[media] media: rcar-vin: allow field to be changed

The driver forced whatever field was set by the source subdevice to be
used. This patch allows the user to change from the default field.
Signed-off-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/rcar-vin/rcar-v4l2.c

@@ -102,6 +102,7 @@ static int __rvin_try_format_source(struct rvin_dev *vin,
 	struct v4l2_subdev_format format = {
 		.which = which,
 	};
+	enum v4l2_field field;
 	int ret;
 
 	sd = vin_to_source(vin);
@@ -114,12 +115,16 @@ static int __rvin_try_format_source(struct rvin_dev *vin,
 
 	format.pad = vin->src_pad_idx;
 
+	field = pix->field;
+
 	ret = v4l2_subdev_call(sd, pad, set_fmt, pad_cfg, &format);
 	if (ret < 0 && ret != -ENOIOCTLCMD)
 		goto done;
 
 	v4l2_fill_pix_format(pix, &format.format);
 
+	pix->field = field;
+
 	source->width = pix->width;
 	source->height = pix->height;
 
@@ -143,6 +148,10 @@ static int __rvin_try_format(struct rvin_dev *vin,
 	rwidth = pix->width;
 	rheight = pix->height;
 
+	/* Keep current field if no specific one is asked for */
+	if (pix->field == V4L2_FIELD_ANY)
+		pix->field = vin->format.field;
+
 	/*
 	 * Retrieve format information and select the current format if the
 	 * requested format isn't supported.