ASoC: Add weak routes for sidetone style paths

Normally DAPM will power up any connected audio path. This is not ideal for sidetone paths as with sidetone paths the audio path is not wanted in itself, it is only desired if the two paths it provides a sidetone between are both active. If the sidetone path causes a power up then it can be hard to minimise pops as we first power up either the sidetone or the main output path and then power the other, with the second power up potentially introducing a DC offset. Address this by introducing the concept of a weak path. If a path is marked as weak then DAPM will ignore that path when walking the graph, though all the relevant controls are still available to the application layer to allow these paths to be configured. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com>

ASoC: Add weak routes for sidetone style paths
Normally DAPM will power up any connected audio path. This is not ideal for sidetone paths as with sidetone paths the audio path is not wanted in itself, it is only desired if the two paths it provides a sidetone between are both active. If the sidetone path causes a power up then it can be hard to minimise pops as we first power up either the sidetone or the main output path and then power the other, with the second power up potentially introducing a DC offset. Address this by introducing the concept of a weak path. If a path is marked as weak then DAPM will ignore that path when walking the graph, though all the relevant controls are still available to the application layer to allow these paths to be configured. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com>
Mark Brown
1 parent 5bef44f9b4
Showing 2 changed files with 89 additions and 0 deletions Side-by-side Diff
include/sound/soc-dapm.h
sound/soc/soc-dapm.c
@@ -348,6 +348,8 @@
 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,
@@ -593,6 +593,9 @@
 	}
  
 	list_for_each_entry(path, &widget->sinks, list_source) {
+		if (path->weak)
+			continue;
+
 		if (path->walked)
 			continue;
  
@@ -643,6 +646,9 @@
 	}
  
 	list_for_each_entry(path, &widget->sources, list_sink) {
+		if (path->weak)
+			continue;
+
 		if (path->walked)
 			continue;
  
@@ -724,6 +730,9 @@
  
 	/* 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;
@@ -1805,6 +1814,84 @@
 	return 0;
 }
 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
...	...	@@ -348,6 +348,8 @@
348	348	void snd_soc_dapm_free(struct snd_soc_dapm_context *dapm);
349	349	int snd_soc_dapm_add_routes(struct snd_soc_dapm_context *dapm,
350	350	const struct snd_soc_dapm_route *route, int num);
	351	+int snd_soc_dapm_weak_routes(struct snd_soc_dapm_context *dapm,
	352	+ const struct snd_soc_dapm_route *route, int num);
351	353
352	354	/* dapm events */
353	355	int snd_soc_dapm_stream_event(struct snd_soc_pcm_runtime *rtd,
...	...	@@ -593,6 +593,9 @@
593	593	}
594	594
595	595	list_for_each_entry(path, &widget->sinks, list_source) {
	596	+ if (path->weak)
	597	+ continue;
	598	+
596	599	if (path->walked)
597	600	continue;
598	601
...	...	@@ -643,6 +646,9 @@
643	646	}
644	647
645	648	list_for_each_entry(path, &widget->sources, list_sink) {
	649	+ if (path->weak)
	650	+ continue;
	651	+
646	652	if (path->walked)
647	653	continue;
648	654
...	...	@@ -724,6 +730,9 @@
724	730
725	731	/* Check if one of our outputs is connected */
726	732	list_for_each_entry(path, &w->sinks, list_source) {
	733	+ if (path->weak)
	734	+ continue;
	735	+
727	736	if (path->connected &&
728	737	!path->connected(path->source, path->sink))
729	738	continue;
...	...	@@ -1805,6 +1814,84 @@
1805	1814	return 0;
1806	1815	}
1807	1816	EXPORT_SYMBOL_GPL(snd_soc_dapm_add_routes);
	1817	+
	1818	+static int snd_soc_dapm_weak_route(struct snd_soc_dapm_context *dapm,
	1819	+ const struct snd_soc_dapm_route *route)
	1820	+{
	1821	+ struct snd_soc_dapm_widget *source = dapm_find_widget(dapm,
	1822	+ route->source,
	1823	+ true);
	1824	+ struct snd_soc_dapm_widget *sink = dapm_find_widget(dapm,
	1825	+ route->sink,
	1826	+ true);
	1827	+ struct snd_soc_dapm_path *path;
	1828	+ int count = 0;
	1829	+
	1830	+ if (!source) {
	1831	+ dev_err(dapm->dev, "Unable to find source %s for weak route\n",
	1832	+ route->source);
	1833	+ return -ENODEV;
	1834	+ }
	1835	+
	1836	+ if (!sink) {
	1837	+ dev_err(dapm->dev, "Unable to find sink %s for weak route\n",
	1838	+ route->sink);
	1839	+ return -ENODEV;
	1840	+ }
	1841	+
	1842	+ if (route->control \|\| route->connected)
	1843	+ dev_warn(dapm->dev, "Ignoring control for weak route %s->%s\n",
	1844	+ route->source, route->sink);
	1845	+
	1846	+ list_for_each_entry(path, &source->sinks, list_source) {
	1847	+ if (path->sink == sink) {
	1848	+ path->weak = 1;
	1849	+ count++;
	1850	+ }
	1851	+ }
	1852	+
	1853	+ if (count == 0)
	1854	+ dev_err(dapm->dev, "No path found for weak route %s->%s\n",
	1855	+ route->source, route->sink);
	1856	+ if (count > 1)
	1857	+ dev_warn(dapm->dev, "%d paths found for weak route %s->%s\n",
	1858	+ count, route->source, route->sink);
	1859	+
	1860	+ return 0;
	1861	+}
	1862	+
	1863	+/**
	1864	+ * snd_soc_dapm_weak_routes - Mark routes between DAPM widgets as weak
	1865	+ * @dapm: DAPM context
	1866	+ * @route: audio routes
	1867	+ * @num: number of routes
	1868	+ *
	1869	+ * Mark existing routes matching those specified in the passed array
	1870	+ * as being weak, meaning that they are ignored for the purpose of
	1871	+ * power decisions. The main intended use case is for sidetone paths
	1872	+ * which couple audio between other independent paths if they are both
	1873	+ * active in order to make the combination work better at the user
	1874	+ * level but which aren't intended to be "used".
	1875	+ *
	1876	+ * Note that CODEC drivers should not use this as sidetone type paths
	1877	+ * can frequently also be used as bypass paths.
	1878	+ */
	1879	+int snd_soc_dapm_weak_routes(struct snd_soc_dapm_context *dapm,
	1880	+ const struct snd_soc_dapm_route *route, int num)
	1881	+{
	1882	+ int i, err;
	1883	+ int ret = 0;
	1884	+
	1885	+ for (i = 0; i < num; i++) {
	1886	+ err = snd_soc_dapm_weak_route(dapm, route);
	1887	+ if (err)
	1888	+ ret = err;
	1889	+ route++;
	1890	+ }
	1891	+
	1892	+ return ret;
	1893	+}
	1894	+EXPORT_SYMBOL_GPL(snd_soc_dapm_weak_routes);
1808	1895
1809	1896	/**
1810	1897	* snd_soc_dapm_new_widgets - add new dapm widgets