Messages in this thread | | | Subject | Re: [PATCH v10 0/7] Add Fieldbus subsystem + support HMS Profinet card | From | Andreas Färber <> | Date | Wed, 17 Apr 2019 19:04:37 +0200 |
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Hi Enrico,
Am 16.04.19 um 18:49 schrieb Enrico Weigelt, metux IT consult: > On 15.04.19 20:31, Sven Van Asbroeck wrote: >>> 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.
I somewhat see your point, but I would not have recognized iec61158 as something relevant to my hardware, whereas fieldbus is understandable.
If you see specific conflicts or differences, please explain them instead of just throwing around bus names. :) Then we can more easily discuss whether to make changes to this framework or whether we indeed need some fieldbus/iec61158/ subdirectory. For your RS-485 I don't see a conflict as that'll just go via tty/serial/ and optionally serdev, no? However, I'd be curious how I/O Link might relate to this, it seems to have no public specifications.
> 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.
While I do like sockets, they seem more useful for packet-based communication, which may be an implementation detail of fieldbus_dev drivers, but AFAIU that's unrelated to Sven's memory-focused subsystem representing a view of the data received, which may be different from the last packet received. Also, when a packet is received via socket, it gets dequeued, whereas you'll want to access the device's memory without restrictions.
Cheers, Andreas
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