TQ2440移植u-boot2016.11-LCD驅動移植并顯示
LCD初始化流程分析
u-boot的LCD初始化代碼是在
common/lcd.c
中，我們找到
lcd_init
函數：
該函數功能流程為：
lcd_ctrl_init
初始化了LCD的硬體參數---->開辟LCD的幀緩沖(緩沖基位址儲存在了
gd->fs_base
變量中)—>清屏—>使能LCD—>設定LCD控制台參數
lcd_ctrl_init
和
lcd_enable
函數是u-boot抽離出的函數接口，需要根據LCD的實際情況進行底層硬體的初始化操作實作這兩個函數；除此之外還需要定義一個名為
panel_info
的
vidinfo_t
結構類型變量，該結構變量儲存了LCD螢幕的大小和顔色位深，用于LCD螢幕的控制台顯示。
LCD驅動移植
我的螢幕是W43，分辨率480x272，驅動編寫參考的TQ2440官方的LCD螢幕驅動代碼修改而來。
添加LCD的相關配置宏：
gedit include/configs/tq2440.h
末尾添加如下代碼：
/*
* LCD configuration
*/
#define CONFIG_LCD /* 該宏用于添加進LCD相關的編譯項 */
#define LCD_BPP LCD_COLOR16 /* 每像素為16bits */
#define CONFIG_LCD_LOGO /* 顯示LOGO */
#define CONFIG_LCD_INFO /* 顯示使用者自定義資訊 */
#define CONFIG_LCD_INFO_BELOW_LOGO /* 使用者自定義資訊與LOGO的位置無關 */
#define CONFIG_SYS_WHITE_ON_BLACK /* 黑底白字 */
#define CONFIG_SYS_CONSOLE_IS_IN_ENV /* 控制台接收自環境變量 */
#define CONFIG_CONSOLE_MUX /* 定義該宏可支援将列印資訊同時輸出到序列槽和LCD */
#define CONFIG_CONSOLE_SCROLL_LINES 16 /* 螢幕顯示總行數 */
/* 以下三個宏為我自己定義的 */
#define CONFIG_TQ2440_LCD /* 該宏用于将tq2440_lcd.c檔案編譯進來 */
#define LCD_XSIZE_TFT 480 /* LCD行數 */
#define LCD_YSIZE_TFT 272 /* LCD列數 */
#define MVAL 13
#define MVAL_USED 0 /* 0:each frame 1:rate by MVAL */
#define INVVDEN 1 /* 0:normal 1:inverted */
#define BSWP 0 /* byte swap control */
#define HWSWP 1 /* half word swap control */
#define CONFIG_TQ2440_LCD_VBPD 1
#define CONFIG_TQ2440_LCD_VFPD 1
#define CONFIG_TQ2440_LCD_VSPW 9
#define CONFIG_TQ2440_LCD_HBPD 1
#define CONFIG_TQ2440_LCD_HFPD 1
#define CONFIG_TQ2440_LCD_HSPW 40
#define CONFIG_TQ2440_LCD_CLKVAL 4
添加tq2440的LCD檔案：
gedit drivers/video/tq2440_lcd.c
粘貼進如下代碼：
#include <common.h>
#include <lcd.h>
#include <asm/system.h>
#include <asm/gpio.h>
#include <asm/arch/s3c24x0_cpu.h>
#include <lcd.h>
#include <version.h>
DECLARE_GLOBAL_DATA_PTR; /* 導入gd_t結構變量gd */
/* to get lower 21bits */
#define M5D(n) ((n) & 0x1FFFFF)
vidinfo_t panel_info =
{
.vl_col = LCD_XSIZE_TFT, /* 列數 */
.vl_row = LCD_YSIZE_TFT, /* 行數 */
.vl_bpix = LCD_BPP, /* 像素位數為16bits，該宏在tq2440.h中被定義 */
};
/* 将LCD緩沖數組轉為二維數組來用 */
#define tq2440_lcd_frame_pbuf ((volatile unsigned short (*)[LCD_XSIZE_TFT])(gd->fb_base))
void tq2440_lcd_clear_screen(unsigned short color)
{
int x = 0, y = 0;
for (y = 0; y < LCD_YSIZE_TFT; y++)
{
for (x = 0; x < LCD_XSIZE_TFT; x++)
{
tq2440_lcd_frame_pbuf[y][x] = color;
}
}
}
void lcd_ctrl_init(void* lcdbase)
{
char vbpd = 0;
char vfpd = 0;
char vspw = 0;
char hbpd = 0;
char hfpd = 0;
char hspw = 0;
char clkval = 0;
char* lcdenv = NULL;
struct s3c24x0_gpio* const gpio = s3c24x0_get_base_gpio();
struct s3c24x0_lcd* const lcd = s3c24x0_get_base_lcd();
/* set lcd frame buffer start adddress */
