ASoC: codecs: nau8822: add support for speaker gain boost setting

The speaker amplifier can be supplied by a higher voltage than the rest of
the codec, namely up to 5V.

When the speaker supply voltage is above 3.6V, the speaker gain boost
setting should be enabled to prevent distortion on speaker and AUX pins.

Enable gain boost setting based on the reading of the VDDSPK supply
regulator's voltage.

Signed-off-by: Alexey Charkov <alchark@flipper.net>

Author: alchark

sound/soc/codecs/nau8822.c

@@ -10,6 +10,7 @@
 //
 // Based on WM8974.c
 
+#include "linux/regulator/consumer.h"
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/kernel.h>
@@ -1168,7 +1169,7 @@ static int nau8822_i2c_probe(struct i2c_client *i2c)
 {
 	struct device *dev = &i2c->dev;
 	struct nau8822 *nau8822 = dev_get_platdata(dev);
-	int ret, i;
+	int ret, i, vddspk;
 
 	if (!nau8822) {
 		nau8822 = devm_kzalloc(dev, sizeof(*nau8822), GFP_KERNEL);
@@ -1189,6 +1190,11 @@ static int nau8822_i2c_probe(struct i2c_client *i2c)
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to get regulators\n");
 
+	vddspk = regulator_get_voltage(nau8822->supplies[SUPPLY_VDDSPK].consumer);
+	if (vddspk < 0 && vddspk != -ENODEV)
+		return dev_err_probe(dev, vddspk,
+				     "Failed to get VDDSPK voltage\n");
+
 	nau8822->regmap = devm_regmap_init_i2c(i2c, &nau8822_regmap_config);
 	if (IS_ERR(nau8822->regmap)) {
 		ret = PTR_ERR(nau8822->regmap);
@@ -1210,6 +1216,17 @@ static int nau8822_i2c_probe(struct i2c_client *i2c)
 		goto err_reg;
 	}
 
+	if (vddspk > 3600000) {
+		ret = regmap_update_bits(nau8822->regmap,
+					 NAU8822_REG_OUTPUT_CONTROL,
+					 NAU8822_SPKBST |
+					 NAU8822_AUX2BST |
+					 NAU8822_AUX1BST, 0x7);
+		if (ret != 0)
+			return dev_err_probe(dev, ret,
+				"Failed to update gain boost control\n");
+	}
+
 	ret = devm_snd_soc_register_component(dev, &soc_component_dev_nau8822,
 						&nau8822_dai, 1);
 	if (ret != 0) {

sound/soc/codecs/nau8822.h

@@ -196,6 +196,15 @@
 
 #define NAU8822_RAUXSMUT			0x01
 
+/* NAU8822_REG_OUTPUT_CONTROL (0x31) */
+#define NAU8822_AOUTIMP				(1 << 0)
+#define NAU8822_TSEN				(1 << 1)
+#define NAU8822_SPKBST				(1 << 2)
+#define NAU8822_AUX2BST				(1 << 3)
+#define NAU8822_AUX1BST				(1 << 4)
+#define NAU8822_RDACLMX				(1 << 5)
+#define NAU8822_LDACLMX				(1 << 6)
+
 /* System Clock Source */
 enum {
 	NAU8822_CLK_MCLK,
@@ -211,7 +220,13 @@ struct nau8822_pll {
 	int freq_out;
 };
 
-#define NAU8822_NUM_SUPPLIES	4
+enum {
+	SUPPLY_VDDA = 0,
+	SUPPLY_VDDB,
+	SUPPLY_VDDC,
+	SUPPLY_VDDSPK,
+	NAU8822_NUM_SUPPLIES
+};
 
 /* Codec Private Data */
 struct nau8822 {