boards: adafruit: add initial support for feather m4 express

The Adafruit Feather M4 Express is a compact, lightweight
ARM development board with an onboard mini NeoPixel, 2 MiB
of SPI flash, charging status indicator and user LEDs, USB
connector, 21 GPIO pins and a small prototyping area.

Signed-off-by: Teresa Zepeda Ventura <teresa.zvent@gmail.com>

boards/adafruit/feather_m4_express/Kconfig.adafruit_feather_m4_express

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+# Copyright (c) 2024 Daikin Comfort Technologies North America, Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_ADAFRUIT_FEATHER_M4_EXPRESS
+	select SOC_SAMD51J19A

boards/adafruit/feather_m4_express/adafruit_feather_m4_express-pinctrl.dtsi

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+/*
+ * Copyright (c) 2022, Gerson Fernando Budke <nandojve@gmail.com>
+ * Copyright (c) 2024 Daikin Comfort Technologies North America, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <dt-bindings/pinctrl/samd51j-pinctrl.h>
+
+&pinctrl {
+	sercom1_spi_default: sercom1_spi_default {
+		group1 {
+			pinmux = <PB23C_SERCOM1_PAD3>,
+				 <PA17C_SERCOM1_PAD1>,
+				 <PB22C_SERCOM1_PAD2>;
+		};
+	};
+
+	sercom2_i2c_default: sercom3_i2c_default {
+		group1 {
+			pinmux = <PA12C_SERCOM2_PAD0>,
+				 <PA13C_SERCOM2_PAD1>;
+		};
+	};
+
+	sercom5_uart_default: sercom5_uart_default {
+		group1 {
+			pinmux = <PB17C_SERCOM5_PAD1>,
+				 <PB16C_SERCOM5_PAD0>;
+		};
+	};
+
+	pwm0_default: pwm0_default {
+		group1 {
+			pinmux = <PA22G_TCC0_WO2>;
+		};
+	};
+	pwm1_default: pwm1_default {
+		group1 {
+			pinmux = <PA18F_TCC1_WO2>,
+				 <PA19F_TCC1_WO3>;
+		};
+	};
+
+	usb_dc_default: usb_dc_default {
+		group1 {
+			pinmux = <PA25H_USB_DP>,
+				 <PA24H_USB_DM>;
+		};
+	};
+};

boards/adafruit/feather_m4_express/adafruit_feather_m4_express.dts

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+/*
+ * Copyright (c) 2020 Google LLC.
+ * Copyright (c) 2024 Daikin Comfort Technologies North America, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+#include <atmel/samd5xx19.dtsi>
+#include "adafruit_feather_m4_express-pinctrl.dtsi"
+
+/ {
+	model = "Adafruit Feather M4 Express";
+	compatible = "adafruit,feather-m4-express";
+
+	chosen {
+		zephyr,console = &sercom5;
+		zephyr,shell-uart = &sercom5;
+		zephyr,sram = &sram0;
+		zephyr,flash = &flash0;
+		zephyr,code-partition = &code_partition;
+	};
+
+	/* These aliases are provided for compatibility with samples */
+	aliases {
+		led0 = &led0;
+		pwm-0 = &tcc0;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+		led0: led_0 {
+			gpios = <&porta 23 0>;
+			label = "LED";
+		};
+	};
+};
+
+&cpu0 {
+	clock-frequency = <120000000>;
+};
+
+&sercom5 {
+	status = "okay";
+	compatible = "atmel,sam0-uart";
+	current-speed = <115200>;
+	rxpo = <1>;
+	txpo = <0>;
+	pinctrl-0 = <&sercom5_uart_default>;
+	pinctrl-names = "default";
+};
+
+&sercom1 {
+	status = "okay";
+	compatible = "atmel,sam0-spi";
+	dipo = <3>;
+	dopo = <0>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	pinctrl-0 = <&sercom1_spi_default>;
+	pinctrl-names = "default";
+};
+
+&tcc0 {
+	status = "okay";
+	compatible = "atmel,sam0-tcc-pwm";
+	prescaler = <8>;
+	#pwm-cells = <2>;
+	pinctrl-0 = <&pwm0_default>;
+	pinctrl-names = "default";
+};
+
+zephyr_udc0: &usb0 {
+	status = "okay";
+	pinctrl-0 = <&usb_dc_default>;
+	pinctrl-names = "default";
+};
+
+&dmac {
+	status = "okay";
+};
+
+&flash0 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		boot_partition: partition@0 {
+			label = "uf2";
+			reg = <0x00000000 DT_SIZE_K(16)>;
+			read-only;
+		};
+
+		code_partition: partition@4000 {
+			label = "code";
+			reg = <0x4000 DT_SIZE_K(512-16-16)>;
+			read-only;
+		};
+
+		/*
+		 * The final 16 KiB is reserved for the application.
+		 * Storage partition will be used by FCB/LittleFS/NVS
+		 * if enabled.
+		 */
+		storage_partition: partition@7c000 {
+			label = "storage";
+			reg = <0x7c000 DT_SIZE_K(16)>;
+		};
+	};
+};

