netdev - Re: [PATCH v6 1/2] net: mdio: add ipq8064 mdio driver

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Message-ID: <20200223201916.GO25745@shell.armlinux.org.uk>
Date:   Sun, 23 Feb 2020 20:19:16 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Christian Lamparter <chunkeey@...il.com>
Cc:     Ansuel Smith <ansuelsmth@...il.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        "David S. Miller" <davem@...emloft.net>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        linux-arm-msm@...r.kernel.org, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/2] net: mdio: add ipq8064 mdio driver

On Sun, Feb 23, 2020 at 12:47:40AM +0100, Christian Lamparter wrote:
> > +static int
> > +ipq8064_mdio_read(struct mii_bus *bus, int phy_addr, int reg_offset)
> > +{
> > +	struct ipq8064_mdio *priv = bus->priv;
> > +	u32 miiaddr = MII_BUSY | MII_CLKRANGE_250_300M;
> > +	u32 ret_val;
> > +	int err;
> > +
> > +	/* Reject clause 45 */
> > +	if (reg_offset & MII_ADDR_C45)
> > +		return -EOPNOTSUPP;
> Heh, C45 on IPQ806X? Ok, anyone know the hardware or is this some fancy
> forward-thinking future-proofing?

Quite simply, the driver as written does not support C45, so it should
reject it, rather than truncating the "reg_offset" and issuing C22
cycles instead.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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