一、LCD驅動程式架構
1.裸機驅動程式碼分析
①LCD初始化：控制器初始化，埠初始化，指明幀緩衝
②LCD圖形顯示：將圖形資料寫入幀緩衝

1. void lcd_init()
   
2. {
   
3.     lcd_port_init();     //初始化gpdcon和gpccon初始化
   
4.     lcd_control_init();   //時序初始化和幀緩衝初始化
   
5.     //開啟LCD電源
   
6.     GPGCON |= 0b11<<8;
   
7.     LCDCON5 |= (1<<3);
   
8.     LCDCON1 |
   = 1;
   
9. }

2.幀緩衝體驗
幀緩衝：記憶體中的一段區域，通過對記憶體的修改。LCD控制器從記憶體中獲取資料，自動的控制LCD的顯示。

1. # cat tq2440.bin > /dev/fb0

將圖片顯示到lcd。

3.幀緩衝架構
/dev/fb0就是幀緩衝，字元裝置
fbmem_init():

1. static int __init
   
2. fbmem_init(void)
   
3. {
   
4.     proc_create("fb", 0, NULL, &fb_proc_fops);
   
5.     if (register_chrdev(
   FB_MAJOR,"fb",&fb_fops))                                                    //註冊裝置檔案，註冊幀緩衝，fp_fops是操作函式集
   
6.         printk("unable to get major %d for fb devs\n", FB_MAJOR);
   
7.     fb_class = class_create(THIS_MODULE, "graphics");
   
8.     if (IS_ERR(fb_class)) {
   
9.         printk(KERN_WARNING "Unable to create fb class; errno = %ld\n"
   , PTR_ERR(fb_class));
   
10.         fb_class = NULL;
    
11.     }
    
12.     return 0;
    
13. }

fb_ops:

1. static const struct file_operations fb_fops = {
   
2.     .owner =    THIS_MODULE,
   
3.     .read =        fb_read,                                        //寫入
   
4.     .write =    fb_write,
   
5.     .unlocked_ioctl = fb_ioctl,
   
6. #ifdef CONFIG_COMPAT
   
7.     .compat_ioctl = fb_compat_ioctl,
   
8. #endif
   
9.     .mmap =        fb_mmap,
   
10.     .open =        fb_open,
    
11.     .release =    fb_release,
    
12. #ifdef HAVE_ARCH_FB_UNMAPPED_AREA
    
13.     .get_unmapped_area = get_fb_unmapped_area,
    
14. #endif
    
15. #ifdef CONFIG_FB_DEFERRED_IO
    
16.     .fsync =    fb_deferred_io_fsync,
    
17. #endif
    
18. };

fb_write:

1. static ssize_t
   
2. fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
   
3. {
   
4.     unsigned long p = *ppos;
   
5.     struct inode *inode = file->f_path.dentry->d_inode;
   
6.     int fbidx = iminor(inode);
   
7.     struct fb_info *info = registered_fb[fbidx];
   
8.     u32 *buffer, *src;
   
9.     u32 __iomem *dst;
   
10.     int c, i, cnt = 0, err = 0;
    
11.     unsigned long total_size;
    
12.     if (!info || !info->screen_base)
    
13.         return -ENODEV;
    
14.     if (info->state != FBINFO_STATE_RUNNING)
    
15.         return -EPERM;
    
16.     if (info->fbops->fb_write)
    
17.         return info->fbops->fb_write(info, buf, count, ppos);
    
18.     total_size = info->screen_size;
    
19.     if (total_size == 0)
    
20.         total_size = info->fix.smem_len;
    
21.     if (p > total_size)
    
22.         return -EFBIG;
    
23.     if (count > total_size) {
    
24.         err = -EFBIG;
    
25.         count = total_size;
    
26.     }
    
27.     if (count + p > total_size) {
    
28.     .........各種info
29. }

info結構：

1. struct fb_info {
   
2.     int node;
   
3.     int flags;
   
