media: imx: imx-mipi-csis: Implement the .get_frame_desc() operation

The CSIS is connected to its sink through an SoC-specific gasket that
needs to be configured. Depending on the platform, the gasket
configuration requires knowing the CSI-2 DT. To provide the needed
information, implement the .get_frame_desc() operation.

Signed-off-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Rui Miguel Silva <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/nxp/imx-mipi-csis.c

···
 	return 0;
 }
 
+static int mipi_csis_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+				    struct v4l2_mbus_frame_desc *fd)
+{
+	struct mipi_csis_device *csis = sd_to_mipi_csis_device(sd);
+	struct v4l2_mbus_frame_desc_entry *entry = &fd->entry[0];
+
+	if (pad != CSIS_PAD_SOURCE)
+		return -EINVAL;
+
+	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_PARALLEL;
+	fd->num_entries = 1;
+
+	memset(entry, 0, sizeof(*entry));
+
+	mutex_lock(&csis->lock);
+
+	entry->flags = 0;
+	entry->pixelcode = csis->csis_fmt->code;
+	entry->bus.csi2.vc = 0;
+	entry->bus.csi2.dt = csis->csis_fmt->data_type;
+
+	mutex_unlock(&csis->lock);
+
+	return 0;
+}
+
 static int mipi_csis_log_status(struct v4l2_subdev *sd)
 {
 	struct mipi_csis_device *csis = sd_to_mipi_csis_device(sd);
···
 	.enum_mbus_code		= mipi_csis_enum_mbus_code,
 	.get_fmt		= mipi_csis_get_fmt,
 	.set_fmt		= mipi_csis_set_fmt,
+	.get_frame_desc		= mipi_csis_get_frame_desc,
 };
 
 static const struct v4l2_subdev_ops mipi_csis_subdev_ops = {