Re: [PATCH net-next v2] net: phy: at803x: fix probe error if copper page is selected

From: David Bauer
Date: Tue Apr 20 2021 - 07:11:45 EST


Hi,

On 4/20/21 12:29 PM, Michael Walle wrote:
> The commit c329e5afb42f ("net: phy: at803x: select correct page on
> config init") selects the copper page during probe. This fails if the
> copper page was already selected. In this case, the value of the copper
> page (which is 1) is propagated through phy_restore_page() and is
> finally returned for at803x_probe(). Fix it, by just using the
> at803x_page_write() directly.

Ouch, i didn't spot that. Thanks for taking care.

>
> Also in case of an error, the regulator is not disabled and leads to a
> WARN_ON() when the probe fails. This couldn't happen before, because
> at803x_parse_dt() was the last call in at803x_probe(). It is hard to
> see, that the parse_dt() actually enables the regulator. Thus move the
> regulator_enable() to the probe function and undo it in case of an
> error.
>
> Fixes: c329e5afb42f ("net: phy: at803x: select correct page on config init")
> Signed-off-by: Michael Walle <michael@xxxxxxxx>

Reviewed-by: David Bauer <mail@xxxxxxxxxxxxxxx>

Best
David

> ---
> Changes since v1:
> - take the bus lock
>
> drivers/net/phy/at803x.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
> index e0f56850edc5..32af52dd5aed 100644
> --- a/drivers/net/phy/at803x.c
> +++ b/drivers/net/phy/at803x.c
> @@ -554,10 +554,6 @@ static int at803x_parse_dt(struct phy_device *phydev)
> phydev_err(phydev, "failed to get VDDIO regulator\n");
> return PTR_ERR(priv->vddio);
> }
> -
> - ret = regulator_enable(priv->vddio);
> - if (ret < 0)
> - return ret;
> }
>
> return 0;
> @@ -579,15 +575,30 @@ static int at803x_probe(struct phy_device *phydev)
> if (ret)
> return ret;
>
> + if (priv->vddio) {
> + ret = regulator_enable(priv->vddio);
> + if (ret < 0)
> + return ret;
> + }
> +
> /* Some bootloaders leave the fiber page selected.
> * Switch to the copper page, as otherwise we read
> * the PHY capabilities from the fiber side.
> */
> if (at803x_match_phy_id(phydev, ATH8031_PHY_ID)) {
> - ret = phy_select_page(phydev, AT803X_PAGE_COPPER);
> - ret = phy_restore_page(phydev, AT803X_PAGE_COPPER, ret);
> + phy_lock_mdio_bus(phydev);
> + ret = at803x_write_page(phydev, AT803X_PAGE_COPPER);
> + phy_unlock_mdio_bus(phydev);
> + if (ret)
> + goto err;
> }
>
> + return 0;
> +
> +err:
> + if (priv->vddio)
> + regulator_disable(priv->vddio);
> +
> return ret;
> }
>
>