Re: Some Alsa SoC questions

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On 08/02/07, Liam Girdwood <lg@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 2007-02-07 at 13:23 -0800, Brad Beveridge wrote:
>
> > On the codec side I've started with the AK4535, and pulled out almost
> > everything interesting.  The AK4550 has two input pins which control a
> > de-emphasis filter for when the codec does ADC conversions, but I
> > don't really know what to do with them.
> >
>
> I would suggest contacting AKM for information on the input pins.
>
> > On to the questions:
> > 1) Is the AK4550 codec really without registers like I think it is?
> > 2) What is the best way to hook up the de-emphasis pins and expose
> > them?  I feel like I need generic functions in the codec to control
> > them, and those generics should somehow hook to machine-specific
> > functions.  I don't know how to do this.
> > 3) Am I basically on the right track here?
>
> Please check 1,2 and 3 with AKM.
Hi, and thanks for the quick reply.
I think I spoke imprecisely with regard to #2.  I know how the
de-emphasis pins are physically hooked up to the SA2410, they are just
GPIOs.  What I am unsure about is exactly how to expose control of
these GPIOs.  My thoughts are that control of these pins is somewhat
analogous to reading/writing registers on a codec, and so therefore
the codec driver should expose an interface to the outside world that
lets you turn on/off the de-emphasis input filter.  To actually
configure the pins, the codec needs to call out to functions in the
machine-specific driver - analogous to the hw_read/hw_write functions.
 Hmm, using these functions may actually be the correct thing to do in
this case.  If they are the correct way to access machine specific
stuff, do I just setup the hw_read/write pointers in my
machine_codec_init function?  (ie the function smdk2440_uda1341_init
in smdk2440.c).

>
> > 4) Does ASoC have a canonical repository that I should be pulling the
> > latest code from?
>
> It soon will. We are about a week or 2 away from hosting our git tree.
Cool, that'll me nice.

Thanks again,
Brad

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