FROMLIST: v4l: async: Introduce helpers for calling async ops callbacks

Add three helper functions to call async operations callbacks. Besides
simplifying callbacks, this allows async notifiers to have no ops set,
i.e. it can be left NULL.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
(cherry picked from commit 6b4257572d7443669a1f83c6f90c2b43620fba6c)
https://git.linuxtv.org/sailus/media_tree.git/log/?h=010f7f4393fd
http://www.spinics.net/lists/linux-media/msg122688.html
Signed-off-by: Marc Herbert <marc.herbert@intel.com>

BUG=b:64133998
TEST=media device topology shows subdevs registered successfully
TEST=no camera regression

Change-Id: I2cb3051601dc068f60dc2072fb9b9a65b916d0a4
Reviewed-on: https://chromium-review.googlesource.com/693690
Commit-Ready: Tomasz Figa <tfiga@chromium.org>
Tested-by: Hyungwoo Yang <hyungwoo.yang@intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>

Author: Sakari Ailus

drivers/media/v4l2-core/v4l2-async.c

@@ -24,6 +24,34 @@
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>
 
+static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
+					  struct v4l2_subdev *subdev,
+					  struct v4l2_async_subdev *asd)
+{
+	if (!n->ops || !n->ops->bound)
+		return 0;
+
+	return n->ops->bound(n, subdev, asd);
+}
+
+static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
+					    struct v4l2_subdev *subdev,
+					    struct v4l2_async_subdev *asd)
+{
+	if (!n->ops || !n->ops->unbind)
+		return;
+
+	n->ops->unbind(n, subdev, asd);
+}
+
+static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
+{
+	if (!n->ops || !n->ops->complete)
+		return 0;
+
+	return n->ops->complete(n);
+}
+
 static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
 {
 #if IS_ENABLED(CONFIG_I2C)
@@ -106,16 +134,13 @@ static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
 {
 	int ret;
 
-	if (notifier->ops->bound) {
-		ret = notifier->ops->bound(notifier, sd, asd);
-		if (ret < 0)
-			return ret;
-	}
+	ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
+	if (ret < 0)
+		return ret;
 
 	ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd);
 	if (ret < 0) {
-		if (notifier->ops->unbind)
-			notifier->ops->unbind(notifier, sd, asd);
+		v4l2_async_notifier_call_unbind(notifier, sd, asd);
 		return ret;
 	}
 
@@ -127,8 +152,8 @@ static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
 	/* Move from the global subdevice list to notifier's done */
 	list_move(&sd->async_list, &notifier->done);
 
-	if (list_empty(&notifier->waiting) && notifier->ops->complete)
-		return notifier->ops->complete(notifier);
+	if (list_empty(&notifier->waiting))
+		return v4l2_async_notifier_call_complete(notifier);
 
 	return 0;
 }
@@ -214,8 +239,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
 		v4l2_async_cleanup(sd);
 
-		if (notifier->ops->unbind)
-			notifier->ops->unbind(notifier, sd, sd->asd);
+		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
 
 		list_move(&sd->async_list, &subdev_list);
 	}
@@ -306,8 +330,7 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
 
 	v4l2_async_cleanup(sd);
 
-	if (notifier->ops->unbind)
-		notifier->ops->unbind(notifier, sd, sd->asd);
+	v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
 
 	mutex_unlock(&list_lock);
 }

include/media/v4l2-async.h

@@ -164,4 +164,5 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd);
  * @sd: pointer to &struct v4l2_subdev
  */
 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
+
 #endif