4.     struct mutex lock;                                //控制io操作鎖
   
5.     struct fb_var_screeninfo var;/*LCD可變引數*/
   
6.     struct fb_fix_screeninfo fix;/*LCD固定引數*/
   
7.     struct fb_monspecs monspecs; /*LCD顯示器標準*/
   
8.     struct work_struct queue; /*幀緩衝事件佇列*/
   
9.     struct fb_pixmap pixmap; /*影象硬體mapper*/
   
10.     struct fb_pixmap sprite; /*游標硬體mapper*/
    
11.     struct fb_cmap cmap; /*當前的顏色表*/
    
12.     struct fb_videomode *mode; /*當前的顯示模式*/
    
13. #ifdef CONFIG_FB_BACKLIGHT
    
14.     struct backlight_device *bl_dev;/*對應的背光裝置*/
    
15.     struct mutex bl_curve_mutex;
    
16.     u8 bl_curve[FB_BACKLIGHT_LEVELS];/*背光調整*/
    
17. #endif
    
18. #ifdef CONFIG_FB_DEFERRED_IO
    
19.     struct delayed_work deferred_work;
    
20.     struct fb_deferred_io *fbdefio;
    
21. #endif
    
22.     struct fb_ops *fbops; /*對底層硬體操作的函式指標*/
    
23.     struct device *device;
    
24.     struct device *dev; /*fb裝置*/
    
25.     int class_flag;
    
26. #ifdef CONFIG_FB_TILEBLITTING
    
27.     struct fb_tile_ops *tileops; /*圖塊Blitting*/
    
28. #endif
    
29.     char __iomem *screen_base; /*虛擬基地址*/
    
30.     unsigned long screen_size; /*LCD IO對映的虛擬記憶體大小*/
    
31.     void *pseudo_palette; /*偽16色顏色表*/
    
32. #define FBINFO_STATE_RUNNING 0
    
33. #define FBINFO_STATE_SUSPENDED 1
    
34.     u32 state; /*LCD的掛起或恢復狀態*/
    
35.     void *fbcon_par;
    
36.     void *par;
    
37. };

主要是fb_var_screeninfo、fb_fix_screeninfo、fb_ops三個結構體：
struct fb_var_screeninfo:主要記錄使用者可以修改的控制器的引數。

1. struct fb_var_screeninfo {
   
2.     __u32 xres;            /* visible resolution        */
   
3.     __u32 yres;
   
4.     __u32 xres_virtual;        /* virtual resolution        */
   
5.     __u32 yres_virtual;
   
6.     __u32 xoffset;            /* offset from virtual to visible */
   
7.     __u32 yoffset;            /* resolution            */
   
8.     __u32 bits_per_pixel;        /* guess what            */每個畫素的位數即BPP
   
9.     __u32 grayscale;        /* != 0 Graylevels instead of colors */
   
10.     struct fb_bitfield red;        /* bitfield in fb mem if true color, */
    
11.     struct fb_bitfield green;    /* else only length is significant */
    
12.     struct fb_bitfield blue;
    
13.     struct fb_bitfield transp;    /* transparency            */    
    
14.     __u32 nonstd;            /* != 0 Non standard pixel format */
    
15.     __u32 activate;            /* see FB_ACTIVATE_*        */
    
16.     __u32 height;            /* height of picture in mm */
    
17.     __u32 width;            /* width of picture in mm */
    
18.     __u32 accel_flags;        /* (OBSOLETE) see fb_info.flags */
    
19.     /* Timing: All values in pixclocks, except pixclock (of course) */
    
20.     __u32 pixclock;            /* pixel clock in ps (pico seconds) */
    
21.     __u32 left_margin;        /* time from sync to picture    */
    
22.     __u32 right_margin;        /* time from picture to sync    */
    
23.     __u32 upper_margin;        /* time from sync to picture    */
    
24.     __u32 lower_margin;
    
