40 
41     /*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... ...*/
42        ret = request_irq(irq, s3c2410fb_irq, IRQF_DISABLED, pdev->name, info); //设置中断
43        info->clk = clk_get(NULL, "lcd");             //获取时钟
44        clk_enable(info->clk);                        //使能时钟
45        ret = s3c2410fb_map_video_memory(info);       //显存地址  
46        ret = s3c2410fb_init_registers(info);         //设置寄存器,配置引脚
47        ... ...
48 　　 
　　　　　　/* 4.注册一个fb_info结构体，里面包含帧缓冲的相关信息 */
49        ret = register_framebuffer(fbinfo);       
50        if (ret < 0) 
51               printk(KERN_ERR "Failed to register framebuffer device: %d
", ret);
52               goto free_video_memory;
53        
54 ... ...
55 return ret;
56