main.c

#include <fcntl.h>
#include <linux/kd.h>
#include <pthread.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include "lv_drivers/display/fbdev.h"
#include "lv_drivers/indev/evdev.h"
#include "lvgl/examples/widgets/lv_example_widgets.h"
#include "lvgl/lvgl.h"

#define DISP_BUF_SIZE (128 * 1024)

int main(void)
{
    /*LittlevGL init*/
    lv_init();

    /*Linux frame buffer device init*/
    fbdev_init();

    /*A small buffer for LittlevGL to draw the screen's content*/
    static lv_color_t buf[DISP_BUF_SIZE];

    /*Initialize a descriptor for the buffer*/
    static lv_disp_draw_buf_t disp_buf;
    lv_disp_draw_buf_init(&disp_buf, buf, NULL, DISP_BUF_SIZE);

    /*Initialize and register a display driver*/
    static lv_disp_drv_t disp_drv;
    lv_disp_drv_init(&disp_drv);
    disp_drv.draw_buf   = &disp_buf;
    disp_drv.flush_cb   = fbdev_flush;
    disp_drv.hor_res    = 480;
    disp_drv.ver_res    = 272;
    lv_disp_drv_register(&disp_drv);

    evdev_init();
    static lv_indev_drv_t indev_drv;
    lv_indev_drv_init(&indev_drv);      /*Basic initialization*/
    indev_drv.type = LV_INDEV_TYPE_POINTER;
    indev_drv.read_cb = evdev_read;

    /*Register the driver in LVGL and save the created input device object*/
    lv_indev_drv_register(&indev_drv);

    /* Run one of the examples. */
    lv_example_slider_3();

    /*Handle LitlevGL tasks (tickless mode)*/
    while(1) {
        lv_task_handler();
        usleep(5000);
    }

    return 0;
}

/*Set in lv_conf.h as `LV_TICK_CUSTOM_SYS_TIME_EXPR`*/
uint32_t custom_tick_get(void)
{
    static uint64_t start_ms = 0;
    if(start_ms == 0) {
        struct timeval tv_start;
        gettimeofday(&tv_start, NULL);
        start_ms = (tv_start.tv_sec * 1000000 + tv_start.tv_usec) / 1000;
    }

    struct timeval tv_now;
    gettimeofday(&tv_now, NULL);
    uint64_t now_ms;
    now_ms = (tv_now.tv_sec * 1000000 + tv_now.tv_usec) / 1000;

    uint32_t time_ms = now_ms - start_ms;
    return time_ms;
}