Hi all,

On  10 May, this message from Geert Uytterhoeven echoed through cyberspace:
[snip]

quoted

quoted

and maybe some more stuffs.

The only device on this I2C bus in the PCI Macs that I know off is the
RADACAL RAMDAC/CLUT (used at least with the control chip), which gets
its timebase factors via I2C.

quoted

Unfortunately, I think we only know how to write to the i2c bus.

Yes.

On the other hand, you I2C gurus mihgt know that, but the R/W bit on the
I2C bus is actually the lsb of the address; i.e address a device with
an even address, and it expects to recive some data; address it with an
odd address, and the device will write data to the bus.

quoted

quoted

More hacking needed before we can implement this one too.

One problem might be that there is as yet no readable device on the bus
;-).

Really? Since i2c devices need to identify on the bus, you must be able to read
something from them.

I did some experimentation on the cuda I2C bus while searching for the
PlanB I2C device. I scanned a whole range of I2C addresses, both read
and write, but didn't find anything apart from RADACAL.

Are there OF methods for the i2c bus on those Macs? My CHRP box has them under
/pci/mac-io@2/misc@0/iic/.

I'll check in OF on the next reboot ;-)

Michel

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