boards: arm: Add adafruit_kb2040 board

boards/arm/adafruit_kb2040/Kconfig.board

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+# Copyright (c) 2022 Pete Johanson
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_ADAFRUIT_KB2040
+	bool "Adafruit KB2040 Board"
+	depends on SOC_RP2040

boards/arm/adafruit_kb2040/Kconfig.defconfig

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+# Copyright (c) 2022 Peter Johanson
+# SPDX-License-Identifier: Apache-2.0
+
+if BOARD_ADAFRUIT_KB2040
+
+config BOARD
+	default "adafruit_kb2040"
+
+config RP2_FLASH_W25Q080
+	default y
+
+endif # BOARD_ADAFRUIT_KB2040

boards/arm/adafruit_kb2040/adafruit_kb2040-pinctrl.dtsi

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+/*
+ * Copyright (c) 2021, Yonatan Schachter
+ * Copyright (c) 2022, Peter Johanson
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <dt-bindings/pinctrl/rpi-pico-rp2040-pinctrl.h>
+
+&pinctrl {
+	uart0_default: uart0_default {
+		group1 {
+			pinmux = <UART0_TX_P0>;
+		};
+		group2 {
+			pinmux = <UART0_RX_P1>;
+			input-enable;
+		};
+	};
+
+	i2c1_default: i2c1_default {
+		group1 {
+			pinmux = <I2C1_SDA_P2>;
+			input-enable;
+		};
+		group2 {
+			pinmux = <I2C1_SCL_P3>;
+			input-enable;
+		};
+	};
+
+	spi0_default: spi0_default {
+		group1 {
+			pinmux = <SPI0_TX_P19>;
+		};
+		group2 {
+			pinmux = <SPI0_RX_P20>;
+			input-enable;
+		};
+		group3 {
+			pinmux = <SPI0_SCK_P18>;
+		};
+	};
+
+	adc_default: adc_default {
+		group1 {
+			pinmux = <ADC_CH0_P26>, <ADC_CH1_P27>, <ADC_CH2_P28>, <ADC_CH3_P29>;
+			input-enable;
+		};
+	};
+};

boards/arm/adafruit_kb2040/adafruit_kb2040.dts

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+/*
+ * Copyright (c) 2021 Yonatan Schachter
+ * Copyright (c) 2022 Peter Johanson
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+
+#include <rpi_pico/rp2040.dtsi>
+#include "adafruit_kb2040-pinctrl.dtsi"
+#include "sparkfun_pro_micro_connector.dtsi"
+#include <freq.h>
+
+/ {
+	chosen {
+		zephyr,sram = &sram0;
+		zephyr,flash = &flash0;
+		zephyr,console = &uart0;
+		zephyr,shell-uart = &uart0;
+		zephyr,code-partition = &code_partition;
+	};
+
+	aliases {
+		watchdog0 = &wdt0;
+	};
+
+	xtal_clk: xtal-clk {
+		compatible = "fixed-clock";
+		clock-frequency = <12000000>;
+		#clock-cells = <0>;
+	};
+};
+
+&flash0 {
+	reg = <0x10000000 DT_SIZE_M(8)>;
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		/* Reserved memory for the second stage bootloader */
+		second_stage_bootloader: partition@0 {
+			label = "second_stage_bootloader";
+			reg = <0x00000000 0x100>;
+			read-only;
+		};
+
+		/*
+		 * Usable flash. Starts at 0x100, after the bootloader. The partition
+		 * size is 8MB minus the 0x100 bytes taken by the bootloader.
+		 */
+		code_partition: partition@100 {
+			label = "code";
+			reg = <0x100 (DT_SIZE_M(8) - 0x100)>;
+			read-only;
+		};
+	};
+};
+
+&uart0 {
+	current-speed = <115200>;
+	status = "okay";
+	pinctrl-0 = <&uart0_default>;
+	pinctrl-names = "default";
+};
+
+&spi0 {
+	status = "okay";
+	pinctrl-0 = <&spi0_default>;
+	pinctrl-names = "default";
+	clock-frequency = <DT_FREQ_M(8)>;
+};
+
+&i2c1 {
+	status = "okay";
+	pinctrl-0 = <&i2c1_default>;
+	pinctrl-names = "default";
+	clock-frequency = <I2C_BITRATE_FAST>;
+};
+
+&gpio0 {
+	status = "okay";
+};
+
+&wdt0 {
+	status = "okay";
+};
+
+&adc {
+	status = "okay";
+	pinctrl-0 = <&adc_default>;
+	pinctrl-names = "default";
+};
+
+zephyr_udc0: &usbd {
+	status = "okay";
+};

