Message ID | 20190624142859.19313-2-jacopo@jmondi.org |
---|---|
State | Superseded |
Headers | show |
Series |
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Related | show |
Hi Jacopo, Thank you for the patch. On Mon, Jun 24, 2019 at 04:28:54PM +0200, Jacopo Mondi wrote: > Add libcamera V4L2 control support, implemented using the V4L2 Extended > Control APIs. This patch defines the types used to create and manage > controls. > > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> > --- > src/libcamera/include/v4l2_controls.h | 79 ++++++++ > src/libcamera/meson.build | 1 + > src/libcamera/v4l2_controls.cpp | 281 ++++++++++++++++++++++++++ > 3 files changed, 361 insertions(+) > create mode 100644 src/libcamera/include/v4l2_controls.h > create mode 100644 src/libcamera/v4l2_controls.cpp > > diff --git a/src/libcamera/include/v4l2_controls.h b/src/libcamera/include/v4l2_controls.h > new file mode 100644 > index 000000000000..aad4ef14ed31 > --- /dev/null > +++ b/src/libcamera/include/v4l2_controls.h > @@ -0,0 +1,79 @@ > +/* SPDX-License-Identifier: LGPL-2.1-or-later */ > +/* > + * Copyright (C) 2019, Google Inc. > + * > + * v4l2_controls.h - V4L2 Controls Support > + */ > + > +#ifndef __LIBCAMERA_V4L2_CONTROLS_H__ > +#define __LIBCAMERA_V4L2_CONTROLS_H__ > + > +#include <string> > +#include <vector> > + > +#include <stdint.h> > + > +#include <linux/v4l2-controls.h> > +#include <linux/videodev2.h> > + > +namespace libcamera { > + > +class V4L2ControlInfo > +{ > +public: > + V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl); > + > + unsigned int id() const { return id_; } > + unsigned int type() const { return type_; } > + size_t size() const { return size_; } > + const std::string &name() const { return name_; } > + > +private: > + unsigned int id_; > + unsigned int type_; > + size_t size_; > + std::string name_; > +}; > + > +class V4L2Control > +{ > +public: > + V4L2Control(unsigned int id, int value = 0) > + : id_(id), value_(value) {} > + > + int64_t value() const { return value_; } > + void setValue(int64_t value) { value_ = value; } > + > + unsigned int id() const { return id_; } > + > +private: > + unsigned int id_; > + int64_t value_; > +}; > + > +class V4L2ControlList > +{ > +public: > + using iterator = std::vector<V4L2Control>::iterator; > + using const_iterator = std::vector<V4L2Control>::const_iterator; > + > + iterator begin() { return controls_.begin(); } > + const_iterator begin() const { return controls_.begin(); } > + iterator end() { return controls_.end(); } > + const_iterator end() const { return controls_.end(); } > + > + bool empty() const { return controls_.empty(); } > + std::size_t size() const { return controls_.size(); } > + > + void clear() { controls_.clear(); } > + int add(unsigned int id, int64_t value = 0); > + > + V4L2Control *getControl(unsigned int id); > + > +private: > + std::vector<V4L2Control> controls_; > +}; > + > +} /* namespace libcamera */ > + > +#endif /* __LIBCAMERA_V4L2_CONTROLS_H__ */ > diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build > index f26ad5b2dc57..985aa7e8ab0e 100644 > --- a/src/libcamera/meson.build > +++ b/src/libcamera/meson.build > @@ -23,6 +23,7 @@ libcamera_sources = files([ > 'stream.cpp', > 'timer.cpp', > 'utils.cpp', > + 'v4l2_controls.cpp', > 'v4l2_device.cpp', > 'v4l2_subdevice.cpp', > 'v4l2_videodevice.cpp', > diff --git a/src/libcamera/v4l2_controls.cpp b/src/libcamera/v4l2_controls.cpp > new file mode 100644 > index 000000000000..ac932d855dd6 > --- /dev/null > +++ b/src/libcamera/v4l2_controls.cpp > @@ -0,0 +1,281 @@ > +/* SPDX-License-Identifier: LGPL-2.1-or-later */ > +/* > + * Copyright (C) 2019, Google Inc. > + * > + * v4l2_controls.cpp - V4L2 Controls Support > + */ > + > +#include "v4l2_controls.h" > + > +/** > + * \file v4l2_controls.h > + * \brief Support for V4L2 Controls using the V4L2 Extended Controls APIs > + * > + * The V4L2 Control API allows application to inspect and modify sets of > + * configurable parameters on the video device or subdevice of interest. The > + * nature of the parameters an application could modify using the control > + * framework depends on what the driver implements support for, and on the > + * characteristics of the underlying hardware platform. Generally controls are > + * used to modify user visible settings, such as the image brightness and > + * exposure time, or non-standard parameters which cannot be controlled through > + * the V4L2 format negotiation API. > + * > + * Controls