boards/adafruit/feather_m4_express/adafruit_feather_m4_express.yaml

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+identifier: adafruit_feather_m4_express
+name: Adafruit Feather M4 Express
+type: mcu
+arch: arm
+ram: 192
+flash: 512
+toolchain:
+  - zephyr
+  - gnuarmemb
+  - xtools
+supported:
+  - dma
+  - gpio
+  - hwinfo
+  - pwm
+  - spi
+  - uart
+  - usb_device
+  - watchdog
+vendor: adafruit

boards/adafruit/feather_m4_express/adafruit_feather_m4_express_defconfig

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+# Copyright (c) 2024 Daikin Comfort Technologies North America, Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_SOC_ATMEL_SAMD5X_OSCULP32K_AS_MAIN=y
+
+CONFIG_BOOTLOADER_BOSSA=y
+CONFIG_BOOTLOADER_BOSSA_ADAFRUIT_UF2=y
+CONFIG_BUILD_OUTPUT_HEX=y
+CONFIG_BUILD_OUTPUT_UF2=y
+
+CONFIG_ARM_MPU=y
+CONFIG_HW_STACK_PROTECTION=y
+
+CONFIG_CONSOLE=y
+CONFIG_SERIAL=y
+CONFIG_UART_CONSOLE=y
+CONFIG_UART_INTERRUPT_DRIVEN=y

boards/adafruit/feather_m4_express/board.cmake

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+# Copyright (c) 2020 Google LLC.
+# SPDX-License-Identifier: Apache-2.0
+
+include(${ZEPHYR_BASE}/boards/common/bossac.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/openocd.board.cmake)

boards/adafruit/feather_m4_express/board.yml

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+board:
+  name: adafruit_feather_m4_express
+  full_name: Feather M4 Express
+  vendor: adafruit
+  socs:
+    - name: samd51j19a

