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From: David Brownell <david-b@pacbell.net>
To: Vitaly Wool <vwool@ru.mvista.com>
Cc: linux-kernel@vger.kernel.org, spi-devel-general@sourceforge.net
Subject: Re: [PATCH 2.6-git] SPI: add set_clock() to bitbang
Date: Thu, 22 Dec 2005 13:37:39 -0800	[thread overview]
Message-ID: <200512221337.39305.david-b@pacbell.net> (raw)
In-Reply-To: <43AB1958.1070407@ru.mvista.com>


> >This is actually not needed.  Clocks are set through the setup() method
> ...
>
> Where is it supposed to call setup? I guess it's anyway gonna be 
> per-transfer, right?
> Or am I missing something?

When the device is created, the core calls setup() to get things like
chipselect polarity sorted out and put into the inactive state.   That
matches the board-specific defaults associated with that device, which
would be a function of voltage, routing, and more.

And from then on, it'd be rare to ever call setup() again ... though
drivers certainly could do that between spi_message interactions with
a given device.

- Dave

  reply	other threads:[~2005-12-22 21:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-22 15:04 [PATCH 2.6-git] SPI: add set_clock() to bitbang Vitaly Wool
2005-12-22 16:40 ` David Brownell
2005-12-22 21:23   ` Vitaly Wool
2005-12-22 21:37     ` David Brownell [this message]
2005-12-22 21:42       ` Vitaly Wool
2005-12-23  0:37         ` David Brownell
2005-12-23  7:08           ` Vitaly Wool
2005-12-23  8:28             ` David Brownell
2005-12-23  8:38               ` Vitaly Wool

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