boards/arm/adafruit_kb2040/adafruit_kb2040.yaml

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+identifier: adafruit_kb2040
+name: Adafruit KB2040
+type: mcu
+arch: arm
+flash: 8192
+ram: 264
+toolchain:
+  - zephyr
+  - gnuarmemb
+  - xtools
+supported:
+  - uart
+  - gpio
+  - adc
+  - i2c
+  - spi
+  - hwinfo
+  - watchdog
+  - pwm

boards/arm/adafruit_kb2040/adafruit_kb2040_defconfig

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+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_SOC_SERIES_RP2XXX=y
+CONFIG_SOC_RP2040=y
+CONFIG_BOARD_ADAFRUIT_KB2040=y
+
+CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=125000000
+
+# enable uart driver
+CONFIG_SERIAL=y
+CONFIG_UART_INTERRUPT_DRIVEN=y
+
+# enable console
+CONFIG_CONSOLE=y
+CONFIG_UART_CONSOLE=y
+
+# Enable reset by default
+CONFIG_RESET=y
+
+# Code partition needed to target the correct flash range
+CONFIG_USE_DT_CODE_PARTITION=y
+
+# Output UF2 by default, native bootloader supports it.
+CONFIG_BUILD_OUTPUT_UF2=y

boards/arm/adafruit_kb2040/doc/index.rst

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+.. _adafruit_kb2040:
+
+Adafruit KB2040
+###############
+
+Overview
+********
+
+The Adafruit KB2040 is a small, low-cost, versatile board from
+Adafruit. It is equipped with an RP2040 SoC, an on-board RGB Neopixel,
+a USB connector, and a STEMMA QT connector. The USB bootloader allows
+it to be flashed without any adapter, in a drag-and-drop manner.
+
+Hardware
+********
+- Dual core Arm Cortex-M0+ processor running up to 133MHz
+- 264KB on-chip SRAM
+- 8MB on-board QSPI flash with XIP capabilities
+- 18 GPIO pins
+- 4 Analog inputs
+- 1 UART peripherals
+- 1 SPI controllers
+- 2 I2C controllers (one via STEMMA QT connector)
+- 16 PWM channels
+- USB 1.1 controller (host/device)
+- 8 Programmable I/O (PIO) for custom peripherals
+- On-board RGB LED
+- 1 Watchdog timer peripheral
+
+
+.. figure:: img/kb2040.jpg
+     :align: center
+     :alt: Adafruit KB2040
+
+     Adafruit KB2040 (Image courtesy of Adafruit)
+
+Supported Features
+==================
+
+The adafruit_kb2040 board configuration supports the following
+hardware features:
+
+.. list-table::
+   :header-rows: 1
+
+   * - Peripheral
+     - Kconfig option
+     - Devicetree compatible
+   * - NVIC
+     - N/A
+     - :dtcompatible:`arm,v6m-nvic`
+   * - UART
+     - :kconfig:option:`CONFIG_SERIAL`
+     - :dtcompatible:`raspberrypi,pico-uart`
+   * - GPIO
+     - :kconfig:option:`CONFIG_GPIO`
+     - :dtcompatible:`raspberrypi,pico-gpio`
+   * - ADC
+     - :kconfig:option:`CONFIG_ADC`
+     - :dtcompatible:`raspberrypi,pico-adc`
+   * - I2C
+     - :kconfig:option:`CONFIG_I2C`
+     - :dtcompatible:`snps,designware-i2c`
+   * - SPI
+     - :kconfig:option:`CONFIG_SPI`
