libcamera: camera_lens: Add a new class to model a camera lens

The CameraLens class abstracts camera lens and provides helper
functions to ease interactions with them.

Signed-off-by: Han-Lin Chen <hanlinchen@chromium.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/internal/camera_lens.h

@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Google Inc.
+ *
+ * camera_lens.h - A camera lens controller
+ */
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include <libcamera/base/class.h>
+#include <libcamera/base/log.h>
+
+namespace libcamera {
+
+class MediaEntity;
+class V4L2Subdevice;
+
+class CameraLens : protected Loggable
+{
+public:
+	explicit CameraLens(const MediaEntity *entity);
+	~CameraLens();
+
+	int init();
+	int setFocusPostion(int32_t position);
+
+	const std::string &model() const { return model_; }
+
+protected:
+	std::string logPrefix() const override;
+
+private:
+	LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraLens)
+
+	int validateLensDriver();
+
+	const MediaEntity *entity_;
+	std::unique_ptr<V4L2Subdevice> subdev_;
+
+	std::string model_;
+};
+
+} /* namespace libcamera */

include/libcamera/internal/meson.build

@@ -14,6 +14,7 @@ libcamera_internal_headers = files([
     'byte_stream_buffer.h',
     'camera.h',
     'camera_controls.h',
+    'camera_lens.h',
     'camera_sensor.h',
     'camera_sensor_properties.h',
     'control_serializer.h',