are identified by a numerical ID, defined by the V4L2 kernel headers > + * and have an associated type. Each control has a value, which is the data that > + * can be modified with V4L2Device::setControls() or retrieved with > + * V4L2Device::getControls(). > + * > + * The control's type along with the control's flags define the type of the > + * control's value content. Controls can transport a single data value stored in > + * variable inside the control, or they might as well deal with more complex > + * data types, such as arrays of matrices, stored in a contiguous memory > + * locations associated with the control and called 'the payload'. Such controls > + * are called 'compound controls' and are currently not supported by the > + * libcamera V4L2 control framework. > + * > + * libcamera implements support for controls using the V4L2 Extended Control > + * API, which allows future handling of controls with payloads of arbitrary > + * sizes. > + * > + * The libcamera V4L2 Controls framework operates on lists of controls, wrapped > + * by the V4L2ControlList class, to match the V4L2 extended controls API. The > + * interface to set and get control is implemented by the V4L2Device class, and > + * this file only provides the data type definitions. > + * > + * \todo Add support for compound controls > + */ > + > +namespace libcamera { > + > +/** > + * \class V4L2ControlInfo > + * \brief Information on a V4L2 control > + * > + * The V4L2ControlInfo class represents all the information related to a V4L2 > + * control, such as its ID, its type, its user-readable name and the expected > + * size of its value data. > + * > + * V4L2ControlInfo instances are created by inspecting the fieldS of a struct > + * v4l2_query_ext_ctrl structure, after it has been filled by the device driver > + * as a consequence of a VIDIOC_QUERY_EXT_CTRL ioctl call. > + * > + * This class does not contain the control value, but only static information on > + * the control, which shall be cached by the caller at initialisation time or > + * the first time the control information is accessed. > + */ > + > +/** > + * \brief Construct a V4L2ControlInfo from a struct v4l2_query_ext_ctrl > + * \param ctrl The struct v4l2_query_ext_ctrl as returned by the kernel > + */ > +V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl) > +{ > + id_ = ctrl.id; > + type_ = ctrl.type; > + name_ = static_cast<const char *>(ctrl.name); > + size_ = ctrl.elem_size * ctrl.elems; > +} > + > +/** > + * \fn V4L2ControlInfo::id() > + * \brief Retrieve the control ID > + * \return The V4L2 control ID > + */ > + > +/** > + * \fn V4L2ControlInfo::type() > + * \brief Retrieve the control type as defined by V4L2_CTRL_TYPE_* > + * \return The V4L2 control type > + */ > + > +/** > + * \fn V4L2ControlInfo::size() > + * \brief Retrieve the control value data size (in bytes) > + * \return The V4L2 control value data size > + */ > + > +/** > + * \fn V4L2ControlInfo::name() > + * \brief Retrieve the control user readable name > + * \return The V4L2 control user readable name > + */ > + > +/** > + * \class V4L2Control > + * \brief A V4L2 control value > + * > + * The V4L2Control class represent the value of a V4L2 control. The class > + * stores values that have been read from or will be applied to a V4L2 device. > + * > + * The value stored in the class instances does not reflect what is actually > + * applied to the hardware but is a pure software cache optionally initialized > + * at control creation time and modified by a control read or write operation. > + * > + * The write and read controls the V4L2Control class instances are not meant > + * to be directly used but are instead intended to be grouped in > + * V4L2ControlList instances, which are then passed as parameters to > + * V4L2Device::setControls() and V4L2Device::getControls() operations. > + */ > + > +/** > + * \fn V4L2Control::V4L2Control > + * \brief Construct a V4L2 control with \a id and \a value > + * \param id The V4L2 control ID > + * \param value The control value > + */ > + > +/** > + * \fn V4L2Control::value() > + * \brief Retrieve the value of the control > + * > + * This method returns the cached control value, initially set by > + * V4L2ControlList::add() and then updated when the controls are read or > + * written with V4L2Device::getControls() and V4L2Device::setControls(). > + * > + * \return The V4L2 control value > + */ > + > +/** > + * \fn V4L2Control::setValue() > + * \brief Set the