需求说明

由于设备位置问题，屏幕需要翻转180°显示才好安装，如果没有旋转功能，则需要重新做代码布局，找到
LVGL8的文档，发现显示部分已经有这个的配置，只需要做以下简单配置就搞定了。

硬件部分

芯片：采用华芯微特的SWM341S芯片

屏幕：4.3寸屏幕 分辨率：800x480
触摸：GT9x

关键代码

关键代码在void lv_port_disp_init(void)这个函数，以下是关键代码部分，缺一不可。

        disp_drv.sw_rotate = 1;
        disp_drv.rotated = LV_DISP_ROT_180;

完整配置

适配代码所在文件
proting/lv_port_disp.c
这个文件具体根据你项目来，以下是文件具体内容：

/**
 * @file lv_port_disp_templ.c
 *
 */

 /*Copy this file as "lv_port_disp.c" and set this value to "1" to enable content*/
#if 1

/*********************
 *      INCLUDES
 *********************/
#include "lv_port_disp.h"
#include "lv_conf.h"
#include "../lvgl/lvgl.h"
#include "main.h"
/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/
static void disp_init(void);

static void disp_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t * color_p);
#if LV_USE_GPU
static void gpu_blend(lv_disp_drv_t * disp_drv, lv_color_t * dest, const lv_color_t * src, uint32_t length, lv_opa_t opa);
static void gpu_fill(lv_disp_drv_t * disp_drv, lv_color_t * dest_buf, lv_coord_t dest_width,
        const lv_area_t * fill_area, lv_color_t color);
#endif

/**********************
 *  STATIC VARIABLES
 **********************/

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

void lv_port_disp_init(void)
{
    /*-------------------------
     * Initialize your display
     * -----------------------*/
    disp_init();

    /*-----------------------------
     * Create a buffer for drawing
     *----------------------------*/

    /**
     * LVGL requires a buffer where it internally draws the widgets.
     * Later this buffer will passed to your display driver's `flush_cb` to copy its content to your display.
     * The buffer has to be greater than 1 display row
     *
     * There are 3 buffering configurations:
     * 1. Create ONE buffer:
     *      LVGL will draw the display's content here and writes it to your display
     *
     * 2. Create TWO buffer:
     *      LVGL will draw the display's content to a buffer and writes it your display.
     *      You should use DMA to write the buffer's content to the display.
     *      It will enable LVGL to draw the next part of the screen to the other buffer while
     *      the data is being sent form the first buffer. It makes rendering and flushing parallel.
     *
     * 3. Double buffering
     *      Set 2 screens sized buffers and set disp_drv.full_refresh = 1.
     *      This way LVGL will always provide the whole rendered screen in `flush_cb`
     *      and you only need to change the frame buffer's address.
     */

    /* Example for 1) */
    // static lv_disp_buf_t draw_buf_dsc_1;
    // static lv_color_t draw_buf_1[LV_HOR_RES_MAX * 10];                          /*A buffer for 10 rows*/
    // lv_disp_buf_init(&draw_buf_dsc_1, draw_buf_1, NULL, LV_HOR_RES_MAX * 10);   /*Initialize the display buffer*/

    /* Example for 2) */
    // static lv_disp_buf_t draw_buf_dsc_2;
    // static lv_color_t draw_buf_2_1[LV_HOR_RES_MAX * 10];                        /*A buffer for 10 rows*/
    // static lv_color_t draw_buf_2_2[LV_HOR_RES_MAX * 10];                        /*An other buffer for 10 rows*/
    // lv_disp_buf_init(&draw_buf_dsc_2, draw_buf_2_1, draw_buf_2_2, LV_HOR_RES_MAX * 10);   /*Initialize the display buffer*/

    /* Example for 3) */
    static lv_disp_draw_buf_t draw_buf_dsc_3;
    static lv_color_t draw_buf_3_1[LV_HOR_RES_MAX * LV_VER_RES_MAX]__attribute__((section(".SDRAM"))); /*A screen sized buffer*/
    static lv_color_t draw_buf_3_2[LV_HOR_RES_MAX * LV_VER_RES_MAX]__attribute__((section(".SDRAM"))); /*An other screen sized buffer*/
    lv_disp_draw_buf_init(&draw_buf_dsc_3, draw_buf_3_1, draw_buf_3_2, LV_HOR_RES_MAX * LV_VER_RES_MAX);   /*Initialize the display buffer*/


