Re: pandaboard audio system

[Stefan K. <ste...@ge...>]

Hi,

On 05/26/2013 03:20 AM, gaober wrote:
> hi!
> i want to implenment the audio system for pandaboard.there are some
> questions.
> i find directory /os/src/drivers/audio_out/linux,do i need it?

No, that directory points to the audio driver for Genode on top of
Linux. I assume you're using Fiasco.OC or the base-hw ARM kernel for the
Pandaboard, so you don't need it, but might use it for reference of the
audio_out session server side.
Another driver implementing the "audio_out" session interface, which
runs on top of x86 32Bit e.g. OKL4, Fiasco.OC, or NOVA, can be found in
"dde_oss/src/drivers/oss".
As the title suggests it's a port of the OSS audio drivers, and targets
various audio hardware found on x86 platforms.

> shold i implenment the audio system by using dde method?or should i
> write audio driver in addition?Maybe the twl6040 driver?

Well, I would say it depends. Of course, it's always nicer to have a
driver written from scratch without the additional need of a Linux
environment.
On the other hand, you can profit from the knowledge inside the driver
code in Linux (mostly written by people with more documentation, or
contact available, at least when they were contracted by the hardware
vendor).
So it's dependent on the hardware's complexity, the time you want, or
are able to invest, and the documentation available for the audio
device. A third option between writing things from scratch, just on the
basis of reference manuals, or porting Linux drivers, is to
analyse/trace the I/O memory accesses of the Linux driver, understand
it, and write a driver on that basis.

> do you have some suggestions,please?

Without having prior knowledge about the device, no. But I would start
with trying to write it from scratch, considering the Linux kernel
driver as additional reference.

Regards
Stefan

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-- 
Stefan Kalkowski
Genode Labs

http://www.genode-labs.com/ · http://genode.org/