An Arduino-style "Blinky" patching to ZMK firmware (zmk-firmware/zmk/app/src/main.c)

main.c

/*
 * Copyright (c) 2020 The ZMK Contributors
 *
 * SPDX-License-Identifier: MIT
 */

#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/settings/settings.h>

#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(zmk, CONFIG_ZMK_LOG_LEVEL);

#if IS_ENABLED(CONFIG_ZMK_DISPLAY)

#include <zmk/display.h>
#include <lvgl.h>

#endif

// pseudo arduino: begin vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
#include <zephyr/drivers/gpio.h>    // GPIO_XXXX

#define LED0_NODE DT_ALIAS(led0)    // red

static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);

#define pinMode         gpio_pin_configure_dt
#define digitalWrite    gpio_pin_set_dt

void setup(void) {
	pinMode(&led, GPIO_OUTPUT_ACTIVE);
}

void loop(void) {
    digitalWrite(&led, 1);   // HIGH
    k_msleep(500);

    digitalWrite(&led, 0);   // LOW
    k_msleep(500);
}
// pseudo arduino: end ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


int main(void) {
    LOG_INF("Welcome to ZMK!\n");

// pseudo arduino: begin vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    setup();

    while (1) {
        loop();
    }
// pseudo arduino: end ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

#if IS_ENABLED(CONFIG_SETTINGS)
    settings_subsys_init();
    settings_load();
#endif

#ifdef CONFIG_ZMK_DISPLAY
    zmk_display_init();

#if IS_ENABLED(CONFIG_ARCH_POSIX)
    // Workaround for an SDL display issue:
    // https://github.com/zephyrproject-rtos/zephyr/issues/71410
    while (1) {
        lv_task_handler();
        k_sleep(K_MSEC(10));
    }
#endif

#endif /* CONFIG_ZMK_DISPLAY */

    return 0;
}