Revert "net: phy: microchip: force IRQ polling mode for lan88xx"

This reverts commit 853e14cf36f6b16a372444a1eff54a3d7c6c1268 which is
commit 30a41ed32d3088cd0d682a13d7f30b23baed7e93 upstream.

It is reported to cause NFS boot problems on a Raspberry Pi 3b so revert
it from this branch for now.

Cc: Fiona Klute <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: Sasha Levin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reported-by: Mark Brown <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
(cherry picked from commit 2edc296e2107a003e383f87cdc7e29bddcb6b17e)
Signed-off-by: Vijayendra Suman <[email protected]>

Author: gregkh

drivers/net/phy/microchip.c

@@ -31,6 +31,47 @@ static int lan88xx_write_page(struct phy_device *phydev, int page)
 	return __phy_write(phydev, LAN88XX_EXT_PAGE_ACCESS, page);
 }
 
+static int lan88xx_phy_config_intr(struct phy_device *phydev)
+{
+	int rc;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		/* unmask all source and clear them before enable */
+		rc = phy_write(phydev, LAN88XX_INT_MASK, 0x7FFF);
+		rc = phy_read(phydev, LAN88XX_INT_STS);
+		rc = phy_write(phydev, LAN88XX_INT_MASK,
+			       LAN88XX_INT_MASK_MDINTPIN_EN_ |
+			       LAN88XX_INT_MASK_LINK_CHANGE_);
+	} else {
+		rc = phy_write(phydev, LAN88XX_INT_MASK, 0);
+		if (rc)
+			return rc;
+
+		/* Ack interrupts after they have been disabled */
+		rc = phy_read(phydev, LAN88XX_INT_STS);
+	}
+
+	return rc < 0 ? rc : 0;
+}
+
+static irqreturn_t lan88xx_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_status;
+
+	irq_status = phy_read(phydev, LAN88XX_INT_STS);
+	if (irq_status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (!(irq_status & LAN88XX_INT_STS_LINK_CHANGE_))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
 static int lan88xx_suspend(struct phy_device *phydev)
 {
 	struct lan88xx_priv *priv = phydev->priv;
@@ -347,9 +388,8 @@ static struct phy_driver microchip_phy_driver[] = {
 	.config_aneg	= lan88xx_config_aneg,
 	.link_change_notify = lan88xx_link_change_notify,
 
-	/* Interrupt handling is broken, do not define related
-	 * functions to force polling.
-	 */
+	.config_intr	= lan88xx_phy_config_intr,
+	.handle_interrupt = lan88xx_handle_interrupt,
 
 	.suspend	= lan88xx_suspend,
 	.resume		= genphy_resume,