Am Freitag, 10. März 2006 07:20 schrieb Christoph Scheurer:
> > > Do you know how to talk to the i2c via user-space?(Something like
> > > libusb or tty system). Then a non-w1 approach would be easy. There is
> > > an example implementation for the DS2482 in the kernel; module, and the
> > > communication structure is an easy match for OWFS.
> >
> > If you load the i2c_dev module you get /dev/i2c-? device files to
> > communicate with i2c. This is e.g. what sensors-detect from lm-sensors
> > uses.
>
> Sorry, that was too unspecific. What I mean is: one could just use an empty
> I2C-slave module with only the basic I2C communication support that
> recognizes the DS2482 and move all the W1 specific functions to OWFS.
>
Besides having only a brief look into the w1 kernel code, I think handling the
remote chips is a userspace task, like with RS232 host adapter interface in
kernelspace and modem/terminal control by a userspace program.
In an ideal world, the kernel code should render the differences between i2c,
parallel, serial and usb host adapters transparent and enumerate the adapters
somewhere in /sys/bus/w1, where they can be symlinked to /dev nodes on
demand.
The owfs project, in having far more than one access method (fuse, owhttpd,
owserver, owtcl etc.) to the onewire, shows the demand for additional
user-level control code. There is no way these features will get into the
kernel sometime. I'm not into bashing Evgeniy's efforts, but besides from
some very low-level applications - like implementing a streamlined battery
monitoring interface for both onewire *and other* service processors - the
onewire has very little use for the kernel itself. Please tell otherwise, I'd
really like to know.
I'll think Evgeniy's code can be improved to do other than *iso*chronous
polling of remote chips, but I don't think that's the way it should be done.
In contrast, it should provide a transparent interface where the onewire
discover sequence can be triggered, where alarms are monitored, and where
remote chips can be accessed by a user-space library.
Kind regards
Jan Kandziora
--
Williams and Holland's Law:
If enough data is collected, anything may
be proven by statistical methods.
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