Add RGB666_1X24_CPADHI media bus format

Commit 9e74d2926a ("staging: imx-drm: add LVDS666 support for parallel
display") describes a 24-bit bus format where three 6-bit components each
take the lower part of 8 bits with the two high bits zero padded. Add a
component-wise padded media bus format RGB666_1X24_CPADHI to support this
connection.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Emil Renner Berthing <kernel@esmil.dk>

Documentation/DocBook/media/v4l/subdev-formats.xml

@@ -91,7 +91,9 @@ see <xref linkend="colorspaces" />.</entry>
 	<listitem><para>For formats where the total number of bits per pixel is smaller
 	than the number of bus samples per pixel times the bus width, a padding
 	value stating if the bytes are padded in their most high order bits
-	(PADHI) or low order bits (PADLO).</para></listitem>
+	(PADHI) or low order bits (PADLO). A "C" prefix is used for component-wise
+	padding in the most high order bits (CPADHI) or low order bits (CPADLO)
+	of each separate component.</para></listitem>
 	<listitem><para>For formats where the number of bus samples per pixel is larger
 	than 1, an endianness value stating if the pixel is transferred MSB first
 	(BE) or LSB first (LE).</para></listitem>
@@ -480,6 +482,36 @@ see <xref linkend="colorspaces" />.</entry>
 	      <entry>b<subscript>1</subscript></entry>
 	      <entry>b<subscript>0</subscript></entry>
 	    </row>
+	    <row id="MEDIA-BUS-FMT-RGB666-1X24_CPADHI">
+	      <entry>MEDIA_BUS_FMT_RGB666_1X24_CPADHI</entry>
+	      <entry>0x1015</entry>
+	      <entry></entry>
+	      &dash-ent-8;
+	      <entry>0</entry>
+	      <entry>0</entry>
+	      <entry>r<subscript>5</subscript></entry>
+	      <entry>r<subscript>4</subscript></entry>
+	      <entry>r<subscript>3</subscript></entry>
+	      <entry>r<subscript>2</subscript></entry>
+	      <entry>r<subscript>1</subscript></entry>
+	      <entry>r<subscript>0</subscript></entry>
+	      <entry>0</entry>
+	      <entry>0</entry>
+	      <entry>g<subscript>5</subscript></entry>
+	      <entry>g<subscript>4</subscript></entry>
+	      <entry>g<subscript>3</subscript></entry>
+	      <entry>g<subscript>2</subscript></entry>
+	      <entry>g<subscript>1</subscript></entry>
+	      <entry>g<subscript>0</subscript></entry>
+	      <entry>0</entry>
+	      <entry>0</entry>
+	      <entry>b<subscript>5</subscript></entry>
+	      <entry>b<subscript>4</subscript></entry>
+	      <entry>b<subscript>3</subscript></entry>
+	      <entry>b<subscript>2</subscript></entry>
+	      <entry>b<subscript>1</subscript></entry>
+	      <entry>b<subscript>0</subscript></entry>
+	    </row>
 	    <row id="MEDIA-BUS-FMT-BGR888-1X24">
 	      <entry>MEDIA_BUS_FMT_BGR888_1X24</entry>
 	      <entry>0x1013</entry>

include/uapi/linux/media-bus-format.h

@@ -33,7 +33,7 @@
 
 #define MEDIA_BUS_FMT_FIXED			0x0001
 
-/* RGB - next is	0x1015 */
+/* RGB - next is	0x1016 */
 #define MEDIA_BUS_FMT_RGB444_1X12		0x100e
 #define MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE	0x1001
 #define MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE	0x1002
@@ -45,6 +45,7 @@
 #define MEDIA_BUS_FMT_RGB565_2X8_BE		0x1007
 #define MEDIA_BUS_FMT_RGB565_2X8_LE		0x1008
 #define MEDIA_BUS_FMT_RGB666_1X18		0x1009
+#define MEDIA_BUS_FMT_RGB666_1X24_CPADHI	0x1015
 #define MEDIA_BUS_FMT_RGB666_1X7X3_SPWG		0x1010
 #define MEDIA_BUS_FMT_BGR888_1X24		0x1013
 #define MEDIA_BUS_FMT_GBR888_1X24		0x1014