/**
 *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if defined(DEVICE_TRNG)
#define MBEDTLS_ENTROPY_HARDWARE_ALT
#endif

#if defined(DEVICE_RTC)
#define MBEDTLS_HAVE_TIME_DATE
#endif

#if defined(MBEDTLS_CONFIG_HW_SUPPORT)
#include "mbedtls_device.h"
#endif

/**
 *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if defined(DEVICE_TRNG)
#define MBEDTLS_ENTROPY_HARDWARE_ALT
#endif

#if defined(MBEDTLS_CONFIG_HW_SUPPORT)
#include "mbedtls_device.h"
#endif

--- 
+++ 
@@ -21,6 +21,10 @@
 #define MBEDTLS_ENTROPY_HARDWARE_ALT
 #endif
 
+#if defined(DEVICE_RTC)
+#define MBEDTLS_HAVE_TIME_DATE
+#endif
+
 #if defined(MBEDTLS_CONFIG_HW_SUPPORT)
 #include "mbedtls_device.h"
 #endif
Integrate mbed OS RTC with mbed TLS

The integration is simply to define the macro MBEDTLS_HAVE_TIME_DATE
in the features/mbedtls/platform/inc/platform_mbed.h. The default
implementation of the mbedtls_time() function provided by mbed TLS is
sufficient to work with mbed OS because both use POSIX functions.
