Add SNTP-synced system time

Kconfig

@@ -10,6 +10,78 @@ config MEMFAULT_APP_OVERRIDE_SOFTWARE_VERSION
 	  Set this to override the built-in software version string from the
 	  VERSION file. Primarily used for building in CI.
 
+config WIFI_WATCHDOG_ENABLE
+	bool "Enable WiFi watchdog"
+	default y
+	depends on WIFI && MEMFAULT
+	help
+	  Enable WiFi watchdog that monitors WiFi connectivity and reboots
+	  if a known network is available but not connected for a configurable
+	  period of time.
+
+config WIFI_WATCHDOG_TIMEOUT_MINUTES
+	int "WiFi watchdog timeout in minutes"
+	default 5
+	depends on WIFI_WATCHDOG_ENABLE
+	help
+	  Time in minutes to wait before triggering a reboot when WiFi
+	  credentials are configured, a known network is detected, but
+	  WiFi is not connected.
+
+config WIFI_WATCHDOG_CHECK_INTERVAL_SECONDS
+	int "WiFi watchdog check interval in seconds"
+	default 30
+	depends on WIFI_WATCHDOG_ENABLE
+	help
+	  Interval in seconds between WiFi watchdog checks.
+
+config SNTP_TIME_SYNC_ENABLE
+	bool "Enable SNTP time synchronization"
+	default y
+	depends on SNTP && WIFI
+	help
+	  Synchronizes the kernel real-time clock via an NTP server each time
+	  a WiFi connection is established, and then periodically at the
+	  interval set by SNTP_TIME_SYNC_RESYNC_INTERVAL_SECONDS.
+	  Uses the Zephyr SNTP client (sntp_init/query/close) directly.
+
+config SNTP_TIME_SYNC_SERVER
+	string "NTP server hostname"
+	default "pool.ntp.org"
+	depends on SNTP_TIME_SYNC_ENABLE
+	help
+	  Hostname of the NTP server to query for time synchronization.
+
+config SNTP_TIME_SYNC_RESYNC_INTERVAL_SECONDS
+	int "Periodic SNTP re-sync interval (seconds)"
+	default 21600  # 6 hours
+	depends on SNTP_TIME_SYNC_ENABLE
+	help
+	  How often to re-sync the clock while WiFi is connected.
+	  The initial sync is triggered immediately on WiFi connect.
+
+choice HEARTBEAT_LED_TYPE
+	prompt "Select heartbeat LED variant"
+	default HEARTBEAT_LED_STRIP if $(dt_alias_enabled,led-strip)
+	default HEARTBEAT_LED_GPIO if $(dt_alias_enabled,heartbeat-led)
+
+config HEARTBEAT_LED_STRIP
+	bool "WS2812 RGB LED strip"
+	depends on LED_STRIP
+	help
+	  Enable heartbeat LED using a WS2812 RGB LED strip.
+	  GREEN when WiFi is connected, RED otherwise.
+	  Blinks at a 1-second interval.
+
+config HEARTBEAT_LED_GPIO
+	bool "GPIO LED"
+	depends on GPIO
+	help
+	  Enable heartbeat LED using a simple GPIO-driven LED.
+	  Blinks at a 1-second interval unconditionally.
+
+endchoice
+
 endmenu
 
 config MEMFAULT_BUILTIN_DEVICE_INFO_SOFTWARE_VERSION

boards/esp32c3_devkitm.overlay

@@ -4,10 +4,54 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
 
 &coretemp {
 	status = "okay";
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO8 via SPI2 */
+&spi2 {
+	/* Workaround to support WS2812 driver */
+	line-idle-low;
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-spi";
+
+		/* SPI */
+		reg = <0>;
+		spi-max-frequency = <6400000>;
+
+		/* WS2812 */
+		chain-length = <1>;
+		spi-cpha;
+		spi-one-frame = <0xf0>;
+		spi-zero-frame = <0xc0>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+	};
+};
+
+&pinctrl {
+	spim2_default: spim2_default {
+		group2 {
+			/* WS2812 data on GPIO8 */
+			pinmux = <SPIM2_MOSI_GPIO8>;
+		};
+	};
+};
+
+/* Enable the ESP32-C3 RTC timer counter so it can be used for time persistence
+ * across soft resets via the counter API and __noinit RAM anchor. */
+&rtc_timer {
+        status = "okay";
+};

boards/esp32c6_devkitc_esp32c6_hpcore.conf

@@ -0,0 +1,3 @@
+# Enable DMA for heartbeat LED
+CONFIG_DMA=y
+CONFIG_LED_STRIP=y

boards/esp32c6_devkitc_esp32c6_hpcore.overlay

@@ -4,10 +4,51 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
 
 &coretemp {
 	status = "okay";
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO8 via I2S */
+&i2s_default {
+	group1 {
+		pinmux = <I2S_O_SD_GPIO8>;
+	};
+};
+
+i2s_led: &i2s {
+	status = "okay";
+
+	dmas = <&dma 3>;
+	dma-names = "tx";
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-i2s";
+
+		reg = <0>;
+		chain-length = <1>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+		reset-delay = <500>;
+	};
+};
+
+&dma {
+	status = "okay";
+};
+
+/* Enable the ESP32-C6 RTC timer counter so it can be used for time persistence
+ * across soft resets via the counter API and __noinit RAM anchor. */
+&rtc_timer {
+        status = "okay";
+};

