[libcamera-devel] [PATCH v1 7/9] ipa: raspberrypi: Add line length calculations helper functions

[Laurent Pinchart]

Hi Naush,

Thank you for the patch.

On Mon, Oct 03, 2022 at 09:39:33AM +0100, Naushir Patuck via libcamera-devel wrote:
> Add CamHelper::hblankToLineLength() to calculate the line length duration
> from the horizontal blanking (in pixels) value.
> 
> Add CamHelper::LineLengthToHblank() to calculate the horizontal blanking (in

s/Line/line/

> pixels) value from the line length duration.
> 
> Add CamHelper::lineLengthPckToDuration() to calculate the line length duration
> from the line length in pixels.
> 
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> ---
>  src/ipa/raspberrypi/cam_helper.cpp | 16 ++++++++++++++++
>  src/ipa/raspberrypi/cam_helper.h   |  3 +++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/src/ipa/raspberrypi/cam_helper.cpp b/src/ipa/raspberrypi/cam_helper.cpp
> index 916632f83037..c255ab0cb53f 100644
> --- a/src/ipa/raspberrypi/cam_helper.cpp
> +++ b/src/ipa/raspberrypi/cam_helper.cpp
> @@ -19,6 +19,7 @@
>  using namespace RPiController;
>  using namespace libcamera;
>  using libcamera::utils::Duration;
> +using namespace std::literals::chrono_literals;
>  
>  namespace libcamera {
>  LOG_DECLARE_CATEGORY(IPARPI)
> @@ -102,6 +103,21 @@ uint32_t CamHelper::getVBlanking(Duration &exposure,
>  	return vblank;
>  }
>  
> +Duration CamHelper::hblankToLineLength(uint32_t hblank) const
> +{
> +	return (mode_.width + hblank) * (1.0s / mode_.pixelRate);

The previous patch performs the exact same calculation in
IPARPi::fillDeviceStatus(). The next patch then replaces that code with
this function. Could this patch be moved before 6/9, and this function
be used there already ?

> +}
> +
> +uint32_t CamHelper::lineLengthToHblank(const Duration &lineLength) const
> +{
> +	return (lineLength * mode_.pixelRate / 1.0s) - mode_.width;
> +}
> +
> +Duration CamHelper::lineLengthPckToDuration(uint32_t lineLengthPck) const
> +{
> +	return hblankToLineLength(lineLengthPck - mode_.width);

I would have written

	return lineLengthPck * (1.0s / mode_.pixelRate);

to avoid subtracting mode_.width to add it back in hblankToLineLength().
I don't mind much either way.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> +}
> +
>  void CamHelper::setCameraMode(const CameraMode &mode)
>  {
>  	mode_ = mode;
> diff --git a/src/ipa/raspberrypi/cam_helper.h b/src/ipa/raspberrypi/cam_helper.h
> index 1bbdd715d2b1..b5c0726ff00e 100644
> --- a/src/ipa/raspberrypi/cam_helper.h
> +++ b/src/ipa/raspberrypi/cam_helper.h
> @@ -85,6 +85,9 @@ public:
>  	virtual uint32_t getVBlanking(libcamera::utils::Duration &exposure,
>  				      libcamera::utils::Duration minFrameDuration,
>  				      libcamera::utils::Duration maxFrameDuration) const;
> +	libcamera::utils::Duration hblankToLineLength(uint32_t hblank) const;
> +	uint32_t lineLengthToHblank(const libcamera::utils::Duration &duration) const;
> +	libcamera::utils::Duration lineLengthPckToDuration(uint32_t lineLengthPck) const;
>  	virtual uint32_t gainCode(double gain) const = 0;
>  	virtual double gain(uint32_t gainCode) const = 0;
>  	virtual void getDelays(int &exposureDelay, int &gainDelay,

-- 
Regards,

Laurent Pinchart