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"
#include "libcamera/internal/v4l2_request.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(Span<const uint32_t> ids, const V4L2Request *request = nullptr);
    int setControls(ControlList *ctrls, const V4L2Request *request = nullptr);
 
    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 */