[sane-devel] Intend to write driver(s)

Stéphane VOLTZ stef.dev at free.fr
Sun Aug 5 16:39:14 UTC 2007

Le samedi 4 août 2007, Robert Brijder a écrit :
> Hi Leandro,
> Sorry for the very late reaction. I do have some information for you
> which may help.
> Look at the site http://zub.fei.tuke.sk/primax/ of Peter Popovec.
> It contains a sane backend for the E3 ASIC, which our scanners have.
> The only thing lacking in this backend is that it is for parallel port
> scanners and not for USB. Luckily, the chip which does the bridging of
> parallel port over USB is well known, it is the GeneSys Logic GL640.
> There are many duplicate implementations of this USB bridge already in
> the SANE backends, it appears to reside in at least 3 backends:
> genesys, canon630u, and u12. So I guess it wouldn't be hard to
> implement this in your sane backend. BTW: Does anybody know, Is there
> a good reason for implementing this chip this many times?

	Where is there an USB bridge in the genesys backend ? For the 2 others, I 
don't know. But you have two implementation where you can choose the best 
one. And may be separate it into a library to use for your future backend, 
and that maybe would let refactor the two other.

> It seems the modifications are mostly necessary in the port.c file (of
> the sane backend of Peter Popovec) to get it working. I guess there
> should be a USB version for the following functions.
> epp_off();
> epp_read();
> epp_read_one();
> epp_write();
> epp_write_one();
> switcher_online ();
> switcher_offline ();
> The first five are not that hard I think, but I do not really have a
> clue yet how to do the last two functions.
> If we can get USB support working, at least 6 new devices would be
> supported. This would be nice. I contacted Peter Popovec, but since he
> does not have such a USB scanner he would rather not implemented this
> himself.
> I guess I answered your first question: we should edit the backend of
> Peter Popovec. The second question: I don't know if it is possible to
> damage the scanner. The third question: the backend of Peter Popovec
> does not seem to have any licencing issues, this in contrast to the
> viceo backend.
> All the best,
> Robert


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