Refactor power saving logic into display drivers and add ST7789 support

display/low_level_display.h

@@ -40,6 +40,11 @@ public:
     // Optional: Orientation control (not commonly needed for bitmap displays)
     virtual void set_rotation(uint8_t rotation) { (void)rotation; }
     
+    // Power saving hooks
+    virtual void on_idle_2min() {}
+    virtual void on_idle_10min() {}
+    virtual void on_user_interaction() {}
+
     // Factory method - creates display based on type, using board_config.h for pins
     static LowLevelDisplay* create(DisplayType type, int width, int height);
 };

display/low_level_display_epaper.cpp

@@ -141,3 +141,24 @@ void LowLevelDisplayEPaper::sleep() {
     printf("Putting e-paper display to sleep...\n");
     EPD_4IN2_V2_Sleep();
 }
+
+void LowLevelDisplayEPaper::on_idle_2min() {
+    // E-paper doesn't dim
+}
+
+void LowLevelDisplayEPaper::on_idle_10min() {
+    if (!is_sleeping) {
+        sleep();
+        is_sleeping = true;
+        printf("E-Paper: Entered sleep mode\n");
+    }
+}
+
+void LowLevelDisplayEPaper::on_user_interaction() {
+    if (is_sleeping) {
+        printf("E-Paper: Waking from sleep...\n");
+        init(); // Re-initialize to wake up
+        is_sleeping = false;
+        printf("E-Paper: Ready\n");
+    }
+}

display/low_level_display_epaper.h

@@ -44,6 +44,14 @@ public:
     void clear_display();  // Full clear with refresh
     void full_refresh();   // Force full screen refresh (slower but removes ghosting)
     void sleep();          // Put display in low power mode
+
+    // Power saving hooks
+    void on_idle_2min() override;
+    void on_idle_10min() override;
+    void on_user_interaction() override;
+
+private:
+    bool is_sleeping = false;
 };
 
 #endif // LOW_LEVEL_DISPLAY_EPAPER_H

display/low_level_display_st7789.cpp

@@ -69,11 +69,51 @@ void LowLevelDisplayST7789::refresh() {
 }
 
 void LowLevelDisplayST7789::set_backlight(bool on) {
-    // TODO: Implement
-    (void)on;
+    set_brightness(on ? 100 : 0);
+}
+
+void LowLevelDisplayST7789::set_brightness(uint8_t brightness) {
+    st7789_set_brightness(brightness);
+}
+
+uint8_t LowLevelDisplayST7789::get_brightness() const {
+    return st7789_get_brightness();
 }
 
 void LowLevelDisplayST7789::set_rotation(uint8_t rotation) {
     // TODO: Implement
     (void)rotation;
 }
+
+void LowLevelDisplayST7789::on_idle_2min() {
+    if (!is_dimmed && !is_sleeping) {
+        saved_brightness = get_brightness();
+        set_brightness(5); // Dim to 5%
+        is_dimmed = true;
+        printf("ST7789: Dimmed to 5%%\n");
+    }
+}
+
+void LowLevelDisplayST7789::on_idle_10min() {
+    if (!is_sleeping) {
+        st7789_sleep();
+        is_sleeping = true;
+        is_dimmed = true; // Sleep implies dimmed
+        printf("ST7789: Entered sleep mode\n");
+    }
+}
+
+void LowLevelDisplayST7789::on_user_interaction() {
+    if (is_sleeping) {
+        st7789_wake();
+        // Restore brightness if we have a saved value, or default to 100
+        set_brightness(saved_brightness > 0 ? saved_brightness : 100);
+        is_sleeping = false;
+        is_dimmed = false;
+        printf("ST7789: Woke from sleep\n");
+    } else if (is_dimmed) {
+        set_brightness(saved_brightness > 0 ? saved_brightness : 100);
+        is_dimmed = false;
+        printf("ST7789: Restored brightness\n");
+    }
+}

display/low_level_display_st7789.h

@@ -2,17 +2,7 @@
 #define LOW_LEVEL_DISPLAY_ST7789_H
 
 #include "low_level_display.h"
-
-// ST7789 configuration structure (similar to ST7796)
-struct st7789_config {
-    void* spi;           // SPI instance
-    int gpio_din;        // MOSI pin
-    int gpio_clk;        // Clock pin
-    int gpio_cs;         // Chip select pin
-    int gpio_dc;         // Data/Command pin
-    int gpio_rst;        // Reset pin
-    int gpio_bl;         // Backlight pin
-};
+#include "st7789.h"
 
 class LowLevelDisplayST7789 : public LowLevelDisplay {
 private:
@@ -42,8 +32,22 @@ public:
     // Backlight control
     void set_backlight(bool on) override;
     
+    // Brightness control
+    void set_brightness(uint8_t brightness) override;
+    uint8_t get_brightness() const override;
+
     // Orientation control
     void set_rotation(uint8_t rotation) override;
+
+    // Power saving hooks
+    void on_idle_2min() override;
+    void on_idle_10min() override;
+    void on_user_interaction() override;
+
+private:
+    uint8_t saved_brightness = 100;
+    bool is_dimmed = false;
+    bool is_sleeping = false;
 };
 
 #endif // LOW_LEVEL_DISPLAY_ST7789_H

display/low_level_display_st7796.cpp

@@ -94,3 +94,36 @@ void LowLevelDisplayST7796::set_rotation(uint8_t rotation) {
     // TODO: Add MADCTL register manipulation for rotation
     (void)rotation;
 }
+
+void LowLevelDisplayST7796::on_idle_2min() {
+    if (!is_dimmed && !is_sleeping) {
+        saved_brightness = get_brightness();
+        set_brightness(5); // Dim to 5%
+        is_dimmed = true;
+        printf("TFT: Dimmed to 5%%\n");
+    }
+}
+
+void LowLevelDisplayST7796::on_idle_10min() {
+    if (!is_sleeping) {
+        sleep();
+        is_sleeping = true;
+        is_dimmed = true; // Sleep implies dimmed
+        printf("TFT: Entered sleep mode\n");
+    }
+}
+
+void LowLevelDisplayST7796::on_user_interaction() {
+    if (is_sleeping) {
+        wake();
+        // Restore brightness if we have a saved value, or default to 100
+        set_brightness(saved_brightness > 0 ? saved_brightness : 100);
+        is_sleeping = false;
+        is_dimmed = false;
+        printf("TFT: Woke from sleep\n");
+    } else if (is_dimmed) {
+        set_brightness(saved_brightness > 0 ? saved_brightness : 100);
+        is_dimmed = false;
+        printf("TFT: Restored brightness\n");
+    }
+}

display/low_level_display_st7796.h

@@ -47,6 +47,16 @@ public:
     // Color inversion control
     void set_invert_color(bool inv) { invert_color = inv; }
     bool get_invert_color() const { return invert_color; }
+
+    // Power saving hooks
+    void on_idle_2min() override;
+    void on_idle_10min() override;
+    void on_user_interaction() override;
+
+private:
+    uint8_t saved_brightness = 100;
+    bool is_dimmed = false;
+    bool is_sleeping = false;
 };
 
 #endif // LOW_LEVEL_DISPLAY_ST7796_H