Re: [PATCH] w1-gpio: add external pull-up enable callback

From: Daniel Mack
Date: Wed May 06 2009 - 05:35:01 EST


On Wed, May 06, 2009 at 12:33:07PM +0300, Ville Syrjälä wrote:
> 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.

That's right. Hence I put it where I believe it belongs to.

Thanks,
Daniel
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/