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From:   Heiko Schocher <heiko.schocher@gmail.com>
To:     netdev@vger.kernel.org
Cc:     Heiko Schocher <hs@denx.de>, Clark Wang <xiaoning.wang@nxp.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        NXP Linux Team <linux-imx@nxp.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Shenwei Wang <shenwei.wang@nxp.com>,
        Wei Fang <wei.fang@nxp.com>, linux-kernel@vger.kernel.org
Subject: [PATCH] net: fec: fix probing of fec1 when fec0 is not probed yet
Date:   Thu, 23 Nov 2023 14:27:43 +0100
Message-Id: <20231123132744.62519-1-hs@denx.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

it is possible that fec1 is probed before fec0. On SoCs
with FEC_QUIRK_SINGLE_MDIO set (which means fec1 uses mii
from fec0) init of mii fails for fec1 when fec0 is not yet
probed, as fec0 setups mii bus. In this case fec_enet_mii_init
for fec1 returns with -ENODEV, and so fec1 never comes up.

Return here with -EPROBE_DEFER so interface gets later
probed again.

Found this on imx8qxp based board, using 2 ethernet interfaces,
and from time to time, fec1 interface came not up.

Signed-off-by: Heiko Schocher <hs@denx.de>
---

 drivers/net/ethernet/freescale/fec_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index c3b7694a7485..d956f95e7a65 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -2445,7 +2445,7 @@ static int fec_enet_mii_init(struct platform_device *pdev)
 			mii_cnt++;
 			return 0;
 		}
-		return -ENOENT;
+		return -EPROBE_DEFER;
 	}
 
 	bus_freq = 2500000; /* 2.5MHz by default */
-- 
2.20.1