phylink: Improve error message when validate failed

This should improve the error message when the PHY validate in the MAC
driver failed. I ran into this problem multiple times that I put wrong
interface values into the device tree and was searching why it is
failing with -22 (-EINVAL). This should make it easier to spot the
problem.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---
 drivers/net/phy/phylink.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

On Mon, Mar 02, 2020 at 12:55:02AM +0100, Hauke Mehrtens wrote:
> This should improve the error message when the PHY validate in the MAC
> driver failed. I ran into this problem multiple times that I put wrong
> interface values into the device tree and was searching why it is
> failing with -22 (-EINVAL). This should make it easier to spot the
> problem.

Hi,

This will do as a stop-gap measure to make debugging of that easier,
but in the longer run I want MAC drivers to provide phylink with a
bitmap of the PHY_INTERFACE_MODE_*s they support.

So,

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>

Thanks.

> 
> Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
> ---
>  drivers/net/phy/phylink.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index b4367fab7899..5347275215be 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -797,8 +797,14 @@ static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
>  		config.interface = interface;
>  
>  	ret = phylink_validate(pl, supported, &config);
> -	if (ret)
> +	if (ret) {
> +		phylink_warn(pl, "validation of %s with support %*pb and advertisement %*pb failed: %d\n",
> +			     phy_modes(config.interface),
> +			     __ETHTOOL_LINK_MODE_MASK_NBITS, phy->supported,
> +			     __ETHTOOL_LINK_MODE_MASK_NBITS, config.advertising,
> +			     ret);
>  		return ret;
> +	}
>  
>  	phy->phylink = pl;
>  	phy->phy_link_change = phylink_phy_change;
> -- 
> 2.20.1
> 
>

From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Mon,  2 Mar 2020 00:55:02 +0100

> This should improve the error message when the PHY validate in the MAC
> driver failed. I ran into this problem multiple times that I put wrong
> interface values into the device tree and was searching why it is
> failing with -22 (-EINVAL). This should make it easier to spot the
> problem.
> 
> Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

Applied, thank you.