diff --git a/cpu/sam0_common/periph/adc.c b/cpu/sam0_common/periph/adc.c
index 35290389b2..a9ad2127ac 100644
--- a/cpu/sam0_common/periph/adc.c
+++ b/cpu/sam0_common/periph/adc.c
@@ -28,9 +28,6 @@
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
-/* Only if we actually have any ADCs */
-#if ADC_NUMOF
-
 /* ADC 0 device configuration */
 #define ADC_0_DEV                          ADC
 #define ADC_0_IRQ                          ADC_IRQn
@@ -190,5 +187,3 @@ int adc_sample(adc_t line, adc_res_t res)
     _done();
     return result;
 }
-
-#endif /* #if ADC_NUMOF */
diff --git a/cpu/sam0_common/periph/i2c.c b/cpu/sam0_common/periph/i2c.c
index 4fdda7d24a..bc34d6a551 100644
--- a/cpu/sam0_common/periph/i2c.c
+++ b/cpu/sam0_common/periph/i2c.c
@@ -34,9 +34,6 @@
 #define ENABLE_DEBUG    (0)
 #include "debug.h"
 
-/* guard file in case no I2C device is defined */
-#if I2C_NUMOF
-
 #define SAMD21_I2C_TIMEOUT  (65535)
 
 #define BUSSTATE_UNKNOWN SERCOM_I2CM_STATUS_BUSSTATE(0)
@@ -535,5 +532,3 @@ static inline int _wait_for_response(SercomI2cm *dev, uint32_t max_timeout_count
     }
     return 0;
 }
-
-#endif /* I2C_NUMOF */
diff --git a/cpu/sam0_common/periph/uart.c b/cpu/sam0_common/periph/uart.c
index 86da678d5c..6b2ae0c7a5 100644
--- a/cpu/sam0_common/periph/uart.c
+++ b/cpu/sam0_common/periph/uart.c
@@ -31,9 +31,6 @@
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
-/* do not build the file in case no UART is defined */
-#ifdef UART_NUMOF
-
 /**
  * @brief   Allocate memory to store the callback functions
  */
@@ -195,5 +192,3 @@ void UART_5_ISR(void)
     irq_handler(5);
 }
 #endif
-
-#endif /* UART_NUMOF */
diff --git a/cpu/samd21/periph/pwm.c b/cpu/samd21/periph/pwm.c
index 9f681d8332..68fb66e51e 100644
--- a/cpu/samd21/periph/pwm.c
+++ b/cpu/samd21/periph/pwm.c
@@ -30,9 +30,6 @@
 #include "periph/gpio.h"
 #include "periph/pwm.h"
 
-/* guard file in case no PWM device was specified */
-#ifdef PWM_NUMOF
-
 static inline int _num(pwm_t dev)
 {
     return ((int)(pwm_config[dev].dev) & 0xc00) >> 10;
@@ -189,5 +186,3 @@ void pwm_poweroff(pwm_t dev)
                          GCLK_CLKCTRL_ID(_clk_id(dev)));
     while (GCLK->STATUS.bit.SYNCBUSY) {}
 }
-
-#endif /* PWM_NUMOF */
diff --git a/cpu/samd21/periph/rtc.c b/cpu/samd21/periph/rtc.c
index 96bf878d2b..d9513a5591 100644
--- a/cpu/samd21/periph/rtc.c
+++ b/cpu/samd21/periph/rtc.c
@@ -24,9 +24,6 @@
 #include "periph/rtc.h"
 #include "periph_conf.h"
 
-/* guard file in case no RTC device was specified */
-#if RTC_NUMOF
-
 typedef struct {
     rtc_alarm_cb_t cb;        /**< callback called from RTC interrupt */
     void *arg;                /**< argument passed to the callback */
@@ -199,5 +196,3 @@ void isr_rtc(void)
     }
     cortexm_isr_end();
 }
-
-#endif /* RTC_NUMOF */
diff --git a/cpu/samd21/periph/rtt.c b/cpu/samd21/periph/rtt.c
index a4d0bc2352..f3563b8ab8 100644
--- a/cpu/samd21/periph/rtt.c
+++ b/cpu/samd21/periph/rtt.c
@@ -24,9 +24,6 @@
 #include "periph/rtt.h"
 #include "periph_conf.h"
 
-/* guard file in case no RTT device was specified */
-#if RTT_NUMOF
-
 /* if RTT_PRESCALER is not set, then set it to DIV1 */
 #ifndef RTT_PRESCALER
 #define RTT_PRESCALER       RTC_MODE0_CTRL_PRESCALER_DIV1
@@ -211,6 +208,3 @@ void RTT_ISR(void)
 
     cortexm_isr_end();
 }
-
-
-#endif /* RTT_NUMOF */
diff --git a/cpu/saml21/periph/rtc.c b/cpu/saml21/periph/rtc.c
index 987969b277..5c31c67ed7 100644
--- a/cpu/saml21/periph/rtc.c
+++ b/cpu/saml21/periph/rtc.c
@@ -22,9 +22,6 @@
 #include "periph/rtc.h"
 #include "periph_conf.h"
 
-/* guard file in case no RTC device was specified */
-#if RTC_NUMOF
-
 typedef struct {
     rtc_alarm_cb_t cb;        /**< callback called from RTC interrupt */
     void *arg;                /**< argument passed to the callback */
@@ -234,5 +231,3 @@ void isr_rtc(void)
     }
     cortexm_isr_end();
 }
-
-#endif /* RTC_NUMOF */