ASoC: nau8325: Add software reset during probe

Currently, the driver only performs a hardware reset during the I2C probe
sequence. To ensure all internal states of the codec are properly cleared
without affecting the configuration registers, a software reset is also
required.

According to the hardware specification, writing to the Software Reset
register (R01) twice will reset all internal states safely.

This patch adds the nau8325_software_reset() function, executes it right
after the hardware reset in the probe function, and marks the R01 register
as writeable in the regmap configuration.

Signed-off-by: Neo Chang <YLCHANG2@nuvoton.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://patch.msgid.link/20260408052639.187149-1-YLCHANG2@nuvoton.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: NeoChang10

sound/soc/codecs/nau8325.c

@@ -142,7 +142,7 @@ static bool nau8325_readable_reg(struct device *dev, unsigned int reg)
 static bool nau8325_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
-	case NAU8325_R00_HARDWARE_RST:
+	case NAU8325_R00_HARDWARE_RST ... NAU8325_R01_SOFTWARE_RST:
 	case NAU8325_R03_CLK_CTRL ... NAU8325_R06_INT_CLR_STATUS:
 	case NAU8325_R09_IRQOUT ... NAU8325_R13_DAC_VOLUME:
 	case NAU8325_R29_DAC_CTRL1 ... NAU8325_R2A_DAC_CTRL2:
@@ -670,6 +670,12 @@ static void nau8325_reset_chip(struct regmap *regmap)
 	regmap_write(regmap, NAU8325_R00_HARDWARE_RST, 0x0000);
 }
 
+static void nau8325_software_reset(struct regmap *regmap)
+{
+	regmap_write(regmap, NAU8325_R01_SOFTWARE_RST, 0x0000);
+	regmap_write(regmap, NAU8325_R01_SOFTWARE_RST, 0x0000);
+}
+
 static void nau8325_init_regs(struct nau8325 *nau8325)
 {
 	struct regmap *regmap = nau8325->regmap;
@@ -856,6 +862,7 @@ static int nau8325_i2c_probe(struct i2c_client *i2c)
 	nau8325_print_device_properties(nau8325);
 
 	nau8325_reset_chip(nau8325->regmap);
+	nau8325_software_reset(nau8325->regmap);
 	ret = regmap_read(nau8325->regmap, NAU8325_R02_DEVICE_ID, &value);
 	if (ret) {
 		dev_dbg(dev, "Failed to read device id (%d)", ret);