From patchwork Wed Jun 19 11:08:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 1474 Return-Path: Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [217.70.183.199]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id C548D6194F for ; Wed, 19 Jun 2019 13:07:49 +0200 (CEST) X-Originating-IP: 2.224.242.101 Received: from uno.lan (2-224-242-101.ip172.fastwebnet.it [2.224.242.101]) (Authenticated sender: jacopo@jmondi.org) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 5484BFF803; Wed, 19 Jun 2019 11:07:49 +0000 (UTC) From: Jacopo Mondi To: libcamera-devel@lists.libcamera.org Date: Wed, 19 Jun 2019 13:08:53 +0200 Message-Id: <20190619110858.20980-2-jacopo@jmondi.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190619110858.20980-1-jacopo@jmondi.org> References: <20190619110858.20980-1-jacopo@jmondi.org> MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH v4 1/6] libcamera: Add V4L2Controls X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Jun 2019 11:07:49 -0000 Add Libcamera V4L2 control support, implemented using the V4L2 Extended Control APIs. This patch defines the types used to define and manage controls. Signed-off-by: Jacopo Mondi --- src/libcamera/include/v4l2_controls.h | 96 ++++++++ src/libcamera/meson.build | 1 + src/libcamera/v4l2_controls.cpp | 337 ++++++++++++++++++++++++++ 3 files changed, 434 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..d7b12801329e --- /dev/null +++ b/src/libcamera/include/v4l2_controls.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * v4l2_controls.h - V4L2 Extended Control Support + */ + +#ifndef __LIBCAMERA_V4L2_CONTROLS_H__ +#define __LIBCAMERA_V4L2_CONTROLS_H__ + +#include +#include +#include + +#include + +#include +#include + +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 type_; + std::string name_; + unsigned int id_; + size_t size_; +}; + +class V4L2Control +{ +public: + unsigned int id() const { return id_; } + +private: + friend class V4L2Device; + friend class V4L2Controls; + + V4L2Control(unsigned int id) + : id_(id) {} + V4L2Control(unsigned int id, int value) + : id_(id), value_(value) {} + + long int value() const { return value_; } + void setValue(long int value) { value_ = value; } + + unsigned int id_; + long int value_; +}; + +class V4L2Controls +{ +public: + V4L2Controls &operator=(const V4L2Controls &) = delete; + + using iterator = std::vector::iterator; + using const_iterator = std::vector::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(); } + size_t size() { return controls_.size(); } + void reset() { controls_.clear(); } + + V4L2Control *operator[](unsigned int index) + { + return &controls_[index]; + } + + void add(unsigned int id, long int value); + void add(unsigned int id); + + int get(unsigned int id); + int set(unsigned int id, long int value); + +private: + V4L2Control *getControl(unsigned int id); + + std::vector 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..75b9c29ca133 --- /dev/null +++ b/src/libcamera/v4l2_controls.cpp @@ -0,0 +1,337 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * v4l2_controls.cpp - V4L2 Extended Control Support + */ + +#include "v4l2_controls.h" + +/** + * \file v4l2_controls.h + * \brief Support for V4L2 Controls using the V4L2 Extended Controls APIs. + * + * The V4L2 defined "Control API" allows application to inspect and modify set + * 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 and class. Each control has a 'value', which is + * the data that can be modified with a call to the 'V4L2Device::setControls()' + * operation or retrieved with a call to 'V4L2Device::getControls()'. + * + * A control class defines the control purpose while its type (along with the + * control's flags) defines the type of the control's value content. Controls + * might 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. + * + * \todo Add support for compound controls + * + * Libcamera implements support for control using the V4L2 'Extended Control' + * framework, which allows easier future handling of controls with payloads + * of arbitrary sizes. + * + * The Libcamera V4L2 Controls framework operates on lists of controls, wrapped + * by the V4L2Controls class, to match the V4L2 extended controls framework. + * The interface to set and get control is implemented by the V4L2Device class, + * and this file only provides the data type definitions. + */ + +namespace libcamera { + +/** + * \class V4L2ControlInfo + * \brief Information on a V4L2 control + * + * The V4L2ControlInfo class represent all the informations relative 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 field of + * a struct v4l2_query_ext_ctrl structure, after it has been filled by the + * device driver as a consequence of an VIDIOC_QUERY_EXT_CTRL ioctl call. + * + * This class does not contain the control value, but only static informations + * on the control, which should ideally be cached the first time the control + * is accessed to be reused each time the control value need to be read or + * applied to the hardware. + */ + +/** + * \brief Construct a V4L2ControlInfo from a struct v4l2_query_ext_ctrl + */ +V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl) +{ + id_ = ctrl.id; + type_ = ctrl.type; + name_ = static_cast(ctrl.name); + size_ = ctrl.elem_size * ctrl.elems; +} + +/** + * \fn V4L2ControlInfo::id() + * \brief Retrieve the control id this instance refers to + * \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 only modified by a control read operation or a + * call to V4L2Controls::set(). + * + * The V4L2Control class instances are not meant to be directly used but are + * instead intended to be grouped in V4L2Controls instances, which are then + * passed as parameters to the set and get control operations implemented in + * V4L2Device::setControls() and V4L2Device::setControls() respectively. + * + * In facts, access to the class constructor and to the control value accessor + * and modifier are restricted to the friend V4L2Controls and V4L2Device + * classes. + */ + +/** + * \fn V4L2Control::id() + * \brief