libcamera: v4l2_videodevice: Reintroduce toV4L2PixelFormat()

This is a partial revert of commit 395d43d6d75b ("libcamera:
v4l2_videodevice: Drop toV4L2PixelFormat()")

The function was removed because it incorrectly maps non-contiguous V4L2
format variants (ie V4L2_PIX_FMT_YUV420M) to the API version supported
by the video device (singleplanar API and multiplanar API).  It was
decided at the time to remove the function and let its users call
directly V4L2PixelFormat::fromPixelFormat() which accepts a
'multiplanar' flags.

As we aim to associate multiple V4L2PixelFormat to a single libcamera
format, the next patches will verify which of them is actually supported
by the video device. For now, return the contiguous version
unconditionally.

Re-introduce V4L2VideoDevice::toV4L2PixelFormat() and convert all
the V4L2PixelFormat::fromPixelFormat() users to use it.

The V4L2 compatibility layer is the only outlier as it doesn't have a
video device to poke, hence it still uses
V4L2PixelFormat::fromPixelFormat().

Next patches will implement the device format matching logic and handle
the non-contiguous plane issue in V4L2VideoDevice::toV4L2PixelFormat().

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Paul Elder <paul.elder@ideasonboard.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/src/libcamera/pipeline/ipu3/cio2.cpp b/src/libcamera/pipeline/ipu3/cio2.cpp
index 08e254f7..d4e523af 100644
--- a/src/libcamera/pipeline/ipu3/cio2.cpp
+++ b/src/libcamera/pipeline/ipu3/cio2.cpp
@@ -203,7 +203,7 @@ int CIO2Device::configure(const Size &size, V4L2DeviceFormat *outputFormat)
 	if (itInfo == mbusCodesToPixelFormat.end())
 		return -EINVAL;
 
-	outputFormat->fourcc = V4L2PixelFormat::fromPixelFormat(itInfo->second);
+	outputFormat->fourcc = output_->toV4L2PixelFormat(itInfo->second);
 	outputFormat->size = sensorFormat.size;
 	outputFormat->planesCount = 1;
 
diff --git a/src/libcamera/pipeline/ipu3/imgu.cpp b/src/libcamera/pipeline/ipu3/imgu.cpp
index 59305f85..531879f1 100644
--- a/src/libcamera/pipeline/ipu3/imgu.cpp
+++ b/src/libcamera/pipeline/ipu3/imgu.cpp
@@ -558,7 +558,7 @@ int ImgUDevice::configureVideoDevice(V4L2VideoDevice *dev, unsigned int pad,
 		return 0;
 
 	*outputFormat = {};
-	outputFormat->fourcc = V4L2PixelFormat::fromPixelFormat(formats::NV12);
+	outputFormat->fourcc = dev->toV4L2PixelFormat(formats::NV12);
 	outputFormat->size = cfg.size;
 	outputFormat->planesCount = 2;