diff --git a/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c b/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c
index b292379..5231786 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/therm/fan.c
@@ -134,7 +134,7 @@
 	end = ptimer->read(ptimer);
 
 	if (cycles == 5) {
-		tach = (u64)60000000000;
+		tach = (u64)60000000000ULL;
 		do_div(tach, (end - start));
 		return tach;
 	} else