netdev - Re: [PATCH net-next v1 2/4] net: phy: micrel: add EEE configuration support for KSZ9477 variants of PHYs

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Date:   Fri, 20 Jan 2023 06:50:40 +0100
From:   Oleksij Rempel <o.rempel@...gutronix.de>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Woojung Huh <woojung.huh@...rochip.com>,
        Arun.Ramadoss@...rochip.com,
        Florian Fainelli <f.fainelli@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Vivien Didelot <vivien.didelot@...il.com>,
        UNGLinuxDriver@...rochip.com, Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>, kernel@...gutronix.de,
        Jakub Kicinski <kuba@...nel.org>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH net-next v1 2/4] net: phy: micrel: add EEE configuration
 support for KSZ9477 variants of PHYs

On Thu, Jan 19, 2023 at 03:08:59PM +0100, Andrew Lunn wrote:
> > +static int ksz9477_get_eee_caps(struct phy_device *phydev,
> > +				struct ethtool_eee *data)
> > +{
> > +	int val;
> > +
> > +	/* At least on KSZ8563 (which has same PHY_ID as KSZ9477), the
> > +	 * MDIO_PCS_EEE_ABLE register is a mirror of MDIO_AN_EEE_ADV register.
> > +	 * So, we need to provide this information by driver.
> > +	 */
> > +	data->supported = SUPPORTED_100baseT_Full;
> > +
> > +	/* KSZ8563 is able to advertise not supported MDIO_EEE_1000T.
> > +	 * We need to test if the PHY is 1Gbit capable.
> > +	 */
> > +	val = phy_read(phydev, MII_BMSR);
> > +	if (val < 0)
> > +		return val;
> > +
> > +	if (val & BMSR_ERCAP)
> > +		data->supported |= SUPPORTED_1000baseT_Full;
> 
> This works, but you could also look at phydev->supported and see if
> one of the 1G modes is listed. That should be faster, since there is
> no MDIO transaction involved. Not that this is on any sort of hot
> path.

ack. Sounds good.

Regards,
Oleksij
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