From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <200008300837.JAA16257@hyperion.valhalla.net> Date: Wed, 30 Aug 2000 09:37:37 +0100 Subject: Re: [PATCH] via-cuda (CUDA_COMBINED_FORMAT_IIC) From: "Iain Sandoe" To: mlan@cpu.lu CC: linuxppc-dev@lists.linuxppc.org Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Hi Michel, On Wed, Aug 30, 2000, Michel Lanners wrote: > On 30 Aug, this message from Iain Sandoe echoed through cyberspace: >> 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/