libcamera v0.5.1
Supporting cameras in Linux since 2019
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v4l2_device.h
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2/*
3 * Copyright (C) 2019, Google Inc.
4 *
5 * Common base for V4L2 video devices and subdevices
6 */
7
8#pragma once
9
10#include <map>
11#include <memory>
12#include <optional>
13#include <stdint.h>
14#include <vector>
15
16#include <linux/videodev2.h>
17
18#include <libcamera/base/log.h>
20#include <libcamera/base/span.h>
22
24#include <libcamera/controls.h>
25
27
28namespace libcamera {
29
30class EventNotifier;
31
32class V4L2Device : protected Loggable
33{
34public:
35 void close();
36 bool isOpen() const { return fd_.isValid(); }
37
38 const ControlInfoMap &controls() const { return controls_; }
39
40 ControlList getControls(const std::vector<uint32_t> &ids);
41 int setControls(ControlList *ctrls);
42
43 const struct v4l2_query_ext_ctrl *controlInfo(uint32_t id) const;
44
45 const std::string &deviceNode() const { return deviceNode_; }
46 std::string devicePath() const;
47
49 int setFrameStartEnabled(bool enable);
51
52 void updateControlInfo();
53
54protected:
55 V4L2Device(const std::string &deviceNode);
57
58 int open(unsigned int flags);
59 int setFd(UniqueFD fd);
60
61 int ioctl(unsigned long request, void *argp);
62
63 int fd() const { return fd_.get(); }
64
65 template<typename T>
66 static std::optional<ColorSpace> toColorSpace(const T &v4l2Format,
67 PixelFormatInfo::ColourEncoding colourEncoding);
68
69 template<typename T>
70 static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);
71
72private:
73 static ControlType v4l2CtrlType(uint32_t ctrlType);
74 static std::unique_ptr<ControlId> v4l2ControlId(const v4l2_query_ext_ctrl &ctrl);
75 std::optional<ControlInfo> v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl);
76 std::optional<ControlInfo> v4l2MenuControlInfo(const v4l2_query_ext_ctrl &ctrl);
77
78 void listControls();
79 void updateControls(ControlList *ctrls,
80 Span<const v4l2_ext_control> v4l2Ctrls);
81
82 void eventAvailable();
83
84 std::map<unsigned int, struct v4l2_query_ext_ctrl> controlInfo_;
85 std::vector<std::unique_ptr<ControlId>> controlIds_;
86 ControlIdMap controlIdMap_;
87 ControlInfoMap controls_;
88 std::string deviceNode_;
89 UniqueFD fd_;
90
91 EventNotifier *fdEventNotifier_;
92 bool frameStartEnabled_;
93};
94
95} /* namespace libcamera */
A map of ControlId to ControlInfo.
Definition controls.h:367
Associate a list of ControlId with their values for an object.
Definition controls.h:411
Notify of activity on a file descriptor.
Definition event_notifier.h:20
Base class to support log message extensions.
Definition log.h:92
ColourEncoding
The colour encoding type.
Definition formats.h:23
Generic signal and slot communication mechanism.
Definition signal.h:39
unique_ptr-like wrapper for a file descriptor
Definition unique_fd.h:17
~V4L2Device()
Destroy a V4L2Device.
Definition v4l2_device.cpp:68
Signal< uint32_t > frameStart
A Signal emitted when capture of a frame has started.
Definition v4l2_device.h:50
int setFrameStartEnabled(bool enable)
Enable or disable frame start event notification.
Definition v4l2_device.cpp:483
int ioctl(unsigned long request, void *argp)
Perform an IOCTL system call on the device node.
Definition v4l2_device.cpp:514
static int fromColorSpace(const std::optional< ColorSpace > &colorSpace, T &v4l2Format)
Fill in the color space fields of a V4L2 format from a ColorSpace.
Definition v4l2_device.cpp:1012
const ControlInfoMap & controls() const
Retrieve the supported V4L2 controls and their information.
Definition v4l2_device.h:38
void close()
Close the device node.
Definition v4l2_device.cpp:140
void updateControlInfo()
Update the information for all device controls.
Definition v4l2_device.cpp:759
int open(unsigned int flags)
Open a V4L2 device node.
Definition v4l2_device.cpp:81
bool supportsFrameStartEvent()
Check if frame start event is supported.
Definition v4l2_device.cpp:461
std::string devicePath() const
Retrieve the device path in sysfs.
Definition v4l2_device.cpp:435
const std::string & deviceNode() const
Retrieve the device node path.
Definition v4l2_device.h:45
ControlList getControls(const std::vector< uint32_t > &ids)
Read controls from the device.
Definition v4l2_device.cpp:177
int fd() const
Retrieve the V4L2 device file descriptor.
Definition v4l2_device.h:63
int setControls(ControlList *ctrls)
Write controls to the device.
Definition v4l2_device.cpp:295
int setFd(UniqueFD fd)
Set the file descriptor of a V4L2 device.
Definition v4l2_device.cpp:119
static std::optional< ColorSpace > toColorSpace(const T &v4l2Format, PixelFormatInfo::ColourEncoding colourEncoding)
Convert the color space fields in a V4L2 format to a ColorSpace.
Definition v4l2_device.cpp:933
const struct v4l2_query_ext_ctrl * controlInfo(uint32_t id) const
Retrieve the v4l2_query_ext_ctrl information for the given control.
Definition v4l2_device.cpp:415
V4L2Device(const std::string &deviceNode)
Construct a V4L2Device.
Definition v4l2_device.cpp:59
bool isOpen() const
Check if the V4L2 device node is open.
Definition v4l2_device.h:36
Class and enums to represent color spaces.
Framework to manage controls related to an object.
Types and helper functions to handle libcamera image formats.
Logging infrastructure.
Top-level libcamera namespace.
Definition backtrace.h:17
ControlType
Define the data type of a Control.
Definition controls.h:29
std::unordered_map< unsigned int, const ControlId * > ControlIdMap
A map of numerical control ID to ControlId.
Definition controls.h:364
Signal & slot implementation.
File descriptor wrapper that owns a file descriptor.