drivers: ethernet: phy: ksz9131: add getting status for gigabit mode

Read gigabit status from Master Slave Status Register.

Signed-off-by: Tony Han <tony.han@microchip.com>

Author: TonyHan11

drivers/ethernet/phy/phy_microchip_ksz9131.c

@@ -41,6 +41,9 @@ struct mchp_ksz9131_data {
 #define PHY_ID_KSZ9131     0x00221640
 #define PHY_ID_KSZ9131_MSK (~0xF)
 
+#define PHY_KSZ9131_MSS_ADVERTISE_1000_FULL BIT(11)
+#define PHY_KSZ9131_MSS_ADVERTISE_1000_HALF BIT(10)
+
 #define PHY_KSZ9131_ICS_REG               0x1B
 #define PHY_KSZ9131_ICS_LINK_DOWN_IE_MASK BIT(10)
 #define PHY_KSZ9131_ICS_LINK_UP_IE_MASK   BIT(8)
@@ -375,6 +378,8 @@ static int phy_mchp_ksz9131_get_link(const struct device *dev, struct phy_link_s
 	uint16_t mutual_capabilities = 0;
 	uint16_t anlpar = 0;
 	uint16_t anar = 0;
+	uint16_t mscr = 0;
+	uint16_t mssr = 0;
 	int ret = 0;
 
 	(void)config; /* avoid warnings due to config is only used in LOG_DBG() */
@@ -386,6 +391,27 @@ static int phy_mchp_ksz9131_get_link(const struct device *dev, struct phy_link_s
 		goto done;
 	}
 
+	/* Read AUTO-NEGOTIATION MASTER SLAVE CONTROL REGISTER */
+	ret = ksz9131_read(dev, MII_1KTCR, &mscr);
+	if (ret < 0) {
+		goto done;
+	}
+
+	/* Read AUTO-NEGOTIATION MASTER SLAVE STATUS REGISTER */
+	ret = ksz9131_read(dev, MII_1KSTSR, &mssr);
+	if (ret < 0) {
+		goto done;
+	}
+
+	if (mscr & MII_ADVERTISE_1000_FULL && mssr & PHY_KSZ9131_MSS_ADVERTISE_1000_FULL) {
+		state->speed = LINK_FULL_1000BASE;
+		goto done;
+	}
+	if (mscr & MII_ADVERTISE_1000_HALF && mssr & PHY_KSZ9131_MSS_ADVERTISE_1000_HALF) {
+		state->speed = LINK_HALF_1000BASE;
+		goto done;
+	}
+
 	/* Read currently configured advertising options */
 	ret = ksz9131_read(dev, MII_ANAR, &anar);
 	if (ret < 0) {