diff --git a/drivers/include/periph/gpio.h b/drivers/include/periph/gpio.h
index 8f06b98fe3..961e481438 100644
--- a/drivers/include/periph/gpio.h
+++ b/drivers/include/periph/gpio.h
@@ -43,6 +43,11 @@
  * definitions in `RIOT/boards/ * /include/periph_conf.h` will define the selected
  * GPIO pin.
  *
+ * @warning The scalar GPIO pin type `gpio_t` is deprecated and will be
+ * replaced by a structured GPIO pin type in a future GPIO API. Therefore,
+ * don't use the direct comparison of GPIO pins anymore. Instead, use the
+ * inline comparison functions @ref gpio_is_equal and @ref gpio_is_valid.
+ *
  * # (Low-) Power Implications
  *
  * On almost all platforms, we can only control the peripheral power state of
@@ -253,6 +258,27 @@ void gpio_toggle(gpio_t pin);
  */
 void gpio_write(gpio_t pin, int value);
 
+/**
+ * @brief   Test if a GPIO pin is equal to another GPIO pin
+ *
+ * @param[in] gpio1 First GPIO pin to check
+ * @param[in] gpio2 Second GPIO pin to check
+ */
+static inline int gpio_is_equal(gpio_t gpio1, gpio_t gpio2)
+{
+    return (gpio1 == gpio2);
+}
+
+/**
+ * @brief   Test if a GPIO pin is a valid pin and not declared as undefined.
+ *
+ * @param[in] gpio GPIO pin to check
+ */
+static inline int gpio_is_valid(gpio_t gpio)
+{
+    return (gpio != GPIO_UNDEF);
+}
+
 #ifdef __cplusplus
 }
 #endif