[media] au0828: Cache the decoder info at au0828 dev structure

Instead of seeking for the decoder every time analog stream is
started, cache it. This simplifies the code a little bit.
Requested-by: Hans Verkuil <hverkuil@xs4all.nl>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/au0828/au0828-cards.c

@@ -228,6 +228,10 @@ void au0828_card_analog_fe_setup(struct au0828_dev *dev)
 				"au8522", 0x8e >> 1, NULL);
 		if (sd == NULL)
 			pr_err("analog subdev registration failed\n");
+#ifdef CONFIG_MEDIA_CONTROLLER
+		if (sd)
+			dev->decoder = &sd->entity;
+#endif
 	}
 
 	/* Setup tuners */

drivers/media/usb/au0828/au0828-video.c

@@ -642,11 +642,11 @@ static int au0828_enable_analog_tuner(struct au0828_dev *dev)
 {
 #ifdef CONFIG_MEDIA_CONTROLLER
 	struct media_device *mdev = dev->media_dev;
-	struct media_entity  *entity, *decoder = NULL, *source;
+	struct media_entity  *entity, *source;
 	struct media_link *link, *found_link = NULL;
 	int i, ret, active_links = 0;
 
-	if (!mdev)
+	if (!mdev || !dev->decoder)
 		return 0;
 
 	/*
@@ -656,18 +656,9 @@ static int au0828_enable_analog_tuner(struct au0828_dev *dev)
 	 * 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) {
+	for (i = 0; i < dev->decoder->num_links; i++) {
+		link = &dev->decoder->links[i];
+		if (link->sink->entity == dev->decoder) {
 			found_link = link;
 			if (link->flags & MEDIA_LNK_FL_ENABLED)
 				active_links++;

drivers/media/usb/au0828/au0828.h

@@ -281,6 +281,7 @@ struct au0828_dev {
 #ifdef CONFIG_MEDIA_CONTROLLER
 	struct media_device *media_dev;
 	struct media_pad video_pad, vbi_pad;
+	struct media_entity *decoder;
 #endif
 };