Backlight: Add abstraction for support of different hardware.

firmware/application/portapack.cpp

@@ -31,6 +31,7 @@ using namespace hackrf::one;
 
 #include "clock_manager.hpp"
 
+#include "backlight.hpp"
 #include "touch_adc.hpp"
 #include "audio.hpp"
 
@@ -56,6 +57,9 @@ portapack::IO io {
 	portapack::gpio_unused,
 };
 
+portapack::BacklightCAT4004 backlight_cat4004;
+portapack::BacklightOnOff   backlight_on_off;
+
 lcd::ILI9341 display;
 
 I2C i2c0(&I2CD0);
@@ -147,6 +151,12 @@ static const portapack::cpld::Config& portapack_cpld_config() {
 		;
 }
 
+Backlight* backlight() {
+	return (portapack_model() == PortaPackModel::R2_20170522)
+		? static_cast<portapack::Backlight*>(&backlight_cat4004)
+		: static_cast<portapack::Backlight*>(&backlight_on_off);
+}
+
 static void shutdown_base() {
 	clock_manager.shutdown();
 
@@ -272,6 +282,7 @@ bool init() {
 void shutdown() {
 	gpdma::controller.disable();
 
+	backlight()->off();
 	display.shutdown();
 	
 	radio::disable();