diff --git a/cpu/samd21/include/periph_clock_config.h b/cpu/samd21/include/periph_clock_config.h
index 6d0bc8c18fd3e..ca449793066ce 100644
--- a/cpu/samd21/include/periph_clock_config.h
+++ b/cpu/samd21/include/periph_clock_config.h
@@ -22,34 +22,34 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-    
-    /**
-     * @brief   Default Clock configurations
-     */
+
+/**
+ * @brief   Default Clock configurations
+ */
 #ifndef CLOCK_8MHZ
 #define CLOCK_8MHZ              (8000000UL)
 #endif
-    
+
 #ifndef CLOCK_XOSC32K
 #define CLOCK_XOSC32K           (0)
 #endif
-    
+
 #ifndef XOSC32_RUNSTDBY
 #define XOSC32_RUNSTDBY         (0)
 #endif
-    
+
 #ifndef GEN1_1MHZ
 #define GEN1_1MHZ               (1)
 #endif
-    
+
 #ifndef GEN2_XOSC32
 #define GEN2_XOSC32             (0)
 #endif
-    
+
 #ifndef GEN3_ULP32K
 #define GEN3_ULP32K             (1)
 #endif
-    
+
 #ifdef __cplusplus
 }
 #endif