【Linux驱动】LCD驱动测试

(1) 进入内核源码目录中，make menuconfig -> Device Drivers -> Graphics support -> [M]Support for frame buffer devices

重新编译内核 make uImage ，然后make modules，将driver/video/下的 fb.ko、cfbfillrect.ko、cfbimgblt.ko、cfbcopyarea.ko拷贝到210的根文件中，分别 insmod 安装到内核中。

(2) 安装lcd.ko驱动模块

(3) 应用层读写 frame buffer 测试程序框架

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
int main()
{
int fbfd = 0;
struct fb_var_screeninfo vinfo;
struct fb_fix_screeninfo finfo;
long int screensize = 0;
char *fbp = NULL;
int x,y,r = 0,g = 0, b = 0;
unsigned int rgb;

/*打开设备文件*/
fbfd = open("/dev/fb0", O_RDWR);

/*取得屏幕相关参数*/
ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo);
ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo);

/*计算屏幕缓冲区大小*/
screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

/*映射屏幕缓冲区到用户地址空间*/
fbp=(char*)mmap(0,screensize,PROT_READ | PROT_WRITE,MAP_SHARED, fbfd, 0);
if((int)fbp == -1)
{
printf("Error: failed to map framebuffer device to memory .\n");
return -1;
}
/*下面可通过fbp指针操作缓冲区:显示红 */
for(y = 0;y<(vinfo.yres);y++)//vinfo.yres = 272
{
for(x = 0;x < vinfo.xres;x++)//vinfo.xres=480
{
long location = x*3 + y * vinfo.xres * 3;//用户缓冲区地址移动,一个像素3字节(24位真彩色)
r = 256;
g = 0;
b = 0;
rgb = (r << 16) | (g << 8) | b;    //分别获得相应颜色
*((unsigned short *)(fbp + location)) = rgb;
}
}
/*释放缓冲区，关闭设备*/
munmap(fbp, screensize);
close(fbfd);
}

或者直接使用：cat xxxfile > /dev/fb0 现象：出现花屏。