diff --git a/boards/m4a-24g/include/periph_conf.h b/boards/m4a-24g/include/periph_conf.h
index cea003402..a99fd96d4 100644
--- a/boards/m4a-24g/include/periph_conf.h
+++ b/boards/m4a-24g/include/periph_conf.h
@@ -182,7 +182,7 @@ static const uart_conf_t uart_config[] = {{
 #ifdef MODULE_PERIPH_UART_HW_FC
                                               .tx_pad = UART_PAD_TX_0_RTS_2_CTS_3,
 #else
-                                               .tx_pad = UART_PAD_TX_0,
+                                              .tx_pad = UART_PAD_TX_0,
 #endif
                                               .flags = UART_FLAG_NONE,
                                               .gclk_src = SAM0_GCLK_MAIN,
@@ -200,7 +200,7 @@ static const uart_conf_t uart_config[] = {{
 #ifdef MODULE_PERIPH_UART_HW_FC
                                               .tx_pad = UART_PAD_TX_0_RTS_2_CTS_3,
 #else
-                                               .tx_pad = UART_PAD_TX_0,
+                                              .tx_pad = UART_PAD_TX_0,
 #endif
                                               .flags = UART_FLAG_NONE,
                                               .gclk_src = SAM0_GCLK_MAIN,
@@ -371,30 +371,26 @@ static const i2c_conf_t i2c_config[] = {{.dev = &(SERCOM3->I2CM),
 /** @} */
 
 #ifdef CONFIG_ADC_VREF_DEFAULT
-#undef  ADC_REF_DEFAULT
-#define ADC_REF_DEFAULT        ADC_REFCTRL_REFSEL_INT1V
+#undef ADC_REF_DEFAULT
+#define ADC_REF_DEFAULT ADC_REFCTRL_REFSEL_INT1V
 #endif
 #ifdef CONFIG_ADC_VREF_INTVCC0
-#undef  ADC_REF_DEFAULT
-#define ADC_REF_DEFAULT        ADC_REFCTRL_REFSEL_INTVCC0
+#undef ADC_REF_DEFAULT
+#define ADC_REF_DEFAULT ADC_REFCTRL_REFSEL_INTVCC0
 #endif
 #ifdef CONFIG_ADC_VREF_INTVCC1
-#undef  ADC_REF_DEFAULT
-#define ADC_REF_DEFAULT        ADC_REFCTRL_REFSEL_INTVCC1
+#undef ADC_REF_DEFAULT
+#define ADC_REF_DEFAULT ADC_REFCTRL_REFSEL_INTVCC1
 #endif
 #ifdef CONFIG_ADC_VREF_EXT1
-#undef  ADC_REF_DEFAULT
-#define ADC_REF_DEFAULT        ADC_REFCTRL_REFSEL_AREFA
+#undef ADC_REF_DEFAULT
+#define ADC_REF_DEFAULT ADC_REFCTRL_REFSEL_AREFA
 #endif
 #ifdef CONFIG_ADC_VREF_EXT1
-#undef  ADC_REF_DEFAULT
-#define ADC_REF_DEFAULT        ADC_REFCTRL_REFSEL_AREFB
+#undef ADC_REF_DEFAULT
+#define ADC_REF_DEFAULT ADC_REFCTRL_REFSEL_AREFB
 #endif
-// #ifdef ADC_REF_DEFAULT
-// #undef ADC_REF_DEFAULT
 
-// #endif
-// #endif
 /**
  * @brief ADC configuration
  */