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Subject: Re: [PATCH v10 0/7] Add Fieldbus subsystem + support HMS Profinet
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To:     Sven Van Asbroeck <thesven73@gmail.com>
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From:   "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Organization: metux IT consult
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Date:   Tue, 16 Apr 2019 18:49:35 +0200
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On 15.04.19 20:31, Sven Van Asbroeck wrote:

Hi,

>> Maybe it would be better calling it "IEC-61158" instead of "fieldbus" ?>>> > Yes, we are certainly open to that, if it is more correct and/or
better> accepted by users.
Thanks, I'd really appreciate that :)

Maybe I'm a bit beaurocratic here, but I really believe that precise
naming is important, eg. for avoiding potential conflicts w/ different
fieldbus classes (eg. mvb) that might come in the future.

> Yes. You can open as many handles to the device as you like,
> they will all share the fieldbus memory. When the remote
> fieldbus memory changes, that event will be broadcast to
> all open handles, via poll/select.

Great. When I read your first mail, I got reminded on the old legacy
canbus chardevs (before cansocket came in) that was single-user only.

By the way: any special reason for doing this via device instead of
socket (like we have w/ can) ?

I'm, personally, pretty undecided which way is better. Device nodes give
us easy access control via fs permissions, while socket allows
firewalling.


--mtx

-- 
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@metux.net -- +49-151-27565287