From cb3227f22125da625140cec69a46a690c3f9f347 Mon Sep 17 00:00:00 2001
From: Hauke Petersen <hauke.petersen@fu-berlin.de>
Date: Mon, 18 Nov 2019 17:07:57 +0100
Subject: [PATCH] sys/stdio: add stdio_none

---
 Makefile.dep                |  2 +-
 sys/stdio_none/Makefile     |  1 +
 sys/stdio_none/stdio_none.c | 39 +++++++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 sys/stdio_none/Makefile
 create mode 100644 sys/stdio_none/stdio_none.c

diff --git a/Makefile.dep b/Makefile.dep
index 3abf863f134a..afd060d641ce 100644
--- a/Makefile.dep
+++ b/Makefile.dep
@@ -403,7 +403,7 @@ ifneq (,$(filter newlib,$(USEMODULE)))
   ifeq (,$(filter newlib_syscalls_%,$(USEMODULE)))
     USEMODULE += newlib_syscalls_default
   endif
-  ifeq (,$(filter stdio_rtt stdio_cdc_acm,$(USEMODULE)))
+  ifeq (,$(filter stdio_rtt stdio_cdc_acm stdio_none,$(USEMODULE)))
     USEMODULE += stdio_uart
   endif
 endif
diff --git a/sys/stdio_none/Makefile b/sys/stdio_none/Makefile
new file mode 100644
index 000000000000..48422e909a47
--- /dev/null
+++ b/sys/stdio_none/Makefile
@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base
diff --git a/sys/stdio_none/stdio_none.c b/sys/stdio_none/stdio_none.c
new file mode 100644
index 000000000000..200c08e71ed6
--- /dev/null
+++ b/sys/stdio_none/stdio_none.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2019 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     sys
+ * @{
+ *
+ * @file
+ * @brief       Dummy STDIO implementation that does nothing to preserve energy
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include "stdio_base.h"
+
+void stdio_init(void)
+{
+    /* do nothing */
+}
+
+ssize_t stdio_read(void* buffer, size_t count)
+{
+    (void)buffer;
+    (void)count;
+    return 0;
+}
+
+ssize_t stdio_write(const void* buffer, size_t len)
+{
+    (void)buffer;
+    return (ssize_t)len;
+}