---
 drivers/net/dsa/microchip/ksz8.c     | 6 ++++++
 drivers/net/dsa/microchip/ksz8_reg.h | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz8.c b/drivers/net/dsa/microchip/ksz8.c
index 0f2b8acee80f..62fc59c3da7e 100644
--- a/drivers/net/dsa/microchip/ksz8.c
+++ b/drivers/net/dsa/microchip/ksz8.c
@@ -1297,6 +1297,9 @@ int ksz8_w_phy(struct ksz_device *dev, u16 phy, u16 reg, u16 val)
 	case PHY_REG_KSZ87XX_LPF_BW:
 		if (!ksz_is_ksz87xx(dev))
 			return -EOPNOTSUPP;
+		/* Only accept LPF bandwidth bits [7:6] */
+		if (val & ~KSZ87XX_LPF_VALID_MASK)
+			return -EINVAL;
 		ret = ksz8_ind_write8(dev, TABLE_LINK_MD, KSZ87XX_REG_PHY_LPF, (u8)val);
 		if (ret)
 			return ret;
@@ -1305,6 +1308,9 @@ int ksz8_w_phy(struct ksz_device *dev, u16 phy, u16 reg, u16 val)
 	case PHY_REG_KSZ87XX_EQ_INIT:
 		if (!ksz_is_ksz87xx(dev))
 			return -EOPNOTSUPP;
+		/* Only accept DSP EQ initial value bits [5:0] */
+		if (val & ~KSZ87XX_DSP_EQ_VALID_MASK)
+			return -EINVAL;
 		ret = ksz8_ind_write8(dev, TABLE_LINK_MD, KSZ87XX_REG_DSP_EQ, (u8)val);
 		if (ret)
 			return ret;
diff --git a/drivers/net/dsa/microchip/ksz8_reg.h b/drivers/net/dsa/microchip/ksz8_reg.h
index 5df17c463f7c..cd41214f874e 100644
--- a/drivers/net/dsa/microchip/ksz8_reg.h
+++ b/drivers/net/dsa/microchip/ksz8_reg.h
@@ -206,6 +206,9 @@
 #define KSZ87XX_REG_DSP_EQ			0x08   /* DSP EQ initial value */
 #define KSZ87XX_REG_PHY_LPF			0x4C   /* RX LPF bandwidth */
 
+#define KSZ87XX_DSP_EQ_VALID_MASK	GENMASK(5, 0)
+#define KSZ87XX_LPF_VALID_MASK		GENMASK(7, 6)
+
 /* For KSZ8765. */
 #define PORT_REMOTE_ASYM_PAUSE		BIT(5)
 #define PORT_REMOTE_SYM_PAUSE		BIT(4)
-- 
2.53.0