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[v2] media: imx-csi: Skip first few frames from a BT.656 source

Message ID 20210427140649.3107744-1-festevam@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v2] media: imx-csi: Skip first few frames from a BT.656 source | expand

Commit Message

Fabio Estevam April 27, 2021, 2:06 p.m. UTC 
From: Steve Longerbeam <slongerbeam@gmail.com>

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@gmail.com>
[fabio: fixed checkpatch warning]
Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
Changes since v1:
- Fix Author line, sorry Steve!

 drivers/staging/media/imx/imx-media-csi.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
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Patch

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)