[PATCH] media: sun6i-mipi-csi2: Propagate format to source pad in TRY mode

[Arash Golgol <arash.golgol@gmail.com>]

sun6i-mipi-csi2 does not support any format conversion. So the format
on sink and source pad must always match. This limitation is handled for
ACTIVE state via mbus_format member of bridge private structure.

To enforce this limitation in TRY state, user space should only be able
to set format on sink pad. The sink format must be propagated to source
pad to ensure consistent behavior.

This also aligns the driver with userspace relying on media controller
based format negotiation.

Signed-off-by: Arash Golgol <arash.golgol@gmail.com>
---
 .../sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c   | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
index b06cb73015cd..6ee0f6685663 100644
--- a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
+++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
@@ -369,15 +369,26 @@ static int sun6i_mipi_csi2_set_fmt(struct v4l2_subdev *subdev,
 	struct v4l2_mbus_framefmt *mbus_format = &format->format;
 	struct mutex *lock = &csi2_dev->bridge.lock;
 
+	/* The format on the source pad always matches the sink pad. */
+	if (format->pad != SUN6I_MIPI_CSI2_PAD_SINK)
+		return v4l2_subdev_get_fmt(subdev, state, format);
+
 	mutex_lock(lock);
 
 	sun6i_mipi_csi2_mbus_format_prepare(mbus_format);
 
-	if (format->which == V4L2_SUBDEV_FORMAT_TRY)
-		*v4l2_subdev_state_get_format(state, format->pad) =
-			*mbus_format;
-	else
+	if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
+		struct v4l2_mbus_framefmt *fmt;
+
+		fmt = v4l2_subdev_state_get_format(state, format->pad);
+		*fmt = *mbus_format;
+
+		/* Propagate the format to the source pad. */
+		fmt = v4l2_subdev_state_get_format(state, SUN6I_MIPI_CSI2_PAD_SOURCE);
+		*fmt = *mbus_format;
+	} else {
 		csi2_dev->bridge.mbus_format = *mbus_format;
+	}
 
 	mutex_unlock(lock);
 
-- 
2.34.1