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-contigous 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 now aim to associate multiple V4L2PixelFormat to a single
libcamera format, it is necessary to verify which of them is actually
supported by the video device.

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

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

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>

1 files changed, 1 insertions, 1 deletions

diff --git a/test/libtest/buffer_source.cpp b/test/libtest/buffer_source.cpp
index 84f1169c..dde11f36 100644
--- a/test/libtest/buffer_source.cpp
+++ b/test/libtest/buffer_source.cpp
@@ -72,7 +72,7 @@ int BufferSource::allocate(const StreamConfiguration &config)
 	}
 
 	format.size = config.size;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
+	format.fourcc = video->toV4L2PixelFormat(config.pixelFormat);
 	if (video->setFormat(&format)) {
 		std::cout << "Failed to set format on output device" << std::endl;
 		return TestFail;