e5a9e6e9cd
To prepare for storage of additional information in the ControlRange structure, rename it to ControlInfo. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
143 lines
4.5 KiB
C++
143 lines
4.5 KiB
C++
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2019, Google Inc.
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*
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* v4l2_controls.cpp - V4L2 Controls Support
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*/
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#include "v4l2_controls.h"
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#include <string.h>
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/**
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* \file v4l2_controls.h
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* \brief Support for V4L2 Controls using the V4L2 Extended Controls APIs
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*
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* The V4L2 Control API allows application to inspect and modify sets of
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* configurable parameters on a video device or subdevice. The nature of the
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* parameters an application can modify using the control framework depends on
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* what the driver implements support for, and on the characteristics of the
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* underlying hardware platform. Generally controls are used to modify user
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* visible settings, such as the image brightness and exposure time, or
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* non-standard parameters which cannot be controlled through the V4L2 format
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* negotiation API.
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*
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* Controls are identified by a numerical ID, defined by the V4L2 kernel headers
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* and have an associated type. Each control has a value, which is the data that
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* can be modified with V4L2Device::setControls() or retrieved with
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* V4L2Device::getControls().
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*
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* The control's type along with the control's flags define the type of the
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* control's value content. Controls can transport a single data value stored in
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* variable inside the control, or they might as well deal with more complex
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* data types, such as arrays of matrices, stored in a contiguous memory
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* locations associated with the control and called 'the payload'. Such controls
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* are called 'compound controls' and are currently not supported by the
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* libcamera V4L2 control framework.
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*
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* libcamera implements support for controls using the V4L2 Extended Control
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* API, which allows future handling of controls with payloads of arbitrary
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* sizes.
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*
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* The libcamera V4L2 Controls framework operates on lists of controls, wrapped
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* by the ControlList class, to match the V4L2 extended controls API. The
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* interface to set and get control is implemented by the V4L2Device class, and
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* this file only provides the data type definitions.
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*
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* \todo Add support for compound controls
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*/
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namespace libcamera {
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namespace {
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std::string v4l2_ctrl_name(const struct v4l2_query_ext_ctrl &ctrl)
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{
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size_t len = strnlen(ctrl.name, sizeof(ctrl.name));
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return std::string(static_cast<const char *>(ctrl.name), len);
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}
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ControlType v4l2_ctrl_type(const struct v4l2_query_ext_ctrl &ctrl)
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{
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switch (ctrl.type) {
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case V4L2_CTRL_TYPE_BOOLEAN:
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return ControlTypeBool;
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case V4L2_CTRL_TYPE_INTEGER:
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return ControlTypeInteger32;
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case V4L2_CTRL_TYPE_INTEGER64:
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return ControlTypeInteger64;
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case V4L2_CTRL_TYPE_MENU:
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case V4L2_CTRL_TYPE_BUTTON:
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case V4L2_CTRL_TYPE_BITMASK:
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case V4L2_CTRL_TYPE_INTEGER_MENU:
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/*
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* More precise types may be needed, for now use a 32-bit
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* integer type.
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*/
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return ControlTypeInteger32;
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default:
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return ControlTypeNone;
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}
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}
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} /* namespace */
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/**
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* \class V4L2ControlId
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* \brief V4L2 control static metadata
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*
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* The V4L2ControlId class is a specialisation of the ControlId for V4L2
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* controls.
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*/
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/**
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* \brief Construct a V4L2ControlId from a struct v4l2_query_ext_ctrl
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* \param[in] ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
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*/
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V4L2ControlId::V4L2ControlId(const struct v4l2_query_ext_ctrl &ctrl)
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: ControlId(ctrl.id, v4l2_ctrl_name(ctrl), v4l2_ctrl_type(ctrl))
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{
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}
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/**
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* \class V4L2ControlInfo
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* \brief Convenience specialisation of ControlInfo for V4L2 controls
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*
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* The V4L2ControlInfo class is a specialisation of the ControlInfo for V4L2
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* controls. It offers a convenience constructor from a struct
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* v4l2_query_ext_ctrl, and is otherwise equivalent to the ControlInfo class.
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*/
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/**
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* \brief Construct a V4L2ControlInfo from a struct v4l2_query_ext_ctrl
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* \param[in] ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
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*/
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V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl)
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{
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switch (ctrl.type) {
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case V4L2_CTRL_TYPE_BOOLEAN:
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ControlInfo::operator=(ControlInfo(static_cast<bool>(ctrl.minimum),
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static_cast<bool>(ctrl.maximum),
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static_cast<bool>(ctrl.default_value)));
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break;
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case V4L2_CTRL_TYPE_INTEGER64:
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ControlInfo::operator=(ControlInfo(static_cast<int64_t>(ctrl.minimum),
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static_cast<int64_t>(ctrl.maximum),
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static_cast<int64_t>(ctrl.default_value)));
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break;
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default:
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ControlInfo::operator=(ControlInfo(static_cast<int32_t>(ctrl.minimum),
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static_cast<int32_t>(ctrl.maximum),
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static_cast<int32_t>(ctrl.default_value)));
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break;
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}
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}
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} /* namespace libcamera */
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