Am Montag, 13. März 2006 17:11 schrieb Evgeniy Polyakov:
> Hello.
>
> On Wed, Mar 08, 2006 at 12:18:33AM -0500, Paul Alfille
([EMAIL PROTECTED]) wrote:
> > Just a progress report:
> >
> > After extensive discussions with Evgeniy Polyakov, it looks like OWFS
> > will be able to use the linux kernel 1-wire drivers as a possible 1-wire
> > adapter source.
>
> ...
>
> Found mail archive with this discussion. I'm not subscribed so please
> Cc: me on replies.
>
> Couple of notes after archive reading:
>
> 1. w1 supports on-demans searching in the following way:
> search is performed on $w1_timeout interval basis, which is provided as
> module parameter. By manipulating w1_master_search sysfs file one can
> trigger to search or not on next $w1_timeout interval.
>
Ok. That would mean I could set $w1_timeout to e.g. 0s and disable it by
default. Whenever I want to search, I'll enable the sysfs file, then disable
again immediately. Right?
Searching onewire is a very time-consuming operation, that's why I like to
have it disabled or controlled by the application program. Otherwise we'll
get into naughty situation-dependent timing issues.
> 2. I plan to create demo code for netlink socket communication interface
> for w1 this week. This will completely eliminate any kind of races with
> multiple workers/reset and so on.
>
Fine. Thank you.
> 3. w1 has it's advantages due to it's in-kernel place:
> * some processors (Freescale made) have w1 units which can not be
> accessed
> from userspace without in-kernel driver
>
Ok. Useful in any case.
> * GPIO pins can not be accessed from userspace without in-kernel
> driver (actually there is [1] generic GPIO framwork with w1
> driver tested with pc3487x and natsemi sc1100, but work was
> frozen
> due to lack of hardware)
>
I'm in doubt this is really useful - if the onewire protocol is done
completely in software, things would slow down a lot. It does not add too
much cost to add a DS2482 on the board, as I2C is available most of the time.
Ok, for a few onboard temperature sensors, this will be the best idea. No
discussion needed.
> * w1 supports asynchronous notifications of new devices found,
> which are multicasted for any process over netlink
> socket interface.
>
How is it with the alarm state? Is asynchrous notification planned here, too?
Kind regards
Jan Kandziora
--
You cannot kill time without injuring eternity.
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