From: linux@armlinux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: linux-next: manual merge of the arm-soc tree with Linus' tree
Date: Tue, 6 Sep 2016 11:42:32 +0100 [thread overview]
Message-ID: <20160906104232.GT1041@n2100.armlinux.org.uk> (raw)
In-Reply-To: <7417301.9zVsJPTCb3@wuerfel>
On Tue, Sep 06, 2016 at 12:17:48PM +0200, Arnd Bergmann wrote:
> On Monday, September 5, 2016 7:26:03 PM CEST Russell King - ARM Linux wrote:
> > On Mon, Sep 05, 2016 at 10:58:03AM +1000, Stephen Rothwell wrote:
> > > I fixed it up (I deleted the file) and can carry the fix as
> > > necessary. This is now fixed as far as linux-next is concerned, but any
> > > non trivial conflicts should be mentioned to your upstream maintainer
> > > when your tree is submitted for merging. You may also want to consider
> > > cooperating with the maintainer of the conflicting tree to minimise any
> > > particularly complex conflicts.
> >
> > That's the "simple" way of making the conflict go away, but I'm afraid
> > it's really not that simple.
> >
> > Having just looked at the SMC91x definition for realview, it shows that
> > the SMC91x binding, like many of the conversions that the patch in my
> > tree fixes, has been created without a proper understanding of the
> > hardware. To put it simply, it is broken.
> >
> > The binding only allows _one_ register width to be specified, which is
> > completely incorrect: the binding _must_ allow multiple register widths
> > to be specified. This is what SMC91x has always expected: to be told
> > which register access widths it is permitted to make.
>
> This is what is documented:
>
> Documentation/devicetree/bindings/net/smsc-lan91c111.txt
> - reg-io-width : Mask of sizes (in bytes) of the IO accesses that
> are supported on the device. Valid value for SMSC LAN91c111 are
> 1, 2 or 4. If it's omitted or invalid, the size would be 2 meaning
> 16-bit access only.
>
> and this appears to match what the driver does, although it is a
> rather unconventional definition (I would have expected an array
> of widths in bytes).
It doesn't match what the driver does - have you not been following the
discussion on the breakage caused by your commit b70661c70830 ?
> Almost all of the users leave out the property, so they get 16-bit
> access, nomadik-nhk15 is the only one that actually specifies
> the width explicitly, and it also requests 16-bit only. I don't
> think your patch changes anything for these cases.
Okay, so all the DT users _only_ use 16-bit accesses, and end up
_emulating_ 8-bit accesses through a 16-bit read-modify-write
sequence, even when they may be perfectly capable of 8-bit accesses,
because this fine detail of the SMC91x driver hasn't been understood.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
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next prev parent reply other threads:[~2016-09-06 10:42 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-05 0:58 linux-next: manual merge of the arm-soc tree with Linus' tree Stephen Rothwell
2016-09-05 18:26 ` Russell King - ARM Linux
2016-09-06 10:17 ` Arnd Bergmann
2016-09-06 10:42 ` Russell King - ARM Linux [this message]
2016-09-25 16:07 ` Robert Jarzmik
-- strict thread matches above, loose matches on Subject: below --
2022-05-27 0:39 Stephen Rothwell
2022-05-27 15:38 ` Hawkins, Nick
2022-05-28 0:29 ` Stephen Rothwell
2019-06-23 22:54 Stephen Rothwell
2018-10-28 23:14 Stephen Rothwell
2018-10-29 15:02 ` Tony Lindgren
2018-10-28 23:08 Stephen Rothwell
2016-01-20 22:40 Stephen Rothwell
2015-08-23 23:55 Stephen Rothwell
2015-06-01 0:25 Stephen Rothwell
2015-06-01 7:12 ` Michal Simek
2014-01-30 0:19 Stephen Rothwell
2014-01-30 5:33 ` Kevin Hilman
2014-01-30 21:47 ` Mike Turquette
2014-01-23 0:23 Stephen Rothwell
2013-08-27 8:29 Stephen Rothwell
2013-08-27 16:17 ` Stephen Warren
2013-08-28 0:06 ` Stephen Rothwell
2013-08-27 8:26 Stephen Rothwell
2013-07-08 4:03 Stephen Rothwell
2013-03-18 3:49 Stephen Rothwell
2012-10-04 4:33 Stephen Rothwell
2012-07-30 2:53 Stephen Rothwell
2012-03-15 6:50 Stephen Rothwell
2012-03-15 9:51 ` Laurent Pinchart
2012-03-15 20:01 ` Arnd Bergmann
2012-03-15 21:36 ` Rafael J. Wysocki
2012-03-08 6:07 Stephen Rothwell
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