Add basic clock support

lib/hal/HalClock.cpp

@@ -0,0 +1,181 @@
+#include "HalClock.h"
+
+#include <Arduino.h>
+#include <Logging.h>
+#include <Preferences.h>
+#include <esp_private/esp_clk.h>
+#include <esp_sntp.h>
+#include <sys/time.h>
+
+// ---- RTC-memory state (survives deep sleep, not cold boot) ----------------
+
+static constexpr uint32_t CLOCK_RTC_MAGIC = 0xC10C4B1D;
+
+RTC_NOINIT_ATTR static uint32_t rtcClockMagic;
+RTC_NOINIT_ATTR static time_t rtcEpoch;       // last-known unix epoch
+RTC_NOINIT_ATTR static uint64_t rtcLpTimeUs;  // esp_clk_rtc_time() at capture
+
+static bool clockApproximate = true;
+
+// ---- NVS helpers ----------------------------------------------------------
+
+static constexpr char NVS_NAMESPACE[] = "halclock";
+static constexpr char NVS_KEY[] = "epoch";
+
+static void nvsWrite(time_t epoch) {
+  Preferences prefs;
+  if (prefs.begin(NVS_NAMESPACE, false)) {
+    prefs.putLong64(NVS_KEY, (int64_t)epoch);
+    prefs.end();
+  }
+}
+
+static time_t nvsRead() {
+  Preferences prefs;
+  time_t epoch = 0;
+  if (prefs.begin(NVS_NAMESPACE, true)) {
+    epoch = (time_t)prefs.getLong64(NVS_KEY, 0);
+    prefs.end();
+  }
+  return epoch;
+}
+
+// ---- internal helpers -----------------------------------------------------
+
+static void setSystemClock(time_t epoch) {
+  struct timeval tv = {};
+  tv.tv_sec = epoch;
+  settimeofday(&tv, nullptr);
+}
+
+static bool rtcValid() {
+  return rtcClockMagic == CLOCK_RTC_MAGIC && rtcEpoch > 0;
+}
+
+/// Capture current time + LP timer into RTC memory, and epoch into NVS.
+static void capture() {
+  rtcEpoch = time(nullptr);
+  rtcLpTimeUs = esp_clk_rtc_time();
+  rtcClockMagic = CLOCK_RTC_MAGIC;
+  nvsWrite(rtcEpoch);
+}
+
+// ---- public API -----------------------------------------------------------
+
+namespace HalClock {
+
+bool syncNtp() {
+  if (esp_sntp_enabled()) {
+    esp_sntp_stop();
+  }
+
+  esp_sntp_setoperatingmode(ESP_SNTP_OPMODE_POLL);
+  esp_sntp_setservername(0, "pool.ntp.org");
+  esp_sntp_init();
+
+  int retry = 0;
+  constexpr int maxRetries = 50;  // 5 seconds
+  while (sntp_get_sync_status() != SNTP_SYNC_STATUS_COMPLETED && retry < maxRetries) {
+    vTaskDelay(100 / portTICK_PERIOD_MS);
+    retry++;
+  }
+
+  if (retry >= maxRetries) {
+    LOG_ERR("CLK", "NTP sync timeout");
+    return false;
+  }
+
+  capture();
+  clockApproximate = false;
+  LOG_INF("CLK", "NTP synced, epoch %lld", (long long)rtcEpoch);
+  return true;
+}
+
+void saveBeforeSleep() {
+  if (!isSynced()) {
+    return;
+  }
+  capture();
+  LOG_DBG("CLK", "Saved epoch %lld before sleep", (long long)rtcEpoch);
+}
+
+void restore() {
+  if (rtcValid()) {
+    // RTC memory survived — we woke from deep sleep.
+    // Use the LP timer to compute how much time elapsed during sleep.
+    uint64_t lpNow = esp_clk_rtc_time();
+    time_t estimated = rtcEpoch;
+    if (lpNow > rtcLpTimeUs) {
+      estimated += (time_t)((lpNow - rtcLpTimeUs) / 1000000LL);
+    }
+    setSystemClock(estimated);
+    // Re-capture with current LP baseline
+    rtcEpoch = estimated;
+    rtcLpTimeUs = lpNow;
+    clockApproximate = true;
+    LOG_INF("CLK", "Restored from RTC + LP timer, epoch %lld", (long long)estimated);
+    return;
+  }
+
+  // Cold boot — try NVS.  No elapsed correction possible.
+  time_t epoch = nvsRead();
+  if (epoch > 0) {
+    setSystemClock(epoch);
+    rtcEpoch = epoch;
+    rtcLpTimeUs = esp_clk_rtc_time();
+    rtcClockMagic = CLOCK_RTC_MAGIC;
+    clockApproximate = true;
+    LOG_INF("CLK", "Restored from NVS, epoch %lld (no elapsed correction)", (long long)epoch);
+  }
+}
+
+time_t now() {
+  if (!isSynced()) {
+    return 0;
+  }
+  return time(nullptr);
+}
+
+bool isSynced() {
+  return time(nullptr) > 1577836800;  // > 2020-01-01
+}
+
+bool isApproximate() {
+  return clockApproximate;
+}
+
+void formatTime(char* buf, size_t bufSize, bool use24h) {
+  if (!isSynced()) {
+    snprintf(buf, bufSize, "--:--");
+    return;
+  }
+
+  time_t t = time(nullptr);
+  struct tm timeinfo;
+  localtime_r(&t, &timeinfo);
+
+  const char* prefix = isApproximate() ? "~" : "";
+
+  if (use24h) {
+    snprintf(buf, bufSize, "%s%02d:%02d", prefix, timeinfo.tm_hour, timeinfo.tm_min);
+  } else {
+    int hour = timeinfo.tm_hour % 12;
+    if (hour == 0) hour = 12;
+    const char* ampm = timeinfo.tm_hour < 12 ? "am" : "pm";
+    snprintf(buf, bufSize, "%s%d:%02d%s", prefix, hour, timeinfo.tm_min, ampm);
+  }
+}
+
+void formatLogTime(char* buf, size_t bufSize) {
+  if (!isSynced()) {
+    buf[0] = '\0';
+    return;
+  }
+
+  time_t t = time(nullptr);
+  struct tm timeinfo;
+  localtime_r(&t, &timeinfo);
+  snprintf(buf, bufSize, "%02d:%02d:%02d", timeinfo.tm_hour, timeinfo.tm_min, timeinfo.tm_sec);
+}
+
+}  // namespace HalClock

