libcamera v0.0.0+3423-a7ab5ef1
Supporting cameras in Linux since 2019
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 * v4l2_device.h - 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 <vector>
14
15#include <linux/videodev2.h>
16
17#include <libcamera/base/log.h>
19#include <libcamera/base/span.h>
21
23#include <libcamera/controls.h>
24
25namespace libcamera {
26
27class EventNotifier;
28
29class V4L2Device : protected Loggable
30{
31public:
32 void close();
33 bool isOpen() const { return fd_.isValid(); }
34
35 const ControlInfoMap &controls() const { return controls_; }
36
37 ControlList getControls(const std::vector<uint32_t> &ids);
38 int setControls(ControlList *ctrls);
39
40 const struct v4l2_query_ext_ctrl *controlInfo(uint32_t id) const;
41
42 const std::string &deviceNode() const { return deviceNode_; }
43 std::string devicePath() const;
44
45 int setFrameStartEnabled(bool enable);
47
48 void updateControlInfo();
49
50protected:
51 V4L2Device(const std::string &deviceNode);
53
54 int open(unsigned int flags);
55 int setFd(UniqueFD fd);
56
57 int ioctl(unsigned long request, void *argp);
58
59 int fd() const { return fd_.get(); }
60
61 template<typename T>
62 static std::optional<ColorSpace> toColorSpace(const T &v4l2Format);
63
64 template<typename T>
65 static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);
66
67private:
68 static ControlType v4l2CtrlType(uint32_t ctrlType);
69 static std::unique_ptr<ControlId> v4l2ControlId(const v4l2_query_ext_ctrl &ctrl);
70 ControlInfo v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl);
71 ControlInfo v4l2MenuControlInfo(const v4l2_query_ext_ctrl &ctrl);
72
73 void listControls();
74 void updateControls(ControlList *ctrls,
75 Span<const v4l2_ext_control> v4l2Ctrls);
76
77 void eventAvailable();
78
79 std::map<unsigned int, struct v4l2_query_ext_ctrl> controlInfo_;
80 std::vector<std::unique_ptr<ControlId>> controlIds_;
81 ControlIdMap controlIdMap_;
82 ControlInfoMap controls_;
83 std::string deviceNode_;
84 UniqueFD fd_;
85
86 EventNotifier *fdEventNotifier_;
87 bool frameStartEnabled_;
88};
89
90} /* namespace libcamera */
A map of ControlId to ControlInfo.
Definition: controls.h:305
Describe the limits of valid values for a Control.
Definition: controls.h:268
Associate a list of ControlId with their values for an object.
Definition: controls.h:349
Notify of activity on a file descriptor.
Definition: event_notifier.h:20
Base class to support log message extensions.
Definition: log.h:86
unique_ptr-like wrapper for a file descriptor
Definition: unique_fd.h:18
int get() const
Retrieve the managed file descriptor.
Definition: unique_fd.h:60
bool isValid() const
Check if the UniqueFD owns a valid file descriptor.
Definition: unique_fd.h:61
Base class for V4L2VideoDevice and V4L2Subdevice.
Definition: v4l2_device.h:30
~V4L2Device()
Destroy a V4L2Device.
Definition: v4l2_device.cpp:68
bool isOpen() const
Check if the V4L2 device node is open.
Definition: v4l2_device.h:33
static std::optional< ColorSpace > toColorSpace(const T &v4l2Format)
Convert the color space fields in a V4L2 format to a ColorSpace.
Definition: v4l2_device.cpp:819
int setFrameStartEnabled(bool enable)
Enable or disable frame start event notification.
Definition: v4l2_device.cpp:419
int ioctl(unsigned long request, void *argp)
Perform an IOCTL system call on the device node.
Definition: v4l2_device.cpp:450
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:879
const ControlInfoMap & controls() const
Retrieve the supported V4L2 controls and their information.
Definition: v4l2_device.h:35
void close()
Close the device node.
Definition: v4l2_device.cpp:138
void updateControlInfo()
Update the information for all device controls.
Definition: v4l2_device.cpp:651
Signal< uint32_t > frameStart
A Signal emitted when capture of a frame has started.
Definition: v4l2_device.h:46
int open(unsigned int flags)
Open a V4L2 device node.
Definition: v4l2_device.cpp:81
int fd() const
Retrieve the V4L2 device file descriptor.
Definition: v4l2_device.h:59
std::string devicePath() const
Retrieve the device path in sysfs.
Definition: v4l2_device.cpp:393
ControlList getControls(const std::vector< uint32_t > &ids)
Read controls from the device.
Definition: v4l2_device.cpp:175
int setControls(ControlList *ctrls)
Write controls to the device.
Definition: v4l2_device.cpp:278
int setFd(UniqueFD fd)
Set the file descriptor of a V4L2 device.
Definition: v4l2_device.cpp:119
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:373
V4L2Device(const std::string &deviceNode)
Construct a V4L2Device.
Definition: v4l2_device.cpp:59
const std::string & deviceNode() const
Retrieve the device node path.
Definition: v4l2_device.h:42
Class and enums to represent color spaces.
Framework to manage controls related to an object.
Logging infrastructure.
Top-level libcamera namespace.
Definition: backtrace.h:17
ControlType
Define the data type of a Control.
Definition: controls.h:26
std::unordered_map< unsigned int, const ControlId * > ControlIdMap
A map of numerical control ID to ControlId.
Definition: controls.h:302
Signal & slot implementation.
File descriptor wrapper that owns a file descriptor.