licenses/developer-certificate-of-origin.txt


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Developer Certificate of Origin
Version 1.1

Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
1 Letterman Drive
Suite D4700
San Francisco, CA, 94129

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.


Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified
    it.

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.
/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * Copyright (C) 2019, Raspberry Pi (Trading) Limited
 *
 * cam_helper_ov5647.cpp - camera information for ov5647 sensor
 */

#include <assert.h>

#include "cam_helper.hpp"

using namespace RPiController;

class CamHelperOv5647 : public CamHelper
{
public:
	CamHelperOv5647();
	uint32_t GainCode(double gain) const override;
	double Gain(uint32_t gain_code) const override;
	void GetDelays(int &exposure_delay, int &gain_delay,
		       int &vblank_delay) const override;
	unsigned int HideFramesStartup() const override;
	unsigned int HideFramesModeSwitch() const override;
	unsigned int MistrustFramesStartup() const override;
	unsigned int MistrustFramesModeSwitch() const override;

private:
	/*
	 * Smallest difference between the frame length and integration time,
	 * in units of lines.
	 */
	static constexpr int frameIntegrationDiff = 4;
};

/*
 * OV5647 doesn't output metadata, so we have to use the "unicam parser" which
 * works by counting frames.
 */

CamHelperOv5647::CamHelperOv5647()
	: CamHelper({}, frameIntegrationDiff)
{
}

uint32_t CamHelperOv5647::GainCode(double gain) const
{
	return static_cast<uint32_t>(gain * 16.0);
}

double CamHelperOv5647::Gain(uint32_t gain_code) const
{
	return static_cast<double>(gain_code) / 16.0;
}

void CamHelperOv5647::GetDelays(int &exposure_delay, int &gain_delay,
				int &vblank_delay) const
{
	/*
	 * We run this sensor in a mode where the gain delay is bumped up to
	 * 2. It seems to be the only way to make the delays "predictable".
	 */
	exposure_delay = 2;
	gain_delay = 2;
	vblank_delay = 2;
}

unsigned int CamHelperOv5647::HideFramesStartup() const
{
	/*
	 * On startup, we get a couple of under-exposed frames which
	 * we don't want shown.
	 */
	return 2;
}

unsigned int CamHelperOv5647::HideFramesModeSwitch() const
{
	/*
	 * After a mode switch, we get a couple of under-exposed frames which
	 * we don't want shown.
	 */
	return 2;
}

unsigned int CamHelperOv5647::MistrustFramesStartup() const
{
	/*
	 * First couple of frames are under-exposed and are no good for control
	 * algos.
	 */
	return 2;
}

unsigned int CamHelperOv5647::MistrustFramesModeSwitch() const
{
	/*
	 * First couple of frames are under-exposed even after a simple
	 * mode switch, and are no good for control algos.
	 */
	return 2;
}

static CamHelper *Create()
{
	return new CamHelperOv5647();
}

static RegisterCamHelper reg("ov5647", &Create);