[alsa-devel] ASoC MPC5xxx PSC AC97 audio driver

[jonsmirl at gmail.com]

On Thu, Sep 8, 2011 at 10:32 AM, David Jander <david.jander at protonic.nl> wrote:
>
> Dear Jon,
>
> On Thu, 8 Sep 2011 06:55:56 -0400
> "jonsmirl at gmail.com" <jonsmirl at gmail.com> wrote:
>
>> On Thu, Sep 8, 2011 at 6:45 AM, David Jander <david.jander at protonic.nl>
>> wrote:
>> >
>> > Dear Jon,
>> >
>> > Thanks for replying so quickly.
>> >
>> > On Thu, 8 Sep 2011 06:28:02 -0400
>> > "jonsmirl at gmail.com" <jonsmirl at gmail.com> wrote:
>> >> On Thu, Sep 8, 2011 at 6:16 AM, David Jander <david.jander at protonic.nl>
>> >> wrote:
>> >> >
>> >> > Dear Jon,
>> >>
>> >> Here's the device tree...
>> >> http://git.digispeaker.com/?p=digispeaker-kernel.git;a=blob;f=arch/powerpc/boot/dts/dspeak01.dts;h=50cc247b4da0eb2bc4deb315b1b5348af87e5979;hb=9166a4a4141ab7c8d7a7b97fa5b726e11a8d0ca4
>> >
>> > Thanks... but it uses I2S, not AC97 :-(
>> > It doesn't have a "fsl,mpc5200-pcm" node either, btw.
>> > In the case of I2C, this makes some sense, since the Codec is usually
>> > connected to two different interfaces at the same time (I2S and I2C for
>> > control), so you have 2 device nodes. AC97 OTOH has just one interface. It
>> > is connected to a AC97 bus (a PSC in this case). AFAICS there are no OF
>> > bindings yet for an AC97 bus, so the actual codec doesn't figure and thus
>> > still needs this ugly fabric driver thing.
>>
>> Try the pcm030 device tree...
>>
>> http://git.digispeaker.com/?p=digispeaker-kernel.git;a=blob;f=arch/powerpc/boot/dts/pcm030.dts;h=30bfdc04c6dfacd88a9c6e325e873d75a633bdf5;hb=HEAD
>
> I had also looked at that one.... still no "fsl,mpc5200-pcm" node. I would not
> expect one either, given the way the fabric driver works. But what is the
> reason for this OF compatible string then?
>
> Most important question: Does the mpc5200_dma.c/mpc5200_psc_ac97.c combination
> in current mainline still work correctly?

I haven't booted a mpc5200 in over a year so I don't know. Grant
probably has better info. He'll answer this thread sooner or later.


>
> I am unable (by inference) to say for sure that mpc5200_hpcd_probe() will
> always be called before psc_ac97_of_probe(). If it is not, the latter will
> OOPS.
> In fact, when I try to mimic the same on a MPC5121e, it does get called in the
> opposite order! My theory is that this order may have changed in recent
> versions of kernel/ALSA, and that since that moment this driver has been
> broken and nobody noticed yet. I need to know, because I intend to enhance
> mpc5200_psc_ac97.c, to also support MPC512x, but this is not working the way it
> is written now. If I knew for sure that mpc5200 still works this way, I would
> need to find a bug in my code. In the other case, I'd just go and fix the
> driver for MPC5200 also, but I have no hardware to try it out myself.
>
> Best regards,
>
> --
> David Jander
> Protonic Holland.
>



-- 
Jon Smirl
jonsmirl at gmail.com