[PATCH net v2 2/2] smsc911x: avoid PHY being resumed when interface is not up

From: Wolfram Sang
Date: Mon Mar 20 2023 - 05:22:02 EST


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). The errno is changed
because ENODEV has a special meaning when returned in probe().

Fixes: 3ce9f2bef755 ("net: smsc911x: Stop and start PHY during suspend and resume")
Suggested-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
* no change

In smsc911x_mii_probe(), I remove the sanity check for 'phydev' because
it was already done in smsc911x_mii_init(). Let me know if this is
acceptable or if a more defensive approach is favoured.


drivers/net/ethernet/smsc/smsc911x.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c
index 67cb5eb9c716..8b875bbbc05e 100644
--- a/drivers/net/ethernet/smsc/smsc911x.c
+++ b/drivers/net/ethernet/smsc/smsc911x.c
@@ -1019,12 +1019,7 @@ static int smsc911x_mii_probe(struct net_device *dev)
struct phy_device *phydev = NULL;
int ret;

- /* find the first phy */
phydev = phy_find_first(pdata->mii_bus);
- if (!phydev) {
- netdev_err(dev, "no PHY found\n");
- return -ENODEV;
- }

SMSC_TRACE(pdata, probe, "PHY: addr %d, phy_id 0x%08X",
phydev->mdio.addr, phydev->phy_id);
@@ -1037,8 +1032,6 @@ 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 +1059,7 @@ 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 +1102,15 @@ static int smsc911x_mii_init(struct platform_device *pdev,
goto err_out_free_bus_2;
}

+ phydev = phy_find_first(pdata->mii_bus);
+ if (!phydev) {
+ netdev_err(dev, "no PHY found\n");
+ err = -ENOENT;
+ goto err_out_free_bus_2;
+ }
+
+ phydev->mac_managed_pm = true;
+
return 0;

err_out_free_bus_2:
--
2.30.2