ASoC: soc-core: Add core support for ignoring suspend on selected DAPM widgets

Chancel Liu <chancel.liu@nxp.com> says:

Some audio systems require specific DAPM widgets to remain powered
during system suspend. Introduce a generic and reusable mechanism in
the ASoC core to mark selected DAPM widgets as ignore_suspend.

The unified mechanism consists of two parts:
1. Parse and store the name list of widgets to ignore suspend in
struct snd_soc_card

The list of widgets can be provided either by the machine driver or
parsed from Device Tree. Different machines have different routing and
power requirements. Each machine can specify its own widgets to ignore
suspend through DT property. It enables flexible policy without hard
code. A new helper, snd_soc_of_parse_ignore_suspend_widgets() is added
for this purpose.

2. Apply ignore_suspend flags during snd_soc_bind_card()

After all components have been probed and all DAPM widgets have been
registered, snd_soc_bind_card() performs a unified lookup of the
configured widget names across all DAPM contexts of the card and marks
the matching widgets with ignore_suspend = 1.

Switch to use core ignore-suspend-widgets support for imx-rpmsg driver.

Chancel Liu (3):
  ASoC: dapm: Fix widget lookup with prefixed names across DAPM contexts
  ASoC: soc-core: Add core support for ignoring suspend on selected DAPM
    widgets
  ASoC: fsl: imx-rpmsg: Switch to core ignore-suspend-widgets support

Link: https://patch.msgid.link/20260507013654.2945915-1-chancel.liu@nxp.com

include/sound/soc-dapm.h

@@ -636,6 +636,7 @@ int snd_soc_dapm_new_dai_widgets(struct snd_soc_dapm_context *dapm, struct snd_s
 void snd_soc_dapm_free_widget(struct snd_soc_dapm_widget *w);
 int snd_soc_dapm_link_dai_widgets(struct snd_soc_card *card);
 void snd_soc_dapm_connect_dai_link_widgets(struct snd_soc_card *card);
+int snd_soc_dapm_ignore_suspend_widgets(struct snd_soc_card *card);
 
 int snd_soc_dapm_update_dai(struct snd_pcm_substream *substream,
 			    struct snd_pcm_hw_params *params, struct snd_soc_dai *dai);
@@ -686,6 +687,7 @@ int snd_soc_dapm_sync_unlocked(struct snd_soc_dapm_context *dapm);
 int snd_soc_dapm_force_enable_pin(struct snd_soc_dapm_context *dapm, const char *pin);
 int snd_soc_dapm_force_enable_pin_unlocked(struct snd_soc_dapm_context *dapm, const char *pin);
 int snd_soc_dapm_ignore_suspend(struct snd_soc_dapm_context *dapm, const char *pin);
+bool snd_soc_dapm_pin_has_prefix(struct snd_soc_card *card, const char *pin);
 void snd_soc_dapm_mark_endpoints_dirty(struct snd_soc_card *card);
 
 /* dapm path query */

include/sound/soc.h

@@ -1057,10 +1057,14 @@ struct snd_soc_card {
 	int num_dapm_widgets;
 	const struct snd_soc_dapm_route *dapm_routes;
 	int num_dapm_routes;
+	const char **ignore_suspend_widgets;
+	int num_ignore_suspend_widgets;
 	const struct snd_soc_dapm_widget *of_dapm_widgets;
 	int num_of_dapm_widgets;
 	const struct snd_soc_dapm_route *of_dapm_routes;
 	int num_of_dapm_routes;
+	const char **of_ignore_suspend_widgets;
+	int num_of_ignore_suspend_widgets;
 
