linux-kernel - [PATCH net] net: phy: micrel: fix shared interrupt on LAN8814

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Date:   Tue, 20 Sep 2022 16:16:19 +0200
From:   Michael Walle <michael@...le.cc>
To:     Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     Divya Koppera <Divya.Koppera@...rochip.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Horatiu Vultur <horatiu.vultur@...rochip.com>,
        Michael Walle <michael@...le.cc>
Subject: [PATCH net] net: phy: micrel: fix shared interrupt on LAN8814

Since commit ece19502834d ("net: phy: micrel: 1588 support for LAN8814
phy") the handler always returns IRQ_HANDLED, except in an error case.
Before that commit, the interrupt status register was checked and if
it was empty, IRQ_NONE was returned. Restore that behavior to play nice
with the interrupt line being shared with others.

Fixes: ece19502834d ("net: phy: micrel: 1588 support for LAN8814 phy")
Signed-off-by: Michael Walle <michael@...le.cc>
---
 drivers/net/phy/micrel.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 98e9bc101d96..21b6facf6e76 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -2732,16 +2732,19 @@ static int lan8804_config_intr(struct phy_device *phydev)
 static irqreturn_t lan8814_handle_interrupt(struct phy_device *phydev)
 {
 	int irq_status, tsu_irq_status;
+	int ret = IRQ_NONE;
 
 	irq_status = phy_read(phydev, LAN8814_INTS);
-	if (irq_status > 0 && (irq_status & LAN8814_INT_LINK))
-		phy_trigger_machine(phydev);
-
 	if (irq_status < 0) {
 		phy_error(phydev);
 		return IRQ_NONE;
 	}
 
+	if (irq_status & LAN8814_INT_LINK) {
+		phy_trigger_machine(phydev);
+		ret = IRQ_HANDLED;
+	}
+
 	while (1) {
 		tsu_irq_status = lanphy_read_page_reg(phydev, 4,
 						      LAN8814_INTR_STS_REG);
@@ -2750,12 +2753,15 @@ static irqreturn_t lan8814_handle_interrupt(struct phy_device *phydev)
 		    (tsu_irq_status & (LAN8814_INTR_STS_REG_1588_TSU0_ |
 				       LAN8814_INTR_STS_REG_1588_TSU1_ |
 				       LAN8814_INTR_STS_REG_1588_TSU2_ |
-				       LAN8814_INTR_STS_REG_1588_TSU3_)))
+				       LAN8814_INTR_STS_REG_1588_TSU3_))) {
 			lan8814_handle_ptp_interrupt(phydev);
-		else
+			ret = IRQ_HANDLED;
+		} else {
 			break;
+		}
 	}
-	return IRQ_HANDLED;
+
+	return ret;
 }
 
 static int lan8814_ack_interrupt(struct phy_device *phydev)
-- 
2.30.2