diff --git a/arch/arm/src/cxd56xx/cxd56_adc.c b/arch/arm/src/cxd56xx/cxd56_adc.c
index 728a01bebd..9f3ecdabd4 100644
--- a/arch/arm/src/cxd56xx/cxd56_adc.c
+++ b/arch/arm/src/cxd56xx/cxd56_adc.c
@@ -35,6 +35,7 @@
 #include <nuttx/kmalloc.h>
 #include <nuttx/fs/fs.h>
 #include <nuttx/irq.h>
+#include <nuttx/semaphore.h>
 #include <arch/chip/scu.h>
 #include <arch/chip/adc.h>
 
@@ -172,6 +173,8 @@ struct cxd56adc_dev_s
   struct scufifo_wm_s *wm;        /* water mark */
   struct math_filter_s *filter;   /* math filter */
   struct scuev_notify_s * notify; /* notify */
+  sem_t            exclsem;       /* exclusive semaphore */
+  int              crefs;         /* reference count */
 };
 
 /****************************************************************************
@@ -218,6 +221,7 @@ static struct cxd56adc_dev_s g_lpadc0priv =
   .wm     = NULL,
   .filter = NULL,
   .notify = NULL,
+  .crefs  = 0,
 };
 #endif
 
@@ -233,6 +237,7 @@ static struct cxd56adc_dev_s g_lpadc1priv =
   .wm     = NULL,
   .filter = NULL,
   .notify = NULL,
+  .crefs  = 0,
 };
 #endif
 
@@ -248,6 +253,7 @@ static struct cxd56adc_dev_s g_lpadc2priv =
   .wm     = NULL,
   .filter = NULL,
   .notify = NULL,
+  .crefs  = 0,
 };
 #endif
 
@@ -263,6 +269,7 @@ static struct cxd56adc_dev_s g_lpadc3priv =
   .wm     = NULL,
   .filter = NULL,
   .notify = NULL,
+  .crefs  = 0,
 };
 #endif
 
@@ -278,6 +285,7 @@ static struct cxd56adc_dev_s g_hpadc0priv =
   .wm     = NULL,
   .filter = NULL,
   .notify = NULL,
+  .crefs  = 0,
 };
 #endif
 
@@ -293,6 +301,7 @@ static struct cxd56adc_dev_s g_hpadc1priv =
   .wm     = NULL,
   .filter = NULL,
   .notify = NULL,
+  .crefs  = 0,
 };
 #endif
 
@@ -703,9 +712,23 @@ static int cxd56_adc_open(FAR struct file *filep)
   int type;
 
   DEBUGASSERT(priv != NULL);
-  DEBUGASSERT(priv->seq == NULL);
   DEBUGASSERT(priv->ch < CH_MAX);
 
+  /* Increment reference counter */
+
+  nxsem_wait_uninterruptible(&priv->exclsem);
+
+  priv->crefs++;
+  DEBUGASSERT(priv->crefs > 0);
+
+  if (priv->crefs > 1)
+    {
+      nxsem_post(&priv->exclsem);
+      return OK;
+    }
+
+  DEBUGASSERT(priv->seq == NULL);
+
   type = SCU_BUS_LPADC0 + priv->ch;
 
   /* Open sequencer */
@@ -713,6 +736,7 @@ static int cxd56_adc_open(FAR struct file *filep)
   priv->seq = seq_open(SEQ_TYPE_NORMAL, type);
   if (!priv->seq)
     {
+      nxsem_post(&priv->exclsem);
       return -ENOENT;
     }
 
@@ -725,11 +749,14 @@ static int cxd56_adc_open(FAR struct file *filep)
   ret = set_ofstgain(priv);
   if (ret < 0)
     {
+      nxsem_post(&priv->exclsem);
       return ret;
     }
 
   ainfo("open ch%d freq%d scufifo%d\n", priv->ch, priv->freq, priv->fsize);
 
+  nxsem_post(&priv->exclsem);
+
   return OK;
 }
 
@@ -750,6 +777,19 @@ static int cxd56_adc_close(FAR struct file *filep)
   DEBUGASSERT(priv->seq != NULL);
   DEBUGASSERT(priv->ch < CH_MAX);
 
+  /* Decrement reference counter */
+
+  nxsem_wait_uninterruptible(&priv->exclsem);
+
+  DEBUGASSERT(priv->crefs > 0);
+  priv->crefs--;
+
+  if (priv->crefs > 0)
+    {
+      nxsem_post(&priv->exclsem);
+      return OK;
+    }
+
   /* Close sequencer */
 
   seq_close(priv->seq);
@@ -773,6 +813,8 @@ static int cxd56_adc_close(FAR struct file *filep)
       priv->notify = NULL;
     }
 
+  nxsem_post(&priv->exclsem);
+
   return OK;
 }
 
@@ -1058,6 +1100,7 @@ int cxd56_adcinitialize(void)
       return ret;
     }
 
+  nxsem_init(&g_lpadc0priv.exclsem, 0, 1);
 #endif
 #if defined (CONFIG_CXD56_LPADC1) || defined (CONFIG_CXD56_LPADC0_1) || defined (CONFIG_CXD56_LPADC_ALL)
   ret = register_driver("/dev/lpadc1", &g_adcops, 0666, &g_lpadc1priv);
@@ -1067,6 +1110,7 @@ int cxd56_adcinitialize(void)
       return ret;
     }
 
+  nxsem_init(&g_lpadc1priv.exclsem, 0, 1);
 #endif
 #if defined (CONFIG_CXD56_LPADC2) || defined (CONFIG_CXD56_LPADC_ALL)
   ret = register_driver("/dev/lpadc2", &g_adcops, 0666, &g_lpadc2priv);
@@ -1076,6 +1120,7 @@ int cxd56_adcinitialize(void)
       return ret;
     }
 
+  nxsem_init(&g_lpadc2priv.exclsem, 0, 1);
 #endif
 #if defined (CONFIG_CXD56_LPADC3) || defined (CONFIG_CXD56_LPADC_ALL)
   ret = register_driver("/dev/lpadc3", &g_adcops, 0666, &g_lpadc3priv);
@@ -1085,6 +1130,7 @@ int cxd56_adcinitialize(void)
       return ret;
     }
 
+  nxsem_init(&g_lpadc3priv.exclsem, 0, 1);
 #endif
 #ifdef CONFIG_CXD56_HPADC0
   ret = register_driver("/dev/hpadc0", &g_adcops, 0666, &g_hpadc0priv);
@@ -1094,6 +1140,7 @@ int cxd56_adcinitialize(void)
       return ret;
     }
 
+  nxsem_init(&g_hpadc0priv.exclsem, 0, 1);
 #endif
 #ifdef CONFIG_CXD56_HPADC1
   ret = register_driver("/dev/hpadc1", &g_adcops, 0666, &g_hpadc1priv);
@@ -1103,6 +1150,7 @@ int cxd56_adcinitialize(void)
       return ret;
     }
 
+  nxsem_init(&g_hpadc1priv.exclsem, 0, 1);
 #endif
 
   return ret;