LCD驱动移植之开机logo

移植环境

BootLoader：u-boot-1.1.6

kernel：linux-2.6.30.4

CPU：s3c2440

开发板：TQ2440

LCD：TFT480*272

参考资料：《天嵌Linux移植手册》

移植步骤

1、修改LCD时钟计算方法

内核源码的“drivers/video/s3c2410fb.c”文件，就是 LCD 的驱动源码。修改“drivers/video/s3c2410fb.c”文件

static void s3c2410fb_activate_var(struct fb_info *info)

{

struct s3c2410fb_info *fbi = info->par;

void __iomem *regs = fbi->io;

int type = fbi->regs.lcdcon1 & S3C2410_LCDCON1_TFT;

struct fb_var_screeninfo *var = &info->var;

struct s3c2410fb_mach_info *mach_info = fbi->dev->platform_data;

struct s3c2410fb_display *default_display = mach_info->displays +

mach_info->default_display;

int clkdiv = s3c2410fb_calc_pixclk(fbi, var->pixclock) / 2;

dprintk("%s: var->xres = %dn", __FUNCTION__, var->xres);

dprintk("%s: var->yres = %dn", __FUNCTION__, var->yres);

dprintk("%s: var->bpp = %dn", __FUNCTION__, var->bits_per_pixel);

if (type == S3C2410_LCDCON1_TFT) {

   s3c2410fb_calculate_tft_lcd_regs(info, &fbi->regs);

--clkdiv;

if (clkdiv < 0)

    clkdiv = 0;

} else {

s3c2410fb_calculate_stn_lcd_regs(info, &fbi->regs);

if (clkdiv < 2)

clkdiv = 2;

}

// fbi->regs.lcdcon1 |= S3C2410_LCDCON1_CLKVAL(clkdiv);

fbi->regs.lcdcon1 |= S3C2410_LCDCON1_CLKVAL(default_display->setclkval);

/* write new registers */

完成了这部分修改之后，在 s3c2410fb_display 结构体中添加了一个 setclkval 的变量，那么需要在该结构体的原型中添加上该变量，修改Linux-2.6.30.4 的“arch/arm/mach-s3c2410/include/mach/fb.h”文件，添加如下内容：

/* 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 setclkval; /* clkval */

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;

};

2、修改LCD参数设置

然后修改 LCD 各个参数的配置，该配置参数在“arch/arm/mach-s3c2440/mach-smdk2440.c”文件中的由 107 行开始的结构体中，然后将其改为如下内容即可：

（注意：添加上刚刚添加的那个变量 setclkval 的赋值）

/* LCD driver info */

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 = 480,

.height = 272,

.pixclock = 40000, /* HCLK 100 MHz, divisor 1 */

.setclkval = 0x4,

.xres = 480,

.yres = 272,

.bpp = 16,

.left_margin = 19, /* for HFPD*/

.right_margin = 10, /* for HBPD*/

.hsync_len = 30, /* for HSPW*/

.upper_margin = 4, /* for VFPD*/

.lower_margin = 2, /* for VBPD*/

.vsync_len = 8, /* for VSPW*/

}

static struct s3c2410fb_mach_info smdk2440_fb_info __initdata = {

.displays = &smdk2440_lcd_cfg,

.num_displays = 1,

.default_display = 0,

#if 0

/* currently setup by downloader */

.gpccon = 0xaa940659,

.gpccon_mask = 0xffffffff,

.gpcup = 0x0000ffff,

.gpcup_mask = 0xffffffff,

.gpdcon = 0xaa84aaa0,

.gpdcon_mask = 0xffffffff,

.gpdup = 0x0000faff,

.gpdup_mask = 0xffffffff,

#endif

// .lpcsel = ((0xCE6) & ~7) | 1<<4,

};

然后修改“drivers/video/Kconfig”文件

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

---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 .

If unsure, say N.

config FB_S3C2410_DEBUG

bool "S3C2410 lcd debug messages"

depends on FB_S3C24X0

help

Turn on debugging messages. Note that you can set/unset at run time

through sysfs

然后修改“drivers/video/Makefile”文件，把 109 行的内容改成如下所示：

obj-$(CONFIG_FB_S3C2410) += s3c2410fb.o

3、制作开机logo

首先需要在PC端下载GIMP软件，然后导入一张480*272的bmp图片.

图像->模式->索引，最大颜色数量为224

保存图片为ppm格式，数据类型为ASCII

开机logo就制作好了，将其替换“drivers/video/logo/logo_linux_clut224.ppm”文件

4、配置内核

Device Drivers —>

Graphics support —>

<* > Support for frame buffer devices —>

[* ] Enable firmware EDID

[* ] Enable Video Mode Handling Helpers

*** Frame buffer hardware drivers ***

< * > S3C2410 LCD framebuffer support

<* > Framebuffer Console support

[ * ] Bootup logo —>

[ * ] Standard 224-color Linux logo

5、开机显示logo

配置完毕后，编译出内核镜像，烧写到 TQ2440 开发板中，启动系统时，就可以看到开机logo 的画面，这就表明 LCD 驱动完成了。