[PATCH v4 1/2] ASoC: codecs: nau8360: Block DSP path selection when firmware load fails

[Neo Chang <YLCHANG2@nuvoton.com>]

Block the DSP path selection if the firmware fails to load to prevent
invalid routing states.

If the firmware is not ready, nau8360_dac_mux_put_enum() will print
a rate-limited warning and return -EBUSY. This rejects the invalid
userspace request and maintains the original hardware state without
causing audio wrong status.

Signed-off-by: Neo Chang <YLCHANG2@nuvoton.com>
---
 sound/soc/codecs/nau8360.c | 7 ++++++-
 sound/soc/codecs/nau8360.h | 6 ++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/nau8360.c b/sound/soc/codecs/nau8360.c
index 89b8ee80d6c8..277aa982c341 100644
--- a/sound/soc/codecs/nau8360.c
+++ b/sound/soc/codecs/nau8360.c
@@ -715,10 +715,15 @@ static int nau8360_dac_mux_put_enum(struct snd_kcontrol *kcontrol,
 	int ret = 0;
 
 	if (snd_soc_dapm_get_bias_level(dapm) > SND_SOC_BIAS_STANDBY) {
-		dev_warn(nau8360->dev, "changing path is not allowed during playback");
+		dev_warn_ratelimited(nau8360->dev, "changing path is not allowed during playback");
 		return ret;
 	}
 
+	if (item[0] == NAU8360_DAC_SRC_DSP && !nau8360->load_fw_done) {
+		dev_warn_ratelimited(nau8360->dev, "Cannot enable DSP: Firmware not ready or disabled\n");
+		return -EBUSY;
+	}
+
 	mutex_lock(&nau8360->lock);
 
 	ret = snd_soc_dapm_put_enum_double(kcontrol, ucontrol);
diff --git a/sound/soc/codecs/nau8360.h b/sound/soc/codecs/nau8360.h
index cc640ba8c838..71396747c0fa 100644
--- a/sound/soc/codecs/nau8360.h
+++ b/sound/soc/codecs/nau8360.h
@@ -870,6 +870,12 @@ enum {
 	NAU8360_TDM_TXN,
 };
 
+/* DAC Source Path*/
+enum {
+	NAU8360_DAC_SRC_HW1 = 0,
+	NAU8360_DAC_SRC_DSP,
+};
+
 /* PLL Source */
 enum {
 	NAU8360_PLL_MCLK,
-- 
2.25.1