boards: xtensa: Add support for Lolin S2 Mini

Add support for LOLIN S2 Mini board, a cheap board
also sold as Wemos S2 Mini.

Signed-off-by: Moritz Fischer <moritzf@google.com>

boards/xtensa/esp32s2_lolin_mini/Kconfig.board

@@ -0,0 +1,8 @@
+# ESP32S2 LOLIN S2 MINI board configuration
+
+# Copyright (c) 2023 Google, LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_ESP32S2_LOLIN_MINI
+	bool "ESP32S2 Lolin Mini Board"
+	depends on SOC_ESP32S2

boards/xtensa/esp32s2_lolin_mini/Kconfig.defconfig

@@ -0,0 +1,15 @@
+# ESP32S2 LOLIN S2 MINI board configuration
+
+# Copyright (c) 2023 Google, LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD
+	default "esp32s2_lolin_mini"
+	depends on BOARD_ESP32S2_LOLIN_MINI
+
+config ENTROPY_GENERATOR
+	default y
+
+config HEAP_MEM_POOL_SIZE
+	default 32768 if WIFI
+	default 4096

boards/xtensa/esp32s2_lolin_mini/board.cmake

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: Apache-2.0
+
+if(NOT "${OPENOCD}" MATCHES "^${ESPRESSIF_TOOLCHAIN_PATH}/.*")
+  set(OPENOCD OPENOCD-NOTFOUND)
+endif()
+find_program(OPENOCD openocd PATHS ${ESPRESSIF_TOOLCHAIN_PATH}/openocd-esp32/bin NO_DEFAULT_PATH)
+
+include(${ZEPHYR_BASE}/boards/common/esp32.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/openocd.board.cmake)

boards/xtensa/esp32s2_lolin_mini/doc/index.rst

@@ -0,0 +1,92 @@
+.. _esp32s2_lolin_mini:
+
+ESP32-S2
+########
+
+Overview
+********
+
+ESP32-S2 is a highly integrated, low-power, single-core Wi-Fi Microcontroller SoC, designed to be secure and
+cost-effective, with a high performance and a rich set of IO capabilities. [1]_
+
+The features include the following:
+
+- RSA-3072-based secure boot
+- AES-XTS-256-based flash encryption
+- Protected private key and device secrets from software access
+- Cryptographic accelerators for enhanced performance
+- Protection against physical fault injection attacks
+- Various peripherals:
+
+  - 43x programmable GPIOs
+  - 14x configurable capacitive touch GPIOs
+  - USB OTG
+  - LCD interface
+  - camera interface
+  - SPI
+  - I2S
+  - UART
+  - ADC
+  - DAC
+  - LED PWM with up to 8 channels
+
+System requirements
+*******************
+
+Prerequisites
+-------------
+
+Espressif HAL requires WiFi and Bluetooth binary blobs in order work. Run the command
+below to retrieve those files.
+
+.. code-block:: console
+
+   west blobs fetch hal_espressif
+
+.. note::
+
+   It is recommended running the command above after :file:`west update`.
+
+Building & Flashing
+-------------------
+
+Build and flash applications as usual (see :ref:`build_an_application` and
+:ref:`application_run` for more details).
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/hello_world
+   :board: esp32s2_lolin_mini
+   :goals: build
+
+The usual ``flash`` target will work with the ``esp32s2_lolin_mini`` board
+configuration after putting the board into bootloader mode by holding the '0'
+button then pressing 'RST' and releasing the 'RST' button.
+
+Here is an example for the :ref:`hello_world`
+application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/hello_world
+   :board: esp32s2_lolin_mini
+   :goals: flash
+
+Open a serial port using e.g. screen
+
+.. code-block:: shell
+
+   screen /dev/ttyUSB0 115200
+
+After the board has been manually reset and booted, you should see the following
+message in the monitor:
+
+.. code-block:: console
+
+   ***** Booting Zephyr OS vx.x.x-xxx-gxxxxxxxxxxxx *****
+   Hello World! esp32s2_lolin_mini
+
+References
+**********
+
+.. [1] https://www.espressif.com/en/products/socs/esp32-s2
+.. _`ESP32S2 Technical Reference Manual`: https://espressif.com/sites/default/files/documentation/esp32-s2_technical_reference_manual_en.pdf
+.. _`ESP32S2 Datasheet`: https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf

boards/xtensa/esp32s2_lolin_mini/esp32s2_lolin_mini-pinctrl.dtsi

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2023 Google, LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/dt-bindings/pinctrl/esp-pinctrl-common.h>
+#include <dt-bindings/pinctrl/esp32s2-pinctrl.h>
+#include <zephyr/dt-bindings/pinctrl/esp32s2-gpio-sigmap.h>
+
+&pinctrl {
+
+	uart0_default: uart0_default {
+		group1 {
+			pinmux = <UART0_TX_GPIO16>;
+		};
+		group2 {
+			pinmux = <UART0_RX_GPIO17>;
+			bias-pull-up;
+		};
+	};
+};

