lcd 移植

LCD驱动移植及测试
TQ2440 LCD硬件
东华TFT液晶屏（WXCAT35）,配置为常用的16BPP(5:6:5)模式。

参数如下图所示：
static struct s3c2410fb_display smdk2440_lcd_cfg __initdata = {
.lcdcon5 = S3C2410_LCDCON5_FRM565 |
S3C2410_LCDCON5_INVVLINE |
S3C2410_LCDCON5_INVVFRAME |
S3C2410_LCDCON5_PWREN |
S3C2410_LCDCON5_HWSWP,
.type = S3C2410_LCDCON1_TFT,
.width = 320,
.height = 240,
.pixclock = 100000, //????/*HCLK 100MHZ divisor 3*/
.xres = 320,
.yres = 240,
.bpp = 16,
.left_margin = 20,
.right_margin = 38,
.hsync_len = 30,
.upper_margin = 12,
.lower_margin = 15,
.vsync_len = 3,
};
关于pixclock＝1/VCLK,像素时钟，单位是皮秒。

显示每个像素的时钟周期。

和cpu的HCLK有关。

16BPP模式的数据格式
以上参考：2440LCD控制器详细配置
linux内核配置
Device drivers-> Graphics support ---> Support for frame buffer devices ---> S3C2410 LCD framebuffer support
测试程序
参考：linux framebuffer tutorial
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
int lcd_width;
int lcd_height;
int screen_size;
int line_size;
struct fb_var_screeninfo var_screeninfo;
struct fb_fix_screeninfo fix_screeninfo;
void get_screeninfo(int fb,struct fb_var_screeninfo *var,struct fb_fix_screeninfo *fix)
{
if(ioctl(fb,FBIOGET_VSCREENINFO,var))
{
fprintf(stderr,"ioctl FBIOGET_VSCREENINFO.\n");
exit(1);
}
if(ioctl(fb,FBIOGET_FSCREENINFO,fix))
{
fprintf(stderr,"ioctl FBIOGET_VSCREENINFO.\n");
exit(1);
}
lcd_width=var->width;
lcd_height=var->height;
screen_size=lcd_width*lcd_height*var->bits_per_pixel/8;
line_size=fix->line_length;
printf("var->width:%d\n",var->width);
printf("var->height:%d\n",var->height);
printf("var->bits_per_pixel:%d\n",var->bits_per_pixel);
printf("var->xoffset:%d\n",var->xoffset);
printf("var->yoffset:%d\n",var->yoffset);
printf("fix->line_length:%d\n",fix->line_length);
}
void draw_rect(char *fbp,int x,int y,int w,int h,short color)
{
int i,j;
for(i=0;i<w;i++)
for(j=0;j<h;j++,j++)
*(fbp+i*line_size +y+j)=color;
}
void draw_screen(char *fbp)
{
draw_rect(fbp,0,0,80,80,0xf800);
draw_rect(fbp,80,80,80,80,0x07e0);
draw_rect(fbp,160,160,80,80,0x001f);
}
int main()
{
int fb;
int cmd;
unsigned char *fb_mem;
if((fb=open("/dev/fb0",O_RDWR))<0)
{
printf("cannot open /dev/fb0\n");
exit(0);
}
get_screeninfo(fb,&var_screeninfo,&fix_screeninfo);
fb_mem=(unsigned char*)mmap(0,screen_size,PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);//关键！！！把内核空间映射到用户空间
if ((int)fb_mem == -1)
{
printf("Error: failed to map framebuffer device to memory.\n");
exit(4);
}
printf("The framebuffer device was mapped to memory successfully.\n");
memset(fb_mem,0,screen_size);
/*do something here use fb_mem*/
draw_screen(fb_mem);
munmap(fb_mem, screen_size);
close(fb);
return 0;
}
交叉编译：arm-linux-gcc lcdtest.c -o lcdtest
测试结果：
系统启动加载framebuffer驱动：
运行测试程序：
问题：LCD一段时间后会自动关闭，解决方案参考：十分钟黑屏问题。