linux-kernel - [PATCH v4 08/15] media: rcar-csi2: Move {enable|disable}

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Message-Id: <20251216-rcar-streams-v4-8-f28b4831cc67@ideasonboard.com>
Date: Tue, 16 Dec 2025 17:18:25 +0200
From: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
To: Niklas Söderlund <niklas.soderlund@...natech.se>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: linux-media@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Niklas Söderlund <niklas.soderlund+renesas@...natech.se>, 
 Mauro Carvalho Chehab <mchehab+huawei@...nel.org>, 
 Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Jacopo Mondi <jacopo.mondi@...asonboard.com>, 
 Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
Subject: [PATCH v4 08/15] media: rcar-csi2: Move {enable|disable}_streams()
 calls

With multiple streams the operation to enable the CSI-2 hardware and to
call {enable|disable}_streams() on upstream subdev will need to be
handled separately.

Prepare for that by moving {enable|disable}_streams() calls out from
rcsi2_start() and rcsi2_stop().

On Gen3, a side effect of this change is that if the sink side devices
call .enable_streams() on rcar-csi2 multiple times, the second call will
fail. This is because we always use stream ID 0, so the second call
would attempt to enable the same stream again, leading to an error. In
other words, a normal single-stream setup continues to work, but trying
to use the current driver's custom VC based routing will fail.

On Gen4, this doesn't matter as the rcar-isp behaves in a similar way as
described above, and thus rcar-csi2 will only get a single
.enable_streams() call.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
---
 drivers/media/platform/renesas/rcar-csi2.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
index 7305cc4a04cb..158fa447e668 100644
--- a/drivers/media/platform/renesas/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-csi2.c
@@ -1822,20 +1822,12 @@ static int rcsi2_start(struct rcar_csi2 *priv, struct v4l2_subdev_state *state)
 		return ret;
 	}
 
-	ret = v4l2_subdev_enable_streams(priv->remote, priv->remote_pad,
-					 BIT_ULL(0));
-	if (ret) {
-		rcsi2_enter_standby(priv);
-		return ret;
-	}
-
 	return 0;
 }
 
 static void rcsi2_stop(struct rcar_csi2 *priv)
 {
 	rcsi2_enter_standby(priv);
-	v4l2_subdev_disable_streams(priv->remote, priv->remote_pad, BIT_ULL(0));
 }
 
 static int rcsi2_enable_streams(struct v4l2_subdev *sd,
@@ -1857,6 +1849,14 @@ static int rcsi2_enable_streams(struct v4l2_subdev *sd,
 			return ret;
 	}
 
+	ret = v4l2_subdev_enable_streams(priv->remote, priv->remote_pad,
+					 BIT_ULL(0));
+	if (ret) {
+		if (priv->stream_count == 0)
+			rcsi2_stop(priv);
+		return ret;
+	}
+
 	priv->stream_count += 1;
 
 	return ret;
@@ -1867,7 +1867,7 @@ static int rcsi2_disable_streams(struct v4l2_subdev *sd,
 				 u32 source_pad, u64 source_streams_mask)
 {
 	struct rcar_csi2 *priv = sd_to_csi2(sd);
-	int ret = 0;
+	int ret;
 
 	if (source_streams_mask != 1)
 		return -EINVAL;
@@ -1878,9 +1878,14 @@ static int rcsi2_disable_streams(struct v4l2_subdev *sd,
 	if (priv->stream_count == 1)
 		rcsi2_stop(priv);
 
+	ret = v4l2_subdev_disable_streams(priv->remote, priv->remote_pad,
+					  BIT_ULL(0));
+	if (ret)
+		return ret;
+
 	priv->stream_count -= 1;
 
-	return ret;
+	return 0;
 }
 
 static int rcsi2_set_pad_format(struct v4l2_subdev *sd,

-- 
2.43.0