25.     __u32 hsync_len;        /* length of horizontal sync    */
    
26.     __u32 vsync_len;        /* length of vertical sync    */
    
27.     __u32 sync;            /* see FB_SYNC_*        */
    
28.     __u32 vmode;            /* see FB_VMODE_*        */
    
29.     __u32 rotate;            /* angle we rotate counter clockwise */
    
30.     __u32 reserved[5];        /* Reserved for future compatibility */
    
31. };

fb_fix_screeninfo:主要記錄使用者不可以修改的控制器的引數

1. struct fb_fix_screeninfo {
   
2.     char id[16];            /* identification string eg "TT Builtin" */
   
3.     unsigned long smem_start;    /* Start of frame buffer mem */
   
4.                     /* (physical address) */
   
5.     __u32 smem_len;            /* Length of frame buffer mem */
   
6.     __u32 type;            /* see FB_TYPE_*        */
   
7.     __u32 type_aux;            /* Interleave for interleaved Planes */
   
8.     __u32 visual;            /* see FB_VISUAL_*        */
   
9.     __u16 xpanstep;            /* zero if no hardware panning */
   
10.     __u16 ypanstep;            /* zero if no hardware panning */
    
11.     __u16 ywrapstep;        /* zero if no hardware ywrap */
    
12.     __u32 line_length;        /* length of a line in bytes */
    
13.     unsigned long mmio_start;    /* Start of Memory Mapped I/O */
    
14.                     /* (physical address) */
    
15.     __u32 mmio_len;            /* Length of Memory Mapped I/O */
    
16.     __u32 accel;            /* Indicate to driver which    */
    
17.                     /* specific chip/card we have    */
    
18.     __u16 reserved[3];        /* Reserved for future compatibility */
    
19. };

fb_ops:底層硬體操作的函式指標

1. struct fb_ops {
2.     /* open/release and usage marking */
   
3.     struct module *owner;
   
4.     int (*fb_open)(struct fb_info *info, int user);
   
5.     int (*fb_release)(struct fb_info *info, int user);
   
6.     /* For framebuffers with strange non linear layouts or that do not
   
7.      * work with normal memory mapped access
   
8.      */
   
9.     ssize_t (*fb_read)(struct fb_info *info, char __user *buf,
   
10.              size_t count, loff_t *ppos);
    
11.     ssize_t (*fb_write)(struct fb_info *info, const char __user *buf,
    
12.              size_t count, loff_t *ppos);
    
13.     /* checks var and eventually tweaks it to something supported,
    
14.      * DO NOT MODIFY PAR */
    
15.     int (*fb_check_var)(struct fb_var_screeninfo *var, struct fb_info *info);
    
16.     /* set the video mode according to info->var */
    
17.     int (*fb_set_par)(struct fb_info *info);
    
18.     /* set color register */
    
19.     int (*fb_setcolreg)(unsigned regno, unsigned red, unsigned green,
    
20.              unsigned blue, unsigned transp, struct fb_info *info);
    
21.     /* set color registers in batch */
    
22.     int (*fb_setcmap)(struct fb_cmap *cmap, struct fb_info *info);
    
23.     /* blank display */
    
24.     int (*fb_blank)(int blank, struct fb_info *info);
    
25.     /* pan display */
    
26.     int (*fb_pan_display)(struct fb_var_screeninfo *var, struct fb_info *info);
    
27.     /* Draws a rectangle */
    
28.     void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);
    
29.     /* Copy data from area to another */
    
30.     void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);
    
31.     /* Draws a image to the display */
    
32.     void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);
    
33.     /* Draws cursor */
    
34.     int (*fb_cursor) (struct fb_info *info, struct fb_cursor *cursor);
    
35.     /* Rotates the display */
    
36.     void (*fb_rotate)(struct fb_info *info, int angle);
    
37.     /* wait for blit idle, optional */
    
38.     int (*fb_sync)(struct fb_info *info);
    
39.     /* perform fb specific ioctl (optional) */
    
40.     int (*fb_ioctl)(struct fb_info *info, unsigned int cmd,
    
41.             unsigned long arg);
    
42.     /* Handle 32bit compat ioctl (optional) */
    
43.     int (*fb_compat_ioctl)(struct fb_info *info, unsigned cmd,
    
44.             unsigned long arg);
    
