net: dsa: mv88e6xxx: use BMSR_ANEGCOMPLETE bit for filling an_complete

Commit ede359d8 ("net: dsa: mv88e6xxx: Link in pcs_get_state() if AN
is bypassed") added the ability to link if AN was bypassed, and added
filling of state->an_complete field, but set it to true if AN was
enabled in BMCR, not when AN was reported complete in BMSR.

This was done because for some reason, when I wanted to use BMSR value
to infer an_complete, I was looking at BMSR_ANEGCAPABLE bit (which was
always 1), instead of BMSR_ANEGCOMPLETE bit.

Use BMSR_ANEGCOMPLETE for filling state->an_complete.

Fixes: ede359d8 ("net: dsa: mv88e6xxx: Link in pcs_get_state() if AN is bypassed")
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/mv88e6xxx/serdes.c

@@ -50,22 +50,17 @@ static int mv88e6390_serdes_write(struct mv88e6xxx_chip *chip,
 }
 
 static int mv88e6xxx_serdes_pcs_get_state(struct mv88e6xxx_chip *chip,
-					  u16 ctrl, u16 status, u16 lpa,
+					  u16 bmsr, u16 lpa, u16 status,
 					  struct phylink_link_state *state)
 {
 	state->link = !!(status & MV88E6390_SGMII_PHY_STATUS_LINK);
+	state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
 
 	if (status & MV88E6390_SGMII_PHY_STATUS_SPD_DPL_VALID) {
 		/* The Spped and Duplex Resolved register is 1 if AN is enabled
 		 * and complete, or if AN is disabled. So with disabled AN we
-		 * still get here on link up. But we want to set an_complete
-		 * only if AN was enabled, thus we look at BMCR_ANENABLE.
-		 * (According to 802.3-2008 section 22.2.4.2.10, we should be
-		 *  able to get this same value from BMSR_ANEGCAPABLE, but tests
-		 *  show that these Marvell PHYs don't conform to this part of
-		 *  the specificaion - BMSR_ANEGCAPABLE is simply always 1.)
+		 * still get here on link up.
 		 */
-		state->an_complete = !!(ctrl & BMCR_ANENABLE);
 		state->duplex = status &
 				MV88E6390_SGMII_PHY_STATUS_DUPLEX_FULL ?
 			                         DUPLEX_FULL : DUPLEX_HALF;
@@ -191,12 +186,12 @@ int mv88e6352_serdes_pcs_config(struct mv88e6xxx_chip *chip, int port,
 int mv88e6352_serdes_pcs_get_state(struct mv88e6xxx_chip *chip, int port,
 				   int lane, struct phylink_link_state *state)
 {
-	u16 lpa, status, ctrl;
+	u16 bmsr, lpa, status;
 	int err;
 
-	err = mv88e6352_serdes_read(chip, MII_BMCR, &ctrl);
+	err = mv88e6352_serdes_read(chip, MII_BMSR, &bmsr);
 	if (err) {
-		dev_err(chip->dev, "can't read Serdes PHY control: %d\n", err);
+		dev_err(chip->dev, "can't read Serdes BMSR: %d\n", err);
 		return err;
 	}
 
@@ -212,7 +207,7 @@ int mv88e6352_serdes_pcs_get_state(struct mv88e6xxx_chip *chip, int port,
 		return err;
 	}
 
-	return mv88e6xxx_serdes_pcs_get_state(chip, ctrl, status, lpa, state);
+	return mv88e6xxx_serdes_pcs_get_state(chip, bmsr, lpa, status, state);
 }
 
 int mv88e6352_serdes_pcs_an_restart(struct mv88e6xxx_chip *chip, int port,
@@ -918,13 +913,13 @@ int mv88e6390_serdes_pcs_config(struct mv88e6xxx_chip *chip, int port,
 static int mv88e6390_serdes_pcs_get_state_sgmii(struct mv88e6xxx_chip *chip,
 	int port, int lane, struct phylink_link_state *state)
 {
-	u16 lpa, status, ctrl;
+	u16 bmsr, lpa, status;
 	int err;
 
 	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
-				    MV88E6390_SGMII_BMCR, &ctrl);
+				    MV88E6390_SGMII_BMSR, &bmsr);
 	if (err) {
-		dev_err(chip->dev, "can't read Serdes PHY control: %d\n", err);
+		dev_err(chip->dev, "can't read Serdes PHY BMSR: %d\n", err);
 		return err;
 	}
 
@@ -942,7 +937,7 @@ static int mv88e6390_serdes_pcs_get_state_sgmii(struct mv88e6xxx_chip *chip,
 		return err;
 	}
 
-	return mv88e6xxx_serdes_pcs_get_state(chip, ctrl, status, lpa, state);
+	return mv88e6xxx_serdes_pcs_get_state(chip, bmsr, lpa, status, state);
 }
 
 static int mv88e6390_serdes_pcs_get_state_10g(struct mv88e6xxx_chip *chip,