diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 8e263b0..456ec66 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -71,6 +71,10 @@
  * The time does not need to be correct, only time differences are used,
  * by contrast with MBEDTLS_HAVE_TIME_DATE
  *
+ * Defining MBEDTLS_HAVE_TIME allows you to specify MBEDTLS_PLATFORM_TIME_ALT,
+ * MBEDTLS_PLATFORM_TIME_MACRO, MBEDTLS_PLATFORM_TIME_TYPE_MACRO and
+ * MBEDTLS_PLATFORM_STD_TIME.
+ *
  * Comment if your system does not support time functions
  */
 #define MBEDTLS_HAVE_TIME
@@ -148,6 +152,8 @@
  * \warning MBEDTLS_PLATFORM_XXX_ALT cannot be defined at the same time as
  * MBEDTLS_PLATFORM_XXX_MACRO!
  *
+ * Requires: MBEDTLS_PLATFORM_TIME_ALT requires MBEDTLS_HAVE_TIME
+ *
  * Uncomment a macro to enable alternate implementation of specific base
  * platform function
  */
@@ -2512,7 +2518,7 @@
 //#define MBEDTLS_PLATFORM_STD_CALLOC        calloc /**< Default allocator to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_FREE            free /**< Default free to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_EXIT            exit /**< Default exit to use, can be undefined */
-//#define MBEDTLS_PLATFORM_STD_TIME            time /**< Default time to use, can be undefined */
+//#define MBEDTLS_PLATFORM_STD_TIME            time /**< Default time to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled */
 //#define MBEDTLS_PLATFORM_STD_FPRINTF      fprintf /**< Default fprintf to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_PRINTF        printf /**< Default printf to use, can be undefined */
 /* Note: your snprintf must correclty zero-terminate the buffer! */
@@ -2528,8 +2534,8 @@
 //#define MBEDTLS_PLATFORM_CALLOC_MACRO        calloc /**< Default allocator macro to use, can be undefined */
 //#define MBEDTLS_PLATFORM_FREE_MACRO            free /**< Default free macro to use, can be undefined */
 //#define MBEDTLS_PLATFORM_EXIT_MACRO            exit /**< Default exit macro to use, can be undefined */
-//#define MBEDTLS_PLATFORM_TIME_MACRO            time /**< Default time macro to use, can be undefined */
-//#define MBEDTLS_PLATFORM_TIME_TYPE_MACRO       time_t /**< Default time macro to use, can be undefined */
+//#define MBEDTLS_PLATFORM_TIME_MACRO            time /**< Default time macro to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled */
+//#define MBEDTLS_PLATFORM_TIME_TYPE_MACRO       time_t /**< Default time macro to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled */
 //#define MBEDTLS_PLATFORM_FPRINTF_MACRO      fprintf /**< Default fprintf macro to use, can be undefined */
 //#define MBEDTLS_PLATFORM_PRINTF_MACRO        printf /**< Default printf macro to use, can be undefined */
 /* Note: your snprintf must correclty zero-terminate the buffer! */