[media] cx231xx: enable the analog tuner at buffer setup

buf_prepare callback is called for every queued buffer. This is
an overkill. Call it at buf_setup, as this should be enough.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/cx231xx/cx231xx-video.c

@@ -100,6 +100,75 @@ static struct cx231xx_fmt format[] = {
 };
 
 
+static int cx231xx_enable_analog_tuner(struct cx231xx *dev)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device *mdev = dev->media_dev;
+	struct media_entity  *entity, *decoder = NULL, *source;
+	struct media_link *link, *found_link = NULL;
+	int i, ret, active_links = 0;
+
+	if (!mdev)
+		return 0;
+
+	/*
+	 * This will find the tuner that is connected into the decoder.
+	 * Technically, this is not 100% correct, as the device may be
+	 * using an analog input instead of the tuner. However, as we can't
+	 * do DVB streaming while the DMA engine is being used for V4L2,
+	 * this should be enough for the actual needs.
+	 */
+	media_device_for_each_entity(entity, mdev) {
+		if (entity->type == MEDIA_ENT_T_V4L2_SUBDEV_DECODER) {
+			decoder = entity;
+			break;
+		}
+	}
+	if (!decoder)
+		return 0;
+
+	for (i = 0; i < decoder->num_links; i++) {
+		link = &decoder->links[i];
+		if (link->sink->entity == decoder) {
+			found_link = link;
+			if (link->flags & MEDIA_LNK_FL_ENABLED)
+				active_links++;
+			break;
+		}
+	}
+
+	if (active_links == 1 || !found_link)
+		return 0;
+
+	source = found_link->source->entity;
+	for (i = 0; i < source->num_links; i++) {
+		struct media_entity *sink;
+		int flags = 0;
+
+		link = &source->links[i];
+		sink = link->sink->entity;
+
+		if (sink == entity)
+			flags = MEDIA_LNK_FL_ENABLED;
+
+		ret = media_entity_setup_link(link, flags);
+		if (ret) {
+			dev_err(dev->dev,
+				"Couldn't change link %s->%s to %s. Error %d\n",
+				source->name, sink->name,
+				flags ? "enabled" : "disabled",
+				ret);
+			return ret;
+		} else
+			dev_dbg(dev->dev,
+				"link %s->%s was %s\n",
+				source->name, sink->name,
+				flags ? "ENABLED" : "disabled");
+	}
+#endif
+	return 0;
+}
+
 /* ------------------------------------------------------------------
 	Video buffer and parser functions
    ------------------------------------------------------------------*/
@@ -667,6 +736,9 @@ buffer_setup(struct videobuf_queue *vq, unsigned int *count, unsigned int *size)
 	if (*count < CX231XX_MIN_BUF)
 		*count = CX231XX_MIN_BUF;
 
+
+	cx231xx_enable_analog_tuner(dev);
+
 	return 0;
 }
 
@@ -703,75 +775,6 @@ static void free_buffer(struct videobuf_queue *vq, struct cx231xx_buffer *buf)
 	buf->vb.state = VIDEOBUF_NEEDS_INIT;
 }
 
-static int cx231xx_enable_analog_tuner(struct cx231xx *dev)
-{
-#ifdef CONFIG_MEDIA_CONTROLLER
-	struct media_device *mdev = dev->media_dev;
-	struct media_entity  *entity, *decoder = NULL, *source;
-	struct media_link *link, *found_link = NULL;
-	int i, ret, active_links = 0;
-
-	if (!mdev)
-		return 0;
-
-	/*
-	 * This will find the tuner that is connected into the decoder.
-	 * Technically, this is not 100% correct, as the device may be
-	 * using an analog input instead of the tuner. However, as we can't
-	 * do DVB streaming while the DMA engine is being used for V4L2,
-	 * this should be enough for the actual needs.
-	 */
-	media_device_for_each_entity(entity, mdev) {
-		if (entity->type == MEDIA_ENT_T_V4L2_SUBDEV_DECODER) {
-			decoder = entity;
-			break;
-		}
-	}
-	if (!decoder)
-		return 0;
-
-	for (i = 0; i < decoder->num_links; i++) {
-		link = &decoder->links[i];
-		if (link->sink->entity == decoder) {
-			found_link = link;
-			if (link->flags & MEDIA_LNK_FL_ENABLED)
-				active_links++;
-			break;
-		}
-	}
-
-	if (active_links == 1 || !found_link)
-		return 0;
-
-	source = found_link->source->entity;
-	for (i = 0; i < source->num_links; i++) {
-		struct media_entity *sink;
-		int flags = 0;
-
-		link = &source->links[i];
-		sink = link->sink->entity;
-
-		if (sink == entity)
-			flags = MEDIA_LNK_FL_ENABLED;
-
-		ret = media_entity_setup_link(link, flags);
-		if (ret) {
-			dev_err(dev->dev,
-				"Couldn't change link %s->%s to %s. Error %d\n",
-				source->name, sink->name,
-				flags ? "enabled" : "disabled",
-				ret);
-			return ret;
-		} else
-			dev_dbg(dev->dev,
-				"link %s->%s was %s\n",
-				source->name, sink->name,
-				flags ? "ENABLED" : "disabled");
-	}
-#endif
-	return 0;
-}
-
 static int
 buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
 	       enum v4l2_field field)
@@ -826,8 +829,6 @@ buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
 
 	buf->vb.state = VIDEOBUF_PREPARED;
 
-	cx231xx_enable_analog_tuner(dev);
-
 	return 0;
 
 fail: