drm: lcdif: Add support for YUV planes

The LCDIF includes a color space converter that supports YUV input. Use
it to support YUV planes, either through the converter if the output
format is RGB, or in conversion bypass mode otherwise.
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220930083955.31580-5-laurent.pinchart@ideasonboard.com

drivers/gpu/drm/mxsfb/lcdif_regs.h

@@ -212,7 +212,10 @@
 #define CTRLDESCL0_5_YUV_FORMAT_UY2VY1	(0x3 << 14)
 #define CTRLDESCL0_5_YUV_FORMAT_MASK	GENMASK(15, 14)
 
-#define CSC0_CTRL_CSC_MODE_RGB2YCbCr	GENMASK(2, 1)
+#define CSC0_CTRL_CSC_MODE_YUV2RGB	(0x0 << 1)
+#define CSC0_CTRL_CSC_MODE_YCbCr2RGB	(0x1 << 1)
+#define CSC0_CTRL_CSC_MODE_RGB2YUV	(0x2 << 1)
+#define CSC0_CTRL_CSC_MODE_RGB2YCbCr	(0x3 << 1)
 #define CSC0_CTRL_CSC_MODE_MASK		GENMASK(2, 1)
 #define CSC0_CTRL_BYPASS		BIT(0)