G'Day,
> Nice work. I've been going through your code.
Thanks: I appreciate it!
> One basic question: What exactly is this "adapter" and which architecture
> supports it?
It is not a true adaptor: Texas Instruments' OMAP development boards
have hardware support for 1-Wire. I recently wrote a kernel driver for
this, and needed to add support for my driver to owfs. I am just
finishing off some documentation on the hardware support and my driver,
if you are interested --- though I would not imagine it would be
particularly interesting to anyone not using OMAP boards.
> Specific comments:
> 1. in ow_omap.c : OMAP_reset, are we missing something? I see a loop, with
> fsync, but no body.
That would be a typo I had not noticed: it should have a semi-colon at
the end. fsync() could return -EBUSY if the bus were currently in use,
which meant you needed to wait a moment before you could use it (at the
time I felt that was a cleaner solution than blocking). Due to a
hardware bug, if you try to do anything while another operation is
completing, you risk corrupting data (`anything' includes even reading
status registers!). That will not be relevant soon, however, as my next
version of the driver will be blocking when performing operations, and
as such there is no -EBUSY signal.
> 2. How big a send/recieve buffer does the adapter have?
At the moment, I am buffering everything in kernel, and sending it one
byte (or bit, if performing Search ROM) at a time. I am considering
changing that in future, but at the moment there is no hard limit.
> 3. Is there a characteristic major/minot device number to test for in
> OMAP_detect
ow_ds9097.c had no such thing, so I did not realise I needed to test
anything like that. Because there is no device assigned to this (and,
really, there probably never will be), this may need to change, but
currently /dev/owire is set to 232/0.
> 4. It's a matter of style. Your ow_omap.h has only static function
> prototypes.
> I've been putting them at the start of the source module and using the *.h
> files for externally visible definitions.
That is simple enough to change --- I mainly do it like that for my own
reference early on anyway. Once I get to a certain point, it works just
as well for me either way.
> 5. Do you have a picture of the adapter for the web site?
Since it is not really an real adaptor, there are no pictures of the
relevant aspect, however if you want a picture of an OMAP development
board there is one of the board I am using here:
http://omap.spectrumdigital.com/osk5912/
-- Matthew
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