ASoC: qcom: Parse "pin-switches" and "widgets" from DT

Merge series from Stephan Gerhold <stephan@gerhold.net>:

Some sound card setups might require extra pin switches to allow
turning off certain audio components. simple-card supports this
already using the "pin-switches" and "widgets" device tree property.
This series makes it possible to use the same properties for the Qcom
sound cards.

To implement that, the function that parses the "pin-switches" property
in simple-card-utils.c is first moved into the ASoC core. Then two
simple function calls are added to the common Qcom sound card DT parser.
Finally there is a small patch for the msm8916-wcd-analog codec to make
it possible to model sound card setups used in some MSM8916 smartphones.
(See PATCH 2/4 for an explanation of some real example use cases.)

Using pin switches rather than patching codec drivers with switches was
originally suggested by Mark Brown on a patch for the tfa989x codec:
https://lore.kernel.org/alsa-devel/YXaMVHo9drCIuD3u@sirena.org.uk/

Documentation/devicetree/bindings/sound/qcom,sm8250.yaml

@@ -39,6 +39,14 @@ properties:
     $ref: /schemas/types.yaml#/definitions/string
     description: User visible long sound card name
 
+  pin-switches:
+    description: List of widget names for which pin switches should be created.
+    $ref: /schemas/types.yaml#/definitions/string-array
+
+  widgets:
+    description: User specified audio sound widgets.
+    $ref: /schemas/types.yaml#/definitions/non-unique-string-array
+
   # Only valid for some compatibles (see allOf if below)
   reg: true
   reg-names: true
@@ -251,7 +259,15 @@ examples:
         reg-names = "mic-iomux", "spkr-iomux";
 
         model = "msm8916";
+        widgets =
+            "Speaker", "Speaker",
+            "Headphone", "Headphones";
+        pin-switches = "Speaker";
         audio-routing =
+            "Speaker", "Speaker Amp OUT",
+            "Speaker Amp IN", "HPH_R",
+            "Headphones", "HPH_L",
+            "Headphones", "HPH_R",
             "AMIC1", "MIC BIAS Internal1",
             "AMIC2", "MIC BIAS Internal2",
             "AMIC3", "MIC BIAS Internal3";

include/sound/soc.h

@@ -1211,6 +1211,7 @@ int snd_soc_of_parse_card_name(struct snd_soc_card *card,
 			       const char *propname);
 int snd_soc_of_parse_audio_simple_widgets(struct snd_soc_card *card,
 					  const char *propname);
+int snd_soc_of_parse_pin_switches(struct snd_soc_card *card, const char *prop);
 int snd_soc_of_get_slot_mask(struct device_node *np,
 			     const char *prop_name,
 			     unsigned int *mask);

sound/soc/codecs/msm8916-wcd-analog.c

@@ -822,8 +822,8 @@ static const struct snd_soc_dapm_route pm8916_wcd_analog_audio_map[] = {
 	{"EAR PA", NULL, "EAR CP"},
 
 	/* Headset (RX MIX1 and RX MIX2) */
-	{"HEADPHONE", NULL, "HPHL PA"},
-	{"HEADPHONE", NULL, "HPHR PA"},
+	{"HPH_L", NULL, "HPHL PA"},
+	{"HPH_R", NULL, "HPHR PA"},
 
 	{"HPHL DAC", NULL, "EAR_HPHL_CLK"},
 	{"HPHR DAC", NULL, "EAR_HPHR_CLK"},
@@ -870,7 +870,8 @@ static const struct snd_soc_dapm_widget pm8916_wcd_analog_dapm_widgets[] = {
 	SND_SOC_DAPM_INPUT("AMIC3"),
 	SND_SOC_DAPM_INPUT("AMIC2"),
 	SND_SOC_DAPM_OUTPUT("EAR"),
-	SND_SOC_DAPM_OUTPUT("HEADPHONE"),
+	SND_SOC_DAPM_OUTPUT("HPH_L"),
+	SND_SOC_DAPM_OUTPUT("HPH_R"),
 
 	/* RX stuff */
 	SND_SOC_DAPM_SUPPLY("INT_LDO_H", SND_SOC_NOPM, 1, 0, NULL, 0),

sound/soc/generic/simple-card-utils.c

@@ -499,57 +499,14 @@ EXPORT_SYMBOL_GPL(asoc_simple_parse_widgets);
 int asoc_simple_parse_pin_switches(struct snd_soc_card *card,
 				   char *prefix)
 {
-	const unsigned int nb_controls_max = 16;
-	const char **strings, *control_name;
-	struct snd_kcontrol_new *controls;
-	struct device *dev = card->dev;
-	unsigned int i, nb_controls;
 	char prop[128];
-	int ret;
 
 	if (!prefix)
 		prefix = "";
 
 	snprintf(prop, sizeof(prop), "%s%s", prefix, "pin-switches");
 
