LovyanGFX working on TTGO-TM-ESP32

TTGO-TM-Lovyan.ino

#include <Arduino.h>
// #define LGFX_USE_V1

#include <LovyanGFX.hpp>

// This is the hardware:
// https://github.com/LilyGO/TTGO-TM-ESP32

// LGFX for TTGO T-Display
class LGFX : public lgfx::LGFX_Device
{
    lgfx::Panel_ST7789 _panel_instance;
    lgfx::Bus_SPI _bus_instance;

public:
    LGFX(void)
    {
        {
            auto cfg = _bus_instance.config();

            cfg.spi_host = VSPI_HOST;
            cfg.spi_mode = 0;
            cfg.freq_write = 40000000;
            cfg.freq_read = 14000000;
            cfg.spi_3wire = true;
            cfg.use_lock = true;
            cfg.dma_channel = 1;
            cfg.pin_sclk = 18;
            cfg.pin_mosi = 23;
            cfg.pin_miso = -1;
            cfg.pin_dc = 16;

            _bus_instance.config(cfg);
            _panel_instance.setBus(&_bus_instance);
        }

        {
            auto cfg = _panel_instance.config();

            cfg.pin_cs = 5;
            cfg.pin_rst = 17;
            cfg.pin_busy = -1;

            cfg.panel_width = 240;
            cfg.panel_height = 320;
            cfg.offset_x = 0;
            cfg.offset_y = 0;
            cfg.offset_rotation = 0;
            cfg.dummy_read_pixel = 16;
            cfg.dummy_read_bits = 1;
            cfg.readable = true;
            cfg.invert = true;
            cfg.rgb_order = false;
            cfg.dlen_16bit = false;
            cfg.bus_shared = true;

            _panel_instance.config(cfg);
        }

        setPanel(&_panel_instance);
    }
};

LGFX lcd;
void setup(void)
{
    lcd.init();
    lcd.print("hello T-Display !");
}

void loop(void)
{
    delay(100);
}

This board: https://github.com/LilyGO/TTGO-TM-ESP32
This board has no backlight controls.