From: Steve Longerbeam <slongerbeam@xxxxxxxxx>
Some BT.656 sensors (e.g. ADV718x) transmit frames with unstable
BT.656 sync codes after initial power on. This confuses the imx
CSI, resulting in vertical and/or horizontal sync issues. Skip
the first 10 frames to avoid the unstable sync codes.
Signed-off-by: Steve Longerbeam <slongerbeam@xxxxxxxxx>
[fabio: fixed checkpatch warning]
Signed-off-by: Fabio Estevam <festevam@xxxxxxxxx>
---
Changes since v1:
- Fix Author line, sorry Steve!
drivers/staging/media/imx/imx-media-csi.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index e3bfd635a89a..5d24dd1379b3 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -750,9 +750,10 @@ static int csi_setup(struct csi_priv *priv)
static int csi_start(struct csi_priv *priv)
{
- struct v4l2_fract *output_fi;
+ struct v4l2_fract *input_fi, *output_fi;
int ret;
+ input_fi = &priv->frame_interval[CSI_SINK_PAD];
output_fi = &priv->frame_interval[priv->active_output_pad];
/* start upstream */
@@ -761,6 +762,17 @@ static int csi_start(struct csi_priv *priv)
if (ret)
return ret;
+ /* Skip first few frames from a BT.656 source */
+ if (priv->upstream_ep.bus_type == V4L2_MBUS_BT656) {
+ u32 delay_usec, bad_frames = 10;
+
+ delay_usec = DIV_ROUND_UP_ULL((u64)USEC_PER_SEC *
+ input_fi->numerator * bad_frames,
+ input_fi->denominator);
+
+ usleep_range(delay_usec, delay_usec + 1000);
+ }
+
if (priv->dest == IPU_CSI_DEST_IDMAC) {
ret = csi_idmac_start(priv);
if (ret)
--
2.25.1
