v4l2_device.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * Common base for V4L2 video devices and subdevices
 */

#pragma once

#include <map>
#include <memory>
#include <optional>
#include <stdint.h>
#include <vector>

#include <linux/videodev2.h>

#include <libcamera/base/log.h>
#include <libcamera/base/signal.h>
#include <libcamera/base/span.h>
#include <libcamera/base/unique_fd.h>

#include <libcamera/color_space.h>
#include <libcamera/controls.h>

#include "libcamera/internal/formats.h"

namespace libcamera {

class EventNotifier;

class V4L2Device : protected Loggable
{
public:
    void close();
    bool isOpen() const { return fd_.isValid(); }

    const ControlInfoMap &controls() const { return controls_; }

    ControlList getControls(const std::vector<uint32_t> &ids);
    int setControls(ControlList *ctrls);

    const struct v4l2_query_ext_ctrl *controlInfo(uint32_t id) const;

    const std::string &deviceNode() const { return deviceNode_; }
    std::string devicePath() const;

    bool supportsFrameStartEvent();
    int setFrameStartEnabled(bool enable);
    Signal<uint32_t> frameStart;

    void updateControlInfo();

protected:
    V4L2Device(const std::string &deviceNode);
    ~V4L2Device();

    int open(unsigned int flags);
    int setFd(UniqueFD fd);

    int ioctl(unsigned long request, void *argp);

    int fd() const { return fd_.get(); }

    template<typename T>
    static std::optional<ColorSpace> toColorSpace(const T &v4l2Format,
                              PixelFormatInfo::ColourEncoding colourEncoding);

    template<typename T>
    static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);

private:
    static ControlType v4l2CtrlType(uint32_t ctrlType);
    static std::unique_ptr<ControlId> v4l2ControlId(const v4l2_query_ext_ctrl &ctrl);
    std::optional<ControlInfo> v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl);
    std::optional<ControlInfo> v4l2MenuControlInfo(const v4l2_query_ext_ctrl &ctrl);

    void listControls();
    void updateControls(ControlList *ctrls,
                Span<const v4l2_ext_control> v4l2Ctrls);

    void eventAvailable();

    std::map<unsigned int, struct v4l2_query_ext_ctrl> controlInfo_;
    std::vector<std::unique_ptr<ControlId>> controlIds_;
    ControlIdMap controlIdMap_;
    ControlInfoMap controls_;
    std::string deviceNode_;
    UniqueFD fd_;

    EventNotifier *fdEventNotifier_;
    bool frameStartEnabled_;
};

} /* namespace libcamera */