lib/hal/HalClock.h

@@ -0,0 +1,64 @@
+#pragma once
+
+#include <cstdint>
+#include <ctime>
+
+/// Lightweight wall-clock facade.
+///
+/// The ESP32-C3 has no battery-backed RTC, so wall-clock time is lost on every
+/// deep-sleep / power cycle.  HalClock bridges this gap using three layers:
+///
+///  - **LP timer** (`esp_clk_rtc_time()`) — keeps running during deep sleep
+///    when `keepClockAlive` is enabled (GPIO13 stays HIGH).  Used to compute
+///    elapsed time and correct the stored epoch on wake.
+///  - **RTC memory** (`RTC_NOINIT_ATTR`) — survives deep sleep, lost on cold
+///    boot.  Stores the epoch + LP timer value captured before sleep.
+///  - **NVS** (flash key-value store) — survives power cycles.  Fallback when
+///    RTC memory is unavailable (cold boot).
+///
+/// Usage:
+///  1. On boot, call `restore()` to seed the system clock from the best
+///     available source (RTC memory + LP correction > NVS).
+///  2. After a successful NTP sync, call `onNtpSynced()`.
+///  3. Before entering deep sleep, call `saveBeforeSleep()`.
+///
+/// `now()` returns the best-effort epoch (0 if never synced).
+namespace HalClock {
+
+/// Perform an NTP sync (requires WiFi to be connected).  Starts SNTP,
+/// waits up to 5 seconds for completion, then captures the result.
+/// Returns true if the sync succeeded.
+bool syncNtp();
+
+/// Call just before deep sleep.  Snapshots the current system time to RTC
+/// memory and NVS so it can be restored on wake / cold boot.
+void saveBeforeSleep();
+
+/// Call on boot to seed the system clock from the best available stored
+/// value.  When RTC memory is valid (deep-sleep wake) and the LP timer was
+/// running, the restored time includes elapsed-time correction.  Falls back
+/// to NVS for cold boot (stale, but better than nothing).
+void restore();
+
+/// Returns the current best-effort wall-clock epoch, or 0 if the clock was
+/// never set.
+time_t now();
+
+/// True if the clock has been set at least once (NTP or restore).
+bool isSynced();
+
+/// True if the last restore was from a backup (not NTP) — i.e. the clock
+/// may have drifted.  Cleared on NTP sync.
+bool isApproximate();
+
+/// Format the current time for display.  Returns "--:--" if the clock was
+/// never synced, prefixes with "~" if approximate.
+/// When use24h is false, formats as "2:05pm" / "12:30am".
+/// Output is written to `buf` (must be at least 16 bytes).
+void formatTime(char* buf, size_t bufSize, bool use24h);
+
+/// Format the current time for log timestamps.  Returns "HH:MM:SS" if
+/// synced, or an empty string if not.
+void formatLogTime(char* buf, size_t bufSize);
+
+}  // namespace HalClock

