net: phy: adin1100: Add interrupt support for link change

An interrupt handler was added to the driver as well as functions
to enable interrupts at the phy.

There are several interrupts maskable at the phy, but only link change
interrupts are handled by the driver yet.
Signed-off-by: Andre Werner <andre.werner@systec-electronic.com>
Link: https://lore.kernel.org/r/20240129135734.18975-3-andre.werner@systec-electronic.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/adin1100.c

@@ -18,6 +18,12 @@
 #define PHY_ID_ADIN1110				0x0283bc91
 #define PHY_ID_ADIN2111				0x0283bca1
 
+#define ADIN_PHY_SUBSYS_IRQ_MASK		0x0021
+#define   ADIN_LINK_STAT_CHNG_IRQ_EN		BIT(1)
+
+#define ADIN_PHY_SUBSYS_IRQ_STATUS		0x0011
+#define   ADIN_LINK_STAT_CHNG			BIT(1)
+
 #define ADIN_FORCED_MODE			0x8000
 #define   ADIN_FORCED_MODE_EN			BIT(0)
 
@@ -136,6 +142,53 @@ static int adin_config_aneg(struct phy_device *phydev)
 	return genphy_c45_config_aneg(phydev);
 }
 
+static int adin_phy_ack_intr(struct phy_device *phydev)
+{
+	/* Clear pending interrupts */
+	int rc = phy_read_mmd(phydev, MDIO_MMD_VEND2,
+			      ADIN_PHY_SUBSYS_IRQ_STATUS);
+
+	return rc < 0 ? rc : 0;
+}
+
+static int adin_config_intr(struct phy_device *phydev)
+{
+	u16 irq_mask;
+	int ret;
+
+	ret = adin_phy_ack_intr(phydev);
+	if (ret)
+		return ret;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED)
+		irq_mask = ADIN_LINK_STAT_CHNG_IRQ_EN;
+	else
+		irq_mask = 0;
+
+	return phy_modify_mmd(phydev, MDIO_MMD_VEND2,
+			      ADIN_PHY_SUBSYS_IRQ_MASK,
+			      ADIN_LINK_STAT_CHNG_IRQ_EN, irq_mask);
+}
+
+static irqreturn_t adin_phy_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_status;
+
+	irq_status = phy_read_mmd(phydev, MDIO_MMD_VEND2,
+				  ADIN_PHY_SUBSYS_IRQ_STATUS);
+	if (irq_status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (!(irq_status & ADIN_LINK_STAT_CHNG))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
 static int adin_set_powerdown_mode(struct phy_device *phydev, bool en)
 {
 	int ret;
@@ -275,6 +328,8 @@ static struct phy_driver adin_driver[] = {
 		.probe			= adin_probe,
 		.config_aneg		= adin_config_aneg,
 		.read_status		= adin_read_status,
+		.config_intr		= adin_config_intr,
+		.handle_interrupt	= adin_phy_handle_interrupt,
 		.set_loopback		= adin_set_loopback,
 		.suspend		= adin_suspend,
 		.resume			= adin_resume,