45.     /* perform fb specific mmap */
    
46.     int (*fb_mmap)(struct fb_info *info, struct vm_area_struct *vma);
    
47.     /* save current hardware state */
    
48.     void (*fb_save_state)(struct fb_info *info);
    
49.     /* restore saved state */
    
50.     void (*fb_restore_state)(struct fb_info *info);
    
51.     /* get capability given var */
    
52.     void (*fb_get_caps)(struct fb_info *info, struct fb_blit_caps *caps,
    
53.              struct fb_var_screeninfo *var);
    
54. };

http://www.cnblogs.com/lishixian/articles/2999923.html

二、LCD驅動程式分析
s3c2410fb_init:

1. int __init s3c2410fb_init(void)
   
2. {
   
3.     int ret = platform_driver_register(&s3c2410fb_driver);                        //註冊平臺驅動裝置
   
4.     if (ret == 0)
   
5.         ret = platform_driver_register(&s3c2412fb_driver);;
   
6.     return ret;
   
7. }

s3c2410fb_driver:

1. static struct platform_driver s3c2410fb_driver = {
   
2.     .probe        = s3c2410fb_probe,                                                //probe函式，裡面呼叫了s3c24xxfb_probe
   
3.     .remove        = s3c2410fb_remove,
   
4.     .suspend    = s3c2410fb_suspend,
   
5.     .resume        = s3c2410fb_resume,
   
6.     .driver        = {
   
7.         .name    = "s3c2410-lcd",
   
8.         .owner    = THIS_MODULE,
   
9.     },
   
10. };

s3c24xxfb_probe:

1. static int __init s3c24xxfb_probe(struct platform_device *pdev,
   
2.                  enum s3c_drv_type drv_type)
   
3. {
   
4.     struct s3c2410fb_info *info;
   
5.     struct s3c2410fb_display *display;
   
6.     struct fb_info *fbinfo;
   
7.     struct s3c2410fb_mach_info *mach_info;
   
8.     struct resource *res;
   
9.     int ret;
   
10.     int irq;
    
11.     int i;
    
12.     int size;
    
13.     u32 lcdcon1;
    
14.     mach_info = pdev->dev.platform_data;
    
15.     if (mach_info == NULL) {
    
16.         dev_err(&pdev->dev,
    
17.             "no platform data for lcd, cannot attach\n");
    
18.         return -EINVAL;
    
19.     }
    
20.     if (mach_info->default_display >= mach_info->num_displays) {
    
21.         dev_err(&pdev->dev, "default is %d but only %d displays\n",
    
22.             mach_info->default_display, mach_info->num_displays);
    
23.         return -EINVAL;
    
24.     }
    
25.     display = mach_info->displays + mach_info->default_display;
    
26.     irq = platform_get_irq(pdev, 0);                                                       //獲取中斷號
    
27.     if (irq < 0) {
    
28.         dev_err(&pdev->dev, "no irq for device\n");
    
29.         return -ENOENT;
    
30.     }
    
31.     fbinfo = framebuffer_alloc(sizeof(struct s3c2410fb_info), &pdev->dev);                 //分配fb_info結構
    
32.     if (!fbinfo)
    
33.         return -ENOMEM;
    
34.     platform_set_drvdata(pdev, fbinfo);
    
35.     info = fbinfo->par;
    
36.     info->dev = &pdev->dev;
    
37.     info->drv_type = drv_type;
    
38.     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);                                   //獲取暫存器地址
    
39.     if (res == NULL) {
    
40.         dev_err(&pdev->dev, "failed to get memory registers\n");
    
41.         ret = -ENXIO;
    
42.         goto dealloc_fb;
    
43.     }
    
44.     size = (res->end - res->start) + 1;
    
45.     info->mem = request_mem_region(res->start, size, pdev->name);
    
46.     if (info->mem == NULL) {
    
47.         dev_err(&pdev->dev, "failed to get memory region\n");
    
48.         ret = -ENOENT;
    
49.         goto dealloc_fb;
    
50.     }
    
51.     info->io =<