netdev - [PATCH net-next] net: stmmac: mdio: fix smatch warning

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Message-ID: <8335ad5a-f5fa-4fb6-b67a-d73c4021291a@gmail.com>
Date: Fri, 24 Oct 2025 21:26:06 +0200
From: Heiner Kallweit <hkallweit1@...il.com>
To: Maxime Coquelin <mcoquelin.stm32@...il.com>,
 Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Andrew Lunn <andrew+netdev@...n.ch>, Paolo Abeni <pabeni@...hat.com>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 David Miller <davem@...emloft.net>
Cc: "moderated list:ARM/STM32 ARCHITECTURE"
 <linux-stm32@...md-mailman.stormreply.com>,
 "linux-arm-kernel@...ts.infradead.org"
 <linux-arm-kernel@...ts.infradead.org>,
 "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
 Russell King - ARM Linux <linux@...linux.org.uk>
Subject: [PATCH net-next] net: stmmac: mdio: fix smatch warning

max_addr is the max number of addresses, not the highest possible address,
therefore check phydev->mdio.addr > max_addr isn't correct.
To fix this change the semantics of max_addr, so that it represents
the highest possible address. IMO this is also a little bit more intuitive
wrt name max_addr.

Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Reported-by: Simon Horman <horms@...nel.org>
Fixes: 4a107a0e8361 ("net: stmmac: mdio: use phy_find_first to simplify stmmac_mdio_register")
Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index 3f8cc3293..1e82850f2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -583,9 +583,9 @@ int stmmac_mdio_register(struct net_device *ndev)
 	struct device_node *mdio_node = priv->plat->mdio_node;
 	struct device *dev = ndev->dev.parent;
 	struct fwnode_handle *fixed_node;
+	int max_addr = PHY_MAX_ADDR - 1;
 	struct fwnode_handle *fwnode;
 	struct phy_device *phydev;
-	int max_addr;
 
 	if (!mdio_bus_data)
 		return 0;
@@ -609,15 +609,12 @@ int stmmac_mdio_register(struct net_device *ndev)
 
 		if (priv->synopsys_id < DWXGMAC_CORE_2_20) {
 			/* Right now only C22 phys are supported */
-			max_addr = MII_XGMAC_MAX_C22ADDR + 1;
+			max_addr = MII_XGMAC_MAX_C22ADDR;
 
 			/* Check if DT specified an unsupported phy addr */
 			if (priv->plat->phy_addr > MII_XGMAC_MAX_C22ADDR)
 				dev_err(dev, "Unsupported phy_addr (max=%d)\n",
 					MII_XGMAC_MAX_C22ADDR);
-		} else {
-			/* XGMAC version 2.20 onwards support 32 phy addr */
-			max_addr = PHY_MAX_ADDR;
 		}
 	} else {
 		new_bus->read = &stmmac_mdio_read_c22;
@@ -626,8 +623,6 @@ int stmmac_mdio_register(struct net_device *ndev)
 			new_bus->read_c45 = &stmmac_mdio_read_c45;
 			new_bus->write_c45 = &stmmac_mdio_write_c45;
 		}
-
-		max_addr = PHY_MAX_ADDR;
 	}
 
 	if (mdio_bus_data->needs_reset)
-- 
2.51.1