linux-kernel - [PATCH net] net: lan966x: check devm_of_phy_get() for -EDEFER

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Message-Id: <20220525231239.1307298-1-michael@walle.cc>
Date:   Thu, 26 May 2022 01:12:39 +0200
From:   Michael Walle <michael@...le.cc>
To:     Horatiu Vultur <horatiu.vultur@...rochip.com>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        UNGLinuxDriver@...rochip.com, Michael Walle <michael@...le.cc>
Subject: [PATCH net] net: lan966x: check devm_of_phy_get() for -EDEFER_PROBE

At the moment, if devm_of_phy_get() returns an error the serdes
simply isn't set. While it is bad to ignore an error in general, there
is a particular bug that network isn't working if the serdes driver is
compiled as a module. In that case, devm_of_phy_get() returns
-EDEFER_PROBE and the error is silently ignored.

The serdes is optional, it is not there if the port is using RGMII, in
which case devm_of_phy_get() returns -ENODEV. Rearrange the error
handling so that -ENODEV will be handled but other error codes will
abort the probing.

Fixes: d28d6d2e37d1 ("net: lan966x: add port module support")
Signed-off-by: Michael Walle <michael@...le.cc>
---
 drivers/net/ethernet/microchip/lan966x/lan966x_main.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
index 6ad68b422129..5784c4161e5e 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
@@ -1120,8 +1120,13 @@ static int lan966x_probe(struct platform_device *pdev)
 		lan966x->ports[p]->fwnode = fwnode_handle_get(portnp);
 
 		serdes = devm_of_phy_get(lan966x->dev, to_of_node(portnp), NULL);
-		if (!IS_ERR(serdes))
-			lan966x->ports[p]->serdes = serdes;
+		if (PTR_ERR(serdes) == -ENODEV)
+			serdes = NULL;
+		if (IS_ERR(serdes)) {
+			err = PTR_ERR(serdes);
+			goto cleanup_ports;
+		}
+		lan966x->ports[p]->serdes = serdes;
 
 		lan966x_port_init(lan966x->ports[p]);
 	}
-- 
2.30.2