net: phy: provide whether link has changed in c37_read_status

Some PHY driver might require additional regs call after
genphy_c37_read_status() is called.

Expand genphy_c37_read_status to provide a bool wheather the link has
changed or not to permit PHY driver to skip additional regs call if
nothing has changed.

Every user of genphy_c37_read_status() is updated with the new
additional bool.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/broadcom.c

@@ -665,10 +665,11 @@ static int bcm54616s_config_aneg(struct phy_device *phydev)
 static int bcm54616s_read_status(struct phy_device *phydev)
 {
 	struct bcm54616s_phy_priv *priv = phydev->priv;
+	bool changed;
 	int err;
 
 	if (priv->mode_1000bx_en)
-		err = genphy_c37_read_status(phydev);
+		err = genphy_c37_read_status(phydev, &changed);
 	else
 		err = genphy_read_status(phydev);
 

drivers/net/phy/phy_device.c

@@ -2621,12 +2621,15 @@ EXPORT_SYMBOL(genphy_read_status);
 /**
  * genphy_c37_read_status - check the link status and update current link state
  * @phydev: target phy_device struct
+ * @changed: pointer where to store if link changed
  *
  * Description: Check the link, then figure out the current state
  *   by comparing what we advertise with what the link partner
  *   advertises. This function is for Clause 37 1000Base-X mode.
+ *
+ *   If link has changed, @changed is set to true, false otherwise.
  */
-int genphy_c37_read_status(struct phy_device *phydev)
+int genphy_c37_read_status(struct phy_device *phydev, bool *changed)
 {
 	int lpa, err, old_link = phydev->link;
 
@@ -2636,9 +2639,13 @@ int genphy_c37_read_status(struct phy_device *phydev)
 		return err;
 
 	/* why bother the PHY if nothing can have changed */
-	if (phydev->autoneg == AUTONEG_ENABLE && old_link && phydev->link)
+	if (phydev->autoneg == AUTONEG_ENABLE && old_link && phydev->link) {
+		*changed = false;
 		return 0;
+	}
 
+	/* Signal link has changed */
+	*changed = true;
 	phydev->duplex = DUPLEX_UNKNOWN;
 	phydev->pause = 0;
 	phydev->asym_pause = 0;

drivers/net/phy/qcom/at803x.c

@@ -912,9 +912,10 @@ static int at8031_config_intr(struct phy_device *phydev)
 static int at8031_read_status(struct phy_device *phydev)
 {
 	struct at803x_priv *priv = phydev->priv;
+	bool changed;
 
 	if (priv->is_1000basex)
-		return genphy_c37_read_status(phydev);
+		return genphy_c37_read_status(phydev, &changed);
 
 	return at803x_read_status(phydev);
 }

include/linux/phy.h

@@ -1876,7 +1876,7 @@ int genphy_write_mmd_unsupported(struct phy_device *phdev, int devnum,
 
 /* Clause 37 */
 int genphy_c37_config_aneg(struct phy_device *phydev);
-int genphy_c37_read_status(struct phy_device *phydev);
+int genphy_c37_read_status(struct phy_device *phydev, bool *changed);
 
 /* Clause 45 PHY */
 int genphy_c45_restart_aneg(struct phy_device *phydev);