Re: [PATCH] via-cuda (CUDA_COMBINED_FORMAT_IIC)

Hi Michel,
On Wed, Aug 30, 2000, Michel Lanners wrote:

On  30 Aug, this message from Iain Sandoe echoed through cyberspace:

quoted

Unfortunately, the one chip I *really* want to probe (the TDA7433 on the
audio card -  i2c address 0x8a) doesn't seem to give a proper response... so
if anyone knows more about this - I'd be interested.

Hmm, are you sure it is actually attached to the CUDA's I2C bus? The
7x00/8x00 series have a video input chip on an I2C bus as well, but not
on CUDA... it's on PlanB, which includes its own I2C implementation. I
don't know about the sound chips in those boxes, however. My first bet
would be looking around AWACS if there is no I2C bus hidden there
somewhere.

Well, you could be right... I'm only going on Apple's h'ware docs (& the
existing Linux & Darwin drivers ;-).

The G3-beige has a perch slot and in the perch slot is one of three types of
card... all of these have either AWACS or Burgundy - but also a "tone
control" chip controlled by i2c.  The so called "tone control" chip does a
fair bit of the level & routing control (which is why I want to access it's
settings)

Apple's stuff from Darwin refers to this as an SGS7433 (and, after looking
at SGS/Thompson's web site) I came up with the TDA7433 which does the right
things.  It has i2c address 0x8a - which is the address that the dmasound
driver writes to to set the volume on g3-beige (using the GET_SET_IIC
command).

With the modified driver posted, the CUDA_COMBINED_FORMAT_IIC command
recognises that there is a device at address 0x8a - but returns all 0xff
bytes instead of the hoped for register contents :-(

I checked the TDA7433 data sheet and it should be able to do
COMBINED_FORMAT...

ah well...

Yes, there are different implementations for i2c on different models...
CUDA, PMU (PlanB and other mac-IO implementations).... and on the newer
machines "cereal" (and multiple i2c busses)...  if the ability to probe the
i2c bus is useful, I guess we'll have a few more drivers to update... :-)

Iain.

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/