diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c
index 3cb88d6fbec0..d11f674e3dc3 100644
--- a/drivers/hwmon/aspeed-pwm-tacho.c
+++ b/drivers/hwmon/aspeed-pwm-tacho.c
@@ -159,7 +159,7 @@
  * 11: reserved.
  */
 #define M_TACH_MODE 0x02 /* 10b */
-#define M_TACH_UNIT 0x0210
+#define M_TACH_UNIT 0x0420
 #define INIT_FAN_CTRL 0xFF
 
 /* How long we sleep in us while waiting for an RPM result. */