ALSA controls should return 1 if the value in the control changed but the
control put operation hwvad_put_init_mode() only returns 0 or a negative
error code, causing ALSA to not generate any change events.

Add a suitable check in the function before updating the vad_init_mode
variable.

Fixes: 29dbfeecab85 ("ASoC: fsl_micfil: Add Hardware Voice Activity Detector support")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
 sound/soc/fsl/fsl_micfil.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_micfil.c b/sound/soc/fsl/fsl_micfil.c
index 97f24c9bdd68..1c826e0cb1d5 100644
--- a/sound/soc/fsl/fsl_micfil.c
+++ b/sound/soc/fsl/fsl_micfil.c
@@ -407,13 +407,18 @@ static int hwvad_put_init_mode(struct snd_kcontrol *kcontrol,
 	unsigned int *item = ucontrol->value.enumerated.item;
 	struct fsl_micfil *micfil = snd_soc_component_get_drvdata(comp);
 	int val = snd_soc_enum_item_to_val(e, item[0]);
+	bool change = false;
+
+	if (val < MICFIL_HWVAD_ENVELOPE_MODE || val > MICFIL_HWVAD_ENERGY_MODE)
+		return -EINVAL;
 
 	/* 0 - Envelope-based Mode
 	 * 1 - Energy-based Mode
 	 */
+	change = (micfil->vad_init_mode != val);
 	micfil->vad_init_mode = val;
 
-	return 0;
+	return change;
 }
 
 static int hwvad_get_init_mode(struct snd_kcontrol *kcontrol,
-- 
2.34.1