From e3611ad209582a222562ec88332c8ad9f85e2937 Mon Sep 17 00:00:00 2001
From: 0r31 <37673727+0r31@users.noreply.github.com>
Date: Sun, 26 Jan 2020 08:08:40 +0100
Subject: [PATCH] Fix MKS Base + Digipot compile error (#16636)

---
 .../HAL_LPC1768/include/digipot_mcp4451_I2C_routines.c    | 1 -
 .../HAL_LPC1768/include/digipot_mcp4451_I2C_routines.h    | 1 +
 Marlin/src/HAL/HAL_LPC1768/include/i2c_util.h             | 8 ++++++++
 Marlin/src/feature/digipot/digipot_mcp4451.cpp            | 2 +-
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.c b/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.c
index 8dc8c61b45..dd83c7a971 100644
--- a/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.c
+++ b/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.c
@@ -36,7 +36,6 @@
 #endif
 
 #include "digipot_mcp4451_I2C_routines.h"
-#include "i2c_util.h"
 
 // These two routines are exact copies of the lpc17xx_i2c.c routines.  Couldn't link to
 // to the lpc17xx_i2c.c routines so had to copy them into this file & rename them.
diff --git a/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.h b/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.h
index 6d6fafa8bb..db6715e2b6 100644
--- a/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.h
+++ b/Marlin/src/HAL/HAL_LPC1768/include/digipot_mcp4451_I2C_routines.h
@@ -33,6 +33,7 @@
 #include <lpc17xx_i2c.h>
 #include <lpc17xx_pinsel.h>
 #include <lpc17xx_libcfg_default.h>
+#include "i2c_util.h"
 
 uint8_t digipot_mcp4451_start(uint8_t sla);
 uint8_t digipot_mcp4451_send_byte(uint8_t data);
diff --git a/Marlin/src/HAL/HAL_LPC1768/include/i2c_util.h b/Marlin/src/HAL/HAL_LPC1768/include/i2c_util.h
index 671a1e3746..1ca3fc1844 100644
--- a/Marlin/src/HAL/HAL_LPC1768/include/i2c_util.h
+++ b/Marlin/src/HAL/HAL_LPC1768/include/i2c_util.h
@@ -45,4 +45,12 @@
 #include <lpc17xx_pinsel.h>
 #include <lpc17xx_libcfg_default.h>
 
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
 void configure_i2c(const uint8_t clock_option);
+
+#ifdef __cplusplus
+  }
+#endif
diff --git a/Marlin/src/feature/digipot/digipot_mcp4451.cpp b/Marlin/src/feature/digipot/digipot_mcp4451.cpp
index 13022abad1..48b4d154be 100644
--- a/Marlin/src/feature/digipot/digipot_mcp4451.cpp
+++ b/Marlin/src/feature/digipot/digipot_mcp4451.cpp
@@ -77,7 +77,7 @@ void digipot_i2c_set_current(const uint8_t channel, const float current) {
 
 void digipot_i2c_init() {
   #if MB(MKS_SBASE)
-    configure_i2c();
+    configure_i2c(16); // Setting clock_option to 16 ensure the I2C bus is initialized at 400kHz
   #else
     Wire.begin();
   #endif