Save/load time to/from storage in time_manager

components/time/CMakeLists.txt

@@ -1,5 +1,5 @@
 idf_component_register(
   SRCS "time_manager.c"
   INCLUDE_DIRS "."
-  REQUIRES console_wrapper lwip settings
+  REQUIRES console_wrapper lwip nvs_flash settings
 )

components/time/time_manager.c

@@ -10,10 +10,15 @@
 
 #include "esp_log.h"
 #include "esp_sntp.h"
+#include "freertos/FreeRTOS.h"
+#include "nvs_flash.h"
 #include <time.h>
 
 #define TAG "Time"
 
+#define NVS_NAMESPACE "time"
+#define TIMESTAMP_KEY "timestamp"
+
 static void handle_timezone_update(const char *timezone)
 {
 	setenv("TZ", timezone, 1);
@@ -54,6 +59,29 @@ static const char *sync_status_description(sntp_sync_status_t status)
 	}
 }
 
+static int store_time(void)
+{
+	esp_err_t error;
+
+	nvs_handle_t nvs;
+	error = nvs_open(NVS_NAMESPACE, NVS_READWRITE, &nvs);
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error opening NVS: %04x", error);
+		return 1;
+	}
+
+	struct timeval tv;
+	gettimeofday(&tv, NULL);
+	error = nvs_set_u64(nvs, TIMESTAMP_KEY, tv.tv_sec);
+	if (error == ESP_OK)
+		ESP_LOGI(TAG, "Stored time");
+	else
+		ESP_LOGE(TAG, "Error storing time: %04x", error);
+
+	nvs_close(nvs);
+	return error == ESP_OK ? 0 : 1;
+}
+
 static int command_func(int argc, char **argv)
 {
 	if (argc == 1) {
@@ -65,10 +93,13 @@ static int command_func(int argc, char **argv)
 			const sntp_sync_status_t status = sntp_get_sync_status();
 			printf("%s\n", sync_status_description(status));
 			return 0;
+		} else if (strcmp(argv[1], "store") == 0) {
+			return store_time();
 		} else {
 			Time time;
-			if (sscanf(argv[1], "%02u:%02u", &time.hour, &time.minute) < 2
+			const int result
-			    || time.hour > 23 || time.minute > 59) {
+			    = sscanf(argv[1], "%02u:%02u", &time.hour, &time.minute);
+			if (result < 2 || time.hour > 23 || time.minute > 59) {
 				printf("Invalid time\n");
 				return 1;
 			}
@@ -81,6 +112,16 @@ static int command_func(int argc, char **argv)
 	}
 }
 
+static void time_saver_func(void *arg)
+{
+	(void)arg;
+	const TickType_t delay = CONFIG_TIME_SAVE_PERIOD_MS / portTICK_PERIOD_MS;
+	while (1) {
+		(void)store_time();
+		vTaskDelay(delay);
+	}
+}
+
 void time_manager_init(void)
 {
 	char timezone[SETTINGS_MAX_VALUE_SIZE];
@@ -100,6 +141,31 @@ void time_manager_init(void)
 	console_register(
 	    "time", "Get / set time and SNTP status",
 	    "time OR time <HH:MM> OR time sntp-status", command_func);
+
+	// Attempt to load time from storage
+	esp_err_t error;
+	nvs_handle_t nvs;
+	error = nvs_open(NVS_NAMESPACE, NVS_READONLY, &nvs);
+	if (error == ESP_OK) {
+		uint64_t timestamp;
+		error = nvs_get_u64(nvs, TIMESTAMP_KEY, &timestamp);
+		if (error == ESP_OK) {
+			struct timeval tv = { .tv_sec = (time_t)timestamp };
+			settimeofday(&tv, NULL);
+		} else {
+			if (error != ESP_ERR_NVS_NOT_FOUND)
+				ESP_LOGE(TAG, "Error getting stored time: %04x", error);
+		}
+		nvs_close(nvs);
+	} else {
+		if (error != ESP_ERR_NVS_NOT_FOUND)
+			ESP_LOGE(TAG, "Error opening NVS: %04x", error);
+	}
+
+	// Start task to save time to storage
+	(void)xTaskCreate(
+	    &time_saver_func, "time saver", CONFIG_DEFAULT_TASK_STACK, NULL, 1,
+	    NULL);
 }
 
 Time get_time(void)

main/Kconfig.projbuild

@@ -30,4 +30,10 @@ menu "Bedside clock settings"
      config WIFI_MAX_RETRIES
             int "Maximum number of times to retry connecting to WiFi network"
             default 10
+     config TIME_SAVE_PERIOD_MS
+            int "How often (in ms) to save the time to persistent storage"
+            default 300000
+     config DEFAULT_TASK_STACK
+            int "Default task stack size (in words)"
+            default 4096
 endmenu