boards/esp32s3_devkitc_esp32s3_procpu.conf

@@ -1,3 +1,7 @@
 # Enable external SPI RAM
 CONFIG_SPI=y
 CONFIG_ESP_SPIRAM=y
+
+# Enable DMA for heartbeat LED
+CONFIG_DMA=y
+CONFIG_LED_STRIP=y

boards/esp32s3_devkitc_esp32s3_procpu.overlay

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
@@ -16,3 +18,42 @@
 &psram0 {
 	size = <DT_SIZE_M(2)>;
 };
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO38 via I2S0 */
+&i2s0_default {
+	group1 {
+		pinmux = <I2S0_O_SD_GPIO38>;
+	};
+};
+
+i2s_led: &i2s0 {
+	status = "okay";
+
+	dmas = <&dma 3>;
+	dma-names = "tx";
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-i2s";
+
+		reg = <0>;
+		chain-length = <1>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+		reset-delay = <500>;
+	};
+};
+
+&dma {
+	status = "okay";
+};
+
+/* Enable the ESP32-S3 RTC timer counter so it can be used for time persistence
+ * across soft resets via the counter API and __noinit RAM anchor. */
+&rtc_timer {
+        status = "okay";
+};

boards/esp32s3_devkitm_esp32s3_procpu.conf

@@ -0,0 +1,3 @@
+# Enable DMA + LED_STRIP for heartbeat LED
+CONFIG_DMA=y
+CONFIG_LED_STRIP=y

boards/esp32s3_devkitm_esp32s3_procpu.overlay

@@ -4,10 +4,54 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/dt-bindings/led/led.h>
+
 &wifi {
 	status = "okay";
 };
 
 &coretemp {
 	status = "okay";
 };
+
+/* Enable the ESP32-S3 RTC timer counter so it can be used for time persistence
+ * across soft resets via the counter API and __noinit RAM anchor. */
+&rtc_timer {
+        status = "okay";
+};
+
+/ {
+	aliases {
+		led-strip = &led_strip;
+	};
+};
+
+/* WS2812 RGB LED on GPIO48 via SPI3 */
+&spi3 {
+	/* Workaround to support WS2812 driver */
+	line-idle-low;
+
+	led_strip: ws2812@0 {
+		compatible = "worldsemi,ws2812-spi";
+
+		/* SPI */
+		reg = <0>;
+		spi-max-frequency = <6400000>;
+
+		/* WS2812 */
+		chain-length = <1>;
+		spi-cpha;
+		spi-one-frame = <0xf0>;
+		spi-zero-frame = <0xc0>;
+		color-mapping = <LED_COLOR_ID_GREEN LED_COLOR_ID_RED LED_COLOR_ID_BLUE>;
+	};
+};
+
+&pinctrl {
+	spim3_default: spim3_default {
+		group2 {
+			/* WS2812 data on GPIO48 */
+			pinmux = <SPIM3_MOSI_GPIO48>;
+		};
+	};
+};

boards/esp_wrover_kit_procpu.conf

@@ -0,0 +1 @@
+CONFIG_HEARTBEAT_LED_GPIO=y

boards/esp_wrover_kit_procpu.overlay

@@ -1,3 +1,15 @@
 &wifi {
 	status = "okay";
 };
+
+/* Enable the ESP32 RTC timer counter so it can be used for time persistence
+ * across soft resets via the counter API and __noinit RAM anchor. */
+&rtc_timer {
+	status = "okay";
+};
+
+/ {
+	aliases {
+		heartbeat-led = &red_led;
+	};
+};

config/memfault_metrics_heartbeat_config.def

@@ -0,0 +1,11 @@
+// Define the WiFi scan result count max metric
+// This tracks the maximum number of WiFi scan results seen during each heartbeat period
+MEMFAULT_METRICS_KEY_DEFINE(wifi_scan_result_count_max, kMemfaultMetricType_Unsigned)
+
+// Number of successful SNTP time synchronizations in this heartbeat period
+MEMFAULT_METRICS_KEY_DEFINE(sntp_sync_count, kMemfaultMetricType_Unsigned)
+
+// Clock error corrected by the most recent SNTP sync (seconds, signed).
+// Only recorded when the system clock was already valid (> 2023) before the
+// sync, so the initial 1970-epoch → real-time jump is excluded.
+MEMFAULT_METRICS_KEY_DEFINE(sntp_sync_delta_seconds, kMemfaultMetricType_Signed)

config/memfault_reboot_reason_user_config.def

@@ -0,0 +1,2 @@
+// Wi-Fi Watchdog is not desirable, but should not impact stability score.
+MEMFAULT_EXPECTED_REBOOT_REASON_DEFINE(WifiWatchdog)