Subject: Re: [spi-devel-general] Re: question on spi_bitbang
From: Stephen Street <stephen@streetfiresound.com>
Reply-To: stephen@streetfiresound.com
To: David Brownell <david-b@pacbell.net>
Cc: Kumar Gala <galak@kernel.crashing.org>,
       spi-devel-general@lists.sourceforge.net,
       linux kernel mailing list <linux-kernel@vger.kernel.org>
In-Reply-To: <200603311011.00981.david-b@pacbell.net>
References: <1B2FA58D-1F7F-469E-956D-564947BDA59A@kernel.crashing.org>
	 <200603311011.00981.david-b@pacbell.net>
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Organization: StreetFire Sound Labs
Date: Fri, 31 Mar 2006 10:19:40 -0800
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On Fri, 2006-03-31 at 10:11 -0800, David Brownell wrote:
> I don't know how your particular hardware works, but if you have a
> real SPI controller it would probably be more natural to have your
> setup() function handle that mode register earlier, out of the main
> transfer loop ... unless that mode register is shared among all
> chipselects, in which case you'd use the setup_transfer() call for
> that, inside the transfer loop.  (That call hasn't yet been merged
> into the mainline kernel yet; it's in the MM tree.)
> 
Is setup_transfer() a change to framework API or just the bit_bang
driver?

> The chipselect() call should only affect the chipselect signal and,
> when you're activating a chip, its initial clock polarity.  Though
> if you're not using the latest from the MM tree, that's also your
> hook for ensuring that the SPI mode is set up right.
> 
Ditto?

-Stephen

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