diff --git a/drivers/bus/intel-ixp4xx-eb.c b/drivers/bus/intel-ixp4xx-eb.c
index f5ba6bee6fd8..320cf307db05 100644
--- a/drivers/bus/intel-ixp4xx-eb.c
+++ b/drivers/bus/intel-ixp4xx-eb.c
@@ -33,7 +33,7 @@
 #define IXP4XX_EXP_TIMING_STRIDE	0x04
 #define IXP4XX_EXP_CS_EN		BIT(31)
 #define IXP456_EXP_PAR_EN		BIT(30) /* Only on IXP45x and IXP46x */
-#define IXP4XX_EXP_T1_MASK		GENMASK(28, 27)
+#define IXP4XX_EXP_T1_MASK		GENMASK(29, 28)
 #define IXP4XX_EXP_T1_SHIFT		28
 #define IXP4XX_EXP_T2_MASK		GENMASK(27, 26)
 #define IXP4XX_EXP_T2_SHIFT		26