[PATCH v2] [media] imx: csi: enable double write reduction

[Philipp Zabel]

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: Philipp Zabel <p.za...@pengutronix.de>
---
Changes since v1:
 - Move odd row skipping setup into existing switch statement.
---
 drivers/staging/media/imx/imx-media-csi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/media/imx/imx-media-csi.c 
b/drivers/staging/media/imx/imx-media-csi.c
index a2d26693912ec..f2d64d1eeff80 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/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:
-- 
2.11.0