boards: arm: add support for STM32G081B Evaluation board

Support the ST STM32G081B Evaluation board with STM32G081RB SoC

Tested with:
    - `samples/basic/blinky`
    - `samples/basic/button`

Flashed samples via On-Board ST-LINK with:
    - west flash

Signed-off-by: Sam Hurst <sbh1187@gmail.com>

boards/arm/stm32g081b_eval/Kconfig.board

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+# STM32G081B Evaluation board configuration
+
+# Copyright 2021 The Chromium OS Authors
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_STM32G081B_EVAL
+	bool "STM32G081B Evaluation Board"
+	depends on SOC_STM32G081XX

boards/arm/stm32g081b_eval/Kconfig.defconfig

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+# STM32G081B evaluation board configuration
+
+# Copyright 2021 The Chromium OS Authors
+# SPDX-License-Identifier: Apache-2.0
+
+if BOARD_STM32G081B_EVAL
+
+config BOARD
+	default "stm32g081b_eval"
+
+endif # BOARD_STM32G081B_EVAL

boards/arm/stm32g081b_eval/board.cmake

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+# SPDX-License-Identifier: Apache-2.0
+
+board_runner_args(stm32cubeprogrammer "--port=swd" "--reset=hw")
+
+include(${ZEPHYR_BASE}/boards/common/stm32cubeprogrammer.board.cmake)
+

boards/arm/stm32g081b_eval/doc/index.rst

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+.. _stm32g081b_eval_board:
+
+ST STM32G081B Evaluation
+########################
+
+Overview
+********
+The STM32G081B-EVAL Evaluation board is a high-end development platform, for
+Arm Cortex-M0+ core-based STM32G081RBT6 microcontroller, with USB Type-C and
+power delivery controller interfaces (UCPD), compliant with USB type-C r1.2
+and USB PD specification r3.0, two I2Cs, two SPIs, five USARTs, one LP UART,
+one 12-bit ADC, two 12-bit DACs, two GP comparators, two LP timers, internal
+32 KB SRAM and 128 KB Flash, CEC, SWD debugging support. The full range of
+hardware features on the STM32G081B-EVAL Evaluation board includes a mother
+board, a legacy peripheral daughterboard and a USB-C and Power Delivery
+daughterboard, which help to evaluate all peripherals (USB Type-C connector
+with USB PD, motor control connector, RS232, RS485, Audio DAC, microphone ADC,
+TFT LCD, IrDA, IR LED, IR receiver, LDR, MicroSD card, CEC on two HDMI
+connectors, smart card slot, RF E2PROM & Temperature sensor…), and to develop
+applications.
+
+The board integrates an ST-LINK/V2-1 as an embedded in-circuit debugger and
+programmer for the STM32 MCU. The daughterboard and extension connectors
+provide an easy way to connect a daughterboard or wrapping board for the
+user's specific applications.
+
+The USB-C and Power Delivery daughterboard
+features two independent USB-C ports controlled by an STM32G0. USB-C port 1
+is dual role power (DRP) and can provide up-to 45 W. USB-C Port 2 is sink
+only. Both support USB PD protocol and alternate mode functionality.
+
+Application firmware examples are provided to evaluate the USB-C technology
+through various use cases.
+
+
+
+- Mother board
+    - STM32G081RBT6 microcontroller with 128 Kbytes of Flash memory and
+      32 Kbytes of RAM in LQFP64 package
+    - MCU voltage choice fixed 3.3 V or adjustable from 1.65 V to 3.6 V
+    - I2C compatible serial interface
+    - RTC with backup battery
+    - 8-Gbyte or more SPI interface microSD card
+    - Potentiometer
+    - 4 color user LEDs and one LED as MCU low-power alarm
+    - Reset, Tamper and User buttons
+    - 4-direction control and selection joystick
+    - Board connectors:
+        - 5 V power jack
+        - RS-232 and RS485 communications
+        - Stereo audio jack including analog microphone input
+        - microSD card
+        - Extension I2C connector
+        - Motor-control connector
+    - Board extension connectors:
+        - Daughterboard connectors for legacy peripheral daughter board or
+          USB-C daughterboard
+        - Extension connectors for daughterboard or wire-wrap board
+    - Flexible power-supply options:
+        - 5 V power jack
+        - ST-LINK/V2-1 USB connector
+        - Daughterboard
+    - On-board ST-LINK/V2-1 debugger/programmer with USB re-enumeration
+      capability: mass storage, virtual COM port and debug port
+    - Legacy peripheral daughterboard
+        - IrDA transceiver
+        - IR LED and IR receiver
+        - Light dependent resistor (LDR)
+        - Temperature Sensor
+        - Board connectors:
+            - Two HDMI connectors with DDC and CEC
+            - Smart card slot
+    - USB-C and Power Delivery daughterboard
+        - Mux for USB3.1 Gen1 / DisplayPort input and Type-C port1 output
+        - Mux for Type-C port2 input and DisplayPort output / USB2.0
+        - VCONN on Type-C port1
+        - USB PD on Type-C port1
+        - Board connectors:
+            - Type-C port1 DRP (dual-role port)
+            - Type-C port2 Sink
+            - DisplayPort input
+            - DisplayPort output
+            - USB 3.1 Gen1 Type-B receptacle
+            - USB2.0 Type-A receptacle
+            - 19 V power jack for USB PD
+
+.. image:: img/stm32g081b_eval.jpg
+   :width: 426px
+   :height: 597px
+   :align: center
+   :alt: STM32G081B-EVAL
+
+More information about the board can be found at the `STM32G081B-EVAL website`_.
+
+
+More information about STM32G081RB can be found here:
+- `G081RB on www.st.com`_
+- `STM32G081 reference manual`_
+
+
+Supported Features
+==================
+
+The Zephyr stm32g081b_eval 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               |
++-----------+------------+-------------------------------------+
+| GPIO      | on-chip    | gpio                                |
++-----------+------------+-------------------------------------+
+| WATCHDOG  | on-chip    | independent watchdog                |
++-----------+------------+-------------------------------------+
+
+Other hardware features are not yet supported in this Zephyr port.
+
+The default configuration can be found in the defconfig file:
+``boards/arm/stm32g081b_eval/stm32g081b_eval_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_3 TX/RX       : PC10/PC11 (ST-Link Virtual Port Com)
+- BUTTON (JOY_SEL)   : PA0
+- BUTTON (JOY_LEFT)  : PC8
+- BUTTON (JOY_DOWN)  : PC3
+- BUTTON (JOY_RIGHT) : PC7
+- BUTTON (JOY_UP)    : PC2
+- LED1        : PD5
+- LED2        : PD6
+- LED3        : PD8
+- LED4        : PD9
+
+For mode details please refer to `STM32G0 Evaluation board User Manual`_.
+
+Programming and Debugging
+*************************
+
+Applications for the ``stm32g081b_eval`` board configuration can be built and
+flashed in the usual way (see :ref:`build_an_application` and
+:ref:`application_run` for more details).
+
+Flashing
+========
+
+The STM32G081B Evaluation board includes an ST-LINK/V2-1 embedded debug tool interface.
+
+.. code-block:: console
+
+   $ west flash
+
+Flashing an application to the STM32G081B_EVAL
+----------------------------------------------
+
+Here is an example for the :ref:`blinky-sample` application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/basic/blinky
+   :board: stm32g081b_eval
+   :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: stm32g081b_eval
+   :maybe-skip-config:
+   :goals: debug
+
+References
+**********
+
+.. target-notes::
+
+.. _STM32G081B-EVAL website:
+   https://www.st.com/en/evaluation-tools/stm32g081b-eval.html
+
+.. _STM32G081 reference manual:
+   https://www.st.com/resource/en/reference_manual/rm0444-stm32g0x1-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
+
+.. _STM32G0 Evaluation board User Manual:
+   https://www.st.com/resource/en/user_manual/um2403-evaluation-board-with-stm32g081rb-mcu-stmicroelectronics.pdf
+
+.. _G081RB on www.st.com:
+   http://www.st.com/en/microcontrollers/stm32g081rb.html

