boards: arm: Add support for nucleo-g031k8 board

Support for the NUCLEO-G031K8 board containing the
STM32G031K8 SoC.

This board is based on the already existing nucleo_l031k6.

Signed-off-by: Marco Peter <marco.peter@joylab.ch>

boards/arm/nucleo_g031k8/Kconfig.board

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+# STM32 Nucleo-32 development board with STM32G031K8 MCU configuration
+
+# Copyright (c) 2022 Joylab AG <team@joylab.ch>
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_G031K8
+	bool "NUCLEO-32 G031K8 Development Board"
+	depends on SOC_STM32G031XX

boards/arm/nucleo_g031k8/Kconfig.defconfig

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+# STM32 Nucleo-32 development board with STM32G031K8 MCU
+
+# Copyright (c) 2022 Joylab AG <team@joylab.ch>
+# SPDX-License-Identifier: Apache-2.0
+
+if BOARD_NUCLEO_G031K8
+
+config BOARD
+	default "nucleo_g031k8"
+
+config SPI_STM32_INTERRUPT
+	default y
+	depends on SPI
+
+endif # BOARD_NUCLEO_G031K8

boards/arm/nucleo_g031k8/board.cmake

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+# SPDX-License-Identifier: Apache-2.0
+
+board_runner_args(jlink "--device=STM32G031K8" "--speed=4000")
+
+include(${ZEPHYR_BASE}/boards/common/openocd.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/jlink.board.cmake)

boards/arm/nucleo_g031k8/doc/index.rst

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+.. _nucleo_g031k8_board:
+
+ST Nucleo G031K8
+################
+
+Overview
+********
+The STM32 Nucleo-32 board provides an affordable and flexible way for users to try
+out new concepts and build prototypes by choosing from the various combinations of
+performance and power consumption features, provided by the STM32
+microcontroller.
+
+The Arduino™ Nano V3 connectivity support allows the easy expansion of the
+functionality of the STM32 Nucleo open development platform with a wide choice of
+specialized shields.
+
+The STM32 Nucleo-32 board does not require any separate probe as it integrates the
+ST-LINK debugger/programmer.
+
+The STM32 Nucleo-32 board comes with the STM32 comprehensive free software
+libraries and examples available with the STM32Cube MCU Package.
+
+
+.. image:: img/nucleo_g031k8.jpg
+   :width: 426px
+   :height: 653px
+   :align: center
+   :alt: Nucleo G031K8
+
+More information about the board can be found at the `Nucleo G031K8 website`_.
+
+Hardware
+********
+Nucleo G031K8 provides the following hardware components:
+
+- STM32 microcontroller in 32-pin package featuring 64 Kbytes of Flash memory
+  and 8 Kbytes of SRAM.
+- Extension resource:
+
+  - Arduino* Nano V3 connectivity
+
+- On-board ST-LINK/V2-1 debugger/programmer with SWD connector:
+
+- Flexible board power supply:
+
+  - USB VBUS or external source (3.3V, 5V, 7 - 12V)
+  - Current consumption measurement (IDD)
+
+- Four LEDs:
+
+  - USB communication (LD1), power LED (LD2), user LED (LD3),
+    USB power fault LED (LD4)
+
+- One push-button: RESET
+
+- USB re-enumeration capability. Three different interfaces supported on USB:
+
+  - Virtual COM port
+  - Mass storage
+  - Debug port
+
+More information about STM32G031K8 can be found in the
+`STM32G0x1 reference manual`_
+
+Supported Features
+==================
+
+The Zephyr nucleo_g031k8 board configuration supports the following hardware features:
+
++-----------+------------+-------------------------------------+
+| Interface | Controller | Driver/Component                    |
++===========+============+=====================================+
+| NVIC      | on-chip    | nested vector interrupt controller  |
++-----------+------------+-------------------------------------+
+| UART      | on-chip    | serial port-polling;                |
+|           |            | serial port-interrupt               |
++-----------+------------+-------------------------------------+
+| PINMUX    | on-chip    | pinmux                              |
++-----------+------------+-------------------------------------+
+| GPIO      | on-chip    | gpio                                |
++-----------+------------+-------------------------------------+
+| CLOCK     | on-chip    | reset and clock control             |
++-----------+------------+-------------------------------------+
+| I2C       | on-chip    | i2c controller                      |
++-----------+------------+-------------------------------------+
+| SPI       | on-chip    | spi controller                      |
++-----------+------------+-------------------------------------+
+
+Other hardware features are not yet supported in this Zephyr port.
+
+The default configuration can be found in the defconfig file:
+``boards/arm/nucleo_g031k8/nucleo_g031k8_defconfig``
+
+Connections and IOs
+===================
+
+Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as
+input (with or without pull-up or pull-down), or as peripheral alternate function. Most of the
+GPIO pins are shared with digital or analog alternate functions. All GPIOs are high current
+capable except for analog inputs.
+
+Default Zephyr Peripheral Mapping:
+----------------------------------
+
+- UART_2 TX/RX : PA2/PA3 (ST-Link Virtual Port Com)
+- I2C2 SCL/SDA : PA9/PA10 (Arduino I2C)
+- SPI1 SCK/MISO/MOSI : PB3/PB4/PB5 (Arduino SPI)
+- LD3       : PC6
+
+For mode details please refer to `STM32 Nucleo-32 board User Manual`_.
+
+Programming and Debugging
+*************************
+
+Applications for the ``nucleo_g031k8`` board configuration can be built and
+flashed in the usual way (see :ref:`build_an_application` and
+:ref:`application_run` for more details).
+
+Flashing
+========
+
+Nucleo G031K8 board includes an ST-LINK/V2-1 embedded debug tool interface.
+This interface is supported by the openocd version included in the Zephyr SDK.
+
+Flashing an application to Nucleo G031K8
+----------------------------------------
+
+Here is an example for the :ref:`blinky-sample` application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/basic/blinky
+   :board: nucleo_g031k8
+   :goals: build flash
+
+You will see the LED blinking every second.
+
+Debugging
+=========
+
+You can debug an application in the usual way.  Here is an example for the
+:ref:`hello_world` application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/hello_world
+   :board: nucleo_g031k8
+   :maybe-skip-config:
+   :goals: debug
+
+Restriction
+***********
+
+On some boards, the board reset line is not used by the controller.
+Therefore the reset button, reset-pin and the ST-Link reset have no effect.
+To enable those functionalities, the option byte NRST_mode in the User
+Configuration needs to be changed from 2 to 1 or 3 - depending on the
+requirements.
+
+References
+**********
+
+.. target-notes::
+
+.. _Nucleo G031K8 website:
+   http://www.st.com/en/evaluation-tools/nucleo-g031k8.html
+
+.. _STM32G0x1 reference manual:
+   https://www.st.com/resource/en/reference_manual/rm0444-stm32g0x1-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
+
+.. _STM32 Nucleo-32 board User Manual:
+   https://www.st.com/resource/en/user_manual/um2591-stm32g0-nucleo32-board-mb1455-stmicroelectronics.pdf