 	/* lists of probed devices belonging to this card */
 	struct list_head component_dev_list;
@@ -1337,6 +1341,7 @@ void snd_soc_of_parse_node_prefix(struct device_node *np,
 int snd_soc_of_parse_audio_routing(struct snd_soc_card *card,
 				   const char *propname);
 int snd_soc_of_parse_aux_devs(struct snd_soc_card *card, const char *propname);
+int snd_soc_of_parse_ignore_suspend_widgets(struct snd_soc_card *card, const char *propname);
 
 unsigned int snd_soc_daifmt_clock_provider_flipped(unsigned int dai_fmt);
 unsigned int snd_soc_daifmt_clock_provider_from_bitmap(unsigned int bit_frame);

sound/soc/fsl/imx-rpmsg.c

@@ -87,7 +87,6 @@ static int imx_rpmsg_late_probe(struct snd_soc_card *card)
 	int ret;
 
 	if (data->lpa) {
-		struct snd_soc_component *codec_comp;
 		struct device_node *codec_np;
 		struct device_driver *codec_drv;
 		struct device *codec_dev = NULL;
@@ -107,22 +106,6 @@ static int imx_rpmsg_late_probe(struct snd_soc_card *card)
 			}
 		}
 		if (codec_dev) {
-			codec_comp = snd_soc_lookup_component_nolocked(codec_dev, NULL);
-			if (codec_comp) {
-				int i, num_widgets;
-				const char *widgets;
-				struct snd_soc_dapm_context *dapm;
-
-				num_widgets = of_property_count_strings(data->card.dev->of_node,
-									"ignore-suspend-widgets");
-				for (i = 0; i < num_widgets; i++) {
-					of_property_read_string_index(data->card.dev->of_node,
-								      "ignore-suspend-widgets",
-								      i, &widgets);
-					dapm = snd_soc_component_to_dapm(codec_comp);
-					snd_soc_dapm_ignore_suspend(dapm, widgets);
-				}
-			}
 			codec_drv = codec_dev->driver;
 			if (codec_drv->pm) {
 				memcpy(&lpa_pm, codec_drv->pm, sizeof(lpa_pm));
@@ -274,6 +257,15 @@ static int imx_rpmsg_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (data->lpa && of_property_present(np, "ignore-suspend-widgets")) {
+		ret = snd_soc_of_parse_ignore_suspend_widgets(&data->card,
+							      "ignore-suspend-widgets");
+		if (ret) {
+			dev_err(&pdev->dev, "failed to parse ignore-suspend-widgets: %d\n", ret);
+			goto fail;
+		}
+	}
+
 	platform_set_drvdata(pdev, &data->card);
 	snd_soc_card_set_drvdata(&data->card, data);
 	ret = devm_snd_soc_register_card(&pdev->dev, &data->card);

sound/soc/soc-core.c

@@ -2289,6 +2289,10 @@ static int snd_soc_bind_card(struct snd_soc_card *card)
 	if (ret < 0)
 		goto probe_end;
 
+	ret = snd_soc_dapm_ignore_suspend_widgets(card);
+	if (ret < 0)
+		goto probe_end;
+
 	snd_soc_dapm_new_widgets(card);
 	snd_soc_card_fixup_controls(card);
 
@@ -3279,6 +3283,45 @@ int snd_soc_of_parse_aux_devs(struct snd_soc_card *card, const char *propname)
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_parse_aux_devs);
 
+int snd_soc_of_parse_ignore_suspend_widgets(struct snd_soc_card *card,
+					    const char *propname)
+{
+	struct device_node *np = card->dev->of_node;
+	int num_widgets;
+	const char **widgets;
+	int i;
+
+	num_widgets = of_property_count_strings(np, propname);
+	if (num_widgets < 0) {
+		dev_err(card->dev,
+			"ASoC: Property '%s' does not exist\n", propname);
+		return -EINVAL;
+	}
+
+	widgets = devm_kcalloc(card->dev, num_widgets, sizeof(char *), GFP_KERNEL);
+	if (!widgets)
+		return -ENOMEM;
+
+	for (i = 0; i < num_widgets; i++) {
+		const char *name;
+		int ret = of_property_read_string_index(np, propname, i, &name);
+
+		if (ret) {
+			dev_err(card->dev,
+				"ASoC: Property '%s' could not be read: %d\n",
+				propname, ret);
+			return -EINVAL;
+		}
+		widgets[i] = name;
+	}
+
+	card->num_of_ignore_suspend_widgets = num_widgets;
+	card->of_ignore_suspend_widgets = widgets;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_of_parse_ignore_suspend_widgets);
+
 unsigned int snd_soc_daifmt_clock_provider_flipped(unsigned int dai_fmt)
 {
 	unsigned int inv_dai_fmt = dai_fmt & ~SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK;

