By default tegra_channel_get_remote_csi_subdev returns next device in pipe
assuming it is CSI but in case of Tegra20 and Tegra30 it can also be VIP
or even HOST.

Define tegra_channel_get_remote_csi_subdev within CSI and add check if
returned device is actually CSI by comparing subdevice operations.

Previous tegra_channel_get_remote_csi_subdev definition in VI rename to
tegra_channel_get_remote_bridge_subdev and use it only in VI driver since
core VI driver does not care about source and does not call any specific
functions.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
 drivers/staging/media/tegra-video/csi.c | 16 ++++++++++++++++
 drivers/staging/media/tegra-video/vi.c  | 14 +++++++-------
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/media/tegra-video/csi.c b/drivers/staging/media/tegra-video/csi.c
index 9e3bd6109781..ef5f054b6d49 100644
--- a/drivers/staging/media/tegra-video/csi.c
+++ b/drivers/staging/media/tegra-video/csi.c
@@ -445,6 +445,22 @@ static const struct v4l2_subdev_ops tegra_csi_ops = {
 	.pad    = &tegra_csi_pad_ops,
 };
 
+struct v4l2_subdev *tegra_channel_get_remote_csi_subdev(struct tegra_vi_channel *chan)
+{
+	struct media_pad *pad;
+	struct v4l2_subdev *subdev;
+
+	pad = media_pad_remote_pad_first(&chan->pad);
+	if (!pad)
+		return NULL;
+
+	subdev = media_entity_to_v4l2_subdev(pad->entity);
+	if (!subdev)
+		return NULL;
+
+	return subdev->ops == &tegra_csi_ops ? subdev : NULL;
+}
+
 static int tegra_csi_channel_alloc(struct tegra_csi *csi,
 				   struct device_node *node,
 				   unsigned int port_num, unsigned int lanes,
diff --git a/drivers/staging/media/tegra-video/vi.c b/drivers/staging/media/tegra-video/vi.c
index 90473729b546..04b538e8b514 100644
--- a/drivers/staging/media/tegra-video/vi.c
+++ b/drivers/staging/media/tegra-video/vi.c
@@ -160,8 +160,8 @@ static void tegra_channel_buffer_queue(struct vb2_buffer *vb)
 	wake_up_interruptible(&chan->start_wait);
 }
 
-struct v4l2_subdev *
-tegra_channel_get_remote_csi_subdev(struct tegra_vi_channel *chan)
+static struct v4l2_subdev *
+tegra_channel_get_remote_bridge_subdev(struct tegra_vi_channel *chan)
 {
 	struct media_pad *pad;
 
@@ -182,7 +182,7 @@ tegra_channel_get_remote_source_subdev(struct tegra_vi_channel *chan)
 	struct v4l2_subdev *subdev;
 	struct media_entity *entity;
 
-	subdev = tegra_channel_get_remote_csi_subdev(chan);
+	subdev = tegra_channel_get_remote_bridge_subdev(chan);
 	if (!subdev)
 		return NULL;
 
@@ -204,7 +204,7 @@ static int tegra_channel_enable_stream(struct tegra_vi_channel *chan)
 	struct v4l2_subdev *subdev;
 	int ret;
 
-	subdev = tegra_channel_get_remote_csi_subdev(chan);
+	subdev = tegra_channel_get_remote_bridge_subdev(chan);
 	ret = v4l2_subdev_call(subdev, video, s_stream, true);
 	if (ret < 0 && ret != -ENOIOCTLCMD)
 		return ret;
@@ -217,7 +217,7 @@ static int tegra_channel_disable_stream(struct tegra_vi_channel *chan)
 	struct v4l2_subdev *subdev;
 	int ret;
 
-	subdev = tegra_channel_get_remote_csi_subdev(chan);
+	subdev = tegra_channel_get_remote_bridge_subdev(chan);
 	ret = v4l2_subdev_call(subdev, video, s_stream, false);
 	if (ret < 0 && ret != -ENOIOCTLCMD)
 		return ret;
@@ -1630,11 +1630,11 @@ static int tegra_vi_graph_notify_complete(struct v4l2_async_notifier *notifier)
 		goto unregister_video;
 	}
 
-	subdev = tegra_channel_get_remote_csi_subdev(chan);
+	subdev = tegra_channel_get_remote_bridge_subdev(chan);
 	if (!subdev) {
 		ret = -ENODEV;
 		dev_err(vi->dev,
-			"failed to get remote csi subdev: %d\n", ret);
+			"failed to get remote bridge subdev: %d\n", ret);
 		goto unregister_video;
 	}
 
-- 
2.48.1