boards: seeed: xioa_esp32c6 external antenna support

This PR adds adds The RF switch node and support for
the extenal antenna.

Signed-off-by: Mario Paja <[email protected]>

Author: mariopaja

boards/seeed/xiao_esp32c6/CMakeLists.txt

@@ -0,0 +1,4 @@
+# Copyright (c) 2025 Mario Paja
+# SPDX-License-Identifier: Apache-2.0
+zephyr_library()
+zephyr_library_sources(xiao_esp32c6_hpcore_init.c)

boards/seeed/xiao_esp32c6/Kconfig

@@ -5,3 +5,10 @@ config HEAP_MEM_POOL_ADD_SIZE_BOARD
 	int
 	default 4096 if BOARD_XIAO_ESP32C6_ESP32C6_HPCORE
 	default 256 if BOARD_XIAO_ESP32C6_ESP32C6_LPCORE
+
+config XIAO_ESP32C6_EXT_ANTENNA
+	bool "XIAO ESP32C6 External Antenna"
+	default n
+	help
+	  Select the external antenna of the XIAO ESP32-C6.
+	  By default, the onboard antenna is used.

boards/seeed/xiao_esp32c6/xiao_esp32c6_hpcore.dts

@@ -37,6 +37,17 @@
 		watchdog0 = &wdt0;
 	};
 
+	rf_switch {
+		compatible = "gpio-keys";
+		rf_switch_en: rf_switch_en {
+			gpios = <&gpio0 3 GPIO_ACTIVE_LOW>;
+			label = "Activate RF switch control";
+		};
+		ext_ant: ext_ant {
+			gpios = <&gpio0 14 GPIO_ACTIVE_HIGH>;
+			label = "External Antenna Selector";
+		};
+	};
 };
 
 &trng0 {

boards/seeed/xiao_esp32c6/xiao_esp32c6_hpcore_init.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2025 Mario Paja
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/init.h>
+
+static int board_init(void)
+{
+	const struct gpio_dt_spec rf_switch_en =
+		GPIO_DT_SPEC_GET(DT_NODELABEL(rf_switch_en), gpios);
+	const struct gpio_dt_spec ext_ant_sel = GPIO_DT_SPEC_GET(DT_NODELABEL(ext_ant), gpios);
+
+	if (!device_is_ready(rf_switch_en.port)) {
+		return -ENODEV;
+	}
+	gpio_pin_configure_dt(&rf_switch_en, GPIO_OUTPUT);
+
+	if (!device_is_ready(ext_ant_sel.port)) {
+		return -ENODEV;
+	}
+	gpio_pin_configure_dt(&ext_ant_sel, GPIO_OUTPUT);
+
+	gpio_pin_set_dt(&rf_switch_en, 1);
+
+#ifdef CONFIG_XIAO_ESP32C6_EXT_ANTENNA
+	gpio_pin_set_dt(&ext_ant_sel, 1);
+#else
+	gpio_pin_set_dt(&ext_ant_sel, 0);
+#endif
+
+	return 0;
+}
+
+SYS_INIT(board_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);