diff --git a/arch/arm/src/sama5/sam_trng.c b/arch/arm/src/sama5/sam_trng.c
index b9294611423..089c9f248ef 100644
--- a/arch/arm/src/sama5/sam_trng.c
+++ b/arch/arm/src/sama5/sam_trng.c
@@ -59,6 +59,9 @@
 #include "sam_periphclks.h"
 #include "sam_trng.h"
 
+#if defined(CONFIG_SAMA5_TRNG)
+#if defined(CONFIG_DEV_RANDOM) || defined(CONFIG_DEV_URANDOM_ARCH)
+
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
@@ -325,14 +328,10 @@ errout:
 }
 
 /****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: devrandom_register
+ * Name: sam_rng_initialize
  *
  * Description:
- *   Initialize the TRNG hardware and register the /dev/random driver.
+ *   Initialize the TRNG hardware.
  *
  * Input Parameters:
  *   None
@@ -342,7 +341,7 @@ errout:
  *
  ****************************************************************************/
 
-int devrandom_register(void)
+static int sam_rng_initialize(void)
 {
   int ret;
 
@@ -375,17 +374,78 @@ int devrandom_register(void)
 
   putreg32(TRNG_CR_DISABLE | TRNG_CR_KEY, SAM_TRNG_CR);
 
-  /* Register the character driver */
-
-  ret = register_driver("/dev/random", &g_trngops, 0644, NULL);
-  if (ret < 0)
-    {
-      ferr("ERROR: Failed to register /dev/random\n");
-      return ret;
-    }
-
   /* Enable the TRNG interrupt at the AIC */
 
   up_enable_irq(SAM_IRQ_TRNG);
   return OK;
 }
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: devrandom_register
+ *
+ * Description:
+ *   Initialize the TRNG hardware and register the /dev/random driver.
+ *   Must be called BEFORE devurandom_register.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_RANDOM
+int devrandom_register(void)
+{
+  int ret;
+
+  ret = sam_rng_initialize();
+  if (ret >= 0)
+    {
+      ret = register_driver("/dev/random", &g_trngops, 0644, NULL);
+      if (ret < 0)
+        {
+          ferr("ERROR: Failed to register /dev/random\n");
+        }
+    }
+
+  return ret;
+}
+#endif
+
+/****************************************************************************
+ * Name: devurandom_register
+ *
+ * Description:
+ *   Register /dev/urandom
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_URANDOM_ARCH
+int devurandom_register(void)
+{
+  int ret;
+
+#ifndef CONFIG_DEV_RANDOM
+  ret = sam_rng_initialize();
+  if (ret >= 0)
+#endif
+    {
+      ret = register_driver("/dev/urandom", &g_trngops, 0644, NULL);
+      if (ret < 0)
+        {
+          ferr("ERROR: Failed to register /dev/urandom\n");
+        }
+    }
+
+  return ret;
+}
+#endif
+
+#endif /* CONFIG_DEV_RANDOM || CONFIG_DEV_URANDOM_ARCH */
+#endif /* CONFIG_SAMA5_TRNG */
diff --git a/arch/arm/src/samv7/sam_trng.c b/arch/arm/src/samv7/sam_trng.c
index 89c7630b21c..d9951cace36 100644
--- a/arch/arm/src/samv7/sam_trng.c
+++ b/arch/arm/src/samv7/sam_trng.c
@@ -60,6 +60,9 @@
 #include "sam_periphclks.h"
 #include "sam_trng.h"
 
+#if defined(CONFIG_SAMV7_TRNG)
+#if defined(CONFIG_DEV_RANDOM) || defined(CONFIG_DEV_URANDOM_ARCH)
+
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
@@ -326,14 +329,10 @@ errout:
 }
 
 /****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: devrandom_register
+ * Name: sam_rng_initialize
  *
  * Description:
- *   Initialize the TRNG hardware and register the /dev/random driver.
+ *   Initialize the TRNG hardware.
  *
  * Input Parameters:
  *   None
@@ -343,7 +342,7 @@ errout:
  *
  ****************************************************************************/
 
-int devrandom_register(void)
+static int sam_rng_initialize(void)
 {
   int ret;
 
@@ -376,17 +375,77 @@ int devrandom_register(void)
 
   putreg32(TRNG_CR_DISABLE | TRNG_CR_KEY, SAM_TRNG_CR);
 
-  /* Register the character driver */
-
-  ret = register_driver("/dev/random", &g_trngops, 0644, NULL);
-  if (ret < 0)
-    {
-      ferr("ERROR: Failed to register /dev/random\n");
-      return ret;
-    }
-
   /* Enable the TRNG interrupt at the AIC */
 
