Re: [PATCH][W1]w1_therm: release the bus during conversion onexternally powered devices
From: Evgeniy Polyakov
Date: Thu Nov 17 2011 - 08:41:41 EST
+gregkh
On Wed, Nov 16, 2011 at 12:43:16AM +0100, Maciej Szmigiero (mhej@xxxxx) wrote:
> w1_therm devices can either be bus powered or externally powered.
>
> When device is bus powered during temperature conversion the bus
> have to be left high to provide necessary power. Some masters also allow
> strong power-up to be enabled in this case.
> Naturally, no communication over bus can occur during that time.
>
> However, if device has external power then there is no such restriction,
> and host can talk to other devices during temperature conversion.
>
> There is command which allows us to check how device is powered,
> this patch uses it to release the bus on externally w1_therm powered devices
> during temperature conversion.
>
> Also, this changes uninterruptible sleeps there into interruptible ones to
> avoid long uninterruptible sleep if w1 subsystem happens to grab bus for
> scan during w1_therm_read().
Patch looks good, but I do not have such hardware to test it.
So, if it doesn't break things I'm ok to push it upstream.
Greg, please pull it into your tree, thank you.
> Signed-off-by: Maciej Szmigiero <mhej@xxxxx>
Acked-by: Evgeniy Polyakov <zbr@xxxxxxxxxxx>
--
Evgeniy Polyakov
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