boards/adafruit/feather_m4_express/doc/index.rst

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+.. zephyr:board:: adafruit_feather_m4_express
+
+Overview
+********
+
+The Adafruit Feather M4 Express is a compact, lightweight
+ARM development board with an onboard mini NeoPixel, 2 MiB
+of SPI flash, charging status indicator and user LEDs, USB
+connector, 21 GPIO pins and a small prototyping area.
+
+Hardware
+********
+
+- ATSAMD51J19A ARM Cortex-M4 processor at 120 MHz
+- 512 KiB of flash memory and 192 KiB of RAM
+- 2 MiB of SPI flash
+- Internal trimmed 8 MHz oscillator
+- A user LED
+- An RGB NeoPixel LED
+- Native USB port
+- One reset button
+
+Supported Features
+==================
+
+The ``adafruit_feather_m4_express`` board target supports the following
+hardware features:
+
++-----------+------------+------------------------------------------+
+| Interface | Controller | Driver/Component                         |
++===========+============+==========================================+
+| SYSTICK   | on-chip    | systick                                  |
++-----------+------------+------------------------------------------+
+| WDT       | on-chip    | Watchdog                                 |
++-----------+------------+------------------------------------------+
+| GPIO      | on-chip    | I/O ports                                |
++-----------+------------+------------------------------------------+
+| USART     | on-chip    | Serial ports                             |
++-----------+------------+------------------------------------------+
+| SPI       | on-chip    | Serial Peripheral Interface ports        |
++-----------+------------+------------------------------------------+
+| TRNG      | on-chip    | True Random Number Generator             |
++-----------+------------+------------------------------------------+
+| HWINFO    | on-chip    | Unique 128 bit serial number             |
++-----------+------------+------------------------------------------+
+| RTC       | on-chip    | Real-Time Counter                        |
++-----------+------------+------------------------------------------+
+| USB       | on-chip    | USB device                               |
++-----------+------------+------------------------------------------+
+| WDT       | on-chip    | Watchdog Timer                           |
++-----------+------------+------------------------------------------+
+| PWM       | on-chip    | PWM                                      |
++-----------+------------+------------------------------------------+
+
+Other hardware features are not currently supported by Zephyr.
+
+The default configuration can be found in the Kconfig file
+:zephyr_file:`boards/adafruit/feather_m4_express/adafruit_feather_m4_express_defconfig`.
+
+Zephyr can use the default Cortex-M SYSTICK timer or the SAM0 specific RTC.
+To use the RTC, set :code:`CONFIG_CORTEX_M_SYSTICK=n` and set
+:code:`CONFIG_SYS_CLOCK_TICKS_PER_SEC` to no more than 32 kHZ divided by 7,
+i.e. no more than 4500.
+
+Connections and IOs
+===================
+
+The `Adafruit Learning System`_ has detailed information about
+the board including `pinouts`_ and the `schematic`_.
+
+System Clock
+============
+
+The SAMD51 MCU is configured to use the 32 kHz internal oscillator
+with the on-chip PLL generating the 120 MHz system clock.
+
+Serial Port
+===========
+
+The SAMD51 MCU has 6 SERCOM based USARTs.  On the Feather, SERCOM5 is
+the Zephyr console and is available on pins 0 (RX) and 1 (TX).
+
+SPI Port
+========
+
+The SAMD51 MCU has 6 SERCOM based SPIs. On the Feather, SERCOM1 can be put
+into SPI mode and used to connect to devices over the SCK (SCLK), MO (MOSI), and
+MI (MISO) pins.
+
+PWM
+===
+
+The SAMD51 has three PWM generators with up to six channels each.  :code:`TCC_0`
+has a resolution of 24 bits and all other generators are 16 bit.  :code:`TCC_1`
+pin 2 is mapped to PA18 (D7) and pin 3 is mapped to PA19 (D9).
+
+USB Device Port
+===============
+
+The SAMD51 MCU has a USB device port that can be used to communicate
+with a host PC.  See the :ref:`usb` sample applications for
+more, such as the :zephyr:code-sample:`usb-cdc-acm` sample which sets up a virtual
+serial port that echos characters back to the host PC.
+
+Programming and Debugging
+*************************
+
+The Feather ships with a the BOSSA compatible UF2 bootloader.  The
+bootloader can be entered by quickly tapping the reset button twice.
+
+Additionally, if :kconfig:option:`CONFIG_USB_CDC_ACM` is enabled then the
+bootloader will be entered automatically when you run :code:`west flash`.
+
+Flashing
+========
+
+#. Build the Zephyr kernel and the :zephyr:code-sample:`hello_world` sample application:
+
+   .. zephyr-app-commands::
+      :zephyr-app: samples/hello_world
+      :board: adafruit_feather_m4_express
+      :goals: build
+      :compact:
+
+#. Connect the feather to your host computer using USB
+
+#. Connect a 3.3 V USB to serial adapter to the board and to the
+   host.  See the `Serial Port`_ section above for the board's pin
+   connections.
+
+#. Run your favorite terminal program to listen for output. Under Linux the
+   terminal should be :code:`/dev/ttyUSB0`. For example:
+
+   .. code-block:: console
+
+      $ minicom -D /dev/ttyUSB0 -o
+
+   The -o option tells minicom not to send the modem initialization
+   string. Connection should be configured as follows:
+
+   - Speed: 115200
+   - Data: 8 bits
+   - Parity: None
+   - Stop bits: 1
+
+#. Tap the reset button twice quickly to enter bootloader mode
+
+#. Flash the image:
+
+   .. zephyr-app-commands::
+      :zephyr-app: samples/hello_world
+      :board: adafruit_feather_m4_express
+      :goals: flash
+      :compact:
+
+   You should see "Hello World! adafruit_feather_m4_express" in your terminal.
+
+Debugging
+=========
+
+In addition to the built-in bootloader, the Feather can be flashed and
+debugged using a SWD probe such as the Segger J-Link.
+
+#. Connect the board to the probe by connecting the :code:`SWCLK`,
+   :code:`SWDIO`, :code:`RESET`, :code:`GND`, and :code:`3V3` pins on the
+   Feather to the :code:`SWCLK`, :code:`SWDIO`, :code:`RESET`, :code:`GND`,
+   and :code:`VTref` pins on the `J-Link`_.
+
+#. Flash the image:
+
+   .. zephyr-app-commands::
+      :zephyr-app: samples/hello_world
+      :board: adafruit_feather_m4_express
+      :goals: flash
+      :flash-args: -r openocd
+      :compact:
+
+#. Start debugging:
+
+   .. zephyr-app-commands::
+      :zephyr-app: samples/hello_world
+      :board: adafruit_feather_m4_express
+      :goals: debug
+      :compact:
+
+References
+**********
+
+.. target-notes::
+
+.. _Adafruit Learning System:
+    https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51
+
+.. _pinouts:
+    https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51/pinouts
+
+.. _schematic:
+    https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51/downloads
+
+.. _J-Link:
+    https://www.segger.com/products/debug-probes/j-link/technology/interface-description/

boards/adafruit/feather_m4_express/pre_dt_board.cmake

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+# Copyright (c) 2021 Linaro Limited
+# SPDX-License-Identifier: Apache-2.0
+
+# Suppress "unique_unit_address_if_enabled" to handle the following overlaps:
+# - /soc/pinmux@41004400 & /soc/gpio@41004400
+# - /soc/pinmux@41004480 & /soc/gpio@41004480
+list(APPEND EXTRA_DTC_FLAGS "-Wno-unique_unit_address_if_enabled")

boards/adafruit/feather_m4_express/support/openocd.cfg

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+source [find interface/jlink.cfg]
+
+transport select swd
+
+set CHIPNAME atsamd51j19a
+source [find target/atsame5x.cfg]
+
+# TODO(http://openocd.zylin.com/#/c/5706/): lower the clock speed to workaround
+# an erase timeout.
+adapter_khz 500
+reset_config srst_only
+
+$_TARGETNAME configure -event gdb-attach {
+        echo "Debugger attaching: halting execution"
+        reset halt
+}
+
+$_TARGETNAME configure -event gdb-detach {
+        echo "Debugger detaching: resuming execution"
+        resume
+}