Disable SPI, I²C, touch controller and display controller in sleep mode.

Re-enable them on wake up.

Remove delays that were not needed in st7889 driver.

Hopefully, it'll improve the battery life!

src/Components/Gfx/Gfx.cpp

@@ -85,4 +85,12 @@ void Gfx::pixel_draw(uint8_t x, uint8_t y, uint16_t color) {
   lcd.DrawPixel(x, y, color);
 }
 
+void Gfx::Sleep() {
+  lcd.Sleep();
+}
+
+void Gfx::Wakeup() {
+  lcd.Wakeup();
+}
+
 

src/Components/Gfx/Gfx.h

@@ -16,6 +16,9 @@ namespace Pinetime {
         void DrawChar(const FONT_INFO *font, uint8_t c, uint8_t *x, uint8_t y, uint16_t color);
         void FillRectangle(uint8_t x, uint8_t y, uint8_t width, uint8_t height, uint16_t color);
 
+        void Sleep();
+        void Wakeup();
+
       private:
         Drivers::St7789& lcd;
         const uint8_t width = 240;