sound/soc/soc-dapm.c

@@ -2912,20 +2912,18 @@ static struct snd_soc_dapm_widget *dapm_find_widget(
 {
 	struct snd_soc_dapm_widget *w;
 	struct snd_soc_dapm_widget *fallback = NULL;
-	char prefixed_pin[80];
-	const char *pin_name;
-	const char *prefix = dapm_prefix(dapm);
-
-	if (prefix) {
-		snprintf(prefixed_pin, sizeof(prefixed_pin), "%s %s",
-			 prefix, pin);
-		pin_name = prefixed_pin;
-	} else {
-		pin_name = pin;
-	}
+	bool pin_has_prefix = snd_soc_dapm_pin_has_prefix(dapm->card, pin);
+	bool match;
 
 	for_each_card_widgets(dapm->card, w) {
-		if (!strcmp(w->name, pin_name)) {
+		match = false;
+
+		if (!strcmp(pin, w->name))
+			match = true;
+		else if (!pin_has_prefix && !snd_soc_dapm_widget_name_cmp(w, pin))
+			match = true;
+
+		if (match) {
 			if (w->dapm == dapm)
 				return w;
 			else
@@ -4612,6 +4610,36 @@ void snd_soc_dapm_connect_dai_link_widgets(struct snd_soc_card *card)
 	}
 }
 
+int snd_soc_dapm_ignore_suspend_widgets(struct snd_soc_card *card)
+{
+	struct snd_soc_dapm_widget *w;
+	int i;
+
+	for (i = 0; i < card->num_ignore_suspend_widgets; i++) {
+		w = dapm_find_widget(snd_soc_card_to_dapm(card),
+				     card->ignore_suspend_widgets[i], true);
+		if (!w) {
+			dev_err(card->dev, "ASoC: DAPM unknown ignore suspend widget %s\n",
+				card->ignore_suspend_widgets[i]);
+			return -EINVAL;
+		}
+		w->ignore_suspend = 1;
+	}
+
+	for (i = 0; i < card->num_of_ignore_suspend_widgets; i++) {
+		w = dapm_find_widget(snd_soc_card_to_dapm(card),
+				     card->of_ignore_suspend_widgets[i], true);
+		if (!w) {
+			dev_err(card->dev, "ASoC: DAPM unknown ignore suspend widget %s\n",
+				card->of_ignore_suspend_widgets[i]);
+			return -EINVAL;
+		}
+		w->ignore_suspend = 1;
+	}
+
+	return 0;
+}
+
 static void dapm_stream_event(struct snd_soc_pcm_runtime *rtd, int stream, int event)
 {
 	struct snd_soc_dai *dai;
@@ -4878,6 +4906,33 @@ int snd_soc_dapm_ignore_suspend(struct snd_soc_dapm_context *dapm,
 }
 EXPORT_SYMBOL_GPL(snd_soc_dapm_ignore_suspend);
 
+/**
+ * snd_soc_dapm_pin_has_prefix - check if given pin has a known prefix
+ * @card: card to be checked
+ * @pin: pin name
+ *
+ * Returns true if given pin has a known prefix
+ */
+bool snd_soc_dapm_pin_has_prefix(struct snd_soc_card *card, const char *pin)
+{
+	struct snd_soc_component *component;
+	const char *prefix;
+	size_t prefix_len;
+
+	for_each_card_components(card, component) {
+		prefix = component->name_prefix;
+		if (!prefix)
+			continue;
+
+		prefix_len = strlen(prefix);
+		if (!strncmp(pin, prefix, prefix_len) && pin[prefix_len] == ' ')
+			return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(snd_soc_dapm_pin_has_prefix);
+
 /**
  * snd_soc_dapm_free - free dapm resources
  * @dapm: DAPM context