Re: [PATCH v2] net: ethernet: support "fixed-link" DT key/node on nb8800 driver

[Sebastian Frias]

On 02/05/2016 02:58 PM, Måns Rullgård wrote:
> Sebastian Frias <sf84@xxxxxxxxxxx> writes:
>
> > Signed-off-by: Sebastian Frias <sf84@xxxxxxxxxxx>
> > ---
> >   drivers/net/ethernet/aurora/nb8800.c | 15 ++++++++++++---
> >   1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/aurora/nb8800.c
> > b/drivers/net/ethernet/aurora/nb8800.c
> > index ecc4a33..dd7bedc 100644
> > --- a/drivers/net/ethernet/aurora/nb8800.c
> > +++ b/drivers/net/ethernet/aurora/nb8800.c
> > @@ -1462,9 +1462,18 @@ static int nb8800_probe(struct platform_device *pdev)
> >
> >   	priv->phy_node = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
> >   	if (!priv->phy_node) {
> > -		dev_err(&pdev->dev, "no PHY specified\n");
> > -		ret = -ENODEV;
> > -		goto err_free_bus;
> > +		if (of_phy_is_fixed_link(pdev->dev.of_node)) {
> > +			ret = of_phy_register_fixed_link(pdev->dev.of_node);
> > +			if (ret < 0) {
> > +				dev_err(&pdev->dev, "bad fixed-link spec\n");
> > +				goto err_free_bus;
> > +			}
> > +			priv->phy_node = of_node_get(pdev->dev.of_node);
> > +		} else {
> > +			dev_err(&pdev->dev, "no PHY specified\n");
> > +			ret = -ENODEV;
> > +			goto err_free_bus;
> > +		}
> >   	}
>
> Maybe it would be clearer to reduce the if() nesting a bit, like this
> for instance:
>
> 	if (of_phy_is_fixed_link(pdev->dev.of_node)) {
> 		ret = of_phy_register_fixed_link(pdev->dev.of_node);
> 		if (ret < 0) {
> 			dev_err(&pdev->dev, "bad fixed-link spec\n");
> 			goto err_free_bus;
> 		}
> 		priv->phy_node = of_node_get(pdev->dev.of_node);
> 	}
>
> 	if (!priv->phy_node)
> 		priv->phy_node = of_parse_phandle(pdev->dev.of_node,
> 						  "phy-handle", 0);
>
> 	if (!priv->phy_node) {
> 		dev_err(&pdev->dev, "no PHY specified\n");
> 		ret = -ENODEV;
> 		goto err_free_bus;
> 	}

Thanks Måns for your comments.
With old code + my patch, we only hit 1 comparison in the general case, 
and a 2nd one in "fixed-link" case.
With your suggestion above, it would mean that we hit 3 comparisons all 
the time.
If you are ok with the 3 comparisons, I can post a v3.