boards: gardena: Add smart garden radio module

This adds support for the SiM3U/Si4467 based SoM used on the GARDENA
smart Gateway [1] (art. no 19000 and 19005).

[1] https://github.com/husqvarnagroup/smart-garden-gateway-public

Signed-off-by: Michael Zimmermann <michael.zimmermann@grandcentrix.net>

boards/gardena/index.rst

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+.. _boards-gardena:
+
+GARDENA GmbH
+############
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

boards/gardena/sgrm/Kconfig.sgrm

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+# Copyright (c) 2024 GARDENA GmbH
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_SGRM
+	select SOC_PART_NUMBER_SIM3U167BGM

boards/gardena/sgrm/board.cmake

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+# Copyright (c) 2024 GARDENA GmbH
+#
+# SPDX-License-Identifier: Apache-2.0
+
+include(${ZEPHYR_BASE}/boards/common/openocd.board.cmake)
+
+board_runner_args(jlink "--device=SiM3U167")
+include(${ZEPHYR_BASE}/boards/common/jlink.board.cmake)

boards/gardena/sgrm/board.yml

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+# Copyright (c) 2024 GARDENA GmbH
+#
+# SPDX-License-Identifier: Apache-2.0
+
+board:
+  name: sgrm
+  full_name: Smart Garden Radio Module
+  vendor: gardena
+  socs:
+    - name: sim3u167

boards/gardena/sgrm/doc/index.rst

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+.. _gardena_sgrm:
+
+GARDENA Smart Garden Radio Module
+#################################
+
+Overview
+********
+
+This is a SoM that is used as a radio module by the GARDENA smart gateway (manual_, `FOSS parts`_).
+
+.. figure:: sgrm.webp
+   :align: center
+   :alt: GARDENA smart Gateway with radio module
+
+
+.. _manual: https://www.gardena.com/tdrdownload//pub000070911/doc000120830
+.. _FOSS parts: https://github.com/husqvarnagroup/smart-garden-gateway-public
+
+Hardware
+********
+
+- Silicon Labs SiM3U167-B-GM_ SoC
+- Silicon Labs Si4467_ transceiver (via SPI)
+- Controls an RGB LED via high drive pins. It's expected to mirror the state of 3 low-drive pins
+  coming from the Linux SoC.
+- UART is connected to the Linux SoC. Usually it's used for PPP, but it can also be used for
+  debugging when PPP is not active.
+
+.. _SiM3U167-B-GM: https://www.silabs.com/mcu/32-bit-microcontrollers/precision32-sim3u1xx/device.SiM3U167-B-GQ?tab=specs
+.. _Si4467: https://www.silabs.com/wireless/proprietary/ezradiopro-sub-ghz-ics/device.si4467?tab=specs
+
+Supported Features
+==================
+
+The ``sgrm`` board target supports the following hardware features:
+
++-----------+------------+-------------------------------------+
+| Interface | Controller | Driver/Component                    |
++===========+============+=====================================+
+| NVIC      | on-chip    | nested vector interrupt controller  |
++-----------+------------+-------------------------------------+
+| SYSTICK   | on-chip    | systick                             |
++-----------+------------+-------------------------------------+
+| DMA       | on-chip    | dma                                 |
++-----------+------------+-------------------------------------+
+| FLASH     | on-chip    | flash memory                        |
++-----------+------------+-------------------------------------+
+| GPIO      | on-chip    | gpio                                |
++-----------+------------+-------------------------------------+
+| UART      | on-chip    | serial port-polling;                |
+|           |            | serial port-interrupt               |
++-----------+------------+-------------------------------------+
+
+Connections and IOs
+===================
+
++--------+--------------------------+----------------------------------------------------+
+| Pin    | Name                     | Note                                               |
++========+==========================+====================================================+
+| PB0.0  | TX (O)                   | Serial connection to the Linux SoM                 |
++--------+--------------------------+                                                    |
+| PB0.1  | RX (I)                   |                                                    |
++--------+--------------------------+                                                    |
+| PB0.2  | RTS (O)                  |                                                    |
++--------+--------------------------+                                                    |
+| PB0.3  | CTS (I)                  |                                                    |
++--------+--------------------------+----------------------------------------------------+
+| PB0.4  | LED red (I)              | Controlled by the Linux SoM                        |
++--------+--------------------------+                                                    |
+| PB0.5  | LED green (I)            |                                                    |
++--------+--------------------------+                                                    |
+| PB0.6  | LED blue (I)             |                                                    |
++--------+--------------------------+----------------------------------------------------+
+| PB0.13 | TX (O)                   | UART1 for debugging (no connection to Linux SoM)   |
++--------+--------------------------+                                                    |
+| PB0.14 | RX (I)                   |                                                    |
++--------+--------------------------+----------------------------------------------------+
+| PB4.0  | LED red (O)              | Mirrors PB0.4                                      |
++--------+--------------------------+----------------------------------------------------+
+| PB4.1  | LED green (O)            | Mirrors PB0.5                                      |
++--------+--------------------------+----------------------------------------------------+
+| PB4.2  | LED blue (O)             | Mirrors PB0.6                                      |
++--------+--------------------------+----------------------------------------------------+
+
+Programming and Debugging
+*************************
+
+Flashing
+========
+
+The easiest way is to do this via SSH from the Linux SoM that's connected to the SiM3U SoM.
+
+On your building machine:
+
+.. code-block:: shell
+
+   scp -O build/zephyr/zephyr.hex root@IP:/tmp/
+
+On the gateway:
+
+.. code-block:: shell
+
+   openocd -f board/gardena_radio.cfg -c 'program /tmp/zephyr.hex verify exit'
+   reset-rm
+
+Debugging
+=========
+
+The easiest way is to do this via SSH from the Linux gateway as well:
+
+.. code-block:: shell
+
+   openocd -f board/gardena_radio.cfg -c init

