(AT91RM2000 - ARM) Driver that puts data over SSC to FPGA

(AT91RM2000 - ARM) Driver that puts data over SSC to FPGA

[Michel Müller]

Hello,

I am trying to write an ALSA-driver that puts the audio data over the 
SSC channel to the FPGA. This FPGA routes the Data to the AD/DA chips.

I tried to figure out how I can do this with the ASoC Interfaces but I 
am currently stuck. Currently there is an Atmel SSC and PCM Interface 
that I can probably use. If I want to use the ASoC API I need to have a 
Codec Driver. But I don't have direct access to the codec.

How should I proceed? I have 2 possibilities I think: Writing a Codec 
Driver / Writing an Alsa Driver as described in the guide of Takashi Iwai.

If I write a character device that transfers data to the FPGA over the 
SSC I can hear sound, but I want to use ALSA because the use of audio 
applications will be easy and flexible.

Thank you in advance!

Regards,
Michel

Re: (AT91RM2000 - ARM) Driver that puts data over SSC to FPGA

[Mark Brown]

On Tue, Sep 22, 2009 at 03:04:51PM +0200, Michel Müller wrote:

> I tried to figure out how I can do this with the ASoC Interfaces but I 
> am currently stuck. Currently there is an Atmel SSC and PCM Interface 
> that I can probably use. If I want to use the ASoC API I need to have a 
> Codec Driver. But I don't have direct access to the codec.

> How should I proceed? I have 2 possibilities I think: Writing a Codec 
> Driver / Writing an Alsa Driver as described in the guide of Takashi Iwai.

In this system your FPGA is doing the job of the CODEC as far as the CPU
is concerned so the most natural thing would probably be to implement a
CODEC driver for it.  This should be fairly straightforward, especially
if there's not much software control of the FPGA.