diff --git a/boards/remote-pa/board.c b/boards/remote-pa/board.c
index cf9e638676..382172a921 100644
--- a/boards/remote-pa/board.c
+++ b/boards/remote-pa/board.c
@@ -60,7 +60,7 @@ static void rf_switch_init(void)
     RF_SWITCH_PORT->DIR |= (1 << RF_SWITCH_PIN);
 
     /* configure io-mux for used pins */
-    IOC->OVER[RF_SWITCH_PIN] = IOC_OVERRIDE_OE;
+    IOC_PXX_OVER[RF_SWITCH_PIN] = IOC_OVERRIDE_OE;
 
     /* Set to default */
     RF_SWITCH_INTERNAL;
diff --git a/cpu/cc2538/include/periph_cpu.h b/cpu/cc2538/include/periph_cpu.h
index 83d7877c17..3307fcbe97 100644
--- a/cpu/cc2538/include/periph_cpu.h
+++ b/cpu/cc2538/include/periph_cpu.h
@@ -127,24 +127,13 @@ static inline uint8_t gpio_pp_num(gpio_t pin)
 }
 
 /**
- * @brief   Helper function to enable gpio hardware control
+ * @brief   Configure an alternate function for the given pin
  *
  * @param[in] pin   gpio pin
+ * @param[in] sel   Setting for IOC select register, (-1) to ignore
+ * @param[in] over  Setting for IOC override register, (-1) to ignore
  */
-static inline void gpio_hw_ctrl(gpio_t pin)
-{
-    gpio(pin)->AFSEL |= gpio_pin_mask(pin);
-}
-
-/**
- * @brief   Helper function to enable gpio software control
- *
- * @param[in] pin   gpio pin
- */
-static inline void gpio_sw_ctrl(gpio_t pin)
-{
-    gpio(pin)->AFSEL &= ~gpio_pin_mask(pin);
-}
+void gpio_init_af(gpio_t pin, int sel, int over);
 
 /**
  * @brief   Define a custom GPIO_UNDEF value
diff --git a/cpu/cc2538/periph/gpio.c b/cpu/cc2538/periph/gpio.c
index ab05014d5c..d3bb64440c 100644
--- a/cpu/cc2538/periph/gpio.c
+++ b/cpu/cc2538/periph/gpio.c
@@ -46,7 +46,7 @@ int gpio_init(gpio_t pin, gpio_mode_t mode)
     gpio(pin)->IE &= ~gpio_pin_mask(pin);
     gpio(pin)->AFSEL &= ~gpio_pin_mask(pin);
     /* configure pull configuration */
-    IOC->OVER[gpio_pp_num(pin)] = mode;
+    IOC_PXX_OVER[gpio_pp_num(pin)] = mode;
 
     /* set pin direction */
     if (mode == IOC_OVERRIDE_OE) {
@@ -184,3 +184,19 @@ void isr_gpiod(void)
 {
     handle_isr(GPIO_D, 3);
 }
+
+/* CC2538 specific add-on GPIO functions */
+
+void gpio_init_af(gpio_t pin, int sel, int over)
+{
+    assert(pin != GPIO_UNDEF);
+
+    if (over >= 0) {
+        IOC_PXX_OVER[gpio_pp_num(pin)] = over;
+    }
+    if(sel >= 0) {
+        IOC_PXX_SEL[gpio_pp_num(pin)] = sel;
+    }
+    /* enable alternative function mode */
+    gpio(pin)->AFSEL |= gpio_pin_mask(pin);
+}