src/gstreamer/gstlibcamera-utils.h

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * v4l2_controls.cpp - V4L2 Controls Support
 */

#include "libcamera/internal/v4l2_controls.h"

#include <string.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 a video device or subdevice. The nature of the
 * parameters an application can 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 ControlList 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 {

namespace {

std::string v4l2_ctrl_name(const struct v4l2_query_ext_ctrl &ctrl)
{
	size_t len = strnlen(ctrl.name, sizeof(ctrl.name));
	return std::string(static_cast<const char *>(ctrl.name), len);
}

ControlType v4l2_ctrl_type(const struct v4l2_query_ext_ctrl &ctrl)
{
	switch (ctrl.type) {
	case V4L2_CTRL_TYPE_U8:
		return ControlTypeByte;

	case V4L2_CTRL_TYPE_BOOLEAN:
		return ControlTypeBool;

	case V4L2_CTRL_TYPE_INTEGER:
		return ControlTypeInteger32;

	case V4L2_CTRL_TYPE_INTEGER64:
		return ControlTypeInteger64;

	case V4L2_CTRL_TYPE_MENU:
	case V4L2_CTRL_TYPE_BUTTON:
	case V4L2_CTRL_TYPE_BITMASK:
	case V4L2_CTRL_TYPE_INTEGER_MENU:
		/*
		 * More precise types may be needed, for now use a 32-bit
		 * integer type.
		 */
		return ControlTypeInteger32;

	default:
		return ControlTypeNone;
	}
}

} /* namespace */

/**
 * \class V4L2ControlId
 * \brief V4L2 control static metadata
 *
 * The V4L2ControlId class is a specialisation of the ControlId for V4L2
 * controls.
 */

/**
 * \brief Construct a V4L2ControlId from a struct v4l2_query_ext_ctrl
 * \param[in] ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
 */
V4L2ControlId::V4L2ControlId(const struct v4l2_query_ext_ctrl &ctrl)
	: ControlId(ctrl.id, v4l2_ctrl_name(ctrl), v4l2_ctrl_type(ctrl))
{
}

/**
 * \class V4L2ControlInfo
 * \brief Convenience specialisation of ControlInfo for V4L2 controls
 *
 * The V4L2ControlInfo class is a specialisation of the ControlInfo for V4L2
 * controls. It offers a convenience constructor from a struct
 * v4l2_query_ext_ctrl, and is otherwise equivalent to the ControlInfo class.
 */

/**
 * \brief Construct a V4L2ControlInfo from a struct v4l2_query_ext_ctrl
 * \param[in] ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
 */
V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl)
{
	switch (ctrl.type) {
	case V4L2_CTRL_TYPE_U8:
		ControlInfo::operator=(ControlInfo(static_cast<uint8_t>(ctrl.minimum),
						   static_cast<uint8_t>(ctrl.maximum),
						   static_cast<uint8_t>(ctrl.default_value)));
		break;

	case V4L2_CTRL_TYPE_BOOLEAN:
		ControlInfo::operator=(ControlInfo(static_cast<bool>(ctrl.minimum),
						   static_cast<bool>(ctrl.maximum),
						   static_cast<bool>(ctrl.default_value)));
		break;

	case V4L2_CTRL_TYPE_INTEGER64:
		ControlInfo::operator=(ControlInfo(static_cast<int64_t>(ctrl.minimum),
						   static_cast<int64_t>(ctrl.maximum),
						   static_cast<int64_t>(ctrl.default_value)));
		break;

	default:
		ControlInfo::operator=(ControlInfo(static_cast<int32_t>(ctrl.minimum),
						   static_cast<int32_t>(ctrl.maximum),
						   static_cast<int32_t>(ctrl.default_value)));
		break;
	}
}

} /* namespace libcamera */
Age	Commit message (Collapse)	Author
2021-11-24	gstreamer: Convert to pragma once	Kieran Bingham
	Remove the verbose #ifndef/#define/#endif pattern for maintaining header idempotency, and replace it with a simple #pragma once. This simplifies the headers, and prevents redundant changes when header files get moved. Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
2021-09-28	gstreamer: Fix spelling of the work manager used in a util function	Vedant Paranjape
	Fix all name in all instances of the function gst_libcamera_get_camera_mananger to gst_libcamera_get_camera_manager. Spelling of manager was incorrect. This patch has no functional changes. Signed-off-by: Vedant Paranjape <vedantparanjape160201@gmail.com> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-08-26	gstreamer: Fix concurrent access issues to CameraManager	Nicolas Dufresne
	It's not allowed to have multiple instances of CameraManager. This requirement is not easy for GStreamer were the device monitor and the camerasrc, or two camerasrc instances don't usually have any interaction between each other. Fix this by implementing a minimalist singleton around CameraManager constructor and start()/stop() operations. Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-03-07	gst: utils: Factor-out the task resume helper	Jakub Adam
	Task resume will be added in the core GStreamer API in the future and we will need to call this in another location in the following patches. Signed-off-by: Jakub Adam <jakub.adam@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-03-07	gst: utils: Add StreamConfiguration helpers	Nicolas Dufresne
	This adds helpers to deal with the conversion from StreamConfiguration to caps and vice-versa. This is needed to implement caps negotiation. Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-03-07	gst: utils: Add simple scoped lockers for GMutex and GRectMutex	Nicolas Dufresne
	While GLib has locker implementation already using g_autoptr(), recursive mutex locker was only introduced in recent GLib. Implement a simple locker for GMutex and GRectMutex in order to allow making locking simpler and safer. Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-03-07	gst: Add utility to convert StreamFormats to GstCaps	Nicolas Dufresne
	This transforms the basic information found in StreamFormats to GstCaps. This can be handy to reply to early caps query or inside a device provider. Note that we ignored generated range as they are harmful to caps negotiation. We also don't simplify the caps for readability reasons, so some of the discrete value may be included in a range. Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>