    /*-----------------------------------
     * Register the display in LVGL
     *----------------------------------*/

    static lv_disp_drv_t disp_drv;                         /*Descriptor of a display driver*/
    lv_disp_drv_init(&disp_drv);                    /*Basic initialization*/

    /*Set up the functions to access to your display*/

    /*Set the resolution of the display*/
    disp_drv.hor_res = LV_HOR_RES_MAX;
    disp_drv.ver_res = LV_VER_RES_MAX;

    /*Used to copy the buffer's content to the display*/
    disp_drv.flush_cb = disp_flush;
        //屏幕翻转180°
        disp_drv.sw_rotate = 1;
        disp_drv.rotated = LV_DISP_ROT_180;
    /*Set a display buffer*/
    disp_drv.draw_buf = &draw_buf_dsc_3;
        
#if LV_USE_GPU
    /*Optionally add functions to access the GPU. (Only in buffered mode, LV_VDB_SIZE != 0)*/

    /*Blend two color array using opacity*/
    disp_drv.gpu_blend_cb = gpu_blend;

    /*Fill a memory array with a color*/
    disp_drv.gpu_fill_cb = gpu_fill;
#endif

    /*Finally register the driver*/
    lv_disp_drv_register(&disp_drv);
}

/**********************
 *   STATIC FUNCTIONS
 **********************/

/*Initialize your display and the required peripherals.*/
static void disp_init(void)
{
    /*LCD显示屏移植*/
    rgb_init();
    LCD_Start(LCD);
}

/*Flush the content of the internal buffer the specific area on the display
 *You can use DMA or any hardware acceleration to do this operation in the background but
 *'lv_disp_flush_ready()' has to be called when finished.*/
static void disp_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t * color_p)
{
    /*The most simple case (but also the slowest) to put all pixels to the screen one-by-one*/

//    int32_t x;
//    int32_t y;
//    for(y = area->y1; y <= area->y2; y++) {
//        for(x = area->x1; x <= area->x2; x++) {
//            /*Put a pixel to the display. For example:*/
//            /*put_px(x, y, *color_p)*/
//            color_p++;
//        }
//    }

/*LCD显示屏移植*/
    LCD->L[0].ADDR = (uint32_t)color_p;
    LCD->CR |= (1 << LCD_CR_VBPRELOAD_Pos);
    /*IMPORTANT!!!
     *Inform the graphics library that you are ready with the flushing*/
    lv_disp_flush_ready(disp_drv);
}

/*OPTIONAL: GPU INTERFACE*/
#if LV_USE_GPU

/* If your MCU has hardware accelerator (GPU) then you can use it to blend to memories using opacity
 * It can be used only in buffered mode (LV_VDB_SIZE != 0 in lv_conf.h)*/
static void gpu_blend(lv_disp_drv_t * disp_drv, lv_color_t * dest, const lv_color_t * src, uint32_t length, lv_opa_t opa)
{
    /*It's an example code which should be done by your GPU*/
    uint32_t i;
    for(i = 0; i < length; i++) {
        dest[i] = lv_color_mix(dest[i], src[i], opa);
    }
}

/* If your MCU has hardware accelerator (GPU) then you can use it to fill a memory with a color
 * It can be used only in buffered mode (LV_VDB_SIZE != 0 in lv_conf.h)*/
static void gpu_fill(lv_disp_drv_t * disp_drv, lv_color_t * dest_buf, lv_coord_t dest_width,
                    const lv_area_t * fill_area, lv_color_t color)
{
    /*It's an example code which should be done by your GPU*/
    int32_t x, y;
    dest_buf += dest_width * fill_area->y1; /*Go to the first line*/

    for(y = fill_area->y1; y <= fill_area->y2; y++) {
        for(x = fill_area->x1; x <= fill_area->x2; x++) {
            dest_buf[x] = color;
        }
        dest_buf+=dest_width;    /*Go to the next line*/
    }
}

#endif  /*LV_USE_GPU*/

#else /* Enable this file at the top */

/*This dummy typedef exists purely to silence -Wpedantic.*/
typedef int keep_pedantic_happy;
#endif