libcamera: v4l2_device: Adjust colorspace based on pixel format

V4L2 has no "none" YCbCr encoding, and thus reports an encoding for all
formats, including RGB and raw formats. This causes the libcamera
ColorSpace to report incorrect encodings for non-YUV formats. Fix it by
overriding the encoding reported by the kernel to YCbCrEncoding::None
for non-YUV pixel formats and media bus formats.

Similarly, override the quantization range of non-YUV formats to full
range, as limited range isn't used for RGB and raw formats.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

include/libcamera/internal/v4l2_device.h

@@ -22,6 +22,8 @@
 #include <libcamera/color_space.h>
 #include <libcamera/controls.h>
 
+#include "libcamera/internal/formats.h"
+
 namespace libcamera {
 
 class EventNotifier;
@@ -59,7 +61,8 @@ protected:
 	int fd() const { return fd_.get(); }
 
 	template<typename T>
-	static std::optional<ColorSpace> toColorSpace(const T &v4l2Format);
+	static std::optional<ColorSpace> toColorSpace(const T &v4l2Format,
+						      PixelFormatInfo::ColourEncoding colourEncoding);
 
 	template<typename T>
 	static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);