media: v4l2-common: add pixel encoding support

It is often useful to figure out if a pixel_format is either YUV or RGB
especially for driver who can perform the pixel encoding conversion.

Instead of having each driver implement its own "is_this_yuv/rgb"
function based on a restricted set of pixel value, it is better to do
this in centralized manner.

We therefore add a pixel_enc member to the v4l2_format_info structure to
quickly identify the related pixel encoding.
And add helper functions to check pixel encoding.
Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

include/media/v4l2-common.h

@@ -456,9 +456,25 @@ int v4l2_s_parm_cap(struct video_device *vdev,
 
 /* Pixel format and FourCC helpers */
 
+/**
+ * enum v4l2_pixel_encoding - specifies the pixel encoding value
+ *
+ * @V4L2_PIXEL_ENC_UNKNOWN:	Pixel encoding is unknown/un-initialized
+ * @V4L2_PIXEL_ENC_YUV:		Pixel encoding is YUV
+ * @V4L2_PIXEL_ENC_RGB:		Pixel encoding is RGB
+ * @V4L2_PIXEL_ENC_BAYER:	Pixel encoding is Bayer
+ */
+enum v4l2_pixel_encoding {
+	V4L2_PIXEL_ENC_UNKNOWN = 0,
+	V4L2_PIXEL_ENC_YUV = 1,
+	V4L2_PIXEL_ENC_RGB = 2,
+	V4L2_PIXEL_ENC_BAYER = 3,
+};
+
 /**
  * struct v4l2_format_info - information about a V4L2 format
  * @format: 4CC format identifier (V4L2_PIX_FMT_*)
+ * @pixel_enc: Pixel encoding (see enum v4l2_pixel_encoding above)
  * @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
@@ -469,6 +485,7 @@ int v4l2_s_parm_cap(struct video_device *vdev,
  */
 struct v4l2_format_info {
 	u32 format;
+	u8 pixel_enc;
 	u8 mem_planes;
 	u8 comp_planes;
 	u8 bpp[4];
@@ -478,8 +495,22 @@ struct v4l2_format_info {
 	u8 block_h[4];
 };
 
-const struct v4l2_format_info *v4l2_format_info(u32 format);
+static inline bool v4l2_is_format_rgb(const struct v4l2_format_info *f)
+{
+	return f && f->pixel_enc == V4L2_PIXEL_ENC_RGB;
+}
 
+static inline bool v4l2_is_format_yuv(const struct v4l2_format_info *f)
+{
+	return f && f->pixel_enc == V4L2_PIXEL_ENC_YUV;
+}
+
+static inline bool v4l2_is_format_bayer(const struct v4l2_format_info *f)
+{
+	return f && f->pixel_enc == V4L2_PIXEL_ENC_BAYER;
+}
+
+const struct v4l2_format_info *v4l2_format_info(u32 format);
 void v4l2_apply_frmsize_constraints(u32 *width, u32 *height,
 				    const struct v4l2_frmsize_stepwise *frmsize);
 int v4l2_fill_pixfmt(struct v4l2_pix_format *pixfmt, u32 pixelformat,