lcd->lcdsaddr1 = (((unsigned int)tq2440_lcd_frame_pbuf >> 22) << 21) | M5D((unsigned int)tq2440_lcd_frame_pbuf >> 1);
/* set lcd frame buffer end adddress */
lcd->lcdsaddr2 = M5D(((unsigned int)tq2440_lcd_frame_pbuf + (LCD_XSIZE_TFT * LCD_YSIZE_TFT * 2)) >> 1);
/* set virtul screen page wigth */
lcd->lcdsaddr3 = (((LCD_XSIZE_TFT - LCD_XSIZE_TFT) / 1) << 11) | (LCD_XSIZE_TFT / 1);
lcdenv = getenv("dwVBPD");
vbpd = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_VBPD;
lcdenv = getenv("dwVFPD");
vfpd = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_VFPD;
lcdenv = getenv("dwVSPW");
vspw = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_VSPW;
lcdenv = getenv("dwHBPD");
hbpd = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_HBPD;
lcdenv = getenv("dwHFPD");
hfpd = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_HFPD;
lcdenv = getenv("dwHSPW");
hspw = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_HSPW;
lcdenv = getenv("dwCLKVAL");
clkval = lcdenv ? (int)simple_strtol(lcdenv, NULL, 10) : CONFIG_TQ2440_LCD_CLKVAL;
/* clear screen */
tq2440_lcd_clear_screen(0x0000);
/* initialize VD[7:0] */
gpio->gpcup = 0xFFFFFFFF;
gpio->gpccon = 0xAAAAAAAA;
/* initialize VD[15:8] */
gpio->gpdup = 0xFFFFFFFF;
gpio->gpdcon = 0xAAAAAAAA;
/* lcd config */
lcd->lcdcon1 = (clkval << 8) | (MVAL_USED << 7) | (3 << 5) | (12 << 1) | 0;
lcd->lcdcon2 = (vbpd << 24) | ((LCD_YSIZE_TFT - 1) << 14) | (vfpd << 6) | vspw;
lcd->lcdcon3 = (hbpd << 19) | ((LCD_XSIZE_TFT - 1) << 8) | hfpd;
lcd->lcdcon4 = (MVAL << 8) | hspw;
lcd->lcdcon5 = (1 << 11) | (0 << 10) | (1 << 9) | (1 << 8) | (0 << 7) | (0 << 6) | (1 << 3) | (BSWP << 1) | HWSWP;
/* make lcd sub interrupt */
lcd->lcdintmsk |= 0x3;
/* disable lpc3480 */
lcd->lpcsel &= ~(0x7);
/* disbale temp palette */
lcd->tpal = 0x0;
/* disable gpg4 pull-up */
gpio->gpgup &= ~(1 << 4);
/* set gpg4 mode to lcd_pwrdn */
gpio->gpgcon |= 3 << 8;
/* set gpg4 to high */
gpio->gpgdat |= 1 << 4;
/* enable pwren signal */
lcd->lcdcon5 |= 1 << 3;
/* set signal polarity to normal */
lcd->lcdcon5 &= ~(1 << 5);
}
void lcd_enable(void)
{
struct s3c24x0_lcd* const lcd = s3c24x0_get_base_lcd();
/* Enable the video output and the LCD control signal. */
lcd->lcdcon1 |= (1 << 0);
}
#ifdef CONFIG_LCD_INFO
void lcd_show_board_info(void)
{
lcd_printf("%s (%s - %s)\n", U_BOOT_VERSION, U_BOOT_DATE, U_BOOT_TIME);
}
#endif
添加進編譯項：
gedit drivers/video/Makefile
末尾添加一行：
obj-$(CONFIG_TQ2440_LCD) += tq2440_lcd.o
測試
編譯後使用tftp下載下傳到記憶體0x30008000處并運作程式，檢視效果：
下面操作将輸出資訊重定向到LCD上顯示：
使用以下指令檢視可以将輸出資訊重定向到哪些裝置：
coninfo
可以看到可以将輸出資訊重定向到序列槽和LCD，serial就是我們使用的序列槽一，标志為IO，也就是說可以輸入輸出，LCD為
.O
，也就是說隻能輸出不能輸入。
将輸出資訊同時重定向到LCD和序列槽一：
setenv stdout 'lcd,serial'
ends…