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Date:   Wed, 23 Mar 2022 20:39:48 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Michael Walle <michael@walle.cc>
Cc:     Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "David S . Miller" <davem@davemloft.net>,
        Xu Liang <lxu@maxlinear.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC net-next 2/5] net: phy: support indirect c45 access
 in get_phy_c45_ids()
Message-ID: <Yjt3hHWt0mW6er8/@lunn.ch>
References: <20220323183419.2278676-1-michael@walle.cc>
 <20220323183419.2278676-3-michael@walle.cc>
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> +static int mdiobus_probe_mmd_read(struct mii_bus *bus, int prtad, int devad,
> +				  u16 regnum)
> +{
> +	int ret;
> +
> +	/* For backwards compatibility, treat MDIOBUS_NO_CAP as c45 capable */
> +	if (bus->probe_capabilities == MDIOBUS_NO_CAP ||
> +	    bus->probe_capabilities >= MDIOBUS_C45)

Maybe we should do the work and mark up those that are C45 capable. At
a quick count, see 16 of them.

> +		return mdiobus_c45_read(bus, prtad, devad, regnum);
> +
> +	mutex_lock(&bus->mdio_lock);
> +
> +	/* Write the desired MMD Devad */
> +	ret = __mdiobus_write(bus, prtad, MII_MMD_CTRL, devad);
> +	if (ret)
> +		goto out;
> +
> +	/* Write the desired MMD register address */
> +	ret = __mdiobus_write(bus, prtad, MII_MMD_DATA, regnum);
> +	if (ret)
> +		goto out;
> +
> +	/* Select the Function : DATA with no post increment */
> +	ret = __mdiobus_write(bus, prtad, MII_MMD_CTRL,
> +			      devad | MII_MMD_CTRL_NOINCR);
> +	if (ret)
> +		goto out;

Make mmd_phy_indirect() usable, rather then repeat it.

     Andrew