boards: Add initial support for the Raspberry Pi Pico 2

The Raspberry Pi Pico 2 is Raspberry Pi's first board fitted with their
RP2350 SoC.

This adds a minimal board definition, sufficient to build and run
`samples/hello_world` and `samples/basic/blinky` on the board. Images
can be run on the target using either OpenOCD. Raspberry Pi's `picotool`
can create a UF2 binary, which ensures that errata RP2350-E10 is avoided
e.g.

```
> picotool uf2 convert build\rpi_pico_2\hello_world\zephyr\zephyr.elf \
    build\rpi_pico_2\hello_world\zephyr\zephyr.uf2 \
    --family rp2350-arm-s --abs-block`
```

Raspberry Pi Pico 2 is a low-cost, high-performance microcontroller
board with flexible digital interfaces. Key features include:

- RP2350 microcontroller chip designed by Raspberry Pi in the United
  Kingdom
- Dual Cortex-M33 or Hazard3 processors at up to 150MHz
- 520KB of SRAM, and 4MB of on-board flash memory
- USB 1.1 with device and host support
- Low-power sleep and dormant modes
- Drag-and-drop programming using mass storage over USB
- 26x multi-function GPIO pins including 3 that can be used for ADC
- 2x SPI, 2x I2C, 2x UART, 3x 12-bit 500ksps Analogue to Digital
  Converter (ADC), 24x controllable PWM channels
- 2x Timer with 4 alarms, 1x AON Timer
- Temperature sensor
- 3x Programmable IO (PIO) blocks, 12 state machines total for custom
  peripheral support
    - Flexible, user-programmable high-speed IO
    - Can emulate interfaces such as SD Card and VGA

The Raspberry Pi Pico 2 comes as a castellated module which allows
soldering direct to carrier boards.

Signed-off-by: Andrew Featherstone <andrew.featherstone@gmail.com>

boards/raspberrypi/rpi_pico_2/Kconfig.defconfig

@@ -0,0 +1,9 @@
+# Copyright (c) 2024 Andrew Featherstone
+# SPDX-License-Identifier: Apache-2.0
+
+if BOARD_RPI_PICO_2
+
+config USB_SELF_POWERED
+	default n
+
+endif # BOARD_RPI_PICO_2

boards/raspberrypi/rpi_pico_2/Kconfig.rpi_pico_2

@@ -0,0 +1,5 @@
+# Copyright (c) 2024 Andrew Featherstone
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_RPI_PICO_2
+	select SOC_RP2350

boards/raspberrypi/rpi_pico_2/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: rpi_pico_2
+  vendor: raspberrypi
+  socs:
+  - name: rp2350

