linux-kernel - Re: Regmap and register ranges

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Message-ID: <20130518112353.GR1627@sirena.org.uk>
Date:	Sat, 18 May 2013 12:23:53 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Regmap and register ranges

On Fri, May 17, 2013 at 02:52:46PM -0700, Dmitry Torokhov wrote:
> On Fri, May 17, 2013 at 09:50:25PM +0100, Mark Brown wrote:

> > The general idea is that the pages should be mapped in to virtual
> > addresses rather than real ones so in your example you might add a
> > prefix so all the registers are numbered 0x10000 to 0x1ffff.  The
> > physical registers and the ones inside the paged range aren't supposed
> > to overlap.

> The issue I have with doing an arbitrary offset is that then data
> exposed in debugfs does not match the data from device's specification.

Adding a random prefix on the front does mean you can just ignore the
prefix.  But this seems a fairly odd way for the device to do things to
be honest...  paging every single register is a bit random.

> > We should probably either do sanity checks for this at init time or come
> > up with a sensible way to support this in case someone does decide to do
> > it, though this is the first time anyone noticed.

> Does this mean you'll be open to patches allowing this scenario?

Obviously I'm always open to patches that aren't crazy, though I do
reserve the right to define what's crazy :)

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