gpio: add noop GPIO implementation

components/ocs_io/gpio/noop_gpio.h

@@ -0,0 +1,68 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Tendry Lab
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include "ocs_core/noncopyable.h"
+#include "ocs_io/gpio/igpio.h"
+
+namespace ocs {
+namespace io {
+namespace gpio {
+
+class NoopGpio : public IGpio, private core::NonCopyable<> {
+public:
+    //! Initialize.
+    //!
+    //! @params
+    //!  - @p gpio_num - GPIO number to be reported to the caller.
+    explicit NoopGpio(GpioNum gpio_num)
+        : gpio_num_(gpio_num) {
+    }
+
+    //! Return GPIO number.
+    GpioNum get_num() const override {
+        return gpio_num_;
+    }
+
+    //! Non-operational level getting.
+    status::StatusCode get_level(Level& level) override {
+        level = 0;
+
+        return status::StatusCode::OK;
+    }
+
+    //! Non-operational level setting.
+    status::StatusCode set_level(Level) override {
+        return status::StatusCode::OK;
+    }
+
+    //! Non-operational state flipping.
+    status::StatusCode flip() override {
+        return status::StatusCode::OK;
+    }
+
+    //! Non-operational GPIO enabling.
+    status::StatusCode turn_on() override {
+        return status::StatusCode::OK;
+    }
+
+    //! Non-operational GPIO disabling.
+    status::StatusCode turn_off() override {
+        return status::StatusCode::OK;
+    }
+
+    //! Non-operational direction setting.
+    status::StatusCode set_direction(Direction) override {
+        return status::StatusCode::OK;
+    }
+
+private:
+    const GpioNum gpio_num_ { static_cast<GpioNum>(0) };
+};
+
+} // namespace gpio
+} // namespace io
+} // namespace ocs