media: imx: csi: enable double write reduction

For 4:2:0 subsampled YUV formats, avoid chroma overdraw by only writing
chroma for even lines. Reduces necessary write memory bandwidth by 25%.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Acked-by: NSteve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/imx/imx-media-csi.c

@@ -357,6 +357,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
 		passthrough = (sensor_ep->bus_type != V4L2_MBUS_CSI2 &&
 			       sensor_ep->bus.parallel.bus_width >= 16);
 		passthrough_bits = 16;
+		/* Skip writing U and V components to odd rows */
+		ipu_cpmem_skip_odd_chroma_rows(priv->idmac_ch);
 		break;
 	case V4L2_PIX_FMT_YUYV:
 	case V4L2_PIX_FMT_UYVY: