diff --git a/drivers/audio/audio_null.c b/drivers/audio/audio_null.c
index f599f0972f..526e8d2049 100644
--- a/drivers/audio/audio_null.c
+++ b/drivers/audio/audio_null.c
@@ -583,6 +583,9 @@ static int null_stop(FAR struct audio_lowerhalf_s *dev)
   FAR void *value;
 
   /* Send a message to stop all audio streaming */
+  /* REVISIT: There should be a check to see if the worker thread is still
+   * running.
+   */
 
   term_msg.msgId = AUDIO_MSG_STOP;
   term_msg.u.data = 0;
diff --git a/drivers/audio/vs1053.c b/drivers/audio/vs1053.c
index 26c2aae418..d06d3881c8 100644
--- a/drivers/audio/vs1053.c
+++ b/drivers/audio/vs1053.c
@@ -647,9 +647,9 @@ static int vs1053_getcaps(FAR struct audio_lowerhalf_s *lower, int type,
               /* Report the Sample rates we support */
 
               pCaps->ac_controls.b[0] = AUDIO_SAMP_RATE_8K | AUDIO_SAMP_RATE_11K |
-                                      AUDIO_SAMP_RATE_16K | AUDIO_SAMP_RATE_22K |
-                                      AUDIO_SAMP_RATE_32K | AUDIO_SAMP_RATE_44K |
-                                      AUDIO_SAMP_RATE_48K;
+                                        AUDIO_SAMP_RATE_16K | AUDIO_SAMP_RATE_22K |
+                                        AUDIO_SAMP_RATE_32K | AUDIO_SAMP_RATE_44K |
+                                        AUDIO_SAMP_RATE_48K;
               break;
 
             case AUDIO_FMT_MP3:
@@ -779,7 +779,7 @@ static int vs1053_configure(FAR struct audio_lowerhalf_s *lower,
             case AUDIO_FU_VOLUME:
               /* Set the volume */
 
-              dev->volume = pCaps->ac_controls.hw[0]);
+              dev->volume = pCaps->ac_controls.hw[0];
               vs1053_setvolume(dev);
 
               break;
@@ -789,7 +789,7 @@ static int vs1053_configure(FAR struct audio_lowerhalf_s *lower,
             case AUDIO_FU_BALANCE:
               /* Set the volume */
 
-              dev->balance = pCaps->ac_controls.hw[0]);
+              dev->balance = pCaps->ac_controls.hw[0];
               vs1053_setvolume(dev);
 
               break;
diff --git a/drivers/audio/wm8904.c b/drivers/audio/wm8904.c
index 952708f102..c3e4514fe7 100644
--- a/drivers/audio/wm8904.c
+++ b/drivers/audio/wm8904.c
@@ -563,8 +563,7 @@ static int wm8904_getcaps(FAR struct audio_lowerhalf_s *dev, int type,
 
   /* Fill in the caller's structure based on requested info */
 
-  caps->ac_format[0]  = 0;
-  caps->ac_format[1]  = 0;
+  caps->ac_format.hw  = 0;
   caps->ac_controls.w = 0;
 
   switch (caps->ac_type)
@@ -619,9 +618,9 @@ static int wm8904_getcaps(FAR struct audio_lowerhalf_s *dev, int type,
               /* Report the Sample rates we support */
 
               caps->ac_controls.b[0] = AUDIO_SAMP_RATE_8K | AUDIO_SAMP_RATE_11K |
-                                     AUDIO_SAMP_RATE_16K | AUDIO_SAMP_RATE_22K |
-                                     AUDIO_SAMP_RATE_32K | AUDIO_SAMP_RATE_44K |
-                                     AUDIO_SAMP_RATE_48K;
+                                       AUDIO_SAMP_RATE_16K | AUDIO_SAMP_RATE_22K |
+                                       AUDIO_SAMP_RATE_32K | AUDIO_SAMP_RATE_44K |
+                                       AUDIO_SAMP_RATE_48K;
               break;
 
             case AUDIO_FMT_MP3: