From 82e960b6426f2287345e75cdfbe885d2c014f669 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joakim=20Nohlg=C3=A5rd?= <joakim.nohlgard@eistec.se>
Date: Fri, 23 Feb 2018 17:13:53 +0100
Subject: [PATCH] kinetis: Set LPUART clock source during uart_lpuart_init

---
 cpu/kinetis/include/cpu_conf_kinetis.h |  5 +++++
 cpu/kinetis/periph/uart.c              | 23 ++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/cpu/kinetis/include/cpu_conf_kinetis.h b/cpu/kinetis/include/cpu_conf_kinetis.h
index 0a7aee7262..49c41f9318 100644
--- a/cpu/kinetis/include/cpu_conf_kinetis.h
+++ b/cpu/kinetis/include/cpu_conf_kinetis.h
@@ -72,6 +72,11 @@ extern "C"
 #if !defined(OSC0) && defined(OSC)
 #define OSC0 OSC
 #endif
+#if !defined(SIM_SOPT2_LPUART0SRC_MASK) && defined(SIM_SOPT2_LPUARTSRC_MASK)
+#define SIM_SOPT2_LPUART0SRC_MASK SIM_SOPT2_LPUARTSRC_MASK
+#define SIM_SOPT2_LPUART0SRC_SHIFT SIM_SOPT2_LPUARTSRC_SHIFT
+#define SIM_SOPT2_LPUART0SRC SIM_SOPT2_LPUARTSRC
+#endif
 #if !defined(SIM_SCGC5_LPTMR_SHIFT) && defined(SIM_SCGC5_LPTIMER_SHIFT)
 #define SIM_SCGC5_LPTMR_SHIFT SIM_SCGC5_LPTIMER_SHIFT
 #endif
diff --git a/cpu/kinetis/periph/uart.c b/cpu/kinetis/periph/uart.c
index 64bca7cbef..50d8529819 100644
--- a/cpu/kinetis/periph/uart.c
+++ b/cpu/kinetis/periph/uart.c
@@ -63,6 +63,15 @@
 #define LPUART_OVERSAMPLING_RATE (16)
 #endif
 
+/* Default LPUART clock setting to avoid compilation failures, define this in
+ * periph_conf.h to set board specific configuration if using the LPUART. */
+#ifndef LPUART_0_SRC
+#define LPUART_0_SRC            0
+#endif
+#ifndef LPUART_1_SRC
+#define LPUART_1_SRC            0
+#endif
+
 /**
  * @brief Runtime configuration space, holds pointers to callback functions for RX
  */
@@ -296,7 +305,19 @@ static inline void uart_init_lpuart(uart_t uart, uint32_t baudrate)
     LPUART_Type *dev = uart_config[uart].dev;
     uint32_t clk = uart_config[uart].freq;
 
-    /* Remember to select a module clock in board_init! (SIM->SOPT2[LPUART0SRC]) */
+    /* Set LPUART clock source */
+#ifdef SIM_SOPT2_LPUART0SRC
+    if (dev == LPUART0) {
+        SIM->SOPT2 = (SIM->SOPT2 & ~SIM_SOPT2_LPUART0SRC_MASK) |
+            SIM_SOPT2_LPUART0SRC(LPUART_0_SRC);
+    }
+#endif
+#ifdef SIM_SOPT2_LPUART1SRC
+    if (dev == LPUART1) {
+        SIM->SOPT2 = (SIM->SOPT2 & ~SIM_SOPT2_LPUART1SRC_MASK) |
+            SIM_SOPT2_LPUART1SRC(LPUART_1_SRC);
+    }
+#endif
 
     /* Select mode */
     /* transmitter and receiver disabled */