Retrieve the control id this instance refers to + * \return The V4L2Control id + */ + +/** + * \class V4L2Controls + * \brief Wraps a list of V4L2Control + * + * The V4L2Controls class works as a wrapper 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 V4L2Controls class, and use + * them as argument for the V4L2Device::setControls() and + * V4L2Device::getControls() operations, which write and read a list of + * controls from or to a V4L2 device (a video device or a subdevice). + * + * Controls are added to a V4L2Controls instance with the add() method, with + * or without an initial value. + * + * To write controls to a device, the controls of interest should be added + * with an initial value by calling V4L2Controls::add(unsigned int id, long + * int value) to prepare for a write operation. The value of controls which + * are already part of the instance could be updated with a call to + * V4L2Controls::set() operation. Once the values of all controls of interest + * have been initialized in a V4L2Controls instance, this should be then + * passed to the V4L2Device::setControls() operation, which applies each + * control in the list to the hardware. + * + * Alternatively a control can be add without any initial value by calling + * V4L2Controls::add(unsigned int id) and then read from the device passing + * the V4L2Controls instance to V4L2Device::getControls() which read each + * control value from the hardware. + * + * Reading controls with an initialized value from the device, overwrites the + * control's value, reflecting what has been actually read from the hardware. + * + * V4L2Controls instances can be reset to remove all controls it contains and + * prepare to be re-used for a new control write/read sequence. Alternatively, + * the value of a control already part of the instance could be updated by using + * the V4L2Controls::set() method, to avoid going through a reset() when a + * control has to be read then written to the hardware in sequence. + * + * In facts, the following pseudo-code sequences lead to the same result: + * + * V4L2Controls controls; + * controls.add(V4L2_CID_xx); + * dev->getControls(&controls); + * controls.set(V4L2_CID_xx, value); + * dev->setControls(&controls); + * + * V4L2Controls controls; + * controls.add(V4L2_CID_xx); + * dev->getControls(&controls); + * controls.reset(); + * controls.add(V4L2_CID_xx, value); + * dev->setControls(&controls); + */ + +/** + * \typedef V4L2Controls::iterator + * \brief Iterator on the V4L2 controls contained in the instance + */ + +/** + * \typedef V4L2Controls::const_iterator + * \brief Const iterator on the V4L2 controls contained in the instance + */ + +/** + * \fn iterator V4L2Controls::begin() + * \brief Retrieve an iterator to the first V4L2Control in the instance + * \return An iterator to the first V4L2 control + */ + +/** + * \fn const_iterator V4L2Controls::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 V4L2Controls::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 V4L2Controls::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 V4L2Controls::empty() + * \brief Verify if the instance does not contain any control + * \return True if the instance does not contain any control, false otherwise + */ + +/** + * \fn V4L2Controls::size() + * \brief Retrieve the number on controls in the instance + * \return The number of V4L2Control stored in the instance + */ + +/** + * \fn V4L2Controls::reset() + * \brief Removes all controls in the instance + */ + +/** + * \fn V4L2Controls::operator[](unsigned int index) + * \brief Access the control at index \a index + * \param index The index to access + */ + +/** + * \brief Add control \a id with a \a value to the instance + * \param id The V4L2 control id (V4L2_CID_xx) + * \param value The V4L2 control value + */ +void V4L2Controls::add(unsigned int id, long int value) +{ + /* Cannot use emplace_back() as the V4L2Control ctor is private. */ + V4L2Control ctrl(id, value); + controls_.push_back(ctrl); +} + +/** + * \brief Add control \a id without an initial value to the instance + * \param id The V4L2 control id (V4L2_CID_xx) + */ +void V4L2Controls::add(unsigned int id) +{ + /* Cannot use emplace_back() as the V4L2Control ctor is private. */ + V4L2Control ctrl(id); + controls_.push_back(ctrl); +} + +/** + * \brief Retrieve the value of the control with \a id + * \param id The V4L2 control id (V4L2_CID_xx) + * + * Retrieve the value of the control with id \a id. + * + * It is important to notice that the returned value is not read from the + * hardware at the time this operation is called, but it's the cached value + * obtained the most recent time the control has been read with + * V4L2Device::getControls() or the value of the control has been set to by the + * user with the add() or set() operation. + * + * \return The V4L2 control value or a negative error code if the control id + * is not part of this instance + */ +int V4L2Controls::get(unsigned int id) +{ + V4L2Control *ctrl = getControl(id); + if (!ctrl) + return -EINVAL; + + return ctrl->value(); +} + +/** + * \brief Set the value of the control with \a id + * \param id The V4L2 control id (V4L2_CID_xx) + * \param value The new V4L2 control value + * + * Set the value of the control with id \a id. + * + * It is important to notice that the value is not applied to the + * hardware at the time this operation is called, but it will only + * be actually pplied only by calling V4L2Device::setControls(). + * + * \return 0 on success or a negative error code if the control id + * is not part of this instance + */ +int V4L2Controls::set(unsigned int id, long int value) +{ + V4L2Control *ctrl = getControl(id); + if (!ctrl) + return -EINVAL; + + ctrl->setValue(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 id \a id or nullptr if the + * control id is not part of this instance. + */ +V4L2Control *V4L2Controls::getControl(unsigned int id) +{ + for (V4L2Control &ctrl : controls_) { + if (ctrl.id() == id) + return &ctrl; + } + + return nullptr; +} + +} /* namespace libcamera */