⚡ (lcd): Turn off backlight same time as lcd turning off command

Save energy use for display
leka · Apr 29, 2022 · b70fe7a · b70fe7a
1 parent 8f36034
commit b70fe7a
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Showing 3 changed files with 28 additions and 0 deletions.
diff --git a/drivers/CoreVideo/include/CoreLCDDriverOTM8009A.hpp b/drivers/CoreVideo/include/CoreLCDDriverOTM8009A.hpp
@@ -30,6 +30,8 @@ class CoreLCDDriverOTM8009A : public interface::LCDDriver
   private:
 	interface::DSIBase &_dsi;
 	mbed::PwmOut _backlight;
+
+	float _previous_brightness_value = {0.F};
 };
 
 namespace lcd::otm8009a {

diff --git a/drivers/CoreVideo/source/CoreLCDDriverOTM8009A.cpp b/drivers/CoreVideo/source/CoreLCDDriverOTM8009A.cpp
@@ -15,16 +15,22 @@ using namespace lcd::otm8009a;
 void CoreLCDDriverOTM8009A::turnOn()
 {
 	_dsi.write(display::turn_on::array, std::size(display::turn_on::array));
+	setBrightness(_previous_brightness_value);
 }
 
 void CoreLCDDriverOTM8009A::turnOff()
 {
 	_dsi.write(display::turn_off::array, std::size(display::turn_off::array));
+	setBrightness(0.F);
 }
 
 void CoreLCDDriverOTM8009A::setBrightness(float value)
 {
 	_backlight.write(value);
+
+	if (value != 0.F) {
+		_previous_brightness_value = value;
+	}
 }
 
 void CoreLCDDriverOTM8009A::initialize()

diff --git a/drivers/CoreVideo/tests/CoreLCDDriverOTM8009A_test.cpp b/drivers/CoreVideo/tests/CoreLCDDriverOTM8009A_test.cpp
@@ -92,3 +92,23 @@ TEST_F(CoreOTM8009ATest, setBrightness)
 
 	ASSERT_EQ(spy_PwmOut_getValue(), 0.5);
 }
+
+TEST_F(CoreOTM8009ATest, setBrightnessTurnOffThenTurnOn)
+{
+	auto initial_brightness_value = 0.4F;
+
+	otm.setBrightness(initial_brightness_value);
+
+	EXPECT_EQ(spy_PwmOut_getValue(), initial_brightness_value);
+
+	EXPECT_CALL(dsimock, write).Times(1);
+	otm.turnOff();
+
+	EXPECT_EQ(spy_PwmOut_getValue(), 0);
+	EXPECT_NE(spy_PwmOut_getValue(), initial_brightness_value);
+
+	EXPECT_CALL(dsimock, write).Times(1);
+	otm.turnOn();
+
+	EXPECT_EQ(spy_PwmOut_getValue(), initial_brightness_value);
+}