libcamera: v4l2_pixelformat: Return the list of V4L2 formats

Multiple V4L2 formats can be associated with a single PixelFormat.
Now that users of V4L2PixelFormat::fromPixelFormat() have been converted
to use V4L2VideoDevice::toV4L2PixelFormat(), return the full list of
V4L2 formats in order to prepare to match them against the ones
supported by the video device.

The V4L2 compatibility layer, not having any video device to interact
with, is converted to use the first returned format unconditionally.

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

4 files changed, 15 insertions, 11 deletions

diff --git a/include/libcamera/internal/v4l2_pixelformat.h b/include/libcamera/internal/v4l2_pixelformat.h
index ed94baf9..d5400f90 100644
--- a/include/libcamera/internal/v4l2_pixelformat.h
+++ b/include/libcamera/internal/v4l2_pixelformat.h
@@ -11,6 +11,7 @@
 #include <ostream>
 #include <stdint.h>
 #include <string>
+#include <vector>
 
 #include <linux/videodev2.h>
 
@@ -44,7 +45,8 @@ public:
 	const char *description() const;
 
 	PixelFormat toPixelFormat() const;
-	static V4L2PixelFormat fromPixelFormat(const PixelFormat &pixelFormat);
+	static const std::vector<V4L2PixelFormat> &
+	fromPixelFormat(const PixelFormat &pixelFormat);
 
 private:
 	uint32_t fourcc_;
diff --git a/src/libcamera/v4l2_pixelformat.cpp b/src/libcamera/v4l2_pixelformat.cpp
index 9f74bd37..90c8fa8d 100644
--- a/src/libcamera/v4l2_pixelformat.cpp
+++ b/src/libcamera/v4l2_pixelformat.cpp
@@ -302,22 +302,24 @@ PixelFormat V4L2PixelFormat::toPixelFormat() const
 }
 
 /**
- * \brief Convert \a pixelFormat to its corresponding V4L2PixelFormat
+ * \brief Retrieve the list of V4L2PixelFormat associated with \a pixelFormat
  * \param[in] pixelFormat The PixelFormat to convert
  *
  * Multiple V4L2 formats may exist for one PixelFormat as V4L2 defines separate
  * 4CCs for contiguous and non-contiguous versions of the same image format.
- * When that is the case, this function returns the contiguous planes format.
  *
- * \return The V4L2PixelFormat corresponding to \a pixelFormat
+ * \return The list of V4L2PixelFormat corresponding to \a pixelFormat
  */
-V4L2PixelFormat V4L2PixelFormat::fromPixelFormat(const PixelFormat &pixelFormat)
+const std::vector<V4L2PixelFormat> &
+V4L2PixelFormat::fromPixelFormat(const PixelFormat &pixelFormat)
 {
+	static const std::vector<V4L2PixelFormat> empty;
+
 	const PixelFormatInfo &info = PixelFormatInfo::info(pixelFormat);
 	if (!info.isValid())
-		return V4L2PixelFormat();
+		return empty;
 
-	return info.v4l2Formats[0];
+	return info.v4l2Formats;
 }
 
 /**
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index f41afa06..2ca22f48 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -2000,7 +2000,7 @@ V4L2VideoDevice::fromEntityName(const MediaDevice *media,
  */
 V4L2PixelFormat V4L2VideoDevice::toV4L2PixelFormat(const PixelFormat &pixelFormat) const
 {
-	return V4L2PixelFormat::fromPixelFormat(pixelFormat);
+	return V4L2PixelFormat::fromPixelFormat(pixelFormat)[0];
 }
 
 /**
diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index 26a227da..55ff62cd 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -182,7 +182,7 @@ void V4L2CameraProxy::setFmtFromConfig(const StreamConfiguration &streamConfig)
 
 	v4l2PixFormat_.width        = size.width;
 	v4l2PixFormat_.height       = size.height;
-	v4l2PixFormat_.pixelformat  = V4L2PixelFormat::fromPixelFormat(streamConfig.pixelFormat);
+	v4l2PixFormat_.pixelformat  = V4L2PixelFormat::fromPixelFormat(streamConfig.pixelFormat)[0];
 	v4l2PixFormat_.field        = V4L2_FIELD_NONE;
 	v4l2PixFormat_.bytesperline = streamConfig.stride;
 	v4l2PixFormat_.sizeimage    = streamConfig.frameSize;
@@ -290,7 +290,7 @@ int V4L2CameraProxy::vidioc_enum_fmt(V4L2CameraFile *file, struct v4l2_fmtdesc *
 		return -EINVAL;
 
 	PixelFormat format = streamConfig_.formats().pixelformats()[arg->index];
-	V4L2PixelFormat v4l2Format = V4L2PixelFormat::fromPixelFormat(format);
+	V4L2PixelFormat v4l2Format = V4L2PixelFormat::fromPixelFormat(format)[0];
 
 	arg->flags = format == formats::MJPEG ? V4L2_FMT_FLAG_COMPRESSED : 0;
 	utils::strlcpy(reinterpret_cast<char *>(arg->description),
@@ -333,7 +333,7 @@ int V4L2CameraProxy::tryFormat(struct v4l2_format *arg)
 
 	arg->fmt.pix.width        = config.size.width;
 	arg->fmt.pix.height       = config.size.height;
-	arg->fmt.pix.pixelformat  = V4L2PixelFormat::fromPixelFormat(config.pixelFormat);
+	arg->fmt.pix.pixelformat  = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
 	arg->fmt.pix.field        = V4L2_FIELD_NONE;
 	arg->fmt.pix.bytesperline = config.stride;
 	arg->fmt.pix.sizeimage    = config.frameSize;