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Date: Tue, 19 Apr 2016 16:26:29 +0100
From: Ruslan Bukin <ruslan.bukin@cl.cam.ac.uk>
To: Ian Lepore <ian@freebsd.org>
Cc: Ruslan Bukin <br@FreeBSD.org>, src-committers@freebsd.org,
 svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject: Re: svn commit: r298268 - head/sys/dev/spibus
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On Tue, Apr 19, 2016 at 08:41:39AM -0600, Ian Lepore wrote:
> On Tue, 2016-04-19 at 14:18 +0000, Ruslan Bukin wrote:
> > Author: br
> > Date: Tue Apr 19 14:18:12 2016
> > New Revision: 298268
> > URL: https://svnweb.freebsd.org/changeset/base/298268
> > 
> > Log:
> >   Add optional chip_select/deselect methods. This is required
> >   when we want to keep CS asserted for multiple transfers.
> > 
> 
> This is missing a now-required mechanism to arbitrate ownership of the
> bus.  If a leaf driver can take over the bus for longer than a single
> transfer, then it needs the same kind of logic as the iicbus uses
> (well, conceptually the same, it doesn't need the same horrible
> implementation).
> 
> I also don't see any default implementation of the new methods, or a
> commit that adds the new functionality to all existing SPI controller
> drivers.
> 

Thanks, Ian.
I just realized we don't require to hold CS for multiple transfers
in our hardware. So I reverted this.

Ruslan