value of the control > + * \param value The new V4L2 control value > + * > + * This method stores the control value, which will be applied to the > + * device when calling V4L2Device::setControls(). > + */ > + > +/** > + * \fn V4L2Control::id() > + * \brief Retrieve the control ID this instance refers to > + * \return The V4L2Control ID > + */ > + > +/** > + * \class V4L2ControlList > + * \brief Container of V4L2Control instances > + * > + * The V4L2ControlList class works as a container for a list of V4L2Control > + * instances. The class provides operations to add a new control to the list, > + * get back a control value, and reset the list of controls it contains. > + * > + * In order to set and get controls, user of the libcamera V4L2 control > + * framework should operate on instances of the V4L2ControlList class, and use > + * them as argument for the V4L2Device::setControls() and > + * V4L2Device::getControls() operations, which write and read a list of > + * controls to or from a V4L2 device (a video device or a subdevice). > + * > + * Controls are added to a V4L2ControlList instance with the add() method, with > + * or without a value. > + * > + * To write controls to a device, the controls of interest shall be added with > + * an initial value by calling V4L2ControlList::add(unsigned int id, int64_t > + * value) to prepare for a write operation. Once the values of all controls of > + * interest have been added, the V4L2ControlList instance is passed to the > + * V4L2Device::setControls(), which sets the controls on the device. > + * > + * To read controls from a device, the desired controls are added with > + * V4L2ControlList::add(unsigned int id) to prepare for a read operation. The > + * V4L2ControlList instance is then passed to V4L2Device::getControls(), which > + * reads the controls from the device and updates the values stored in > + * V4L2ControlList. > + * > + * V4L2ControlList instances can be reset to remove all controls they contain > + * and prepare to be re-used for a new control write/read sequence. > + */ > + > +/** > + * \typedef V4L2ControlList::iterator > + * \brief Iterator on the V4L2 controls contained in the instance > + */ > + > +/** > + * \typedef V4L2ControlList::const_iterator > + * \brief Const iterator on the V4L2 controls contained in the instance > + */ > + > +/** > + * \fn iterator V4L2ControlList::begin() > + * \brief Retrieve an iterator to the first V4L2Control in the instance > + * \return An iterator to the first V4L2 control > + */ > + > +/** > + * \fn const_iterator V4L2ControlList::begin() const > + * \brief Retrieve a constant iterator to the first V4L2Control in the instance > + * \return A constant iterator to the first V4L2 control > + */ > + > +/** > + * \fn iterator V4L2ControlList::end() > + * \brief Retrieve an iterator pointing to the past-the-end V4L2Control in the > + * instance > + * \return An iterator to the element following the last V4L2 control in the > + * instance > + */ > + > +/** > + * \fn const_iterator V4L2ControlList::end() const > + * \brief Retrieve a constant iterator pointing to the past-the-end V4L2Control > + * in the instance > + * \return A constant iterator to the element following the last V4L2 control > + * in the instance > + */ > + > +/** > + * \fn V4L2ControlList::empty() > + * \brief Verify if the instance does not contain any control > + * \return True if the instance does not contain any control, false otherwise > + */ > + > +/** > + * \fn V4L2ControlList::size() > + * \brief Retrieve the number on controls in the instance > + * \return The number of V4L2Control stored in the instance > + */ > + > +/** > + * \fn V4L2ControlList::clear() > + * \brief Remove all controls in the instance > + */ > + > +/** > + * \brief Add control with \a id and optional \a value to the instance > + * \param id The V4L2 control ID (V4L2_CID_*) > + * \param value The V4L2 control value > + * > + * This methods add a new V4L2 control to the V4L2ControlList. The newly s/methods add/method adds/ > + * inserted control should be unique (no other control with \a id should be > + * part of the V4L2 control list) otherwise a negative error code is returned. > + * > + * \return 0 on success or a negative error code otherwise > + * \retval -EBUSY A control with \a id already exists > + */ > +int V4L2ControlList::add(unsigned int id, int64_t value) > +{ > + for (const V4L2Control &ctrl : controls_) { > + if (ctrl.id() == id) > + return -EBUSY; > + } This makes adding controls a O(n^2) operation :-/ What it be better to just say that adding two controls with the same ID leads to undefined results ? > + > + controls_.emplace_back(id, value); > + > + return 0; > +} > + > +/** > + * \brief Get a pointer the control with \a id > + * \param id The V4L2 control ID (V4L2_CID_xx) > + * \return A pointer to the V4L2Control with \a id or nullptr if the > + * control ID is not part of this instance. > + */ > +V4L2Control *V4L2ControlList::getControl(unsigned int id) > +{ > + for (V4L2Control &ctrl : controls_) { > + if (ctrl.id() == id) > + return &ctrl; > + } > + > + return nullptr; > +} > + > +} /* namespace libcamera */
