From c6fbdb4acb5d2726b0659990b6156ac24e5b29c5 Mon Sep 17 00:00:00 2001
From: jingli <jingli@espressif.com>
Date: Tue, 12 Jul 2022 19:00:47 +0800
Subject: [PATCH] examples/system/deep_sleep:

Use nvs instead of RTC_DATA_ATTR to record deep sleep enter time when
the target chip does not have rtc mem.
---
 .../deep_sleep/main/deep_sleep_example_main.c | 50 ++++++++++++++++++-
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/examples/system/deep_sleep/main/deep_sleep_example_main.c b/examples/system/deep_sleep/main/deep_sleep_example_main.c
index f3ea42cd06..7a724e9170 100644
--- a/examples/system/deep_sleep/main/deep_sleep_example_main.c
+++ b/examples/system/deep_sleep/main/deep_sleep_example_main.c
@@ -21,6 +21,14 @@
 #include "esp_log.h"
 #include "driver/rtc_io.h"
 #include "soc/rtc.h"
+#include "nvs_flash.h"
+#include "nvs.h"
+
+#if SOC_RTC_FAST_MEM_SUPPORTED
+static RTC_DATA_ATTR struct timeval sleep_enter_time;
+#else
+static struct timeval sleep_enter_time;
+#endif
 
 #if SOC_TOUCH_SENSOR_SUPPORTED
 #include "soc/sens_periph.h"
@@ -36,8 +44,6 @@
 #endif
 #endif
 
-static RTC_DATA_ATTR struct timeval sleep_enter_time;
-
 #ifdef CONFIG_EXAMPLE_TOUCH_WAKEUP
 #if CONFIG_IDF_TARGET_ESP32
 #define TOUCH_THRESH_NO_USE 0
@@ -47,6 +53,35 @@ static void calibrate_touch_pad(touch_pad_t pad);
 
 void app_main(void)
 {
+    /**
+     * Prefer to use RTC mem instead of NVS to save the deep sleep enter time, unless the chip
+     * does not support RTC mem(such as esp32c2). Because the time overhead of NVS will cause
+     * the recorded deep sleep enter time to be not very accurate.
+     */
+#if !SOC_RTC_FAST_MEM_SUPPORTED
+    // Initialize NVS
+    esp_err_t err = nvs_flash_init();
+    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        // NVS partition was truncated and needs to be erased
+        // Retry nvs_flash_init
+        ESP_ERROR_CHECK(nvs_flash_erase());
+        err = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(err);
+
+    nvs_handle_t nvs_handle;
+    err = nvs_open("storage", NVS_READWRITE, &nvs_handle);
+    if (err != ESP_OK) {
+        printf("Error (%s) opening NVS handle!\n", esp_err_to_name(err));
+    } else {
+        printf("Open NVS done\n");
+    }
+
+    // Get deep sleep enter time
+    nvs_get_i32(nvs_handle, "slp_enter_sec", (int32_t *)&sleep_enter_time.tv_sec);
+    nvs_get_i32(nvs_handle, "slp_enter_usec", (int32_t *)&sleep_enter_time.tv_usec);
+#endif
+
     struct timeval now;
     gettimeofday(&now, NULL);
     int sleep_time_ms = (now.tv_sec - sleep_enter_time.tv_sec) * 1000 + (now.tv_usec - sleep_enter_time.tv_usec) / 1000;
@@ -220,8 +255,19 @@ void app_main(void)
 #endif
 
     printf("Entering deep sleep\n");
+
+    // get deep sleep enter time
     gettimeofday(&sleep_enter_time, NULL);
 
+#if !SOC_RTC_FAST_MEM_SUPPORTED
+    // record deep sleep enter time via nvs
+    ESP_ERROR_CHECK(nvs_set_i32(nvs_handle, "slp_enter_sec", sleep_enter_time.tv_sec));
+    ESP_ERROR_CHECK(nvs_set_i32(nvs_handle, "slp_enter_usec", sleep_enter_time.tv_usec));
+    ESP_ERROR_CHECK(nvs_commit(nvs_handle));
+    nvs_close(nvs_handle);
+#endif
+
+    // enter deep sleep
     esp_deep_sleep_start();
 }