media: imx: Move pads init to probe

If a subdevice is unregistered and then registered again without the
driver being removed and re-probed (which will happen when the media
device is removed and re-probed without also removing/re-probing the
subdevice), media_device_register_entity() is called with a non-zero
entity->num_pads, and then the subdevice's .registered callback calls
media_entity_pads_init(). Thus the subdevice's pad objects are added
to the media device pad list twice, causing list corruption.

One way to fix this would be to create media_entity_pads_destroy(),
and call it in the subdevice's .unregistered callback. But calling
media_entity_pads_init() in the .registered callbacks was done for
legacy reasons and is no longer necessary, so move the call to
media_entity_pads_init() into the subdevice's probe functions. This
fixes the duplicate pad obejcts in the media device pad list.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 9 insertions, 16 deletions

diff --git a/drivers/staging/media/imx/imx-ic-prp.c b/drivers/staging/media/imx/imx-ic-prp.c
index 35e60a120dc1..2a4f77e83ed3 100644
--- a/drivers/staging/media/imx/imx-ic-prp.c
+++ b/drivers/staging/media/imx/imx-ic-prp.c
@@ -428,32 +428,19 @@ static int prp_s_frame_interval(struct v4l2_subdev *sd,
 	return 0;
 }
 
-/*
- * retrieve our pads parsed from the OF graph by the media device
- */
 static int prp_registered(struct v4l2_subdev *sd)
 {
 	struct prp_priv *priv = sd_to_priv(sd);
-	int i, ret;
 	u32 code;
 
-	for (i = 0; i < PRP_NUM_PADS; i++) {
-		priv->pad[i].flags = (i == PRP_SINK_PAD) ?
-			MEDIA_PAD_FL_SINK : MEDIA_PAD_FL_SOURCE;
-	}
-
 	/* init default frame interval */
 	priv->frame_interval.numerator = 1;
 	priv->frame_interval.denominator = 30;
 
 	/* set a default mbus format  */
 	imx_media_enum_ipu_format(&code, 0, CS_SEL_YUV);
-	ret = imx_media_init_mbus_fmt(&priv->format_mbus, 640, 480, code,
-				      V4L2_FIELD_NONE, NULL);
-	if (ret)
-		return ret;
-
-	return media_entity_pads_init(&sd->entity, PRP_NUM_PADS, priv->pad);
+	return imx_media_init_mbus_fmt(&priv->format_mbus, 640, 480, code,
+				       V4L2_FIELD_NONE, NULL);
 }
 
 static const struct v4l2_subdev_pad_ops prp_pad_ops = {
@@ -487,6 +474,7 @@ static const struct v4l2_subdev_internal_ops prp_internal_ops = {
 static int prp_init(struct imx_ic_priv *ic_priv)
 {
 	struct prp_priv *priv;
+	int i;
 
 	priv = devm_kzalloc(ic_priv->ipu_dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -496,7 +484,12 @@ static int prp_init(struct imx_ic_priv *ic_priv)
 	ic_priv->task_priv = priv;
 	priv->ic_priv = ic_priv;
 
-	return 0;
+	for (i = 0; i < PRP_NUM_PADS; i++)
+		priv->pad[i].flags = (i == PRP_SINK_PAD) ?
+			MEDIA_PAD_FL_SINK : MEDIA_PAD_FL_SOURCE;
+
+	return media_entity_pads_init(&ic_priv->sd.entity, PRP_NUM_PADS,
+				      priv->pad);
 }
 
 static void prp_remove(struct imx_ic_priv *ic_priv)