Commit e198be37 authored by Steve Longerbeam's avatar Steve Longerbeam Committed by Mauro Carvalho Chehab
Browse files

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



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 20 frames
to avoid the unstable sync codes.

[fabio: fixed checkpatch warning and increased the frame skipping to 20]

Signed-off-by: default avatarSteve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: default avatarFabio Estevam <festevam@gmail.com>
Reviewed-by: default avatarTim Harvey <tharvey@gateworks.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent ca816468

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

+13 −1
Original line number Diff line number Diff line
@@ -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 = 20;



		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)