diff --git a/include/nuttx/analog/ads1242.h b/include/nuttx/analog/ads1242.h
index ea98a63b24..d8a630bd20 100644
--- a/include/nuttx/analog/ads1242.h
+++ b/include/nuttx/analog/ads1242.h
@@ -51,13 +51,20 @@
  ****************************************************************************/
 
 /* IOCTL Commands ***********************************************************/
+/* Cmd: ANIOC_ADS2142_READ                    Arg: uint32_t *value
+ * Cmd: ANIOC_ADS2142_SET_GAIN                Arg: uint8_t value
+ * Cmd: ANIOC_ADS2142_SET_POSITIVE_INPUT      Arg: uint8_t value
+ * Cmd: ANIOC_ADS2142_SET_NEGATIVE_INPUT      Arg: uint8_t value
+ * Cmd: ANIOC_ADS2142_IS_DATA_READY           Arg: bool *value
+ * Cmd: ANIOC_ADS2142_DO_SYSTEM_OFFSET_CALIB  Arg: None
+ */
 
-#define ANIOC_ADS2142_READ                    _ANIOC(0x0001)  /* Arg: uint32_t *value */
-#define ANIOC_ADS2142_SET_GAIN                _ANIOC(0x0002)  /* Arg: uint8_t value */
-#define ANIOC_ADS2142_SET_POSITIVE_INPUT      _ANIOC(0x0003)  /* Arg: uint8_t value */
-#define ANIOC_ADS2142_SET_NEGATIVE_INPUT      _ANIOC(0x0004)  /* Arg: uint8_t value */
-#define ANIOC_ADS2142_IS_DATA_READY           _ANIOC(0x0005)  /* Arg: bool *value */
-#define ANIOC_ADS2142_DO_SYSTEM_OFFSET_CALIB  _ANIOC(0x0006)  /* Arg: None */
+#define ANIOC_ADS2142_READ                    _ANIOC(ANIOC_USER + 0)
+#define ANIOC_ADS2142_SET_GAIN                _ANIOC(ANIOC_USER + 1)
+#define ANIOC_ADS2142_SET_POSITIVE_INPUT      _ANIOC(ANIOC_USER + 2)
+#define ANIOC_ADS2142_SET_NEGATIVE_INPUT      _ANIOC(ANIOC_USER + 3)
+#define ANIOC_ADS2142_IS_DATA_READY           _ANIOC(ANIOC_USER + 4)
+#define ANIOC_ADS2142_DO_SYSTEM_OFFSET_CALIB  _ANIOC(ANIOC_USER + 5)
 
 /* ADS1242 REGISTER *********************************************************/
 
diff --git a/include/nuttx/fs/ioctl.h b/include/nuttx/fs/ioctl.h
index 19fd8012b0..b18f53e969 100644
--- a/include/nuttx/fs/ioctl.h
+++ b/include/nuttx/fs/ioctl.h
@@ -254,8 +254,9 @@
 #define ANIOC_TRIGGER     _ANIOC(0x0001)  /* Trigger one conversion
                                            * IN: None
                                            * OUT: None */
-
-/* NuttX PWM ioctl definitions (see nuttx/drivers/pwm.h) ****************************/
+#define ANIOC_USER        0x0002          /* Device specific IOCTL commands
+                                           * may follow */
+/* NuttX PWM ioctl definitions (see nuttx/drivers/pwm.h) ********************/
 
 #define _PWMIOCVALID(c)   (_IOC_TYPE(c)==_PWMIOCBASE)
 #define _PWMIOC(nr)       _IOC(_PWMIOCBASE,nr)