netdev - Re: [PATCH RFC 0/7] Clean up PHY MMD accessors

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Message-ID: <20170119195819.GJ27312@n2100.armlinux.org.uk>
Date:   Thu, 19 Jan 2017 19:58:19 +0000
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-usb@...r.kernel.org,
        Microchip Linux Driver Support <UNGLinuxDriver@...rochip.com>,
        netdev@...r.kernel.org, Woojung Huh <woojung.huh@...rochip.com>
Subject: Re: [PATCH RFC 0/7] Clean up PHY MMD accessors

On Thu, Jan 19, 2017 at 11:42:47AM -0800, Florian Fainelli wrote:
> On 01/13/2017 07:20 AM, Russell King - ARM Linux wrote:
> > This series cleans up phylib's MMD accessors, so that we have a common
> > way of accessing the Clause 45 register set.
> > 
> > The current situation is far from ideal - we have phy_(read|write)_mmd()
> > which accesses Clause 45 registers over Clause 45 accesses, and we have
> > phy_(read|write)_mmd_indirect(), which accesses Clause 45 registers via
> > Clause 22 register 13/14.
> > 
> > Generic code uses the indirect methods to access standard Clause 45
> > features, and when we come to add Clause 45 PHY support to phylib, we
> > would need to make these conditional upon the PHY type, or duplicate
> > these functions.
> > 
> > An alternative solution is to merge these accessors together, and select
> > the appropriate access method depending upon the 802.3 clause that the
> > PHY conforms with.  The result is that we have a single set of
> > phy_(read|write)_mmd() accessors.
> > 
> > For cases which require special handling, we still allow PHY drivers to
> > override all MMD accesses - except rather than just overriding the
> > indirect accesses.  This keeps existing overrides working.
> > 
> > Combining the two also has another beneficial side effect - we get rid
> > of similar functions that take arguments in different orders.  The
> > old direct accessors took the phy structure, devad and register number,
> > whereas the indirect accessors took the phy structure, register number
> > and devad in that order.  Care must be taken when updating future
> > drivers that the argument order is correct, and the function name is
> > not merely replaced.
> 
> I really like that series, this is much much cleaner, do you mind
> resubmitting this without a RFC tag so David can apply it?

Hi Florian,

Thanks.

Will do in the next couple of days - I'd prefer to make one change
to the series before submitting it for real: provide compatibility
functions marked as deprecated so this doesn't create a flag day.
We can remove the deprecated _indirect functions later when we know
there's no new users.

I'd like to get the phy.h untanglement stuff into David's tree first.
I'm almost there, my allmodconfig from last night almost built fine
but for something I missed in bgmac.c, and 0-day found a MIPS file
affected by the change.  New code pushed out for 0-day and I'm
expecting tonights allmodconfig to be clear.

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