boards/gardena/sgrm/sgrm-pinctrl.dtsi

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+/*
+ * Copyright (c) 2024 GARDENA GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/pinctrl/si32-pinctrl.h>
+
+&pinctrl {
+	usart0_default: usart0_default {
+		group1 {
+			pinmux = <SI32_MUX(USART0_TX, 0, 0)>,
+				<SI32_MUX(USART0_RTS, 0, 2)>;
+			output-enable;
+		};
+		group2 {
+			pinmux = <SI32_MUX(USART0_RX, 0, 1)>,
+				<SI32_MUX(USART0_CTS, 0, 3)>;
+			input-enable;
+		};
+	};
+
+	usart1_default: usart1_default {
+		group1 {
+			pinmux = <SI32_MUX(USART1_TX, 0, 13)>;
+			output-enable;
+		};
+		group2 {
+			pinmux = <SI32_MUX(USART1_RX, 0, 14)>;
+			input-enable;
+		};
+	};
+};

boards/gardena/sgrm/sgrm.dts

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+/*
+ * Copyright (c) 2024 GARDENA GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+#include <silabs/sim3u167.dtsi>
+#include "sgrm-pinctrl.dtsi"
+
+/ {
+	model = "GARDENA Smart Garden Radio Module";
+	compatible = "gardena,sgrm-sim3u167", "silabs,sim3u167","silabs,sim3u";
+
+	chosen {
+		zephyr,console = &usart1;
+		zephyr,flash = &flash0;
+		zephyr,shell-uart = &usart1;
+		zephyr,sram = &sram0;
+		zephyr,ppp-uart = &usart0;
+	};
+};
+
+&cpu0 {
+	clock-frequency = <76953600>;
+};
+
+&pll0 {
+	status = "okay";
+};
+
+&clk_ahb {
+	clocks = <&pll0>;
+	status = "okay";
+};
+
+&clk_apb {
+	divider = <2>;
+	status = "okay";
+};
+
+&usart0 {
+	current-speed = <500000>;
+	pinctrl-0 = <&usart0_default>;
+	pinctrl-names = "default";
+	hw-flow-control;
+	status = "okay";
+};
+
+&usart1 {
+	current-speed = <115200>;
+	pinctrl-0 = <&usart1_default>;
+	pinctrl-names = "default";
+	status = "okay";
+};
+
+&gpio0 {
+	status = "okay";
+};
+
+&gpio1 {
+	status = "okay";
+};
+
+&gpio2 {
+	disable-pullups;
+	status = "okay";
+};
+
+&gpio3 {
+	status = "okay";
+};
+
+&flash0 {
+	status = "okay";
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		slot0_partition: partition@0 {
+			label = "image-0";
+			reg = <0x00000000 DT_SIZE_K(192)>;
+		};
+
+		storage_partition: partition@30000 {
+			label = "storage";
+			reg = <0x00030000 DT_SIZE_K(64)>;
+		};
+	};
+};

boards/gardena/sgrm/sgrm.yaml

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+# Copyright (c) 2024 GARDENA GmbH
+#
+# SPDX-License-Identifier: Apache-2.0
+
+identifier: sgrm
+name: GARDENA Smart Garden Radio Module
+type: mcu
+arch: arm
+ram: 32
+flash: 256
+toolchain:
+  - gnuarmemb
+  - xtools
+  - zephyr
+supported:
+  - dma
+  - flash
+  - gpio
+  - nvs
+  - uart
+vendor: gardena

boards/gardena/sgrm/sgrm_defconfig

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+# Enable UART driver
+CONFIG_SERIAL=y
+
+# Enable console
+CONFIG_CONSOLE=y
+CONFIG_UART_CONSOLE=y
+
+# Enable GPIO
+CONFIG_GPIO=y

boards/gardena/sgrm/support/openocd.cfg

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+# Copyright (c) 2024 GARDENA GmbH
+#
+# SPDX-License-Identifier: Apache-2.0
+
+source [find interface/ftdi/olimex-arm-usb-ocd-h.cfg]
+source [find interface/ftdi/olimex-arm-jtag-swd.cfg]
+
+source [find target/sim3x.cfg]
+
+# On SiM3U1xx, doing a chip reset also takes down the debug port. For this reason, we disable the
+# chip reset and instead only reset the Cortex M via the AIRCR SYSRESETREQ bit, as suggested in the
+# chip's errata:  https://www.silabs.com/documents/public/errata/SiM3U1xx-SiM3C1xxErrata.pdf
+cortex_m reset_config sysresetreq
+
+$_TARGETNAME configure -event gdb-attach {
+        echo "Debugger attaching: halting execution"
+        reset halt
+        gdb_breakpoint_override hard
+}
+
+$_TARGETNAME configure -event gdb-detach {
+        echo "Debugger detaching: resuming execution"
+        resume
+}