media: v4l: Add HEXTILE compressed format

Add HEXTILE compressed format which is defined in Remote Framebuffer
Protocol (RFC 6143, chapter 7.7.4 Hextile Encoding) and is used by
Encoding Compression Engine (ECE) present on Nuvoton NPCM SoCs.

Signed-off-by: Marvin Lin <milkfafa@gmail.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Author: linkunfa

Documentation/userspace-api/media/v4l/pixfmt-reserved.rst

@@ -288,6 +288,13 @@ please make a proposal on the linux-media mailing list.
       - 'MT2110R'
       - This format is two-planar 10-Bit raster mode and having similitude with
         ``V4L2_PIX_FMT_MM21`` in term of alignment and tiling. Used for AVC.
+    * .. _V4L2-PIX-FMT-HEXTILE:
+
+      - ``V4L2_PIX_FMT_HEXTILE``
+      - 'HXTL'
+      - Compressed format used by Nuvoton NPCM video driver. This format is
+        defined in Remote Framebuffer Protocol (RFC 6143, chapter 7.7.4 Hextile
+        Encoding).
 .. raw:: latex
 
     \normalsize

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -1510,6 +1510,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 		case V4L2_PIX_FMT_AV1_FRAME:	descr = "AV1 Frame"; break;
 		case V4L2_PIX_FMT_MT2110T:	descr = "Mediatek 10bit Tile Mode"; break;
 		case V4L2_PIX_FMT_MT2110R:	descr = "Mediatek 10bit Raster Mode"; break;
+		case V4L2_PIX_FMT_HEXTILE:	descr = "Hextile Compressed Format"; break;
 		default:
 			if (fmt->description[0])
 				return;

include/uapi/linux/videodev2.h

@@ -804,6 +804,7 @@ struct v4l2_pix_format {
 #define V4L2_PIX_FMT_QC08C    v4l2_fourcc('Q', '0', '8', 'C') /* Qualcomm 8-bit compressed */
 #define V4L2_PIX_FMT_QC10C    v4l2_fourcc('Q', '1', '0', 'C') /* Qualcomm 10-bit compressed */
 #define V4L2_PIX_FMT_AJPG     v4l2_fourcc('A', 'J', 'P', 'G') /* Aspeed JPEG */
+#define V4L2_PIX_FMT_HEXTILE  v4l2_fourcc('H', 'X', 'T', 'L') /* Hextile compressed */
 
 /* 10bit raw packed, 32 bytes for every 25 pixels, last LSB 6 bits unused */
 #define V4L2_PIX_FMT_IPU3_SBGGR10	v4l2_fourcc('i', 'p', '3', 'b') /* IPU3 packed 10-bit BGGR bayer */