1 files changed, 14 insertions, 0 deletions

diff --git a/sound/soc/intel/boards/skl_nau88l25_max98357a.c b/sound/soc/intel/boards/skl_nau88l25_max98357a.c
index d2808652b974..fc3f4750c432 100644
--- a/sound/soc/intel/boards/skl_nau88l25_max98357a.c
+++ b/sound/soc/intel/boards/skl_nau88l25_max98357a.c
@@ -382,8 +382,22 @@ static struct snd_pcm_hw_constraint_list constraints_16000 = {
         .list  = rates_16000,
 };
 
+static const unsigned int ch_mono[] = {
+        1,
+};
+
+static const struct snd_pcm_hw_constraint_list constraints_refcap = {
+        .count = ARRAY_SIZE(ch_mono),
+        .list  = ch_mono,
+};
+
 static int skylake_refcap_startup(struct snd_pcm_substream *substream)
 {
+        substream->runtime->hw.channels_max = 1;
+        snd_pcm_hw_constraint_list(substream->runtime, 0,
+                                        SNDRV_PCM_HW_PARAM_CHANNELS,
+                                        &constraints_refcap);
+
         return snd_pcm_hw_constraint_list(substream->runtime, 0,
                                 SNDRV_PCM_HW_PARAM_RATE,
                                 &constraints_16000);