Multiple UARTs/UARTEs on custom board based on nRF52840 DK

Hello, I am relatively new to the Zephyr project and I have made a custom board nrf52840dkbased on the nRF52840 Development Kit (nrf52840dk_nrf52840). It is the nRF52840 Development Kit I am flashing to.

My goal is to define three UARTs or UARTEs that I can use in my application. Below is the relevant device tree files for the custom board nrf52840dk with two UARTEs (uart0 and uart1). This works like a charm on the demonstration program app\src\main.c.

boards\arm\nrf52840dk\nrf52840dk-pinctrl.dtsi

&pinctrl {
	uart0_default: uart0_default {
		group1 {
			psels =	<NRF_PSEL(UART_TX, 0, 6)>,
					<NRF_PSEL(UART_RTS, 0, 5)>;
		};
		group2 {
			psels =	<NRF_PSEL(UART_RX, 0, 8)>,
					<NRF_PSEL(UART_CTS, 0, 7)>;
			bias-pull-up;
		};
	};
	uart0_sleep: uart0_sleep {
		group1 {
			psels =	<NRF_PSEL(UART_TX, 0, 6)>,
					<NRF_PSEL(UART_RX, 0, 8)>,
					<NRF_PSEL(UART_RTS, 0, 5)>,
					<NRF_PSEL(UART_CTS, 0, 7)>;
			low-power-enable;
		};
	};
	uart1_default: uart1_default {
		group1 {
			psels =	<NRF_PSEL(UART_RX, 0, 14)>;
			bias-pull-up;
		};
		group2 {
			psels =	<NRF_PSEL(UART_TX, 0, 16)>;
		};
	};
	uart1_sleep: uart1_sleep {
	   group1 {
			psels =	<NRF_PSEL(UART_RX, 0, 14)>,
		  			<NRF_PSEL(UART_TX, 0, 16)>;
		  low-power-enable;
		};
	};
};

boards\arm\nrf52840dk\nrf52840dk.dts

/dts-v1/;
#include <nordic/nrf52840_qiaa.dtsi>
#include "nrf52840dk-pinctrl.dtsi"

/ {
	model = "nRF52840 DK Board";
	compatible = "nordic,nrf52840dk";

	chosen {
		zephyr,console = &uart0;
		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
	};
};

&uart0 {
	compatible = "nordic,nrf-uarte";
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart0_default>;
	pinctrl-1 = <&uart0_sleep>;
	pinctrl-names = "default", "sleep";
};

&uart1 {
	compatible = "nordic,nrf-uarte";
	current-speed = <115200>;
	status = "okay";
	pinctrl-0 = <&uart1_default>;
	pinctrl-1 = <&uart1_sleep>;
	pinctrl-names = "default", "sleep";
};

app\src\main.c

#include <app_version.h>
#include <zephyr/device.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>

LOG_MODULE_REGISTER(main, CONFIG_LOG_DEFAULT_LEVEL);

#define UART0_DEVICE_NODE DT_NODELABEL(uart0)
#define UART1_DEVICE_NODE DT_NODELABEL(uart1)

static const struct device *const uart0_dev = DEVICE_DT_GET(UART0_DEVICE_NODE);
static const struct device *const uart1_dev = DEVICE_DT_GET(UART1_DEVICE_NODE);

/**
 * @brief Print a null-terminated string, character by character, to the UART
 * interface.
 *
 * @param dev the UART device to print from.
 * @param str the null-terminated string to print.
 */
void print_uart(const struct device *dev, const char *str) {
    const size_t str_len = strlen(str);
    for (size_t i = 0; i < str_len; i++) {
        uart_poll_out(dev, str[i]);
    }
}

/**
 * @brief This is where the magic happens.
 */
int main(void) {
    LOG_INF("Application version %s initialized on board %s!", APP_VERSION_STRING, CONFIG_BOARD);

	// Print on uart0.
    print_uart(uart0_dev, "uart0: ");
    print_uart(uart0_dev, uart0_dev->name);
    print_uart(uart0_dev, "\r\n");

	// Print on uart1.
    print_uart(uart1_dev, "uart1: ");
    print_uart(uart1_dev, uart1_dev->name);
    print_uart(uart1_dev, "\r\n");

    LOG_INF("Application version %s shutting down on board %s!", APP_VERSION_STRING, CONFIG_BOARD);
    return 0;
}

The problems arise when I try to implement another UART: uart2. To begin with, I don’t know if a third UART or UARTE is supported in the first place. In stripped down form, the changes to the respective files are:

boards\arm\nrf52840dk\nrf52840dk-pinctrl.dtsi

// Stripped down version.
&pinctrl {
	uart2_default: uart2_default {
		group1 {
			psels =	<NRF_PSEL(UART_RX, 0, 1)>;
			bias-pull-up;
		};
		group2 {
			psels =	<NRF_PSEL(UART_TX, 0, 2)>;
		};
	};
	uart2_sleep: uart2_sleep {
	   group1 {
			psels =	<NRF_PSEL(UART_RX, 0, 1)>,
		  			<NRF_PSEL(UART_TX, 0, 2)>;
		  low-power-enable;
		};
	};
};

boards\arm\nrf52840dk\nrf52840dk.dtsi

// Stripped down version.
&uart2 {
	compatible = "nordic,nrf-uart";
	current-speed = <115200>;
	status = "okay";
	pinctrl-0 = <&uart2_default>;
	pinctrl-1 = <&uart2_sleep>;
	pinctrl-names = "default", "sleep";
};

app\src\main.c

// Stripped down version.
#define UART2_DEVICE_NODE DT_NODELABEL(uart2)

static const struct device *const uart2_dev = DEVICE_DT_GET(UART2_DEVICE_NODE);

int main(void) {
    // Print on uart2.
    print_uart(uart2_dev, "uart2: ");
    print_uart(uart2_dev, uart2_dev->name);
    print_uart(uart2_dev, "\r\n");
}

When I build the application with the command west build -p always -b nrf52840dk app, the operation fails. The error given is:
devicetree error: path/to/zephyr-uarts-project/zephyr-application/boards/arm/nrf52840dk/nrf52840dk.dts:42 (column 1): parse error: undefined node label 'uart2'

Given that the node label is undefined. Is it possible to define it on my own? For example in a way like this?

boards\arm\nrf52840dk\nrf52840dk.dtsi

// Stripped down version.
/ {
	model = "nRF52840 DK Board";
	compatible = "nordic,nrf52840dk";

	chosen {
		zephyr,console = &uart0;
		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
	};

	soc {
		uart2: uart@some_address_here {
			compatible = "nordic,nrf-uart";  // or "nordic,nrf-uarte"?
			reg = <some_address_here 0x1000>;
			interrupts = <interrupt_number_here NRF_DEFAULT_IRQ_PRIORITY>;
		};
	};
};

Any input on this matter is greatly appreciated. Thank you in advance.