test/camera

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * v4l2_subdevice.cpp - V4L2 Subdevice
 */

#include "v4l2_subdevice.h"

#include <fcntl.h>
#include <iomanip>
#include <sstream>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>

#include <linux/v4l2-subdev.h>

#include <libcamera/geometry.h>

#include "log.h"
#include "media_device.h"
#include "media_object.h"
#include "utils.h"

/**
 * \file v4l2_subdevice.h
 * \brief V4L2 Subdevice API
 */

namespace libcamera {

LOG_DECLARE_CATEGORY(V4L2)

/**
 * \struct V4L2SubdeviceFormat
 * \brief The V4L2 sub-device image format and sizes
 *
 * This structure describes the format of images when transported between
 * separate components connected through a physical bus, such as image sensor
 * and image receiver or between components part of the same System-on-Chip that
 * realize an image transformation pipeline.
 *
 * The format of images when transported on physical interconnections is known
 * as the "media bus format", and it is identified by a resolution and a pixel
 * format identification code, known as the "media bus code", not to be confused
 * with the fourcc code that identify the format of images when stored in memory
 * (see V4L2VideoDevice::V4L2DeviceFormat).
 *
 * Media Bus formats supported by the V4L2 APIs are described in Section
 * 4.15.3.4.1 of the "Part I - Video for Linux API" chapter of the "Linux Media
 * Infrastructure userspace API", part of the Linux kernel documentation.
 *
 * Image media bus formats are properties of the subdev pads.  When images are
 * transported between two media pads identified by a 0-indexed number, the
 * image bus format configured on the two pads should match (according to the
 * underlying driver format matching criteria) in order to prepare for a
 * successful streaming operation. For a more detailed description of the image
 * format negotiation process when performed between V4L2 subdevices, refer to
 * Section 4.15.3.1 of the above mentioned Linux kernel documentation section.
 */

/**
 * \var V4L2SubdeviceFormat::mbus_code
 * \brief The image format bus code
 */

/**
 * \var V4L2SubdeviceFormat::size
 * \brief The image size in pixels
 */

/**
 * \brief Assemble and return a string describing the format
 * \return A string describing the V4L2SubdeviceFormat
 */
const std::string V4L2SubdeviceFormat::toString() const
{
	std::stringstream ss;
	ss << size.toString() << "-" << utils::hex(mbus_code, 4);
	return ss.str();
}

/**
 * \class V4L2Subdevice
 * \brief A V4L2 subdevice as exposed by the Linux kernel
 *
 * The V4L2Subdevice class provides an API to the "Sub-device interface" as
 * described in section 4.15 of the "Linux Media Infrastructure userspace API"
 * chapter of the Linux Kernel documentation.
 *
 * A V4L2Subdevice is constructed from a MediaEntity instance, using the system
 * path of the entity's device node. No API call other than open(), isOpen()
 * and close() shall be called on an unopened device instance. Upon destruction
 * any device left open will be closed, and any resources released.
 */

/**
 * \brief Create a V4L2 subdevice from a MediaEntity using its device node
 * path
 */
V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
	: V4L2Device(entity->deviceNode()), entity_(entity)
{
}

V4L2Subdevice::~V4L2Subdevice()
{
	close();
}

/**
 * \brief Open a V4L2 subdevice
 * \return 0 on success or a negative error code otherwise
 */
int V4L2Subdevice::open()
{
Mode	Name	Size
-rw-r--r--	buffer_import.cpp	4080	log plain
-rw-r--r--	capture.cpp	3842	log plain
-rw-r--r--	configuration_default.cpp	1153	log plain
-rw-r--r--	configuration_set.cpp	2240	log plain
-rw-r--r--	meson.build	707	log plain
-rw-r--r--	statemachine.cpp	4397	log plain