diff --git a/cpu/cc26x0/periph/gpio.c b/cpu/cc26x0/periph/gpio.c
index b277af8c58f15524160959f4c8c4cea8d5dc97bb..0759f5cb60a33ab97593bf64d07ba666d4d0306f 100644
--- a/cpu/cc26x0/periph/gpio.c
+++ b/cpu/cc26x0/periph/gpio.c
@@ -34,7 +34,7 @@ static gpio_isr_ctx_t gpio_chan[GPIO_ISR_CHAN_NUMOF];
 
 int gpio_init(gpio_t pin, gpio_mode_t mode)
 {
-    if ((pin < 0) || (pin > 31))
+    if ((unsigned int)pin > 31)
         return -1;
 
     /* enable GPIO clock */