lib/hal/HalPowerManager.cpp

@@ -52,26 +52,30 @@ void HalPowerManager::setPowerSaving(bool enabled) {
   // Otherwise, no change needed
 }
 
-void HalPowerManager::startDeepSleep(HalGPIO& gpio) const {
+void HalPowerManager::startDeepSleep(HalGPIO& gpio, bool keepClockAlive) const {
   // Ensure that the power button has been released to avoid immediately turning back on if you're holding it
   while (gpio.isPressed(HalGPIO::BTN_POWER)) {
     delay(50);
     gpio.update();
   }
-  // Pre-sleep routines from the original firmware
-  // GPIO13 is connected to battery latch MOSFET, we need to make sure it's low during sleep
-  // Note that this means the MCU will be completely powered off during sleep, including RTC
+  // GPIO13 is connected to the battery latch MOSFET.
+  // When keepClockAlive is false (default): GPIO13 goes LOW, the MCU is
+  // completely powered off during sleep (including the LP timer / RTC memory).
+  // When keepClockAlive is true: GPIO13 stays HIGH, the MCU remains powered
+  // at ~3-4 mA so the LP timer keeps running and RTC memory is preserved.
+  // This allows HalClock to accurately compute elapsed sleep time on wake.
   constexpr gpio_num_t GPIO_SPIWP = GPIO_NUM_13;
   gpio_set_direction(GPIO_SPIWP, GPIO_MODE_OUTPUT);
-  gpio_set_level(GPIO_SPIWP, 0);
+  gpio_set_level(GPIO_SPIWP, keepClockAlive ? 1 : 0);
   esp_sleep_config_gpio_isolate();
   gpio_deep_sleep_hold_en();
   gpio_hold_en(GPIO_SPIWP);
   pinMode(InputManager::POWER_BUTTON_PIN, INPUT_PULLUP);
   // Arm the wakeup trigger *after* the button is released
-  // Note: this is only useful for waking up on USB power. On battery, the MCU will be completely powered off, so the
-  // power button is hard-wired to briefly provide power to the MCU, waking it up regardless of the wakeup source
-  // configuration
+  // Note: when keepClockAlive is false, this is only useful for waking up on USB power. On battery, the MCU will be
+  // completely powered off, so the power button is hard-wired to briefly provide power to the MCU, waking it up
+  // regardless of the wakeup source configuration.
+  // When keepClockAlive is true, this is the actual wakeup mechanism since the MCU stays powered.
   esp_deep_sleep_enable_gpio_wakeup(1ULL << InputManager::POWER_BUTTON_PIN, ESP_GPIO_WAKEUP_GPIO_LOW);
   // Enter Deep Sleep
   esp_deep_sleep_start();

lib/hal/HalPowerManager.h

@@ -29,9 +29,11 @@ class HalPowerManager {
   // Control CPU frequency for power saving
   void setPowerSaving(bool enabled);
 
-  // Setup wake up GPIO and enter deep sleep
-  // Should be called inside main loop() to handle the currentLockMode
-  void startDeepSleep(HalGPIO& gpio) const;
+  // Setup wake up GPIO and enter deep sleep.
+  // When keepClockAlive is true, GPIO13 stays HIGH so the LP timer keeps
+  // running during sleep (~3-4 mA extra).  This allows HalClock to compute
+  // elapsed sleep time and restore the wall clock accurately on wake.
+  void startDeepSleep(HalGPIO& gpio, bool keepClockAlive = false) const;
 
   // Get battery percentage (range 0-100)
   uint16_t getBatteryPercentage() const;