Replace shared_ptr construction with factory pattern to eliminate clang warnings

[Copilot]

Direct construction of shared_ptr from raw pointers (std::shared_ptr<T>(new T(...))) triggers clang warnings when the class has virtual functions but non-virtual destructors. This pattern appeared in all peripheral class GetInstance() methods.

Changes

Peripheral classes (Spi, AuxSpi, Gpio, Pwm, Dma):

• Inherit from std::enable_shared_from_this<T>
• Add factory struct with Create() static method
• Declare factory as friend to access private constructors

Factory pattern implementation:

// Before
instances_[index] = std::shared_ptr<Spi>(new Spi(REG_SPI0));

// After
struct SpiFactory {
  static std::shared_ptr<Spi> Create(SpiRegisterMap* register_map) {
    struct EnableMakeShared : public Spi {
      explicit EnableMakeShared(SpiRegisterMap* reg_map) : Spi(reg_map) {}
    };
    return std::make_shared<EnableMakeShared>(register_map);
  }
};
instances_[index] = SpiFactory::Create(REG_SPI0);

The local EnableMakeShared struct grants make_shared access to private constructors while maintaining encapsulation. External API remains unchanged.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>peripheralのインスタンスをshared_from_this()でshared_ptr化する</issue_title>
<issue_description>- std::shared_ptr<Spi>(new Spi(REG_SPI0));のような書き方ではclangでビルド時にwarningが出る

• 全ペリフェラルクラスのGetInstanceで、newでインスタンス生成し直接shared_ptrに変換するのではなく、shared_from_this()で変換するように修正</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes peripheralのインスタンスをshared_from_this()でshared_ptr化する #4

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.