TQ2440移植u-boot2016.11全过程记录-【4】LCD驱动移植并显示

港控/mmm° 2023-05-28 12:41 17阅读 0赞

# TQ2440移植u-boot2016.11-LCD驱动移植并显示 #

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## **LCD初始化流程分析** ##

**u-boot的LCD初始化代码是在`common/lcd.c`中，我们找到`lcd_init`函数：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxMTUzNDcxNTAz_size_16_color_FFFFFF_t_70]  
**该函数功能流程为：`lcd_ctrl_init`初始化了LCD的硬件参数---->开辟LCD的帧缓冲(缓冲基地址保存在了`gd->fs_base`变量中)—>清屏—>使能LCD—>设置LCD控制台参数**

**`lcd_ctrl_init`和`lcd_enable`函数是u-boot抽离出的函数接口，需要根据LCD的实际情况进行底层硬件的初始化操作实现这两个函数；除此之外还需要定义一个名为`panel_info`的`vidinfo_t`结构类型变量，该结构变量保存了LCD屏幕的大小和颜色位深，用于LCD屏幕的控制台显示。**

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## LCD驱动移植 ##

**我的屏幕是W43，分辨率480x272，驱动编写参考的TQ2440官方的LCD屏幕驱动代码修改而来。**

**添加LCD的相关配置宏：**  
`gedit include/configs/tq2440.h`

**末尾添加如下代码：**

/* * LCD configuration */
    #define CONFIG_LCD /* 该宏用于添加进LCD相关的编译项 */
    #define LCD_BPP LCD_COLOR16 /* 每像素为16bits */
    #define CONFIG_LCD_LOGO /* 显示LOGO */
    #define CONFIG_LCD_INFO /* 显示用户自定义信息 */
    #define CONFIG_LCD_INFO_BELOW_LOGO /* 用户自定义信息与LOGO的位置无关 */
    #define CONFIG_SYS_WHITE_ON_BLACK /* 黑底白字 */
    #define CONFIG_SYS_CONSOLE_IS_IN_ENV /* 控制台接收自环境变量 */
    #define CONFIG_CONSOLE_MUX /* 定义该宏可支持将打印信息同时输出到串口和LCD */
    #define CONFIG_CONSOLE_SCROLL_LINES 16 /* 屏幕显示总行数 */
    
    /* 以下三个宏为我自己定义的 */
    #define CONFIG_TQ2440_LCD /* 该宏用于将tq2440_lcd.c文件编译进来 */
    #define LCD_XSIZE_TFT 480 /* LCD行数 */
    #define LCD_YSIZE_TFT 272 /* LCD列数 */
    
    #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文件：**

`gedit drivers/video/tq2440_lcd.c`

**粘贴进如下代码：**

#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;    /* 导入gd_t结构变量gd */
    
    /* to get lower 21bits */
    #define M5D(n) ((n) & 0x1FFFFF)
    
    vidinfo_t panel_info =
    { 
        .vl_col  = LCD_XSIZE_TFT,    /* 列数 */
        .vl_row  = LCD_YSIZE_TFT,    /* 行数 */
        .vl_bpix = LCD_BPP,          /* 像素位数为16bits，该宏在tq2440.h中被定义 */
    };
    
    /* 将LCD缓冲数组转为二维数组来用 */
    #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

**添加进编译项：**  
`gedit drivers/video/Makefile`

**末尾添加一行：**

obj-$(CONFIG_TQ2440_LCD) += tq2440_lcd.o

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## 测试 ##

**编译后使用tftp下载到内存0x30008000处并运行程序，查看效果：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxMTUzNDcxNTAz_size_16_color_FFFFFF_t_70 1]  
**下面操作将输出信息重定向到LCD上显示：**

**使用以下命令查看可以将输出信息重定向到哪些设备：**  
`coninfo`  
![在这里插入图片描述][20200326114625191.png]  
**可以看到可以将输出信息重定向到串口和LCD，serial就是我们使用的串口一，标志为IO，也就是说可以输入输出，LCD为`.O`，也就是说只能输出不能输入。**

**将输出信息同时重定向到LCD和串口一：**

`setenv stdout 'lcd,serial'`

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxMTUzNDcxNTAz_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxMTUzNDcxNTAz_size_16_color_FFFFFF_t_70 3]

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ends…

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[20200326114625191.png]: /images/20230528/493d08a0ca524bb59a7c2f0d80f9926d.png
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