Am Sonntag, 23. April 2006 08:23 schrieb Christoph Scheurer:
> Hi,
>
> Besides more restrictive electrical specifications and timeouts to prevent
> the bus to be locked, SMBus is a subset of I2C, i.e. for the protocol
> every I2C master device can send all commands a SMBus slave is able to
> understand while this is not true the other way around. Because of this it
> would be better to stick to SMBus commands. If the PXA board is truely I2C
> it should be no problem for it to issue all the SMBus commands. That it is
> not SMBus compliant can only mean that it has other electrical
> characteristics or does not support the timeouts required by SMBus.
>
I'd think some important parts of the i2c support in the PXA board are done in
the custom kernel driver, which can't guarantee the 35ms timeout of smbus
slaves.
I have a special request: It seems the kontron guys haven't used the
generic /dev/i2c interface, but instead build a propietary interface (morons)
and a userspace library, which exports i2c (not smbus) functions only. I'm
still into bugging them to make a driver using the generic i2c interface, but
if this fails, I'd have to port the owfs i2c Interface to that libary.
It would make things easier if you could stick to the raw i2c calls of
the /dev/i2c interface.
(I'm thinking of switching the board manufacturer, too)
Kind regards
Jan
--
Ich vertonne Spam immer in /dev/dsp statt in /dev/null.
Ich mag die Schreie.
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