From 059bb79450b456bb9d59f8c53b49e11476157199 Mon Sep 17 00:00:00 2001
From: Hendrik van Essen <hendrik.vanessen@ml-pa.com>
Date: Tue, 18 Jul 2023 23:00:33 +0200
Subject: [PATCH] sys/stdio_uart: add pseudomodule stdio_clear_rx

---
 makefiles/pseudomodules.inc.mk |  1 +
 makefiles/stdio.inc.mk         |  5 +++++
 sys/include/stdio_base.h       | 10 ++++++++++
 sys/stdio/stdio.c              |  5 +++++
 4 files changed, 21 insertions(+)

diff --git a/makefiles/pseudomodules.inc.mk b/makefiles/pseudomodules.inc.mk
index c6cb490c27d01..7c9642c7117c7 100644
--- a/makefiles/pseudomodules.inc.mk
+++ b/makefiles/pseudomodules.inc.mk
@@ -484,6 +484,7 @@ PSEUDOMODULES += socket_zep_hello
 PSEUDOMODULES += soft_uart_modecfg
 PSEUDOMODULES += stdin
 PSEUDOMODULES += stdio_available
+PSEUDOMODULES += stdio_clear_rx
 PSEUDOMODULES += stdio_cdc_acm
 PSEUDOMODULES += stdio_dispatch
 PSEUDOMODULES += stdio_ethos
diff --git a/makefiles/stdio.inc.mk b/makefiles/stdio.inc.mk
index 16ce5902f64d3..b05daf9db5cea 100644
--- a/makefiles/stdio.inc.mk
+++ b/makefiles/stdio.inc.mk
@@ -75,10 +75,15 @@ ifneq (,$(filter stdin,$(USEMODULE)))
   endif
 endif
 
+ifneq (,$(filter stdio_clear_rx,$(USEMODULE)))
+  USEMODULE += stdin
+endif
+
 ifneq (,$(filter stdio_uart_rx,$(USEMODULE)))
   USEMODULE += isrpipe
   USEMODULE += stdio_uart
   USEMODULE += stdio_available
+  USEMODULE += stdio_clear_rx
 endif
 
 ifneq (,$(filter stdio_uart,$(USEMODULE)))
diff --git a/sys/include/stdio_base.h b/sys/include/stdio_base.h
index 0d0a5a2427b22..8b0b5b7deaa6d 100644
--- a/sys/include/stdio_base.h
+++ b/sys/include/stdio_base.h
@@ -102,6 +102,16 @@ void stdio_init(void);
 int stdio_available(void);
 #endif
 
+#if IS_USED(MODULE_STDIO_CLEAR_RX) || DOXYGEN
+/**
+ * @brief   Clear the input buffer
+ *
+ * @warning This function is only available if the implementation supports
+ *          it and the @c stdio_clear_rx module is enabled.
+ */
+void stdio_clear_rx(void);
+#endif
+
 /**
  * @brief read @p len bytes from stdio uart into @p buffer
  *
diff --git a/sys/stdio/stdio.c b/sys/stdio/stdio.c
index 11fb6c5cf739c..47922674d7855 100644
--- a/sys/stdio/stdio.c
+++ b/sys/stdio/stdio.c
@@ -78,3 +78,8 @@ int stdio_available(void)
     return tsrb_avail(&stdin_isrpipe.tsrb);
 }
 #endif
+
+void stdio_clear_rx(void)
+{
+    tsrb_clear(&stdin_isrpipe.tsrb);
+}