Am 18.02.2015 um 21:19 schrieb Martin Rapavy:
> I was exactly in favor of avoiding w1 because of bus polling. It is
> important for me not to use the bus frequently (the wire is also
> shared for reading out data from sensors). Do you think that the w1
> polling might be turned off using w1_master_search (w1 sysfs
> interface)?
>
That's exactly the purpose of this node. OWFS sends an explicit search
command through the netlink socket to the w1 driver at
module/owlib/src/c/ow_w1.c, line 112ff
so turning off w1_master_search only affects other services which rely
on it. BUT: depending on your hardware, hot-plugging a battery may
already rely on this! It's a bit of a pity this is a global flag and
cannot be turned off by bus. Check your hardware whether it has other
services on another onewire.
Second pitfall: if your hardware has several buses, the w1 driver will
all join them into one.
Nevertheless, patching the DS1WM w1 driver may be sufficient and easy
enough.
>> Option B -------- Write a fake I²C host adaptor kernel driver which
>> creates a new "I²C bus", with your onewire host adaptor the only
>> device "connected" to that "bus. This may be the easiest option if
>> your device behaves very much like the original DS2482. OWFS drops
>> in neatly, no strings attached.
>
> I like this approach but I guess I should have been more clear on
> similarity with DS2482 -- it is conceptually similar (hardware based
> multichannel bus master chip) but the interface is different. The
> interface of that custom chip closely matches DS1WM.
>
Then this is *not* the way to go.
>> Option C -------- Memory-mapped IO from userspace, which is *UGH!*.
>> See module/owlib/src/c/ow/ow_ds2482.c for all the things to write
>> and change. The disadvantage is owfs has to run as root to do
>> MMIO.
> I don't mind running under root. I suppose this is the only feasible
> option if I don't want to use Linux w1. I will have a look into that
> source.
>
Well, if you don't show it to anyone... (^__^);
Kind regards
Jan
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