Re: [PATCH 5/5] net: make mpc5200 fec driver use of_mdio infrastructure

Anton Vorontsov
2009-03-10T19:16:57Z

On Tue, Mar 10, 2009 at 09:22:24AM -0600, Grant Likely wrote:
> From: Grant Likely <grant.likely@secretlab.ca>
[...]
> +static int mpc52xx_fec_notifier_phy_add(struct notifier_block *nb,
> + unsigned long event, void *_dev)
> +{
[...]
> + rc = phy_connect_direct(priv->ndev, priv->phydev,
> + mpc52xx_fec_adjust_link, 0, 0);
> + if (rc) {
> + dev_err(dev, "phy_connect_direct() failed\n");
> + return 0;
> + }
> +
> + rc = register_netdev(priv->ndev);
> + if (rc) {
> + phy_disconnect(priv->phydev);
> + dev_err(dev, "register_netdev() failed\n");
> + }
> +
> + return 0;
> +}
[...]
> static int __devinit
> mpc52xx_fec_probe(struct of_device *op, const struct of_device_id *match)
> @@ -896,7 +874,6 @@ mpc52xx_fec_probe(struct of_device *op, const struct of_device_id *match)
[...]
> + /* Register the new network device immediately if we don't need
> + * to wait for a phy_device first. */
> + if (!priv->phy_node) {
> + if (priv->seven_wire_mode)
> + dev_info(&ndev->dev, "using 7-wire PHY mode\n");
> + else
> + dev_info(&ndev->dev, "Fixed speed MII link: %i%cD\n",
> + priv->speed, priv->duplex ? 'F' : 'H');
> + rv = register_netdev(ndev);
> + if (rv < 0)
> + goto probe_error;
> }
[...]

Two registration points for the netdev... That's ugly. :-/

What problem are you trying to solve w/ these patches, btw?

`ifconfig ethX up` is safe even w/o PHY attached.

All the (user-visible) changes is that we no longer have "ethX"
until PHY is registered, and I can't say that this is good either.

Previously you'd have ethX all the time, and `ifconfig ethX up`
would report user-friendly "PHY not attached" error. Now we have
to guess why ethX isn't there.

I can't say that the probing code is much prettier or easier to
understand... But maybe there are some other problems that you're
solving, which I don't see so far?

That is, can you explain why the changes are needed? Did you
consider other solutions?

Thanks!

p.s.
> eliminates the assumption that the PHY for the FEC is always
> attached to the FEC's own MDIO bus. With this patch, the FEC can
> use a PHY attached to any MDIO bus if it is described in the device
> tree.

AFAIK, Gianfar and UCC Geth drivers can do this too, so I'm assuming
that this isn't the cause for these major changes.

--
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2