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Date:   Tue, 18 Jul 2023 18:52:12 +0100
From:   "Russell King (Oracle)" <linux@armlinux.org.uk>
To:     Andrew Lunn <andrew@lunn.ch>
Cc:     Michael Walle <mwalle@kernel.org>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Yisen Zhuang <yisen.zhuang@huawei.com>,
        Salil Mehta <salil.mehta@huawei.com>,
        Florian Fainelli <florian.fainelli@broadcom.com>,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@broadcom.com>,
        Marek =?iso-8859-1?Q?Beh=FAn?= <kabel@kernel.org>,
        Xu Liang <lxu@maxlinear.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Simon Horman <simon.horman@corigine.com>
Subject: Re: [PATCH net-next v3 03/11] net: phy: replace is_c45 with
 phy_accces_mode
Message-ID: <ZLbRTLRbHW/Xt2hL@shell.armlinux.org.uk>
References: <20230620-feature-c45-over-c22-v3-0-9eb37edf7be0@kernel.org>
 <20230620-feature-c45-over-c22-v3-3-9eb37edf7be0@kernel.org>
 <509889a3-f633-40b0-8349-9ef378818cc7@lunn.ch>
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Sender: Russell King (Oracle) <linux@armlinux.org.uk>
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On Tue, Jul 18, 2023 at 07:40:49PM +0200, Andrew Lunn wrote:
> >  static inline bool phy_has_c45_registers(struct phy_device *phydev)
> >  {
> > -	return phydev->is_c45;
> > +	return phydev->access_mode != PHY_ACCESS_C22;
> >  }
> 
> So this is making me wounder if we have a clean separation between
> register spaces and access methods.
> 
> Should there be a phy_has_c22_registers() ?

Yes, I've been wondering that. I've recently heard about a Realtek PHY
which is supported by our realtek driver, but appears on a SFP that
can only do C45 accesses. However, the realtek driver is written to
use C22 accesses to this PHY - and the PHY supports both. So currently
it doesn't work.

That's just an additional data point for thinking about this, I haven't
formulated a solution to it yet.

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