MFi Program
The MFi Program includes third-party hardware accessories that use Apple's MFi licensed technology to connect electronically to Apple devices. MFi licensed technologies and components include the following:
MFi Game Controller
Developers who wish to develop electronic accessories for iPhone, iPad or iPod using licensed technology should join the MFi Program
AirPlay audio
CarPlay
GymKit
HomeKit
iPod Accessory Protocol (iAP), the protocol used to communicate with iPhone, iPad and iPod
MFi Game Controller
MFi Hearing Aid
Wi-Fi Accessory Configuration (WAC)
MFiを取らなくていいアクセサリー
Accessories that use only standard Bluetooth profiles supported by iOS
HIDに対応しているので、普通のキーボードなんかはMFi認証が不要なはず
Accessories that use only Bluetooth Low Energy (BLE) (note: BLE-enabled HomeKit accessories and BLE-enabled MFi Hearing Aids are part of the MFi Program)
MFiを通ってるとAppleのFrameworkで適切に抽象化される
Apple has specified the look and behavior of the controls to MFi accessory manufacturers. By supporting the Game Controller framework in your game, you support all of these game controllers.