A need for support for SPI interfacing in alsa.

A need for support for SPI interfacing in alsa.

[James Courtier-Dutton]

More and more sound card manufacturers are moving away from AC97 codecs.
Up until recently, this was not really a problem, but I came across a 
new sound card today. The Creative SB Live! 7.1 24bit.
This is based on the Audigy LS.
  *  GENERAL INFO: Audigy LS
  *    Model: SB0310
  *    P17 Chip: CA0106-DAT
  *    AC97 Codec: STAC 9721
  *    ADC: Philips 1361T (Stereo 24bit)
  *    DAC: WM8746EDS (6-channel, 24bit, 192Khz)
  *
  *  GENERAL INFO: SB Live! 7.1 24bit.
  *    Model: SB0410
  *    P17 Chip: CA0106-DAT
  *    AC97 Codec: None
  *    ADC: WM8775EDS (4 Channel)
  *    DAC: CS4382 (114 dB, 24-Bit, 192 kHz, 8-Channel D/A Converter)

The Audigy LS has a Philips 1361T stereo only ADC.
The SB Live! 7.1 24bit has a WM8775EDS 4 channel ADC.

So, now we will have to be able to talk to the ADC chip over it's 
control channel. This control is done via an SPI bus.
The reason we need support now, is that we need to be able to control 
which inputs the WM8775EDS selects.
The WM8665EDS has a stereo ADC, but can select from 4 stereo inputs.

Does anyone know how we might support SPI interfaces? I don't know much 
about them, and there is only one 32bit register and one interrupt pin 
on the P17 chip to control this.

James


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Re: A need for support for SPI interfacing in alsa.

[Lee Revell]

On Sat, 2004-10-02 at 14:38, James Courtier-Dutton wrote:
> More and more sound card manufacturers are moving away from AC97 codecs.
> Up until recently, this was not really a problem, but I came across a 
> new sound card today. The Creative SB Live! 7.1 24bit.
> This is based on the Audigy LS.

Wait, is this a PCI card?  Does it have the FX8010 DSP?  I really hope
this does not mean they are moving away from the emu10k1/emu10k2
architecture in order to support 24/96.  I was hoping they would come
out with an emu10k3 with a similar architecture to the emu10k1/10k2
except running at 96Khz.

Lee



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Re: A need for support for SPI interfacing in alsa.

[Lee Revell]

On Sat, 2004-10-02 at 14:38, James Courtier-Dutton wrote:

> Does anyone know how we might support SPI interfaces? I don't know much 
> about them, and there is only one 32bit register and one interrupt pin 
> on the P17 chip to control this.
> 

Has anyone asked Creative for the info?  I believe they will provide
some specs under NDA.

Lee



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Re: A need for support for SPI interfacing in alsa.

[Jaroslav Kysela]

On Sat, 2 Oct 2004, James Courtier-Dutton wrote:

> Does anyone know how we might support SPI interfaces? I don't know much 
> about them, and there is only one 32bit register and one interrupt pin 
> on the P17 chip to control this.

SPI interface means only serial communication between chips. It does not 
define the chip's registers etc. I suggest to create a library for SPI 
codecs in i2c/other (see i2c/other/ak4117.c for example).

Basically, from the driver view, you can directly control the wires or you 
might only ask to read / write some register and the master chip will do 
rest (like all AC97 bridges do). So, it depends on hardware - no common 
way.

Also, we should move other WM drivers from ice1712 directory to i2c/other 
as well.

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SUSE Labs


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