+     - :dtcompatible:`raspberrypi,pico-spi`
+   * - USB Device
+     - :kconfig:option:`CONFIG_USB_DEVICE_STACK`
+     - :dtcompatible:`raspberrypi,pico-usbd`
+   * - HWINFO
+     - :kconfig:option:`CONFIG_HWINFO`
+     - N/A
+   * - Watchdog Timer (WDT)
+     - :kconfig:option:`CONFIG_WATCHDOG`
+     - :dtcompatible:`raspberrypi,pico-watchdog`
+   * - PWM
+     - :kconfig:option:`CONFIG_PWM`
+     - :dtcompatible:`raspberrypi,pico-pwm`
+
+Pin Mapping
+===========
+
+The peripherals of the RP2040 SoC can be routed to various pins on the board.
+The configuration of these routes can be modified through DTS. Please refer to
+the datasheet to see the possible routings for each peripheral.
+
+Default Zephyr Peripheral Mapping:
+----------------------------------
+
+.. rst-class:: rst-columns
+
+- UART0_TX : P0
+- UART0_RX : P1
+- I2C1_SDA : P2
+- I2C1_SCL : P3
+- SPI0_RX : P20
+- SPI0_SCK : P18
+- SPI0_TX : P19
+
+Programming and Debugging
+*************************
+
+Flashing
+========
+
+Using UF2
+---------
+
+Since it doesn't expose the SWD pins, you must flash the Adafruit KB2040 with
+a UF2 file. By default, building an app for this board will generate a
+`build/zephyr/zephyr.uf2` file. If the KB2040 is powered on with the `BOOTSEL`
+button pressed, it will appear on the host as a mass storage device. The
+UF2 file should be drag-and-dropped to the device, which will flash the KB2040.
+
+.. target-notes::
+
+.. _Getting Started with Raspberry Pi Pico:
+  https://datasheets.raspberrypi.com/pico/getting-started-with-pico.pdf
+
+.. _Primary Guide\: Adafruit KB2040:
+  https://learn.adafruit.com/adafruit-kb2040

boards/arm/adafruit_kb2040/sparkfun_pro_micro_connector.dtsi

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+/*
+ * Copyright (c) 2020 Pete Johanson
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/ {
+	pro_micro: connector {
+		compatible = "sparkfun,pro-micro";
+		#gpio-cells = <2>;
+		gpio-map-mask = <0xffffffff 0xffffffc0>;
+		gpio-map-pass-thru = <0 0x3f>;
+		gpio-map
+			= <0 0 &gpio0 0 0>		/* D0 */
+			, <1 0 &gpio0 1 0>		/* D1 */
+			, <2 0 &gpio0 2 0>		/* D2 */
+			, <3 0 &gpio0 3 0>		/* D3 */
+			, <4 0 &gpio0 4 0>		/* D4/A6 */
+			, <5 0 &gpio0 5 0>		/* D5 */
+			, <6 0 &gpio0 6 0>		/* D6/A7 */
+			, <7 0 &gpio0 7 0>		/* D7 */
+			, <8 0 &gpio0 8 0>		/* D8/A8 */
+			, <9 0 &gpio0 9 0>		/* D9/A9 */
+			, <10 0 &gpio0 10 0>		/* D10/A10 */
+			, <16 0 &gpio0 19 0>	/* D16 */
+			, <14 0 &gpio0 20 0>	/* D14 */
+			, <15 0 &gpio0 18 0>	/* D15 */
+			, <18 0 &gpio0 26 0>	/* D18/A0 */
+			, <19 0 &gpio0 27 0>	/* D19/A1 */
+			, <20 0 &gpio0 28 0>	/* D20/A2 */
+			, <21 0 &gpio0 29 0>	/* D21/A3 */
+			;
+	};
+
+};
+
+pro_micro_i2c: &i2c1 {};
+pro_micro_spi: &spi0 {};
+pro_micro_serial: &uart0 {};