-	if (!of_property_read_bool(dev->of_node, prop))
-		return 0;
-
-	strings = devm_kcalloc(dev, nb_controls_max,
-			       sizeof(*strings), GFP_KERNEL);
-	if (!strings)
-		return -ENOMEM;
-
-	ret = of_property_read_string_array(dev->of_node, prop,
-					    strings, nb_controls_max);
-	if (ret < 0)
-		return ret;
-
-	nb_controls = (unsigned int)ret;
-
-	controls = devm_kcalloc(dev, nb_controls,
-				sizeof(*controls), GFP_KERNEL);
-	if (!controls)
-		return -ENOMEM;
-
-	for (i = 0; i < nb_controls; i++) {
-		control_name = devm_kasprintf(dev, GFP_KERNEL,
-					      "%s Switch", strings[i]);
-		if (!control_name)
-			return -ENOMEM;
-
-		controls[i].iface = SNDRV_CTL_ELEM_IFACE_MIXER;
-		controls[i].name = control_name;
-		controls[i].info = snd_soc_dapm_info_pin_switch;
-		controls[i].get = snd_soc_dapm_get_pin_switch;
-		controls[i].put = snd_soc_dapm_put_pin_switch;
-		controls[i].private_value = (unsigned long)strings[i];
-	}
-
-	card->controls = controls;
-	card->num_controls = nb_controls;
-
-	return 0;
+	return snd_soc_of_parse_pin_switches(card, prop);
 }
 EXPORT_SYMBOL_GPL(asoc_simple_parse_pin_switches);
 

sound/soc/qcom/common.c

@@ -26,6 +26,12 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
 		return ret;
 	}
 
+	if (of_property_read_bool(dev->of_node, "widgets")) {
+		ret = snd_soc_of_parse_audio_simple_widgets(card, "widgets");
+		if (ret)
+			return ret;
+	}
+
 	/* DAPM routes */
 	if (of_property_read_bool(dev->of_node, "audio-routing")) {
 		ret = snd_soc_of_parse_audio_routing(card, "audio-routing");
@@ -39,6 +45,10 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
 			return ret;
 	}
 
+	ret = snd_soc_of_parse_pin_switches(card, "pin-switches");
+	if (ret)
+		return ret;
+
 	ret = snd_soc_of_parse_aux_devs(card, "aux-devs");
 	if (ret)
 		return ret;

sound/soc/soc-core.c

@@ -2823,6 +2823,56 @@ int snd_soc_of_parse_audio_simple_widgets(struct snd_soc_card *card,
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_parse_audio_simple_widgets);
 
+int snd_soc_of_parse_pin_switches(struct snd_soc_card *card, const char *prop)
+{
+	const unsigned int nb_controls_max = 16;
+	const char **strings, *control_name;
+	struct snd_kcontrol_new *controls;
+	struct device *dev = card->dev;
+	unsigned int i, nb_controls;
+	int ret;
+
+	if (!of_property_read_bool(dev->of_node, prop))
+		return 0;
+
+	strings = devm_kcalloc(dev, nb_controls_max,
+			       sizeof(*strings), GFP_KERNEL);
+	if (!strings)
+		return -ENOMEM;
+
+	ret = of_property_read_string_array(dev->of_node, prop,
+					    strings, nb_controls_max);
+	if (ret < 0)
+		return ret;
+
+	nb_controls = (unsigned int)ret;
+
+	controls = devm_kcalloc(dev, nb_controls,
+				sizeof(*controls), GFP_KERNEL);
+	if (!controls)
+		return -ENOMEM;
+
+	for (i = 0; i < nb_controls; i++) {
+		control_name = devm_kasprintf(dev, GFP_KERNEL,
+					      "%s Switch", strings[i]);
+		if (!control_name)
+			return -ENOMEM;
+
+		controls[i].iface = SNDRV_CTL_ELEM_IFACE_MIXER;
+		controls[i].name = control_name;
+		controls[i].info = snd_soc_dapm_info_pin_switch;
+		controls[i].get = snd_soc_dapm_get_pin_switch;
+		controls[i].put = snd_soc_dapm_put_pin_switch;
+		controls[i].private_value = (unsigned long)strings[i];
+	}
+
+	card->controls = controls;
+	card->num_controls = nb_controls;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_of_parse_pin_switches);
+
 int snd_soc_of_get_slot_mask(struct device_node *np,
 			     const char *prop_name,
 			     unsigned int *mask)