关于LCD驱动

Kconfig:

 

config FB_S3C2410

       tristate "S3C2410 LCD framebuffer support"

       depends on FB && ARCH_S3C2410

       select FB_CFB_FILLRECT

       select FB_CFB_COPYAREA

       select FB_CFB_IMAGEBLIT

       select FB_SOFT_CURSOR

       ---help---

         Frame buffer driver for the built-in LCD controller in the Samsung

         S3C2410 processor.

 

         This driver is also available as a module ( = code which can be

         inserted and removed from the running kernel whenever you want). The

         module will be called s3c2410fb. If you want to compile it as a module,

         say M here and read <file:Documentation/modules.txt>.

 

         If unsure, say N.

      

choice

       prompt "LCD select"

       depends on FB_S3C2410

       help

          S3C24x0 LCD size select

 

config FB_S3C2410_S320240

       boolean "3.5 inch 320x240 Samsung LCD"

       depends on FB_S3C2410

       help

          3.5 inch 320x240 Samsung LCD

 

config FB_S3C2410_N240320

       boolean "3.5 inch 240X320 NEC LCD"

       depends on FB_S3C2410

       help

          3.5 inch 240x320 NEC LCD

 

config FB_S3C2410_TFT480272

       boolean "4.3inch(480x272) TFT LCD"

       depends on FB_S3C2410

       help

          480x272 TFT LCD

 

config FB_S3C2410_TFT480290

       boolean "480x290 TFT LCD"

       depends on FB_S3C2410

       help

          480x234 TFT LCD

 

config FB_S3C2410_TFT640480

       boolean "8.4 inch 640x480 TFT LCD"

       depends on FB_S3C2410

       help

          8.4 inch 640x480 TFT LCD

 

config FB_S3C2410_TFT800480

       boolean "7 inch 800x480 TFT LCD"

       depends on FB_S3C2410

       help

          7 inch 800x480 TFT LCD

 

config FB_S3C2410_TFT800600

       boolean "12 inch 800x680 TFT LCD"

       depends on FB_S3C2410

       help

          12 inch 800x600 TFT LCD

 

config FB_S3C2410_TFT1024768

       boolean "1024x768 TFT LCD"

       depends on FB_S3C2410

       help

          1024x768 TFT LCD

 

config FB_S3C2410_VGA640480

       boolean "VGA 640x480"

       depends on FB_S3C2410

       help

          VGA 640x480

 

config FB_S3C2410_VGA800600

       boolean "VGA 800x600"

       depends on FB_S3C2410

       help

          VGA 800x600

 

config FB_S3C2410_VGA1024768

       boolean "VGA 1024x768"

       depends on FB_S3C2410

       help

          VGA 1024x768

 

endchoice        

 

 

Makefile:

 

obj-$(CONFIG_VT)               += console/

obj-$(CONFIG_LOGO)          += logo/

obj-$(CONFIG_SYSFS)                += backlight/

 

obj-$(CONFIG_FB)                  += fb.o

fb-y                              := fbmem.o fbmon.o fbcmap.o fbsysfs.o modedb.o

fb-objs                           := $(fb-y)

 

 

obj-$(CONFIG_FB_S3C2410)        += s3c2410fb.o

 

 

Framebuffer本身不具备任何运算数据的能力,就只好比是一个暂时存放水的水池.CPU将运算后的结果放到这个水池,水池再将结果流到显示器.中间不会对数据做处理. 应用程序也可以直接读写这个水池的内容.在这种机制下，尽管Framebuffer需要真正的显卡驱动的支持，但所有显示任务都有CPU完成,因此CPU负担很重.

 

    在应用程序中，一般通过将 FrameBuffer 设备映射到进程地址空间的方式使用，比如下面的程序就打开 /dev/fb0 设备，并通过 mmap 系统调用进行地址映射，随后用 memset 将屏幕清空（这里假设显示模式是 1024x768-8 位色模式，线性内存模式）：

int fb;
unsigned char* fb_mem;
fb = open ("/dev/fb0", O_RDWR);
fb_mem = mmap (NULL, 1024*768, PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);
memset (fb_mem, 0, 1024*768);

 

（未完）