samples: boards: rpi_pico: Added PIO shell uart example

Simple example showing how to use the PIO based uart as a
console / log backend.

Signed-off-by: TOKITA Hiroshi <[email protected]>
Signed-off-by: Yonatan Schachter <[email protected]>
Signed-off-by: Ionut Catalin Pavel <[email protected]>

Author: iocapa

samples/boards/rpi_pico/uart_pio/CMakeLists.txt

@@ -1,7 +1,5 @@
-# SPDX-License-Identifier: Apache-2.0
-
-cmake_minimum_required(VERSION 3.20.0)
+cmake_minimum_required(VERSION 3.15.0)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
-project(uart_pio)
+project(pio_shell_uart)
 
 target_sources(app PRIVATE src/main.c)

samples/boards/rpi_pico/uart_pio/app-pinctrl.dtsi

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2023, Ionut Pavel <[email protected]>
+ * Copyright (c) 2023 Yonatan Schachter
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/pinctrl/rpi-pico-rp2040-pinctrl.h>
+
+&pinctrl {
+	pio0_uart0_default: pio0_uart0_default {
+		tx_gpio {
+			pinmux = <PIO0_P0>;
+		};
+
+		rx_gpio {
+			pinmux = <PIO0_P1>;
+			input-enable;
+			bias-pull-up;
+		};
+	};
+};

samples/boards/rpi_pico/uart_pio/app.overlay

@@ -0,0 +1,30 @@
+#include "app-pinctrl.dtsi"
+
+/ {
+	chosen {
+		zephyr,console = &pio0_uart0;
+		zephyr,shell-uart = &pio0_uart0;
+	};
+};
+
+&uart0 {
+	status = "disabled";
+};
+
+&pio0 {
+	status = "okay";
+
+	pio0_uart0: pio0_uart0 {
+		compatible = "raspberrypi,pico-uart-pio";
+
+		status = "okay";
+
+		pio,interrupts = <0>;
+		pio,interrupt-names = "shared";
+
+		pinctrl-0 = <&pio0_uart0_default>;
+		pinctrl-names = "default";
+
+		current-speed = <115200>;
+	};
+};

samples/boards/rpi_pico/uart_pio/boards/rpi_pico.overlay

@@ -1 +1,5 @@
-# nothing here
+CONFIG_LOG=y
+CONFIG_SHELL=y
+CONFIG_SERIAL=y
+CONFIG_UART_INTERRUPT_DRIVEN=y
+CONFIG_UART_CONSOLE=y

samples/boards/rpi_pico/uart_pio/prj.conf

@@ -1,36 +1,19 @@
 /*
+ * Copyright (c) 2023 Ionut Pavel <[email protected]>
  * Copyright (c) 2023 Yonatan Schachter
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #include <zephyr/kernel.h>
-#include <zephyr/device.h>
-#include <zephyr/drivers/uart.h>
 
-int main(void)
-{
-	char data;
-	const struct device *uart0 = DEVICE_DT_GET(DT_NODELABEL(pio1_uart0));
-	const struct device *uart1 = DEVICE_DT_GET(DT_NODELABEL(pio1_uart1));
-
-	if (!device_is_ready(uart0)) {
-		return 0;
-	}
-
-	if (!device_is_ready(uart1)) {
-		return 0;
-	}
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(main);
 
+void main(void)
+{
 	while (1) {
-		if (!uart_poll_in(uart0, &data)) {
-			uart_poll_out(uart0, data);
-		}
-
-		if (!uart_poll_in(uart1, &data)) {
-			uart_poll_out(uart1, data);
-		}
+		k_msleep(1000);
+		LOG_INF("One second passed...");
 	}
-
-	return 0;
 }