ALSA controls should return 1 if the value in the control changed but the
control put operation fsl_xcvr_mode_put() 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 mode variable.

Fixes: 28564486866f ("ASoC: fsl_xcvr: Add XCVR ASoC CPU DAI driver")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
 sound/soc/fsl/fsl_xcvr.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/sound/soc/fsl/fsl_xcvr.c b/sound/soc/fsl/fsl_xcvr.c
index 109e3e03f455..ee16cf681488 100644
--- a/sound/soc/fsl/fsl_xcvr.c
+++ b/sound/soc/fsl/fsl_xcvr.c
@@ -277,10 +277,17 @@ static int fsl_xcvr_mode_put(struct snd_kcontrol *kcontrol,
 	struct fsl_xcvr *xcvr = snd_soc_dai_get_drvdata(dai);
 	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
 	unsigned int *item = ucontrol->value.enumerated.item;
+	int val = snd_soc_enum_item_to_val(e, item[0]);
 	struct snd_soc_card *card = dai->component->card;
 	struct snd_soc_pcm_runtime *rtd;
+	int ret;
+
+	if (val < FSL_XCVR_MODE_SPDIF || val > FSL_XCVR_MODE_EARC)
+		return -EINVAL;
 
-	xcvr->mode = snd_soc_enum_item_to_val(e, item[0]);
+	ret = (xcvr->mode != val);
+
+	xcvr->mode = val;
 
 	fsl_xcvr_activate_ctl(dai, fsl_xcvr_arc_mode_kctl.name,
 			      (xcvr->mode == FSL_XCVR_MODE_ARC));
@@ -290,7 +297,7 @@ static int fsl_xcvr_mode_put(struct snd_kcontrol *kcontrol,
 	rtd = snd_soc_get_pcm_runtime(card, card->dai_link);
 	rtd->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream_count =
 		(xcvr->mode == FSL_XCVR_MODE_SPDIF ? 1 : 0);
-	return 0;
+	return ret;
 }
 
 static int fsl_xcvr_mode_get(struct snd_kcontrol *kcontrol,
-- 
2.34.1