diff --git a/src/libcamera/include/v4l2_controls.h b/src/libcamera/include/v4l2_controls.h new file mode 100644 index 000000000000..aad4ef14ed31 --- /dev/null +++ b/src/libcamera/include/v4l2_controls.h @@ -0,0 +1,79 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * v4l2_controls.h - V4L2 Controls Support + */ + +#ifndef __LIBCAMERA_V4L2_CONTROLS_H__ +#define __LIBCAMERA_V4L2_CONTROLS_H__ + +#include <string> +#include <vector> + +#include <stdint.h> + +#include <linux/v4l2-controls.h> +#include <linux/videodev2.h> + +namespace libcamera { + +class V4L2ControlInfo +{ +public: + V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl); + + unsigned int id() const { return id_; } + unsigned int type() const { return type_; } + size_t size() const { return size_; } + const std::string &name() const { return name_; } + +private: + unsigned int id_; + unsigned int type_; + size_t size_; + std::string name_; +}; + +class V4L2Control +{ +public: + V4L2Control(unsigned int id, int value = 0) + : id_(id), value_(value) {} + + int64_t value() const { return value_; } + void setValue(int64_t value) { value_ = value; } + + unsigned int id() const { return id_; } + +private: + unsigned int id_; + int64_t value_; +}; + +class V4L2ControlList +{ +public: + using iterator = std::vector<V4L2Control>::iterator; + using const_iterator = std::vector<V4L2Control>::const_iterator; + + iterator begin() { return controls_.begin(); } + const_iterator begin() const { return controls_.begin(); } + iterator end() { return controls_.end(); } + const_iterator end() const { return controls_.end(); } + + bool empty() const { return controls_.empty(); } + std::size_t size() const { return controls_.size(); } + + void clear() { controls_.clear(); } + int add(unsigned int id, int64_t value = 0); + + V4L2Control *getControl(unsigned int id); + +private: + std::vector<V4L2Control> controls_; +}; + +} /* namespace libcamera */ + +#endif /* __LIBCAMERA_V4L2_CONTROLS_H__ */ diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build index f26ad5b2dc57..985aa7e8ab0e 100644 --- a/src/libcamera/meson.build +++ b/src/libcamera/meson.build @@ -23,6 +23,7 @@ libcamera_sources = files([ 'stream.cpp', 'timer.cpp', 'utils.cpp', + 'v4l2_controls.cpp', 'v4l2_device.cpp', 'v4l2_subdevice.cpp', 'v4l2_videodevice.cpp', diff --git a/src/libcamera/v4l2_controls.cpp b/src/libcamera/v4l2_controls.cpp new file mode 100644 index 000000000000..ac932d855dd6 --- /dev/null +++ b/src/libcamera/v4l2_controls.cpp @@ -0,0 +1,281 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * v4l2_controls.cpp - V4L2 Controls Support + */ + +#include "v4l2_controls.h" + +/** + * \file v4l2_controls.h + * \brief Support for V4L2 Controls using the V4L2 Extended Controls APIs + * + * The V4L2 Control API allows application to inspect and modify sets of + * configurable parameters on the video device or subdevice of interest. The + * nature of the parameters an application could modify using the control + * framework depends on what the driver implements support for, and on the + * characteristics of the underlying hardware platform. Generally controls are + * used to modify user visible settings, such as the image brightness and + * exposure time, or non-standard parameters which cannot be controlled through + * the V4L2 format negotiation API. + * + * Controls are identified by a numerical ID, defined by the V4L2 kernel headers + * and have an associated type. Each control has a value, which is the data that + * can be modified with V4L2Device::setControls() or retrieved with + * V4L2Device::getControls(). + * + * The control's type along with the control's flags define the type of the + * control's value content. Controls can transport a single data value stored in + * variable inside the control, or they might as well