ControllerInterface: Exposse DSU client battery level as an input.

Source/Core/InputCommon/ControllerInterface/Device.h

@@ -22,11 +22,18 @@ namespace ciface
 // range, used for periodic haptic effects though often ignored by devices
 // TODO: Make this configurable.
 constexpr int RUMBLE_PERIOD_MS = 10;
+
 // This needs to be at least as long as the longest rumble that might ever be played.
 // Too short and it's going to stop in the middle of a long effect.
 // Infinite values are invalid for ramp effects and probably not sensible.
 constexpr int RUMBLE_LENGTH_MS = 1000 * 10;
 
+// All inputs (other than accel/gyro) return 1.0 as their maximum value.
+// Battery inputs will almost always be mapped to the "Battery" setting which is a percentage.
+// If someone actually wants to map a battery input to a regular control they can divide by 100.
+// I think this is better than requiring multiplication by 100 for the most common usage.
+constexpr ControlState BATTERY_INPUT_MAX_VALUE = 100.0;
+
 namespace Core
 {
 class Device

Source/Core/InputCommon/ControllerInterface/DualShockUDPClient/DualShockUDPClient.cpp

@@ -102,6 +102,33 @@ private:
 
   using GyroInput = AccelerometerInput;
 
+  class BatteryInput final : public Input
+  {
+    using BatteryState = Proto::DsBattery;
+
+  public:
+    BatteryInput(const BatteryState& battery) : m_battery(battery) {}
+
+    std::string GetName() const override { return "Battery"; }
+
+    ControlState GetState() const override
+    {
+      switch (m_battery)
+      {
+      case BatteryState::Charging:
+      case BatteryState::Charged:
+        return BATTERY_INPUT_MAX_VALUE;
+      default:
+        return ControlState(m_battery) / ControlState(BatteryState::Full) * BATTERY_INPUT_MAX_VALUE;
+      }
+    }
+
+    bool IsDetectable() override { return false; }
+
+  private:
+    const BatteryState& m_battery;
+  };
+
 public:
   void UpdateInput() override;
 
@@ -355,6 +382,8 @@ Device::Device(Proto::DsModel model, int index) : m_model{model}, m_index{index}
   AddInput(new GyroInput("Gyro Roll Left", m_gyro.y, 1));
   AddInput(new GyroInput("Gyro Yaw Right", m_gyro.z, -1));
   AddInput(new GyroInput("Gyro Yaw Left", m_gyro.z, 1));
+
+  AddInput(new BatteryInput(m_pad_data.battery_status));
 }
 
 std::string Device::GetName() const