net: phy: micrel: Adding interrupt support for Link up/Link down in LAN8814 Quad phy

This patch add support for Link up or Link down
interrupt support in LAN8814 Quad phy
Signed-off-by: Divya Koppera <Divya.Koppera@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20211221112217.9502-1-Divya.Koppera@microchip.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/micrel.c

@@ -66,6 +66,19 @@
 #define KSZ8081_LMD_SHORT_INDICATOR		BIT(12)
 #define KSZ8081_LMD_DELTA_TIME_MASK		GENMASK(8, 0)
 
+/* Lan8814 general Interrupt control/status reg in GPHY specific block. */
+#define LAN8814_INTC				0x18
+#define LAN8814_INTS				0x1B
+
+#define LAN8814_INT_LINK_DOWN			BIT(2)
+#define LAN8814_INT_LINK_UP			BIT(0)
+#define LAN8814_INT_LINK			(LAN8814_INT_LINK_UP |\
+						 LAN8814_INT_LINK_DOWN)
+
+#define LAN8814_INTR_CTRL_REG			0x34
+#define LAN8814_INTR_CTRL_REG_POLARITY		BIT(1)
+#define LAN8814_INTR_CTRL_REG_INTR_ENABLE	BIT(0)
+
 /* PHY Control 1 */
 #define MII_KSZPHY_CTRL_1			0x1e
 #define KSZ8081_CTRL1_MDIX_STAT			BIT(4)
@@ -1620,6 +1633,58 @@ static int lan8804_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+static irqreturn_t lan8814_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_status;
+
+	irq_status = phy_read(phydev, LAN8814_INTS);
+	if (irq_status < 0)
+		return IRQ_NONE;
+
+	if (!(irq_status & LAN8814_INT_LINK))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+static int lan8814_ack_interrupt(struct phy_device *phydev)
+{
+	/* bit[12..0] int status, which is a read and clear register. */
+	int rc;
+
+	rc = phy_read(phydev, LAN8814_INTS);
+
+	return (rc < 0) ? rc : 0;
+}
+
+static int lan8814_config_intr(struct phy_device *phydev)
+{
+	int err;
+
+	lanphy_write_page_reg(phydev, 4, LAN8814_INTR_CTRL_REG,
+			      LAN8814_INTR_CTRL_REG_POLARITY |
+			      LAN8814_INTR_CTRL_REG_INTR_ENABLE);
+
+	/* enable / disable interrupts */
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		err = lan8814_ack_interrupt(phydev);
+		if (err)
+			return err;
+
+		err =  phy_write(phydev, LAN8814_INTC, LAN8814_INT_LINK);
+	} else {
+		err =  phy_write(phydev, LAN8814_INTC, 0);
+		if (err)
+			return err;
+
+		err = lan8814_ack_interrupt(phydev);
+	}
+
+	return err;
+}
+
 static struct phy_driver ksphy_driver[] = {
 {
 	.phy_id		= PHY_ID_KS8737,
@@ -1802,6 +1867,8 @@ static struct phy_driver ksphy_driver[] = {
 	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= kszphy_resume,
+	.config_intr	= lan8814_config_intr,
+	.handle_interrupt = lan8814_handle_interrupt,
 }, {
 	.phy_id		= PHY_ID_LAN8804,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,