2 files changed, 89 insertions, 0 deletions

diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index 7415878c8b37..7c5465b14d33 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -348,6 +348,8 @@ int snd_soc_dapm_new_widgets(struct snd_soc_dapm_context *dapm);
 void snd_soc_dapm_free(struct snd_soc_dapm_context *dapm);
 int snd_soc_dapm_add_routes(struct snd_soc_dapm_context *dapm,
 			    const struct snd_soc_dapm_route *route, int num);
+int snd_soc_dapm_weak_routes(struct snd_soc_dapm_context *dapm,
+			     const struct snd_soc_dapm_route *route, int num);
 
 /* dapm events */
 int snd_soc_dapm_stream_event(struct snd_soc_pcm_runtime *rtd,
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index fd2d774797bb..746349faf2db 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -593,6 +593,9 @@ static int is_connected_output_ep(struct snd_soc_dapm_widget *widget)
 	}
 
 	list_for_each_entry(path, &widget->sinks, list_source) {
+		if (path->weak)
+			continue;
+
 		if (path->walked)
 			continue;
 
@@ -643,6 +646,9 @@ static int is_connected_input_ep(struct snd_soc_dapm_widget *widget)
 	}
 
 	list_for_each_entry(path, &widget->sources, list_sink) {
+		if (path->weak)
+			continue;
+
 		if (path->walked)
 			continue;
 
@@ -724,6 +730,9 @@ static int dapm_supply_check_power(struct snd_soc_dapm_widget *w)
 
 	/* Check if one of our outputs is connected */
 	list_for_each_entry(path, &w->sinks, list_source) {
+		if (path->weak)
+			continue;
+
 		if (path->connected &&
 		    !path->connected(path->source, path->sink))
 			continue;
@@ -1806,6 +1815,84 @@ int snd_soc_dapm_add_routes(struct snd_soc_dapm_context *dapm,
 }
 EXPORT_SYMBOL_GPL(snd_soc_dapm_add_routes);
 
+static int snd_soc_dapm_weak_route(struct snd_soc_dapm_context *dapm,
+				   const struct snd_soc_dapm_route *route)
+{
+	struct snd_soc_dapm_widget *source = dapm_find_widget(dapm,
+							      route->source,
+							      true);
+	struct snd_soc_dapm_widget *sink = dapm_find_widget(dapm,
+							    route->sink,
+							    true);
+	struct snd_soc_dapm_path *path;
+	int count = 0;
+
+	if (!source) {
+		dev_err(dapm->dev, "Unable to find source %s for weak route\n",
+			route->source);
+		return -ENODEV;
+	}
+
+	if (!sink) {
+		dev_err(dapm->dev, "Unable to find sink %s for weak route\n",
+			route->sink);
+		return -ENODEV;
+	}
+
+	if (route->control || route->connected)
+		dev_warn(dapm->dev, "Ignoring control for weak route %s->%s\n",
+			 route->source, route->sink);
+
+	list_for_each_entry(path, &source->sinks, list_source) {
+		if (path->sink == sink) {
+			path->weak = 1;
+			count++;
+		}
+	}
+
+	if (count == 0)
+		dev_err(dapm->dev, "No path found for weak route %s->%s\n",
+			route->source, route->sink);
+	if (count > 1)
+		dev_warn(dapm->dev, "%d paths found for weak route %s->%s\n",
+			 count, route->source, route->sink);
+
+	return 0;
+}
+
+/**
+ * snd_soc_dapm_weak_routes - Mark routes between DAPM widgets as weak
+ * @dapm: DAPM context
+ * @route: audio routes
+ * @num: number of routes
+ *
+ * Mark existing routes matching those specified in the passed array
+ * as being weak, meaning that they are ignored for the purpose of
+ * power decisions.  The main intended use case is for sidetone paths
+ * which couple audio between other independent paths if they are both
+ * active in order to make the combination work better at the user
+ * level but which aren't intended to be "used".
+ *
+ * Note that CODEC drivers should not use this as sidetone type paths
+ * can frequently also be used as bypass paths.
+ */
+int snd_soc_dapm_weak_routes(struct snd_soc_dapm_context *dapm,
+			     const struct snd_soc_dapm_route *route, int num)
+{
+	int i, err;
+	int ret = 0;
+
+	for (i = 0; i < num; i++) {
+		err = snd_soc_dapm_weak_route(dapm, route);
+		if (err)
+			ret = err;
+		route++;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_dapm_weak_routes);
+
 /**
  * snd_soc_dapm_new_widgets - add new dapm widgets
  * @dapm: DAPM context