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From: "Ville Syrjälä" <syrjala@sci.fi>
To: Daniel Mack <daniel@caiaq.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] w1-gpio: add external pull-up enable callback
Date: Wed, 6 May 2009 12:33:07 +0300	[thread overview]
Message-ID: <20090506093307.GC17782@sci.fi> (raw)
In-Reply-To: <1241527413-22920-1-git-send-email-daniel@caiaq.de>

On Tue, May 05, 2009 at 02:43:33PM +0200, Daniel Mack wrote:
> On embedded devices, sleep mode conditions can be tricky to handle,
> Especially when processors tend to pull-down the w1 bus during sleep.
> Bus slaves (such as the ds2760) may interpret this as a reason for
> power-down conditions and entirely switch off the device.
> 
> This patch adds a callback function pointer to let users switch on and
> off the external pull-up resistor. This lets the outside world know
> whether the processor is currently actively driving the bus or not.

Looks simple enough but I wonder if you could just do this from the
platform code. I suppose the downside would be that you would enable the
pullup even if w1-gpio is not loaded.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

  reply	other threads:[~2009-05-06  9:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-05 12:43 [PATCH] w1-gpio: add external pull-up enable callback Daniel Mack
2009-05-06  9:33 ` Ville Syrjälä [this message]
2009-05-06  9:34   ` Daniel Mack
2009-05-06 20:28     ` Ville Syrjälä
2009-05-07  1:30       ` Daniel Mack
2009-05-08 18:19         ` Ville Syrjälä
2009-05-08 20:13 ` Daniel Mack
2009-05-08 20:53   ` Evgeniy Polyakov
2009-05-12 13:56 ` Daniel Mack

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