Subject: Re: [PATCH 2/4] of: phy: Warn about unexpected fixed-links in of_mdiobus_register

From: Andrew Lunn <[email-masked]>
Date: Mon, 20 Aug 2018 15:37:34 +0200

On Mon, Aug 20, 2018 at 02:12:36PM +0200, Ahmad Fatoum wrote:
> fixed-links are currently not handled by of_mdiobus_register,
> skip them with a warning instead of trying pointlessly to find their PHY
> address:
> 
> 	libphy: MACB_mii_bus: probed
> 	mdio_bus f0028000.ethernet-ffffffff: fixed-link has invalid PHY address
> 	mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 0
> 	[snip]
> 	mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 31
> 	macb f0028000.ethernet: broken fixed-link specification
> 
> Signed-off-by: Ahmad Fatoum <[email-masked]>
> ---
>  drivers/of/of_mdio.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
> index e92391d6d1bd..9a7ccd299daf 100644
> --- a/drivers/of/of_mdio.c
> +++ b/drivers/of/of_mdio.c
> @@ -229,6 +229,13 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
>  
>  	/* Loop over the child nodes and register a phy_device for each phy */
>  	for_each_available_child_of_node(np, child) {
> +		if (of_phy_is_fixed_link(np)) {
> +			/* fixed-links are handled in the MAC drivers */
> +			dev_warn(&mdio->dev, FW_BUG
> +				"Skipping unexpected fixed-link in device tree");

Hi Ahmad

We should be more specific than "device tree". It is actually the "mdio bus subtree".

Is this patch on its own sufficient to fix your regression? Ideally we
want one small patch which we can add to stable to fix the regression,
and then all the new functionality goes into net-next.

    Andrew