From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <199905101943.VAA00322@piglet.cpu.lu> Date: Mon, 10 May 1999 21:43:21 +0200 (CEST) From: Michel Lanners Reply-To: mlan@cpu.lu Subject: Re: Support for Hydra i2c To: Geert.Uytterhoeven@cs.kuleuven.ac.be cc: bh40@calva.net, frodol@dds.nl, linuxppc-dev@lists.linuxppc.org In-Reply-To: MIME-Version: 1.0 Content-Type: TEXT/plain; CHARSET=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Hi all, On 10 May, this message from Geert Uytterhoeven echoed through cyberspace: [snip] >> > 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. >> >> > 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. >> > 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 ------------------------------------------------------------------------- Michel Lanners | " Read Philosophy. Study Art. 23, Rue Paul Henkes | Ask Questions. Make Mistakes. L-1710 Luxembourg | email mlan@cpu.lu | http://www.cpu.lu/~mlan | Learn Always. " [[ This message was sent via the linuxppc-dev mailing list. Replies are ]] [[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]] [[ reply is of general interest. Please check http://lists.linuxppc.org/ ]] [[ and http://www.linuxppc.org/ for useful information before posting. ]]