diff --git a/arch/arm/src/tiva/tiva_qencoder.h b/arch/arm/src/tiva/tiva_qencoder.h
index 8714f77105..828eaba352 100644
--- a/arch/arm/src/tiva/tiva_qencoder.h
+++ b/arch/arm/src/tiva/tiva_qencoder.h
@@ -46,9 +46,9 @@
  * Pre-processor Definitions
  ************************************************************************************/
 
-#define QEIOC_DIRECTION     _QEIOC(QEIOC_USER)
-#define QEIOC_VELOCITY      _QEIOC(QEIOC_USER+1)
-#define QEIOC_PPR           _QEIOC(QEIOC_USER+2)
+#define QEIOC_DIRECTION     _QEIOC(QE_TIVA_FIRST)
+#define QEIOC_VELOCITY      _QEIOC(QE_TIVA_FIRST+1)
+#define QEIOC_PPR           _QEIOC(QE_TIVA_FIRST+2)
 
 /****************************************************************************
 * Public Function Prototypes
diff --git a/include/nuttx/sensors/as5048b.h b/include/nuttx/sensors/as5048b.h
index 9a274d90ae..76ea307c23 100644
--- a/include/nuttx/sensors/as5048b.h
+++ b/include/nuttx/sensors/as5048b.h
@@ -59,10 +59,10 @@
 
 /* IOCTL Commands ***********************************************************/
 
-#define QEIOC_ZEROPOSITION    _QEIOC(QEIOC_USER+0) /* Arg: int32_t* pointer */
-#define QEIOC_AUTOGAINCTL     _QEIOC(QEIOC_USER+1) /* Arg: uint8_t* pointer */
-#define QEIOC_DIAGNOSTICS     _QEIOC(QEIOC_USER+2) /* Arg: uint8_t* pointer */
-#define QEIOC_MAGNITUDE       _QEIOC(QEIOC_USER+3) /* Arg: int32_t* pointer */
+#define QEIOC_ZEROPOSITION    _QEIOC(QE_AS5048B_FIRST+0) /* Arg: int32_t* pointer */
+#define QEIOC_AUTOGAINCTL     _QEIOC(QE_AS5048B_FIRST+1) /* Arg: uint8_t* pointer */
+#define QEIOC_DIAGNOSTICS     _QEIOC(QE_AS5048B_FIRST+2) /* Arg: uint8_t* pointer */
+#define QEIOC_MAGNITUDE       _QEIOC(QE_AS5048B_FIRST+3) /* Arg: int32_t* pointer */
 
 /* Resolution ***************************************************************/
 
diff --git a/include/nuttx/sensors/qencoder.h b/include/nuttx/sensors/qencoder.h
index 8a240ad131..6e1dde49de 100644
--- a/include/nuttx/sensors/qencoder.h
+++ b/include/nuttx/sensors/qencoder.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/nuttx/qencoder.h
  *
- *   Copyright (C) 2012, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012, 2015, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -67,14 +67,25 @@
 #define QEIOC_POSITION     _QEIOC(0x0001) /* Arg: int32_t* pointer */
 #define QEIOC_RESET        _QEIOC(0x0002) /* Arg: None */
 
-/* User defined ioctl cms should use QEIOC_USER like this:
- *
- * #define QEIOC_MYCMD1    _QEIOC(QEIOC_USER)
- * #define QEIOC_MYCMD2    _QEIOC(QEIOC_USER+1)
- * ...
+#define QE_FIRST           0x0001         /* First required command */
+#define QE_NCMDS           2              /* Two required commands */
+
+/* User defined ioctl commands are also supported. These will be forwarded
+ * by the upper-half QE driver to the lower-half QE driver via the ioclt()
+ * method fo the QE lower-half interface.  However, the lower-half driver
+ * must reserve a block of commands as follows in order prevent IOCTL
+ * command numbers from overlapping.
  */
 
-#define QEIOC_USER         0x0003
+/* See arch/arm/src/tiva/tiva_qencoder.h */
+
+#define QE_TIVA_FIRST      (QE_FIRST + QE_NCMDS)
+#define QE_TIVA_NCMDS      3
+
+/* See include/nuttx/sensors/as5048b.h */
+
+#define QE_AS5048B_FIRST   (QE_TIVA_FIRST + QEIOC_TIVA_NCMDS)
+#define QE_AS5048B_NCMDS   4
 
 /****************************************************************************
  * Public Types