Re: [PATCH v1] net: ag71xx: fix mdio subnode support

From: Andrew Lunn
Date: Mon Sep 30 2019 - 12:26:06 EST


On Mon, Sep 30, 2019 at 04:29:07PM +0200, Oleksij Rempel wrote:
> On Mon, Sep 30, 2019 at 03:42:09PM +0200, Andrew Lunn wrote:
> > On Mon, Sep 30, 2019 at 11:33:10AM +0200, Oleksij Rempel wrote:
> > > The driver was working with fixed phy without any noticeable issues. This bug
> > > was uncovered by introducing dsa ar9331-switch driver.
> > >
> > > Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> > > ---
> > > drivers/net/ethernet/atheros/ag71xx.c | 6 ++++--
> > > 1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/atheros/ag71xx.c b/drivers/net/ethernet/atheros/ag71xx.c
> > > index 6703960c7cf5..d1101eea15c2 100644
> > > --- a/drivers/net/ethernet/atheros/ag71xx.c
> > > +++ b/drivers/net/ethernet/atheros/ag71xx.c
> > > @@ -526,7 +526,7 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
> > > struct device *dev = &ag->pdev->dev;
> > > struct net_device *ndev = ag->ndev;
> > > static struct mii_bus *mii_bus;
> > > - struct device_node *np;
> > > + struct device_node *np, *mnp;
> > > int err;
> > >
> > > np = dev->of_node;
> > > @@ -571,7 +571,9 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
> > > msleep(200);
> > > }
> > >
> > > - err = of_mdiobus_register(mii_bus, np);
> > > + mnp = of_get_child_by_name(np, "mdio");
> > > + err = of_mdiobus_register(mii_bus, mnp);
> > > + of_node_put(mnp);
> > > if (err)
> > > goto mdio_err_put_clk;
> >
> > Hi Oleksij
> >
> > You need to keep backwards compatibility here. If you find an mdio
> > node, use it, but if not, you need to still register np.
> >
> > This is also extending the driver binding, so you need to update the
> > binding documentation.
>
> Hi Andrew,
>
> Normally i would agree. But in this case:
> - this driver is freshly added to the kernel and is different to OpenWrt
> implementation any way. No users from this side.
> - Devicetree binding says:
> Documentation/devicetree/bindings/net/qca,ar71xx.txt
> |Optional properties:
> |- phy-handle : phandle to the PHY device connected to this device.
> |- fixed-link : Assume a fixed link. See fixed-link.txt in the same directory.
> | Use instead of phy-handle.
> |
> |Optional subnodes:
> |- mdio : specifies the mdio bus, used as a container for phy nodes
> | according to phy.txt in the same directory
>
> So, it is driver bug ...ooOO (my personal bug :D)

Hi Oleksij

Ah, O.K. You should of explained that in the commit message.

Is the mdio support just in -rc, or is it older?

You need to add a Fixes: tag.

The patch subject should be [PATCH net] to indicate this is a fix to
the net tree

The patch should be against net, not next-next.

Andrew