From 2604971753937fabd913e17c25d6976905e4f215 Mon Sep 17 00:00:00 2001
From: Francisco Molina <femolina@uc.cl>
Date: Thu, 23 Apr 2020 18:58:11 +0200
Subject: [PATCH 1/2] drivers/periph/rtt.h: ensure RTT_MAX_VALUE is set

---
 drivers/include/periph/rtt.h | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/include/periph/rtt.h b/drivers/include/periph/rtt.h
index 475137cd23..b94e6c4b12 100644
--- a/drivers/include/periph/rtt.h
+++ b/drivers/include/periph/rtt.h
@@ -43,15 +43,22 @@ extern "C" {
 #endif
 
 #ifndef RTT_FREQUENCY
-
 /* Allow mock-RTT for unit tests */
 #ifdef MOCK_RTT_FREQUENCY
 #define RTT_FREQUENCY MOCK_RTT_FREQUENCY
+#else
+#warning "RTT_FREQUENCY undefined. Set RTT_FREQUENCY to the number of ticks " \
+         "per second for the current architecture."
+#endif
+#endif
+
+#ifndef RTT_MAX_VALUE
+/* Allow mock-RTT for unit tests */
+#ifdef MOCK_RTT_MAX_VALUE
 #define RTT_MAX_VALUE MOCK_RTT_MAX_VALUE
 #else
-
-#warning "RTT_FREQUENCY undefined. Set RTT_FREQUENCY to the number of ticks" \
-         "per second for the current architecture."
+#warning "RTT_MAX_VALUE is undefined. Set RTT_MAX_VALUE to the maximum value " \
+         "for the RTT counter, ensure it is (2^n - 1)."
 #endif
 #endif
 

From 0c0f8ec98ff012b842c90e222e1b5c90e158663a Mon Sep 17 00:00:00 2001
From: Francisco Molina <femolina@uc.cl>
Date: Thu, 23 Apr 2020 19:01:36 +0200
Subject: [PATCH 2/2] drivers/periph/rtt.h: add RTT_FREQUENCY & RTT_MAX_VALUE
 doc

---
 drivers/include/periph/rtt.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/include/periph/rtt.h b/drivers/include/periph/rtt.h
index b94e6c4b12..b725f78265 100644
--- a/drivers/include/periph/rtt.h
+++ b/drivers/include/periph/rtt.h
@@ -42,6 +42,25 @@
 extern "C" {
 #endif
 
+/**
+ * @def     RTT_FREQUENCY
+ *
+ * @brief   The desired frequency for the RTT
+ */
+#ifdef DOXYGEN
+#define RTT_FREQUENCY
+#endif
+
+/**
+ * @def     RTT_MAX_VALUE
+ *
+ * @brief   The maximum value for the RTT counter, must be (2^n - 1)
+ *
+ */
+#ifdef DOXYGEN
+#define RTT_MAX_VALUE
+#endif
+
 #ifndef RTT_FREQUENCY
 /* Allow mock-RTT for unit tests */
 #ifdef MOCK_RTT_FREQUENCY