From 335c6bc516f2e456e95f6abbd4b247627f0ebd92 Mon Sep 17 00:00:00 2001
From: Juan Carrano <j.carrano@fu-berlin.de>
Date: Thu, 1 Nov 2018 18:02:39 +0100
Subject: [PATCH] sys/stdio_uart: do not cast function pointer.

There was a function pointer cast in stdio_uart. The warning was
being explicitly supressed in the module's makefile.
This commit removes the suppression and fixes the warning by providing
a wrapper function.
The wrapper was already defined in the AT driver, as part of a fix for
a similar bug there, so the definition was moved to the isrpipe module,
the logic being that using isrpipe in conjunction with a periph uart
is a common enough use-case.
---
 drivers/at/at.c             | 7 +------
 sys/include/isrpipe.h       | 7 +++++++
 sys/isrpipe/isrpipe.c       | 6 ++++++
 sys/stdio_uart/Makefile     | 3 ---
 sys/stdio_uart/stdio_uart.c | 2 +-
 5 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/at/at.c b/drivers/at/at.c
index d02a095cbae1..a7b753aa221a 100644
--- a/drivers/at/at.c
+++ b/drivers/at/at.c
@@ -22,17 +22,12 @@
 #define AT_PRINT_INCOMING (0)
 #endif
 
-static void _isrpipe_write_one_wrapper(void *_isrpipe, uint8_t data)
-{
-    isrpipe_write_one(_isrpipe, (char)data);
-}
-
 int at_dev_init(at_dev_t *dev, uart_t uart, uint32_t baudrate, char *buf, size_t bufsize)
 {
     dev->uart = uart;
     isrpipe_init(&dev->isrpipe, buf, bufsize);
 
-    return uart_init(uart, baudrate, _isrpipe_write_one_wrapper,
+    return uart_init(uart, baudrate, isrpipe_write_uartcb,
                      &dev->isrpipe);
 }
 
diff --git a/sys/include/isrpipe.h b/sys/include/isrpipe.h
index 356eef82cc91..88d783c23e76 100644
--- a/sys/include/isrpipe.h
+++ b/sys/include/isrpipe.h
@@ -64,6 +64,13 @@ void isrpipe_init(isrpipe_t *isrpipe, char *buf, size_t bufsize);
  */
 int isrpipe_write_one(isrpipe_t *isrpipe, char c);
 
+/**
+ * @brief   Wrapper around isrpipe_write_one() to make it compatible with uart_rx_cb_t.
+ *
+ * The parameters are the same as isrpipe_write_one().
+ */
+void isrpipe_write_uartcb(void *_isrpipe, uint8_t data);
+
 /**
  * @brief   Read data from isrpipe (blocking)
  *
diff --git a/sys/isrpipe/isrpipe.c b/sys/isrpipe/isrpipe.c
index 2a9cf9e2f355..df1272101be4 100644
--- a/sys/isrpipe/isrpipe.c
+++ b/sys/isrpipe/isrpipe.c
@@ -17,6 +17,7 @@
  * @}
  */
 
+#include <stdint.h>
 #include "isrpipe.h"
 
 void isrpipe_init(isrpipe_t *isrpipe, char *buf, size_t bufsize)
@@ -37,6 +38,11 @@ int isrpipe_write_one(isrpipe_t *isrpipe, char c)
     return res;
 }
 
+void isrpipe_write_uartcb(void *_isrpipe, uint8_t data)
+{
+    isrpipe_write_one(_isrpipe, (char)data);
+}
+
 int isrpipe_read(isrpipe_t *isrpipe, char *buffer, size_t count)
 {
     int res;
diff --git a/sys/stdio_uart/Makefile b/sys/stdio_uart/Makefile
index 7f3b72f4a69c..48422e909a47 100644
--- a/sys/stdio_uart/Makefile
+++ b/sys/stdio_uart/Makefile
@@ -1,4 +1 @@
-ifeq (gnu, $(TOOLCHAIN))
-  CFLAGS += -Wno-cast-function-type
-endif
 include $(RIOTBASE)/Makefile.base
diff --git a/sys/stdio_uart/stdio_uart.c b/sys/stdio_uart/stdio_uart.c
index 91c9ff91c61d..9caab960a6bc 100644
--- a/sys/stdio_uart/stdio_uart.c
+++ b/sys/stdio_uart/stdio_uart.c
@@ -58,7 +58,7 @@ void stdio_init(void)
     void *arg;
 
 #ifdef MODULE_STDIO_UART_RX
-    cb = (uart_rx_cb_t) isrpipe_write_one;
+    cb = isrpipe_write_uartcb;
     arg = &stdio_uart_isrpipe;
 #else
 #ifdef USE_ETHOS_FOR_STDIO