deal with more complex + * data types, such as arrays of matrices, stored in a contiguous memory + * locations associated with the control and called 'the payload'. Such controls + * are called 'compound controls' and are currently not supported by the + * libcamera V4L2 control framework. + * + * libcamera implements support for controls using the V4L2 Extended Control + * API, which allows future handling of controls with payloads of arbitrary + * sizes. + * + * The libcamera V4L2 Controls framework operates on lists of controls, wrapped + * by the V4L2ControlList class, to match the V4L2 extended controls API. The + * interface to set and get control is implemented by the V4L2Device class, and + * this file only provides the data type definitions. + * + * \todo Add support for compound controls + */ + +namespace libcamera { + +/** + * \class V4L2ControlInfo + * \brief Information on a V4L2 control + * + * The V4L2ControlInfo class represents all the information related to a V4L2 + * control, such as its ID, its type, its user-readable name and the expected + * size of its value data. + * + * V4L2ControlInfo instances are created by inspecting the fieldS of a struct + * v4l2_query_ext_ctrl structure, after it has been filled by the device driver + * as a consequence of a VIDIOC_QUERY_EXT_CTRL ioctl call. + * + * This class does not contain the control value, but only static information on + * the control, which shall be cached by the caller at initialisation time or + * the first time the control information is accessed. + */ + +/** + * \brief Construct a V4L2ControlInfo from a struct v4l2_query_ext_ctrl + * \param ctrl The struct v4l2_query_ext_ctrl as returned by the kernel + */ +V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl) +{ + id_ = ctrl.id; + type_ = ctrl.type; + name_ = static_cast<const char *>(ctrl.name); + size_ = ctrl.elem_size * ctrl.elems; +} + +/** + * \fn V4L2ControlInfo::id() + * \brief Retrieve the control ID + * \return The V4L2 control ID + */ + +/** + * \fn V4L2ControlInfo::type() + * \brief Retrieve the control type as defined by V4L2_CTRL_TYPE_* + * \return The V4L2 control type + */ + +/** + * \fn V4L2ControlInfo::size() + * \brief Retrieve the control value data size (in bytes) + * \return The V4L2 control value data size + */ + +/** + * \fn V4L2ControlInfo::name() + * \brief Retrieve the control user readable name + * \return The V4L2 control user readable name + */ + +/** + * \class V4L2Control + * \brief A V4L2 control value + * + * The V4L2Control class represent the value of a V4L2 control. The class + * stores values that have been read from or will be applied to a V4L2 device. + * + * The value stored in the class instances does not reflect what is actually + * applied to the hardware but is a pure software cache optionally initialized + * at control creation time and modified by a control read or write operation. + * + * The write and read controls the V4L2Control class instances are not meant + * to be directly used but are instead intended to be grouped in + * V4L2ControlList instances, which are then passed as parameters to + * V4L2Device::setControls() and V4L2Device::getControls() operations. + */ + +/** + * \fn V4L2Control::V4L2Control + * \brief Construct a V4L2 control with \a id and \a value + * \param id The V4L2 control ID + * \param value The control value + */ + +/** + * \fn V4L2Control::value() + * \brief Retrieve the value of the control + * + * This method returns the cached control value, initially set by + * V4L2ControlList::add() and then updated when the controls are read or + * written with V4L2Device::getControls() and V4L2Device::setControls(). + * + * \return The V4L2 control value + */ + +/** + * \fn V4L2Control::setValue() + * \brief Set the value of the control + * \param value The new V4L2 control value + * + * This method stores the control value, which will be applied to the + * device when calling V4L2Device::setControls(). + */ + +/** + * \fn V4L2Control::id() + * \brief Retrieve the control ID this instance refers to + * \return The V4L2Control ID + */ + +/** + * \class V4L2ControlList + * \brief Container of V4L2Control instances + * + * The V4L2ControlList class works as a container for a list of V4L2Control + * instances. The class provides operations to add a new control to the list, + * get back a control value, and reset the list of controls it contains. + * + * In order to set and get controls, user of the libcamera V4L2 control + * framework should operate on instances of the V4L2ControlList class, and use + * them as argument for the V4L2Device::setControls() and + * V4L2Device::getControls() operations, which write and read a list of + * controls to or from a V4L2 device (a video device or a subdevice). + * + * Controls are added to a V4L2ControlList instance with the add() method, with + * or without a value. + * + * To write controls to a device, the controls of interest shall be added with + * an initial value by calling V4L2ControlList::add(unsigned int id, int64_t + * value) to prepare for a write operation. Once the values of all controls of + * interest have been added, the V4L2ControlList instance is passed to the + * V4L2Device::setControls(), which sets the controls on the device. + * + * To read controls from a device, the desired controls are added with + * V4L2ControlList::add(unsigned int id) to prepare for a read operation. The + * V4L2ControlList instance is then passed to V4L2Device::getControls(), which + * reads the controls from the device and updates the values stored in + * V4L2ControlList. + * + * V4L2ControlList instances can be reset to remove all controls they contain + * and prepare to be re-used for a new control write/read sequence. + */ + +/** + * \typedef V4L2ControlList::iterator + * \brief Iterator on the V4L2 controls contained in the instance + */ + +/** + * \typedef V4L2ControlList::const_iterator + * \brief Const iterator on the V4L2 controls contained in the instance + */ + +/** + * \fn iterator V4L2ControlList::begin() + * \brief Retrieve an iterator to the first V4L2Control in the instance + * \return An iterator to the first V4L2 control + */ + +/** + * \fn const_iterator V4L2ControlList::begin() const + * \brief Retrieve a constant iterator to the first V4L2Control in the instance + * \return A constant iterator to the first V4L2 control + */ + +/** + * \fn iterator V4L2ControlList::end() + * \brief Retrieve an iterator pointing to the past-the-end V4L2Control in the + * instance + * \return An iterator to the element following the last V4L2 control in the + * instance + */ + +/** + * \fn const_iterator V4L2ControlList::end() const + * \brief Retrieve a constant iterator pointing to the past-the-end V4L2Control + * in the instance + * \return A constant iterator to the element following the last V4L2 control + * in the instance + */ + +/** + * \fn V4L2ControlList::empty() + * \brief Verify if the instance does not contain any control + * \return True if the instance does not contain any control, false otherwise + */ + +/** + * \fn V4L2ControlList::size() + * \brief Retrieve the number on controls in the instance + * \return The number of V4L2Control stored in the instance + */ + +/** + * \fn V4L2ControlList::clear() + * \brief Remove all controls in the instance + */ + +/** + * \brief Add control with \a id and optional \a value to the instance + * \param id The V4L2 control ID (V4L2_CID_*) + * \param value The V4L2 control value + * + * This methods add a new V4L2 control to the V4L2ControlList. The newly + * inserted control should be unique (no other control with \a id should be + * part of the V4L2 control list) otherwise a negative error code is returned. + * + * \return 0 on success or a negative error code otherwise + * \retval -EBUSY A control with \a id already exists + */ +int V4L2ControlList::add(unsigned int id, int64_t value) +{ + for (const V4L2Control &ctrl : controls_) { + if (ctrl.id() == id) + return -EBUSY; + } + + controls_.emplace_back(id, value); + + return 0; +} + +/** + * \brief Get a pointer the control with \a id + * \param id The V4L2 control ID (V4L2_CID_xx) + * \return A pointer to the V4L2Control with \a id or nullptr if the + * control ID is not part of this instance. + */ +V4L2Control *V4L2ControlList::getControl(unsigned int id) +{ + for (V4L2Control &ctrl : controls_) { + if (ctrl.id() == id) + return &ctrl; + } + + return nullptr; +} + +} /* namespace libcamera */
Add libcamera V4L2 control support, implemented using the V4L2 Extended Control APIs. This patch defines the types used to create and manage controls. Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> --- src/libcamera/include/v4l2_controls.h | 79 ++++++++ src/libcamera/meson.build | 1 + src/libcamera/v4l2_controls.cpp | 281 ++++++++++++++++++++++++++ 3 files changed, 361 insertions(+) create mode 100644 src/libcamera/include/v4l2_controls.h create mode 100644 src/libcamera/v4l2_controls.cpp