samples: drivers: pinctrl: add generic sample to show dynamic features

Add a new sample that shows how to change a UART device pins at runtime.

Signed-off-by: Gerard Marull-Paretas <[email protected]>

Author: gmarull

samples/drivers/pinctrl/dynamic/CMakeLists.txt

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(pinctrl_dynamic)
+
+target_sources(app PRIVATE src/main.c)

samples/drivers/pinctrl/dynamic/boards/nrf5340dk_nrf5340_cpuapp.overlay

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		uart = &uart1;
+	};
+
+	zephyr,user {
+		uart_alt_default = <&uart1_alt_default>;
+	};
+};
+
+&pinctrl {
+	/* Alternative pin configuration for UART1 */
+	uart1_alt_default: uart1_alt_default {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 5)>;
+		};
+		group2 {
+			psels = <NRF_PSEL(UART_RX, 1, 7)>;
+			bias-pull-up;
+		};
+	};
+};
+
+&uart1 {
+	status = "okay";
+};

samples/drivers/pinctrl/dynamic/boards/nucleo_h743zi.overlay

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		uart = &usart1;
+	};
+
+	zephyr,user {
+		uart_alt_default = <&usart1_tx_pb6 &usart1_rx_pb7>;
+		uart_alt_reset = <&analog_pa9 &analog_pa10>;
+	};
+};
+
+&usart1 {
+	pinctrl-0 = <&usart1_tx_pa9 &usart1_rx_pa10>;
+	pinctrl-1 = <&analog_pa9 &analog_pa10>;
+	pinctrl-names = "default", "reset";
+	current-speed = <115200>;
+	status = "okay";
+};

samples/drivers/pinctrl/dynamic/prj.conf

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+CONFIG_PINCTRL=y
+CONFIG_PINCTRL_DYNAMIC=y
+CONFIG_SERIAL=y

samples/drivers/pinctrl/dynamic/sample.yaml

@@ -0,0 +1,9 @@
+sample:
+  description: A dynamic pin control sample
+  name: pinctrl_dynamic
+tests:
+  sample.drivers.pinctrl.dynamic:
+    build_only: true
+    platform_allow: nrf52840dk/nrf52840
+    integration_platforms:
+      - nrf52840dk/nrf52840

samples/drivers/pinctrl/dynamic/src/main.c

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/drivers/uart.h>
+
+#define UART_NODE DT_ALIAS(uart)
+
+/* obtain reference to pinctrl config (owned by device) */
+PINCTRL_DT_DEV_CONFIG_DECLARE(UART_NODE);
+struct pinctrl_dev_config *uart_config = PINCTRL_DT_DEV_CONFIG_GET(UART_NODE);
+
+/* define alternate states and build alternate state */
+PINCTRL_DT_STATE_PINS_DEFINE(DT_PATH(zephyr_user), uart_alt_default);
+#if DT_PINCTRL_HAS_NAME(UART_NODE, reset)
+PINCTRL_DT_STATE_PINS_DEFINE(DT_PATH(zephyr_user), uart_alt_reset);
+#endif
+
+static const struct pinctrl_state uart_alt[] = {
+	PINCTRL_DT_STATE_INIT(uart_alt_default, PINCTRL_STATE_DEFAULT),
+#if DT_PINCTRL_HAS_NAME(UART_NODE, reset)
+	PINCTRL_DT_STATE_INIT(uart_alt_reset, PINCTRL_STATE_RESET),
+#endif
+};
+
+static const struct device *const uart = DEVICE_DT_GET(UART_NODE);
+
+static const char *const msg_a = "Hello World (A)!\r\n";
+static const char *const msg_b = "Hello World (B)!\r\n";
+
+int main(void)
+{
+	int ret;
+
+	if (!device_is_ready(uart)) {
+		printf("UART device not ready\n");
+		return 0;
+	}
+
+	for (size_t i = 0U; i < strlen(msg_a); i++) {
+		uart_poll_out(uart, msg_a[i]);
+	}
+
+	ret = device_deinit(uart);
+	if (ret < 0) {
+		printf("Failed to de-initialize UART device (%d)\n", ret);
+		return 0;
+	}
+
+	ret = pinctrl_update_states(uart_config, uart_alt, ARRAY_SIZE(uart_alt));
+	if (ret < 0) {
+		printf("Failed to update pinctrl states\n");
+		return 0;
+	}
+
+	ret = device_init(uart);
+	if (ret < 0) {
+		printf("Failed to initialize UART device (%d)\n", ret);
+		return 0;
+	}
+
+	for (size_t i = 0U; i < strlen(msg_b); i++) {
+		uart_poll_out(uart, msg_b[i]);
+	}
+
+	return 0;
+}