GMSL can transport three synchronization signals: VSync, HSync and Data Enable. The MAX9286 can select either HS or DE as a line valid signal. Not all serializers (and transmission formats) support the DE signal. The MAX9271, used by the RDACM20 and RDACM21 cameras, doesn't document DE support. Nonetheless, the max9286 driver selects the DE signal as line valid in register 0x0c (by not setting the DESEL bit). It's not clear why this works. As HS is a more common line valid qualifier, set the DESEL bit by default. This is needed to support the onsemi MARS cameras. If a camera requires usage of the DE signal in the future, this will need to be made configurable. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> --- drivers/media/i2c/max9286.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c index 07ebb01640a1..446fc238d642 100644 --- a/drivers/media/i2c/max9286.c +++ b/drivers/media/i2c/max9286.c @@ -563,9 +563,12 @@ static void max9286_set_video_format(struct max9286_priv *priv, MAX9286_CSILANECNT(priv->csi2_data_lanes) | info->datatype); - /* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */ - max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS | - MAX9286_HVSRC_D14); + /* + * Enable HS/VS encoding, use HS as line valid source, use D14/15 for + * HS/VS, invert VS. + */ + max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_DESEL | + MAX9286_INVVS | MAX9286_HVSRC_D14); } static void max9286_set_fsync_period(struct max9286_priv *priv) -- Regards, Laurent Pinchart
