linux2.6.24下lcd驱动移植的小结

一、lcd驱动移植网上参考资料
http://blog.chinaunix.net/u1/49924/showart_495463.html
linux-2.6.20的lcd驱动分析

module_init()函数在include/linux/init.h中定义。
内核与buffer驱动发生关系的第一次地点是在s3c2410fb_init函数，该函数就只有一条语句:
 

return platform_driver_register (&s3c2410fb_driver)；

在driver/video/s3c2410fb.c中，s3c2410fb_driver的定义如下:
 

static struct platform_driver s3c2410fb_driver = {   .probe = s3c2410fb_probe,   .remove = s3c2410fb_remove,   .suspend = s3c2410fb_suspend,   .resume = s3c2410fb_resume,   .driver = {    .name = "s3c2410-lcd",    .owner = THIS_MODULE,    },   };

为了向内核添加一个platform设备，程序员应该填写两个数据结构platform_device 和platform_driver，
这两个数据结构的定义都可以在include/linux/platform_device.h文件中找到:

struct platform_device {  const char * name;  int id;  struct device dev;  u32 num_resources;  struct resource * resource; };

struct platform_driver {  int (*probe)(struct platform_device *);  int (*remove)(struct platform_device *);  void (*shutdown)(struct platform_device *);  int (*suspend)(struct platform_device *, pm_message_t state);  int (*suspend_late)(struct platform_device *, pm_message_t state);  int (*resume_early)(struct platform_device *);  int (*resume)(struct platform_device *);  struct device_driver driver; };

arch/arm/plat-s3c24xx/devs.c可以找到填写platform_device的代码:

struct platform_device s3c_device_lcd = {  .name = "s3c2410-lcd",  .id = -1,  .num_resources = ARRAY_SIZE(s3c_lcd_resource),  .resource = s3c_lcd_resource,  .dev = {   .dma_mask = &s3c_device_lcd_dmamask,   .coherent_dma_mask = 0xffffffffUL  } };

void __init s3c24xx_fb_set_platdata(struct s3c2410fb_mach_info *pd) {  struct s3c2410fb_mach_info *npd;  npd = kmalloc(sizeof(*npd), GFP_KERNEL);  if (npd) {   memcpy(npd, pd, sizeof(*npd));   s3c_device_lcd.dev.platform_data = npd;  } else {   printk(KERN_ERR "no memory for LCD platform data/n");  } }

然后在arch/arm/mach-s3c2410/mach-smdk2410.c的smdk2410_map_io函数中调用s3c24xx_fb_set_platdata( )，具体为：

s3c24xx_fb_set_platdata(&smdk2410_lcd_platdata);

 

在调用platform_driver_register (&s3c2410fb_driver)；函数时，传给s3c2410fb_probe()函数的参数为s3c_device_lcd数据结构的地址，platform_device和platform_driver数据结构之间的联系通过name字段来联系。

 

上面主要是讲了platform_device和platform_driver之间的关系和实现的过程，下面讲lcd控制器的硬件和软件参数设置。

 

相关的数据结构定义于include/asm-arm/arch-s3c2410/fb.h中，列出如下:

struct s3c2410fb_hw {  unsigned long lcdcon1;  unsigned long lcdcon2;  unsigned long lcdcon3;  unsigned long lcdcon4;  unsigned long lcdcon5; };

/* LCD description */ struct s3c2410fb_display {  /* LCD type */  unsigned type;  /* Screen size */  unsigned short width;  unsigned short height;  /* Screen info */  unsigned short xres;  unsigned short yres;  unsigned short bpp;  unsigned pixclock; /* pixclock in picoseconds */  unsigned short left_margin; /* value in pixels (TFT) or HCLKs (STN) */  unsigned short right_margin; /* value in pixels (TFT) or HCLKs (STN) */  unsigned short hsync_len; /* value in pixels (TFT) or HCLKs (STN) */  unsigned short upper_margin; /* value in lines (TFT) or 0 (STN) */  unsigned short lower_margin; /* value in lines (TFT) or 0 (STN) */  unsigned short vsync_len; /* value in lines (TFT) or 0 (STN) */  /* lcd configuration registers */  unsigned long lcdcon5; };

struct s3c2410fb_mach_info {  struct s3c2410fb_display *displays; /* attached diplays info */  unsigned num_displays; /* number of defined displays */  unsigned default_display;  /* GPIOs */  unsigned long gpcup;  unsigned long gpcup_mask;  unsigned long gpccon;  unsigned long gpccon_mask;  unsigned long gpdup;  unsigned long gpdup_mask;  unsigned long gpdcon;  unsigned long gpdcon_mask;  /* lpc3600 control register */  unsigned long lpcsel; };

下面的结构定义于include/linux/fb.h

struct fb_info {  int node;  int flags;  struct fb_var_screeninfo var; /* Current var */  struct fb_fix_screeninfo fix; /* Current fix */  struct fb_monspecs monspecs; /* Current Monitor specs */  struct work_struct queue; /* Framebuffer event queue */  struct fb_pixmap pixmap; /* Image hardware mapper */  struct fb_pixmap sprite; /* Cursor hardware mapper */  struct fb_cmap cmap; /* Current cmap */  struct list_head modelist; /* mode list */  struct fb_videomode *mode; /* current mode */ #ifdef CONFIG_FB_BACKLIGHT  /* assigned backlight device */  /* set before framebuffer registration, remove after unregister */  struct backlight_device *bl_dev;  /* Backlight level curve */  struct mutex bl_curve_mutex;  u8 bl_curve[FB_BACKLIGHT_LEVELS]; #endif #ifdef CONFIG_FB_DEFERRED_IO  struct delayed_work deferred_work;  struct fb_deferred_io *fbdefio; #endif  struct fb_ops *fbops;  struct device *device; /* This is the parent */  struct device *dev; /* This is this fb device */  int class_flag; /* private sysfs flags */ #ifdef CONFIG_FB_TILEBLITTING  struct fb_tile_ops *tileops; /* Tile Blitting */ #endif  char __iomem *screen_base; /* Virtual address */  unsigned long screen_size; /* Amount of ioremapped VRAM or 0 */  void *pseudo_palette; /* Fake palette of 16 colors */ #define FBINFO_STATE_RUNNING 0 #define FBINFO_STATE_SUSPENDED 1  u32 state; /* Hardware state i.e suspend */  void *fbcon_par; /* fbcon use-only private area */  /* From here on everything is device dependent */  void *par; };