media: v4l2-common: Add support for fractional bpp

Fraction bytes-per-pixel exist for some packed format. You will find
notably on Rockhip platform that 10bit data is stored fully packed,
meaning that there is 1.25 pixels per bytes. This can be represented
with the fraction 5/4 and can be used to scale the width into a
bytesperline.
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

include/media/v4l2-common.h

@@ -480,6 +480,7 @@ enum v4l2_pixel_encoding {
  * @mem_planes: Number of memory planes, which includes the alpha plane (1 to 4).
  * @comp_planes: Number of component planes, which includes the alpha plane (1 to 4).
  * @bpp: Array of per-plane bytes per pixel
+ * @bpp_div: Array of per-plane bytes per pixel divisors to support fractional pixel sizes.
  * @hdiv: Horizontal chroma subsampling factor
  * @vdiv: Vertical chroma subsampling factor
  * @block_w: Per-plane macroblock pixel width (optional)
@@ -491,6 +492,7 @@ struct v4l2_format_info {
 	u8 mem_planes;
 	u8 comp_planes;
 	u8 bpp[4];
+	u8 bpp_div[4];
 	u8 hdiv;
 	u8 vdiv;
 	u8 block_w[4];