[wpilib] Move motor controllers to motorcontrol package (#3302)

Also deprecate SpeedController in favor of motorcontrol.MotorController and
SpeedControllerGroup in favor of motorcontrol.MotorControllerGroup.

The MotorController interface is derived from the SpeedController interface
so that code such as SpeedController x = new VictorSP(1) continues to
compile (just with a warning).

SpeedControllerGroup and MotorControllerGroup are independent classes;
both implement the MotorController interface.

wpilibc/src/main/native/cpp/motorcontrol/NidecBrushless.cpp

@@ -0,0 +1,81 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/motorcontrol/NidecBrushless.h"
+
+#include <hal/FRCUsageReporting.h>
+#include <wpi/raw_ostream.h>
+
+#include "frc/smartdashboard/SendableBuilder.h"
+#include "frc/smartdashboard/SendableRegistry.h"
+
+using namespace frc;
+
+NidecBrushless::NidecBrushless(int pwmChannel, int dioChannel)
+    : m_dio(dioChannel), m_pwm(pwmChannel) {
+  auto& registry = SendableRegistry::GetInstance();
+  registry.AddChild(this, &m_dio);
+  registry.AddChild(this, &m_pwm);
+  SetExpiration(0.0);
+  SetSafetyEnabled(false);
+
+  // the dio controls the output (in PWM mode)
+  m_dio.SetPWMRate(15625);
+  m_dio.EnablePWM(0.5);
+
+  HAL_Report(HALUsageReporting::kResourceType_NidecBrushless, pwmChannel + 1);
+  registry.AddLW(this, "Nidec Brushless", pwmChannel);
+}
+
+void NidecBrushless::Set(double speed) {
+  if (!m_disabled) {
+    m_speed = speed;
+    m_dio.UpdateDutyCycle(0.5 + 0.5 * (m_isInverted ? -speed : speed));
+    m_pwm.SetRaw(0xffff);
+  }
+  Feed();
+}
+
+double NidecBrushless::Get() const {
+  return m_speed;
+}
+
+void NidecBrushless::SetInverted(bool isInverted) {
+  m_isInverted = isInverted;
+}
+
+bool NidecBrushless::GetInverted() const {
+  return m_isInverted;
+}
+
+void NidecBrushless::Disable() {
+  m_disabled = true;
+  m_dio.UpdateDutyCycle(0.5);
+  m_pwm.SetDisabled();
+}
+
+void NidecBrushless::Enable() {
+  m_disabled = false;
+}
+
+void NidecBrushless::StopMotor() {
+  m_dio.UpdateDutyCycle(0.5);
+  m_pwm.SetDisabled();
+}
+
+void NidecBrushless::GetDescription(wpi::raw_ostream& desc) const {
+  desc << "Nidec " << GetChannel();
+}
+
+int NidecBrushless::GetChannel() const {
+  return m_pwm.GetChannel();
+}
+
+void NidecBrushless::InitSendable(SendableBuilder& builder) {
+  builder.SetSmartDashboardType("Nidec Brushless");
+  builder.SetActuator(true);
+  builder.SetSafeState([=]() { StopMotor(); });
+  builder.AddDoubleProperty(
+      "Value", [=]() { return Get(); }, [=](double value) { Set(value); });
+}