Re: [PATCH net-next] net: phy: at803x: Use devm_regulator_get_enable_optional()

[Simon Horman]

+ Johan and Wolfram

On Tue, Jun 20, 2023 at 07:45:24PM +0200, Christophe JAILLET wrote:
> Le 17/06/2023 à 16:24, Christophe JAILLET a écrit :
> > Use devm_regulator_get_enable_optional() instead of hand writing it. It
> > saves some line of code.
> > 
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> > Compile tested-only.
> > 
> > If my reading is correct, regulator_disable() is still called in the same
> > order, should an error occur or the driver be removed.
> > ---
> >   drivers/net/phy/at803x.c | 44 +++++++---------------------------------
> >   1 file changed, 7 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
> > index 656136628ffd..c1f307d90518 100644
> > --- a/drivers/net/phy/at803x.c
> > +++ b/drivers/net/phy/at803x.c
> > @@ -304,7 +304,6 @@ struct at803x_priv {
> >   	bool is_1000basex;
> >   	struct regulator_dev *vddio_rdev;
> >   	struct regulator_dev *vddh_rdev;
> > -	struct regulator *vddio;
> >   	u64 stats[ARRAY_SIZE(at803x_hw_stats)];
> >   };
> > @@ -824,11 +823,11 @@ static int at803x_parse_dt(struct phy_device *phydev)
> >   		if (ret < 0)
> >   			return ret;
> > -		priv->vddio = devm_regulator_get_optional(&phydev->mdio.dev,
> > -							  "vddio");
> > -		if (IS_ERR(priv->vddio)) {
> 
> Hi,
> 
> my patch is not broken by itself, but the existing code looks spurious.
> 
> If the optional regulator is not found, then -ENODEV is returned,
> at803x_parse_dt() will return this error and the probe will fail.
> 
> It looks that the test should be more subtle.
> 
> I can send a follow up patch, unless there is a better way to fix the
> pre-existing issue.
> 
> See [1] for a more detailed explanation.
> 
> CJ
> 
> [1]: https://lore.kernel.org/all/ZJFqCQ8bbBoX3l1g@xxxxxxxxxxxxxxxxxxxx/

My understanding is that this patch cleans things up (good)
and retains some dubious behaviour (not making it worse or better).

Meanwhile, a solution to the dubious behaviour was discussed in
the context of [1] and moreover a patch linked from there and associated
solution from Wolfram.

If so. I guess we can either:

1) Move forwards with this patch and
   then follow-up with the preferred solution for the dubious behaviour,
   once that solution is decided upon and available.
2) Skip this patch and follow-up later.

FWIIW, either seems fine to me.

> > +		ret = devm_regulator_get_enable_optional(&phydev->mdio.dev,
> > +							 "vddio");
> > +		if (ret) {
> >   			phydev_err(phydev, "failed to get VDDIO regulator\n");
> > -			return PTR_ERR(priv->vddio);
> > +			return ret;
> >   		}
> >   		/* Only AR8031/8033 support 1000Base-X for SFP modules */
> > @@ -856,12 +855,6 @@ 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;
> > -	}
> > -
> >   	if (phydev->drv->phy_id == ATH8031_PHY_ID) {
> >   		int ccr = phy_read(phydev, AT803X_REG_CHIP_CONFIG);
> >   		int mode_cfg;
> > @@ -869,10 +862,8 @@ static int at803x_probe(struct phy_device *phydev)
> >   			.wolopts = 0,
> >   		};
> > -		if (ccr < 0) {
> > -			ret = ccr;
> > -			goto err;
> > -		}
> > +		if (ccr < 0)
> > +			return ccr;
> >   		mode_cfg = ccr & AT803X_MODE_CFG_MASK;
> >   		switch (mode_cfg) {
> > @@ -890,25 +881,11 @@ static int at803x_probe(struct phy_device *phydev)
> >   		ret = at803x_set_wol(phydev, &wol);
> >   		if (ret < 0) {
> >   			phydev_err(phydev, "failed to disable WOL on probe: %d\n", ret);
> > -			goto err;
> > +			return ret;
> >   		}
> >   	}
> >   	return 0;
> > -
> > -err:
> > -	if (priv->vddio)
> > -		regulator_disable(priv->vddio);
> > -
> > -	return ret;
> > -}
> > -
> > -static void at803x_remove(struct phy_device *phydev)
> > -{
> > -	struct at803x_priv *priv = phydev->priv;
> > -
> > -	if (priv->vddio)
> > -		regulator_disable(priv->vddio);
> >   }
> >   static int at803x_get_features(struct phy_device *phydev)
> > @@ -2021,7 +1998,6 @@ static struct phy_driver at803x_driver[] = {
> >   	.name			= "Qualcomm Atheros AR8035",
> >   	.flags			= PHY_POLL_CABLE_TEST,
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.config_aneg		= at803x_config_aneg,
> >   	.config_init		= at803x_config_init,
> >   	.soft_reset		= genphy_soft_reset,
> > @@ -2043,7 +2019,6 @@ static struct phy_driver at803x_driver[] = {
> >   	.name			= "Qualcomm Atheros AR8030",
> >   	.phy_id_mask		= AT8030_PHY_ID_MASK,
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.config_init		= at803x_config_init,
> >   	.link_change_notify	= at803x_link_change_notify,
> >   	.set_wol		= at803x_set_wol,
> > @@ -2059,7 +2034,6 @@ static struct phy_driver at803x_driver[] = {
> >   	.name			= "Qualcomm Atheros AR8031/AR8033",
> >   	.flags			= PHY_POLL_CABLE_TEST,
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.config_init		= at803x_config_init,
> >   	.config_aneg		= at803x_config_aneg,
> >   	.soft_reset		= genphy_soft_reset,
> > @@ -2082,7 +2056,6 @@ static struct phy_driver at803x_driver[] = {
> >   	PHY_ID_MATCH_EXACT(ATH8032_PHY_ID),
> >   	.name			= "Qualcomm Atheros AR8032",
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.flags			= PHY_POLL_CABLE_TEST,
> >   	.config_init		= at803x_config_init,
> >   	.link_change_notify	= at803x_link_change_notify,
> > @@ -2100,7 +2073,6 @@ static struct phy_driver at803x_driver[] = {
> >   	PHY_ID_MATCH_EXACT(ATH9331_PHY_ID),
> >   	.name			= "Qualcomm Atheros AR9331 built-in PHY",
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.suspend		= at803x_suspend,
> >   	.resume			= at803x_resume,
> >   	.flags			= PHY_POLL_CABLE_TEST,
> > @@ -2117,7 +2089,6 @@ static struct phy_driver at803x_driver[] = {
> >   	PHY_ID_MATCH_EXACT(QCA9561_PHY_ID),
> >   	.name			= "Qualcomm Atheros QCA9561 built-in PHY",
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.suspend		= at803x_suspend,
> >   	.resume			= at803x_resume,
> >   	.flags			= PHY_POLL_CABLE_TEST,
> > @@ -2183,7 +2154,6 @@ static struct phy_driver at803x_driver[] = {
> >   	.name			= "Qualcomm QCA8081",
> >   	.flags			= PHY_POLL_CABLE_TEST,
> >   	.probe			= at803x_probe,
> > -	.remove			= at803x_remove,
> >   	.config_intr		= at803x_config_intr,
> >   	.handle_interrupt	= at803x_handle_interrupt,
> >   	.get_tunable		= at803x_get_tunable,
> 
>