   up_enable_irq(SAM_IRQ_TRNG);
   return OK;
 }
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: devrandom_register
+ *
+ * Description:
+ *   Initialize the TRNG hardware and register the /dev/random driver.
+ *   Must be called BEFORE devurandom_register.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_RANDOM
+int devrandom_register(void)
+{
+  int ret;
+
+  ret = sam_rng_initialize();
+  if (ret >= 0)
+    {
+      ret = register_driver("/dev/random", &g_trngops, 0644, NULL);
+      if (ret < 0)
+        {
+          ferr("ERROR: Failed to register /dev/random\n");
+        }
+    }
+
+  return ret;
+}
+#endif
+
+/****************************************************************************
+ * Name: devurandom_register
+ *
+ * Description:
+ *   Register /dev/urandom
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_URANDOM_ARCH
+int devurandom_register(void)
+{
+  int ret;
+
+#ifndef CONFIG_DEV_RANDOM
+  ret = sam_rng_initialize();
+  if (ret >= 0)
+#endif
+    {
+      ret = register_driver("/dev/urandom", &g_trngops, 0644, NULL);
+      if (ret < 0)
+        {
+          ferr("ERROR: Failed to register /dev/urandom\n");
+        }
+    }
+
+  return ret;
+}
+#endif
+
+#endif /* CONFIG_DEV_RANDOM || CONFIG_DEV_URANDOM_ARCH */
diff --git a/arch/arm/src/stm32/stm32_rng.c b/arch/arm/src/stm32/stm32_rng.c
index eda6f5d550c..57743d157d6 100644
--- a/arch/arm/src/stm32/stm32_rng.c
+++ b/arch/arm/src/stm32/stm32_rng.c
@@ -51,11 +51,14 @@
 #include "chip/stm32_rng.h"
 #include "up_internal.h"
 
+#if defined(CONFIG_STM32_RNG)
+#if defined(CONFIG_DEV_RANDOM) || defined(CONFIG_DEV_URANDOM_ARCH)
+
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
 
-static int stm32_rnginitialize(void);
+static int stm32_rng_initialize(void);
 static int stm32_interrupt(int irq, void *context);
 static void stm32_enable(void);
 static void stm32_disable(void);
@@ -98,7 +101,7 @@ static const struct file_operations g_rngops =
  * Private functions
  ****************************************************************************/
 
-static int stm32_rnginitialize()
+static int stm32_rng_initialize()
 {
   uint32_t regval;
 
@@ -263,6 +266,7 @@ static ssize_t stm32_read(struct file *filep, char *buffer, size_t buflen)
  *
  * Description:
  *   Initialize the RNG hardware and register the /dev/random driver.
+ *   Must be called BEFORE devurandom_register.
  *
  * Input Parameters:
  *   None
@@ -272,8 +276,31 @@ static ssize_t stm32_read(struct file *filep, char *buffer, size_t buflen)
  *
  ****************************************************************************/
 
+#ifdef CONFIG_DEV_RANDOM
 int devrandom_register(void)
 {
-  stm32_rnginitialize();
+  stm32_rng_initialize();
   return register_driver("/dev/random", &g_rngops, 0444, NULL);
 }
+#endif
+
+/****************************************************************************
+ * Name: devurandom_register
+ *
+ * Description:
+ *   Register /dev/urandom
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_URANDOM_ARCH
+int devurandom_register(void)
+{
+#ifndef CONFIG_DEV_RANDOM
+  stm32l4_rnginitialize();
+#endif
+  return register_driver("/dev/urandom", &g_rngops, 0444, NULL);
+}
+#endif
+
+#endif /* CONFIG_DEV_RANDOM || CONFIG_DEV_URANDOM_ARCH */
+#endif /* CONFIG_STM32_RNG */
diff --git a/arch/arm/src/stm32l4/stm32l4_rng.c b/arch/arm/src/stm32l4/stm32l4_rng.c
index 63a7b7428aa..64f08dc04b4 100644
--- a/arch/arm/src/stm32l4/stm32l4_rng.c
+++ b/arch/arm/src/stm32l4/stm32l4_rng.c
@@ -52,13 +52,14 @@
 #include "chip/stm32l4_rng.h"
 #include "up_internal.h"
 
-#ifdef CONFIG_STM32L4_RNG
+#if defined(CONFIG_STM32L4_RNG)
+#if defined(CONFIG_DEV_RANDOM) || defined(CONFIG_DEV_URANDOM_ARCH)
 
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
 
-static int stm32l4_rnginitialize(void);
+static int stm32l4_rng_initialize(void);
 static int stm32l4_rnginterrupt(int irq, void *context);
 static void stm32l4_rngenable(void);
 static void stm32l4_rngdisable(void);
@@ -105,7 +106,7 @@ static const struct file_operations g_rngops =
  * Private functions
  ****************************************************************************/
 
-static int stm32l4_rnginitialize(void)
+static int stm32l4_rng_initialize(void)
 {
   _info("Initializing RNG\n");
 
@@ -294,6 +295,7 @@ static ssize_t stm32l4_rngread(struct file *filep, char *buffer, size_t buflen)
  *
  * Description:
  *   Initialize the RNG hardware and register the /dev/random driver.
+ *   Must be called BEFORE devurandom_register.
  *
  * Input Parameters:
  *   None
@@ -303,10 +305,31 @@ static ssize_t stm32l4_rngread(struct file *filep, char *buffer, size_t buflen)
  *
  ****************************************************************************/
 
+#ifdef CONFIG_DEV_RANDOM
 int devrandom_register(void)
 {
-  stm32l4_rnginitialize();
+  stm32l4_rng_initialize();
   return register_driver("/dev/random", &g_rngops, 0444, NULL);
 }
+#endif
 
+/****************************************************************************
+ * Name: devurandom_register
+ *
+ * Description:
+ *   Register /dev/urandom
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_URANDOM_ARCH
+int devurandom_register(void)
+{
+#ifndef CONFIG_DEV_RANDOM
+  stm32l4_rng_initialize();
+#endif
+  return register_driver("/dev/urandom", &g_rngops, 0444, NULL);
+}
+#endif
+
+#endif /* CONFIG_DEV_RANDOM || CONFIG_DEV_URANDOM_ARCH */
 #endif /* CONFIG_STM32L4_RNG */