From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

The RZ/G2L CRU needs to configure the ICnMC.VCSEL bits to specify which
virtual channel should be processed from the four available VCs. To
retrieve this information from the connected subdevice, the
.get_frame_desc() function is called.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 .../platform/renesas/rzg2l-cru/rzg2l-cru.h    |  5 +++
 .../platform/renesas/rzg2l-cru/rzg2l-ip.c     |  5 ---
 .../platform/renesas/rzg2l-cru/rzg2l-video.c  | 34 +++++++++++++++++++
 3 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
index 174760239548..8fbd45c43763 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
@@ -31,6 +31,11 @@
 #define RZG2L_CRU_MIN_INPUT_HEIGHT	240
 #define RZG2L_CRU_MAX_INPUT_HEIGHT	4095
 
+enum rzg2l_csi2_pads {
+	RZG2L_CRU_IP_SINK = 0,
+	RZG2L_CRU_IP_SOURCE,
+};
+
 /**
  * enum rzg2l_cru_dma_state - DMA states
  * @RZG2L_CRU_DMA_STOPPED:   No operation in progress
diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-ip.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-ip.c
index db48118fc817..75c3c4f1d10b 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-ip.c
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-ip.c
@@ -18,11 +18,6 @@ static const struct rzg2l_cru_ip_format rzg2l_cru_ip_formats[] = {
 	{ .code = MEDIA_BUS_FMT_UYVY8_1X16,	.datatype = 0x1e, .bpp = 16 },
 };
 
-enum rzg2l_csi2_pads {
-	RZG2L_CRU_IP_SINK = 0,
-	RZG2L_CRU_IP_SOURCE,
-};
-
 static const struct rzg2l_cru_ip_format *rzg2l_cru_ip_code_to_fmt(unsigned int code)
 {
 	unsigned int i;
diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
index bbf4674f888d..7cd33eb1939c 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
@@ -433,12 +433,46 @@ void rzg2l_cru_stop_image_processing(struct rzg2l_cru_dev *cru)
 	spin_unlock_irqrestore(&cru->qlock, flags);
 }
 
+static int rzg2l_cru_get_virtual_channel(struct rzg2l_cru_dev *cru)
+{
+	struct v4l2_mbus_frame_desc fd = { };
+	struct media_pad *remote_pad;
+	int ret;
+
+	remote_pad = media_pad_remote_pad_unique(&cru->ip.pads[RZG2L_CRU_IP_SINK]);
+	ret = v4l2_subdev_call(cru->ip.remote, pad, get_frame_desc, remote_pad->index, &fd);
+	if (ret < 0 && ret != -ENOIOCTLCMD) {
+		dev_err(cru->dev, "get_frame_desc failed on IP remote subdev\n");
+		return ret;
+	}
+	/* If remote subdev does not implement .get_frame_desc default to VC0. */
+	if (ret == -ENOIOCTLCMD)
+		return 0;
+
+	if (fd.type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2) {
+		dev_err(cru->dev, "get_frame_desc returned invalid bus type %d\n", fd.type);
+		return -EINVAL;
+	}
+
+	if (!fd.num_entries) {
+		dev_err(cru->dev, "get_frame_desc returned zero entries\n");
+		return -EINVAL;
+	}
+
+	return fd.entry[0].bus.csi2.vc;
+}
+
 int rzg2l_cru_start_image_processing(struct rzg2l_cru_dev *cru)
 {
 	struct v4l2_mbus_framefmt *fmt = rzg2l_cru_ip_get_src_fmt(cru);
 	unsigned long flags;
 	int ret;
 
+	ret = rzg2l_cru_get_virtual_channel(cru);
+	if (ret < 0)
+		return ret;
+	cru->csi.channel = ret;
+
 	spin_lock_irqsave(&cru->qlock, flags);
 
 	/* Select a video input */
-- 
2.34.1