diff --git a/hw/display/tc6393xb.c b/hw/display/tc6393xb.c
index 74d10af3d4187c7c746db664d293be1a94fe9aea..0ae63605f01db41fb262e51dc926bc73f26c9b2c 100644
--- a/hw/display/tc6393xb.c
+++ b/hw/display/tc6393xb.c
@@ -172,6 +172,7 @@ static void tc6393xb_gpio_handler_update(TC6393xbState *s)
     int bit;
 
     level = s->gpio_level & s->gpio_dir;
+    level &= MAKE_64BIT_MASK(0, TC6393XB_GPIOS);
 
     for (diff = s->prev_level ^ level; diff; diff ^= 1 << bit) {
         bit = ctz32(diff);