boards/arm/stm32g081b_eval/stm32g081b_eval.dts

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+/*
+ * Copyright 2021 The Chromium OS Authors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+#include <st/g0/stm32g081Xb.dtsi>
+#include <st/g0/stm32g081rbtx-pinctrl.dtsi>
+
+/ {
+	model = "STM32G081B EVAL board";
+	compatible = "st,stm32g081-eval";
+
+	chosen {
+		zephyr,console = &usart3;
+		zephyr,shell-uart = &usart3;
+		zephyr,sram = &sram0;
+		zephyr,flash = &flash0;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+		led_1: led1 {
+			gpios = <&gpiod 5 GPIO_ACTIVE_HIGH>;
+			label = "LED1";
+		};
+		led_2: led2 {
+			gpios = <&gpiod 6 GPIO_ACTIVE_HIGH>;
+			label = "LED2";
+		};
+		led_3: led3 {
+			gpios = <&gpiod 8 GPIO_ACTIVE_HIGH>;
+			label = "LED3";
+		};
+		led_4: led4 {
+			gpios = <&gpiod 9 GPIO_ACTIVE_HIGH>;
+			label = "LED4";
+		};
+	};
+
+	gpio_keys {
+		compatible = "gpio-keys";
+		joy_sel: button0 {
+			label = "JOY_SEL";
+			gpios = <&gpioa 0 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
+		};
+		joy_left: button1 {
+			label = "JOY_LEFT";
+			gpios = <&gpioc 8 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
+		};
+		joy_down: button2 {
+			label = "JOY_DOWN";
+			gpios = <&gpioc 3 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
+		};
+		joy_right: button3 {
+			label = "JOY_RIGHT";
+			gpios = <&gpioc 7 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
+		};
+		joy_up: button4 {
+			label = "JOY_UP";
+			gpios = <&gpioc 2 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
+		};
+	};
+
+	aliases {
+		led0 = &led_1;
+		led1 = &led_2;
+		led2 = &led_3;
+		led3 = &led_4;
+		sw0 = &joy_sel;
+		sw1 = &joy_left;
+		sw2 = &joy_down;
+		sw3 = &joy_right;
+		sw4 = &joy_up;
+	};
+};
+
+&clk_hsi {
+	status = "okay";
+};
+
+&pll {
+	div-m = <1>;
+	mul-n = <8>;
+	div-p = <2>;
+	div-q = <2>;
+	div-r = <2>;
+	clocks = <&clk_hsi>;
+	status = "okay";
+};
+
+&rcc {
+	clocks = <&pll>;
+	clock-frequency = <DT_FREQ_M(64)>;
+	ahb-prescaler = <1>;
+	apb1-prescaler = <1>;
+};
+
+&usart3 {
+	pinctrl-0 = <&usart3_tx_pc10 &usart3_rx_pc11>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};
+
+&iwdg {
+	status = "okay";
+};

boards/arm/stm32g081b_eval/stm32g081b_eval.yaml

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+identifier: stm32g081b_eval
+name: ST STM32G081B Evaluation
+type: mcu
+arch: arm
+toolchain:
+  - zephyr
+  - gnuarmemb
+  - xtools
+ram: 32
+flash: 128
+supported:
+  - uart
+  - gpio
+  - watchdog

boards/arm/stm32g081b_eval/stm32g081b_eval_defconfig

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+# Copyright 2021 The Chromium OS Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_SOC_SERIES_STM32G0X=y
+CONFIG_SOC_STM32G081XX=y
+
+# 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