media: Add parsing for APP14 data segment in jpeg helpers

According to Rec. ITU-T T.872 (06/2012) 6.5.3
APP14 segment is for color encoding, it contains a transform flag, which
may have values of 0, 1 and 2 and are interpreted as follows:
0 - CMYK for images that are encoded with four components
  - RGB for images that are encoded with three components
1 - An image encoded with three components using YCbCr colour encoding.
2 - An image encoded with four components using YCCK colour encoding.

This is used in imx-jpeg decoder, to distinguish between
YUV444 and RGB24.

Signed-off-by: Mirela Rabulea <mirela.rabulea@nxp.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/media/v4l2-jpeg.h b/include/media/v4l2-jpeg.h
index 3a3344a97678..2dba843ce3bd 100644
--- a/include/media/v4l2-jpeg.h
+++ b/include/media/v4l2-jpeg.h
@@ -88,6 +88,24 @@ struct v4l2_jpeg_scan_header {
 };
 
 /**
+ * enum v4l2_jpeg_app14_tf - APP14 transform flag
+ * According to Rec. ITU-T T.872 (06/2012) 6.5.3
+ * APP14 segment is for color encoding, it contains a transform flag,
+ * which may have values of 0, 1 and 2 and are interpreted as follows:
+ * @V4L2_JPEG_APP14_TF_CMYK_RGB: CMYK for images encoded with four components
+ *                               RGB for images encoded with three components
+ * @V4L2_JPEG_APP14_TF_YCBCR: an image encoded with three components using YCbCr
+ * @V4L2_JPEG_APP14_TF_YCCK: an image encoded with four components using YCCK
+ * @V4L2_JPEG_APP14_TF_UNKNOWN: indicate app14 is not present
+ */
+enum v4l2_jpeg_app14_tf {
+	V4L2_JPEG_APP14_TF_CMYK_RGB	= 0,
+	V4L2_JPEG_APP14_TF_YCBCR	= 1,
+	V4L2_JPEG_APP14_TF_YCCK		= 2,
+	V4L2_JPEG_APP14_TF_UNKNOWN	= -1,
+};
+
+/**
  * struct v4l2_jpeg_header - parsed JPEG header
  * @sof: pointer to frame header and size
  * @sos: pointer to scan header and size
@@ -102,6 +120,7 @@ struct v4l2_jpeg_scan_header {
  *                  order, optional
  * @restart_interval: number of MCU per restart interval, Ri
  * @ecs_offset: buffer offset in bytes to the entropy coded segment
+ * @app14_tf: transform flag from app14 data
  *
  * When this structure is passed to v4l2_jpeg_parse_header, the optional scan,
  * quantization_tables, and huffman_tables pointers must be initialized to NULL
@@ -121,6 +140,7 @@ struct v4l2_jpeg_header {
 	struct v4l2_jpeg_reference *huffman_tables;
 	u16 restart_interval;
 	size_t ecs_offset;
+	enum v4l2_jpeg_app14_tf app14_tf;
 };
 
 int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out);