netdev - [PATCH net v3 2/2] smsc911x: avoid PHY being resumed when interface is not up

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Date:   Wed, 22 Mar 2023 08:19:59 +0100
From:   Wolfram Sang <wsa+renesas@...g-engineering.com>
To:     netdev@...r.kernel.org
Cc:     linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Steve Glendinning <steve.glendinning@...well.net>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Florian Fainelli <f.fainelli@...il.com>
Subject: [PATCH net v3 2/2] smsc911x: avoid PHY being resumed when interface is not up

SMSC911x doesn't need mdiobus suspend/resume, that's why it sets
'mac_managed_pm'. However, setting it needs to be moved from init to
probe, so mdiobus PM functions will really never be called (e.g. when
the interface is not up yet during suspend/resume).

Fixes: 3ce9f2bef755 ("net: smsc911x: Stop and start PHY during suspend and resume")
Suggested-by: Heiner Kallweit <hkallweit1@...il.com>
Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
---
Changes since v2:
* kept the original error handling when a PHY is not present in
  mii_probe() to avoid regressions. Because the patch is simpler now, it
  is also easier to backport.

 drivers/net/ethernet/smsc/smsc911x.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c
index 67cb5eb9c716..01aac820ac30 100644
--- a/drivers/net/ethernet/smsc/smsc911x.c
+++ b/drivers/net/ethernet/smsc/smsc911x.c
@@ -1037,8 +1037,6 @@ static int smsc911x_mii_probe(struct net_device *dev)
 		return ret;
 	}
 
-	/* Indicate that the MAC is responsible for managing PHY PM */
-	phydev->mac_managed_pm = true;
 	phy_attached_info(phydev);
 
 	phy_set_max_speed(phydev, SPEED_100);
@@ -1066,6 +1064,7 @@ static int smsc911x_mii_init(struct platform_device *pdev,
 			     struct net_device *dev)
 {
 	struct smsc911x_data *pdata = netdev_priv(dev);
+	struct phy_device *phydev;
 	int err = -ENXIO;
 
 	pdata->mii_bus = mdiobus_alloc();
@@ -1108,6 +1107,10 @@ static int smsc911x_mii_init(struct platform_device *pdev,
 		goto err_out_free_bus_2;
 	}
 
+	phydev = phy_find_first(pdata->mii_bus);
+	if (phydev)
+		phydev->mac_managed_pm = true;
+
 	return 0;
 
 err_out_free_bus_2:
-- 
2.30.2