boards/raspberrypi/rpi_pico_2/rpi_pico_2-common.dtsi

@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2024 Andrew Featherstone
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <freq.h>
+
+#include <raspberrypi/rpi_pico/rp2350.dtsi>
+#include "rpi_pico_2-pinctrl.dtsi"
+#include <zephyr/dt-bindings/pwm/pwm.h>
+
+#include <zephyr/dt-bindings/i2c/i2c.h>
+
+
+/ {
+	chosen {
+		zephyr,sram = &sram0;
+		zephyr,flash = &flash0;
+		zephyr,console = &uart0;
+		zephyr,shell-uart = &uart0;
+		zephyr,code-partition = &code_partition;
+	};
+
+	aliases {
+	};
+
+	pico_header: connector {
+		compatible = "raspberrypi,pico-header";
+		#gpio-cells = <2>;
+		gpio-map-mask = <0xffffffff 0xffffffc0>;
+		gpio-map-pass-thru = <0 0x3f>;
+		gpio-map = <0 0 &gpio0 0 0>,	/* GP0 */
+			<1 0 &gpio0 1 0>,	/* GP1 */
+			<2 0 &gpio0 2 0>,	/* GP2 */
+			<3 0 &gpio0 3 0>,	/* GP3 */
+			<4 0 &gpio0 4 0>,	/* GP4 */
+			<5 0 &gpio0 5 0>,	/* GP5 */
+			<6 0 &gpio0 6 0>,	/* GP6 */
+			<7 0 &gpio0 7 0>,	/* GP7 */
+			<8 0 &gpio0 8 0>,	/* GP8 */
+			<9 0 &gpio0 9 0>,	/* GP9 */
+			<10 0 &gpio0 10 0>,	/* GP10 */
+			<11 0 &gpio0 11 0>,	/* GP11 */
+			<12 0 &gpio0 12 0>,	/* GP12 */
+			<13 0 &gpio0 13 0>,	/* GP13 */
+			<14 0 &gpio0 14 0>,	/* GP14 */
+			<15 0 &gpio0 15 0>,	/* GP15 */
+			<16 0 &gpio0 16 0>,	/* GP16 */
+			<17 0 &gpio0 17 0>,	/* GP17 */
+			<18 0 &gpio0 18 0>,	/* GP18 */
+			<19 0 &gpio0 19 0>,	/* GP19 */
+			<20 0 &gpio0 20 0>,	/* GP20 */
+			<21 0 &gpio0 21 0>,	/* GP21 */
+			<22 0 &gpio0 22 0>,	/* GP22 */
+			<26 0 &gpio0 26 0>,	/* GP26 */
+			<27 0 &gpio0 27 0>,	/* GP27 */
+			<28 0 &gpio0 28 0>;	/* GP28 */
+	};
+};
+
+&flash0 {
+	reg = <0x10000000 DT_SIZE_M(4)>;
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		/* Reserved memory for an image definition block. The block is much
+		 * smaller than 256 bytes, but in practice the linker places the vector
+		 * table at a much larger alignment offset.
+		 */
+		image_def: partition@0 {
+			label = "image_def";
+			reg = <0x00000000 0x100>;
+			read-only;
+		};
+
+		/*
+		 * Usable flash. Starts at 0x100, after the image definition block.
+		 * The partition size is 4MB minus the 0x100 bytes taken by the
+		 * image definition.
+		 */
+		code_partition: partition@100 {
+			label = "code-partition";
+			reg = <0x100 (DT_SIZE_M(4) - 0x100)>;
+			read-only;
+		};
+	};
+};
+
+&clocks {
+	pinctrl-0 = <&clocks_default>;
+	pinctrl-names = "default";
+};
+
+&uart0 {
+	current-speed = <115200>;
+	status = "okay";
+	pinctrl-0 = <&uart0_default>;
+	pinctrl-names = "default";
+};
+
+&gpio0 {
+	status = "okay";
+};
+
+&timer0 {
+	status = "disabled";
+};
+
+zephyr_udc0: &usbd {
+	status = "okay";
+};
+
+&pwm {
+	pinctrl-0 = <&pwm_ch4b_default>;
+	pinctrl-names = "default";
+	divider-int-0 = <255>;
+};
+
+&vreg {
+	regulator-always-on;
+	regulator-allowed-modes = <REGULATOR_RPI_PICO_MODE_NORMAL>;
+};
+
+pico_serial: &uart0 {};

boards/raspberrypi/rpi_pico_2/rpi_pico_2-pinctrl.dtsi

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2024, Andrew Featherstone
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/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;
+		};
+	};
+
+	spi0_default: spi0_default {
+		group1 {
+			pinmux = <SPI0_CSN_P17>, <SPI0_SCK_P18>, <SPI0_TX_P19>;
+		};
+		group2 {
+			pinmux = <SPI0_RX_P16>;
+			input-enable;
+		};
+	};
+
+	pwm_ch4b_default: pwm_ch4b_default {
+		group1 {
+			pinmux = <PWM_4B_P25>;
+		};
+	};
+
+	clocks_default: clocks_default {
+	};
+};

boards/raspberrypi/rpi_pico_2/rpi_pico_2.dts

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2024 Andrew Featherstone
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+
+#include "rpi_pico_2-common.dtsi"
+
+/ {
+	leds {
+		compatible = "gpio-leds";
+		led0: led_0 {
+			gpios = <&gpio0 25 GPIO_ACTIVE_HIGH>;
+			label = "LED";
+		};
+	};
+
+	pwm_leds {
+		compatible = "pwm-leds";
+		status = "disabled";
+		pwm_led0: pwm_led_0 {
+			pwms = <&pwm 9 PWM_MSEC(20) PWM_POLARITY_NORMAL>;
+			label = "PWM_LED";
+		};
+	};
+
+	aliases {
+		led0 = &led0;
+		pwm-led0 = &pwm_led0;
+	};
+};

boards/raspberrypi/rpi_pico_2/rpi_pico_2.yaml

@@ -0,0 +1,15 @@
+identifier: rpi_pico_2
+name: Raspberry Pi Pico 2
+type: mcu
+arch: arm
+flash: 4096
+ram: 520
+toolchain:
+  - zephyr
+  - gnuarmemb
+  - xtools
+supported:
+  - clock
+  - gpio
+  - hwinfo
+  - uart

boards/raspberrypi/rpi_pico_2/rpi_pico_2_defconfig

@@ -0,0 +1,9 @@
+CONFIG_CLOCK_CONTROL=y
+CONFIG_CONSOLE=y
+CONFIG_GPIO=y
+CONFIG_RESET=y
+CONFIG_SERIAL=y
+CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=150000000
+CONFIG_UART_CONSOLE=y
+CONFIG_UART_INTERRUPT_DRIVEN=y
+CONFIG_USE_DT_CODE_PARTITION=y