add some code

main/boards/common/power_save_timer.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <functional>
+
+#include <esp_timer.h>
+#include <esp_pm.h>
+
+class PowerSaveTimer {
+public:
+    PowerSaveTimer(int cpu_max_freq, int seconds_to_sleep = 20, int seconds_to_shutdown = -1);
+    ~PowerSaveTimer();
+
+    void SetEnabled(bool enabled);
+    void OnEnterSleepMode(std::function<void()> callback);
+    void OnExitSleepMode(std::function<void()> callback);
+    void OnShutdownRequest(std::function<void()> callback);
+    void WakeUp();
+
+private:
+    void PowerSaveCheck();
+
+    esp_timer_handle_t power_save_timer_ = nullptr;
+    bool enabled_ = false;
+    bool in_sleep_mode_ = false;
+    bool is_wake_word_running_ = false;
+    int ticks_ = 0;
+    int cpu_max_freq_;
+    int seconds_to_sleep_;
+    int seconds_to_shutdown_;
+
+    std::function<void()> on_enter_sleep_mode_;
+    std::function<void()> on_exit_sleep_mode_;
+    std::function<void()> on_shutdown_request_;
+};