boards/xtensa/esp32s2_lolin_mini/esp32s2_lolin_mini.dts

@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2023 Google, LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+
+#include <espressif/esp32s2.dtsi>
+#include "esp32s2_lolin_mini-pinctrl.dtsi"
+
+/ {
+	model = "esp32s2_lolin_mini";
+	compatible = "espressif,esp32s2";
+
+	aliases {
+		sw0 = &user_button;
+		led0 = &user_led;
+		watchdog0 = &wdt0;
+	};
+
+	chosen {
+		zephyr,sram = &sram0;
+		zephyr,console = &uart0;
+		zephyr,shell-uart = &uart0;
+		zephyr,flash = &flash0;
+	};
+
+	power-states {
+		light_sleep: light_sleep {
+			compatible = "zephyr,power-state";
+			power-state-name = "standby";
+			min-residency-us = <200>;
+			exit-latency-us = <60>;
+		};
+
+		deep_sleep: deep_sleep {
+			compatible = "zephyr,power-state";
+			power-state-name = "soft-off";
+			min-residency-us = <2000>;
+			exit-latency-us = <212>;
+		};
+	};
+
+	leds {
+		compatible = "gpio-leds";
+		user_led: led {
+			gpios =  <&gpio0 15 GPIO_ACTIVE_HIGH>;
+			label = "LED1";
+		};
+	};
+
+	gpio_keys {
+		compatible = "gpio-keys";
+		user_button: user_button {
+			label = "0";
+			gpios = <&gpio0 0 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+		};
+	};
+};
+
+&cpu0 {
+	clock-frequency = <ESP32_CLK_CPU_240M>;
+	cpu-power-states = <&deep_sleep &light_sleep>;
+};
+
+&uart0 {
+	status = "okay";
+	current-speed = <115200>;
+	pinctrl-0 = <&uart0_default>;
+	pinctrl-names = "default";
+};
+
+&gpio0 {
+	status = "okay";
+};
+
+&gpio1 {
+	status = "okay";
+};
+
+&timer0 {
+	status = "disabled";
+};
+
+&timer1 {
+	status = "disabled";
+};
+
+&timer2 {
+	status = "disabled";
+};
+
+&timer3 {
+	status = "disabled";
+};
+
+&trng0 {
+	status = "okay";
+};
+
+&flash0 {
+	status = "okay";
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		/* Reserve 60kB for the bootloader */
+		boot_partition: partition@1000 {
+			label = "mcuboot";
+			reg = <0x00001000 0x0000F000>;
+			read-only;
+		};
+
+		/* Reserve 1024kB for the application in slot 0 */
+		slot0_partition: partition@10000 {
+			label = "image-0";
+			reg = <0x00010000 0x00100000>;
+		};
+
+		/* Reserve 1024kB for the application in slot 1 */
+		slot1_partition: partition@110000 {
+			label = "image-1";
+			reg = <0x00110000 0x00100000>;
+		};
+
+		/* Reserve 256kB for the scratch partition */
+		scratch_partition: partition@210000 {
+			   label = "image-scratch";
+			   reg = <0x00210000 0x00040000>;
+		};
+
+		storage_partition: partition@250000 {
+			label = "storage";
+			reg = <0x00250000 0x00006000>;
+		};
+	};
+};
+
+&wdt0 {
+	status = "okay";
+};

boards/xtensa/esp32s2_lolin_mini/esp32s2_lolin_mini.yaml

@@ -0,0 +1,14 @@
+identifier: esp32s2_lolin_mini
+name: Lolin ESP32-S2 Mini
+type: mcu
+arch: xtensa
+toolchain:
+  - zephyr
+supported:
+  - gpio
+  - watchdog
+  - uart
+testing:
+  ignore_tags:
+    - net
+    - bluetooth

boards/xtensa/esp32s2_lolin_mini/esp32s2_lolin_mini_defconfig

@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_XTENSA_RESET_VECTOR=n
+
+CONFIG_BOARD_ESP32S2_LOLIN_MINI=y
+CONFIG_SOC_ESP32S2=y
+CONFIG_MAIN_STACK_SIZE=2048
+
+CONFIG_CONSOLE=y
+CONFIG_SERIAL=y
+CONFIG_UART_CONSOLE=y
+
+CONFIG_XTENSA_USE_CORE_CRT1=n
+
+CONFIG_GPIO=y
+
+CONFIG_GEN_ISR_TABLES=y
+CONFIG_GEN_IRQ_VECTOR_TABLE=n
+
+CONFIG_CLOCK_CONTROL=y
+
+CONFIG_BOOTLOADER_ESP_IDF=y

boards/xtensa/esp32s2_lolin_mini/support/openocd.cfg

@@ -0,0 +1,4 @@
+set ESP_RTOS none
+
+source [find interface/ftdi/esp32s2_kaluga_v1.cfg]
+source [find target/esp32s2.cfg]

tests/lib/heap/testcase.yaml

@@ -8,6 +8,6 @@
 tests:
   libraries.heap:
     tags: heap
-    platform_exclude: m2gl025_miv qemu_xtensa esp32s2_saola esp32s3_devkitm
+    platform_exclude: m2gl025_miv qemu_xtensa esp32s2_saola esp32s3_devkitm esp32s2_lolin_mini
     filter: not CONFIG_SOC_NSIM
     timeout: 480