From 002057f91868a1febb62b624d3d1829f6a00522a Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Thu, 9 Nov 2017 10:03:06 +0100
Subject: [PATCH] sys: make uart_stdio RX optional

---
 Makefile.dep                   | 12 +++++++++++-
 makefiles/pseudomodules.inc.mk |  1 +
 sys/stdio_uart/stdio_uart.c    | 31 +++++++++++++++++++++++++++----
 3 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/Makefile.dep b/Makefile.dep
index f89090bbb5..f8cc68c8b4 100644
--- a/Makefile.dep
+++ b/Makefile.dep
@@ -396,8 +396,18 @@ ifneq (,$(filter stdio_rtt,$(USEMODULE)))
   USEMODULE += xtimer
 endif
 
-ifneq (,$(filter stdio_uart,$(USEMODULE)))
+ifneq (,$(filter shell,$(USEMODULE)))
+  ifneq (,$(filter stdio_uart,$(USEMODULE)))
+    USEMODULE += stdio_uart_rx
+  endif
+endif
+
+ifneq (,$(filter stdio_uart_rx,$(USEMODULE)))
   USEMODULE += isrpipe
+  USEMODULE += stdio_uart
+endif
+
+ifneq (,$(filter stdio_uart,$(USEMODULE)))
   FEATURES_REQUIRED += periph_uart
 endif
 
diff --git a/makefiles/pseudomodules.inc.mk b/makefiles/pseudomodules.inc.mk
index 6132f5b16d..60dd770d8f 100644
--- a/makefiles/pseudomodules.inc.mk
+++ b/makefiles/pseudomodules.inc.mk
@@ -67,6 +67,7 @@ PSEUDOMODULES += sock
 PSEUDOMODULES += sock_ip
 PSEUDOMODULES += sock_tcp
 PSEUDOMODULES += sock_udp
+PSEUDOMODULES += stdio_uart_rx
 
 # print ascii representation in function od_hex_dump()
 PSEUDOMODULES += od_string
diff --git a/sys/stdio_uart/stdio_uart.c b/sys/stdio_uart/stdio_uart.c
index cb2a32a5f6..91c9ff91c6 100644
--- a/sys/stdio_uart/stdio_uart.c
+++ b/sys/stdio_uart/stdio_uart.c
@@ -27,6 +27,8 @@
  * @}
  */
 
+#include <errno.h>
+
 #include "stdio_uart.h"
 
 #include "board.h"
@@ -45,16 +47,31 @@ extern ethos_t ethos;
 #define ENABLE_DEBUG 0
 #include "debug.h"
 
-
+#ifdef MODULE_STDIO_UART_RX
 static char _rx_buf_mem[STDIO_UART_RX_BUFSIZE];
 isrpipe_t stdio_uart_isrpipe = ISRPIPE_INIT(_rx_buf_mem);
+#endif
 
 void stdio_init(void)
 {
-#ifndef USE_ETHOS_FOR_STDIO
-    uart_init(STDIO_UART_DEV, STDIO_UART_BAUDRATE, (uart_rx_cb_t) isrpipe_write_one, &stdio_uart_isrpipe);
+    uart_rx_cb_t cb;
+    void *arg;
+
+#ifdef MODULE_STDIO_UART_RX
+    cb = (uart_rx_cb_t) isrpipe_write_one;
+    arg = &stdio_uart_isrpipe;
 #else
-    uart_init(ETHOS_UART, ETHOS_BAUDRATE, (uart_rx_cb_t) isrpipe_write_one, &stdio_uart_isrpipe);
+#ifdef USE_ETHOS_FOR_STDIO
+#error "ethos needs stdio_uart_rx"
+#endif
+    cb = NULL;
+    arg = NULL;
+#endif
+
+#ifndef USE_ETHOS_FOR_STDIO
+    uart_init(STDIO_UART_DEV, STDIO_UART_BAUDRATE, cb, arg);
+#else
+    uart_init(ETHOS_UART, ETHOS_BAUDRATE, cb, arg);
 #endif
 #if MODULE_VFS
     vfs_bind_stdio();
@@ -63,7 +80,13 @@ void stdio_init(void)
 
 ssize_t stdio_read(void* buffer, size_t count)
 {
+#ifdef MODULE_STDIO_UART_RX
     return (ssize_t)isrpipe_read(&stdio_uart_isrpipe, (char *)buffer, count);
+#else
+    (void)buffer;
+    (void)count;
+    return -ENOTSUP;
+#endif
 }
 
 ssize_t stdio_write(const void* buffer, size_t len)