[RFC 4/5] media: i2c: max9286: Fetch PIXEL_RATE in s_stream

[Jacopo Mondi <jacopo+renesas@jmondi.org>]

The max9286 driver needs to fetch the remote serializer PIXEL_RATE
control value in order to compute its own one, as the sum of the
values reported by the connected subdevices.

Currently the control is verified to be present at notifier's bound
time, which requires the serializer driver to register the control at
probe time. As the serializer driver might need to register the control
later, by adding the control handler of its connected sensor, post-pone
the max9286 check for the control availability at start stream time.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 drivers/media/i2c/max9286.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index 1b92d18a1f94..98fc90339a9e 100644
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -595,7 +595,7 @@ static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
 	max9286_check_config_link(priv, priv->source_mask);
 	max9286_configure_i2c(priv, false);
 
-	return max9286_set_pixelrate(priv);
+	return 0;
 }
 
 static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
@@ -674,6 +674,10 @@ static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
 	int ret;
 
 	if (enable) {
+		ret = max9286_set_pixelrate(priv);
+		if (ret)
+			return ret;
+
 		/*
 		 * The frame sync between cameras is transmitted across the
 		 * reverse channel as GPIO. We must open all channels while
-- 
2.32.0