boards/arm/nucleo_g031k8/nucleo_g031k8.dts

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+/*
+ * Copyright (c) 2022 Joylab AG <team@joylab.ch>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+#include <st/g0/stm32g031X8.dtsi>
+#include <st/g0/stm32g031k(4-6-8)tx-pinctrl.dtsi>
+
+/ {
+	model = "STMicroelectronics STM32G031K8-NUCLEO board";
+	compatible = "st,stm32g031k8-nucleo";
+
+	chosen {
+		zephyr,console = &usart2;
+		zephyr,shell-uart = &usart2;
+		zephyr,sram = &sram0;
+		zephyr,flash = &flash0;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+		green_led_3: led_3 {
+			gpios = <&gpioc 6 GPIO_ACTIVE_HIGH>;
+			label = "User LD3";
+		};
+	};
+
+	aliases {
+		led0 = &green_led_3;
+	};
+};
+
+&clk_hsi {
+	status = "okay";
+};
+
+&pll {
+	div-m = <1>;
+	mul-n = <8>;
+	div-r = <2>;
+	clocks = <&clk_hsi>;
+	status = "okay";
+};
+
+&rcc {
+	clocks = <&pll>;
+	clock-frequency = <DT_FREQ_M(64)>;
+	ahb-prescaler = <1>;
+	apb1-prescaler = <1>;
+};
+
+&usart1 {
+	pinctrl-0 = <&usart1_tx_pb6 &usart1_rx_pb7>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+};
+
+&usart2 {
+	pinctrl-0 = <&usart2_tx_pa2 &usart2_rx_pa3>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};
+
+&i2c1 {
+	pinctrl-0 = <&i2c1_scl_pa9 &i2c1_sda_pa10>;
+	pinctrl-names = "default";
+	clock-frequency = <I2C_BITRATE_FAST>;
+	status = "okay";
+};
+
+&i2c2 {
+	pinctrl-0 = <&i2c2_scl_pa11 &i2c2_sda_pa12>;
+	pinctrl-names = "default";
+	clock-frequency = <I2C_BITRATE_FAST>;
+	status = "okay";
+};
+
+&spi1 {
+	pinctrl-0 = <&spi1_sck_pb3 &spi1_miso_pb4 &spi1_mosi_pb5>;
+	pinctrl-names = "default";
+	status = "okay";
+};

boards/arm/nucleo_g031k8/nucleo_g031k8.yaml

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+identifier: nucleo_g031k8
+name: ST Nucleo G031K8
+type: mcu
+arch: arm
+toolchain:
+  - zephyr
+  - gnuarmemb
+  - xtools
+supported:
+  - gpio
+  - i2c
+  - spi
+ram: 8
+flash: 64

boards/arm/nucleo_g031k8/nucleo_g031k8_defconfig

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+# SPDX-License-Identifier: Apache-2.0
+
+# Zephyr Kernel Configuration
+CONFIG_SOC_SERIES_STM32G0X=y
+
+# Platform Configuration
+CONFIG_SOC_STM32G031XX=y
+
+# Kernel Options due to Low Memory (8k)
+CONFIG_MAIN_STACK_SIZE=640
+CONFIG_IDLE_STACK_SIZE=200
+CONFIG_ISR_STACK_SIZE=512
+
+# Serial Drivers
+CONFIG_SERIAL=y
+CONFIG_UART_INTERRUPT_DRIVEN=y
+# enable console
+CONFIG_CONSOLE=y
+CONFIG_UART_CONSOLE=y
+
+# GPIO Controller
+CONFIG_GPIO=y
+
+# Enable Clocks
+CONFIG_CLOCK_CONTROL=y
+
+# enable pin controller
+CONFIG_PINCTRL=y

boards/arm/nucleo_g031k8/support/openocd.cfg

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+# This is an ST NUCLEO-G031K8 board with single STM32G031K8 chip.
+# http://www.st.com/en/evaluation-tools/nucleo-g031k8.html
+
+source [find interface/stlink-dap.cfg]
+
+transport select dapdirect_swd
+
+source [find target/stm32g0x.cfg]
+
+# There is only system reset line and JTAG/SWD command can be issued when SRST
+reset_config srst_only
+
+$_TARGETNAME configure -event gdb-attach {
+        echo "Debugger attaching: halting execution"
+        reset halt
+        gdb_breakpoint_override hard
+}
+
+$_TARGETNAME configure -event gdb-detach {
+        echo "Debugger detaching: resuming execution"
+        resume
+}