diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 240b6cf1d97c..72e073895ed9 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -376,7 +376,7 @@ static __init int hpet_mmap_enable(char *str)
 	pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
 	return 1;
 }
-__setup("hpet_mmap", hpet_mmap_enable);
+__setup("hpet_mmap=", hpet_mmap_enable);
 
 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
 {