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From: David Jander <david.jander@protonic.nl>
To: "jonsmirl@gmail.com" <jonsmirl@gmail.com>
Cc: Grant Likely <grant.likely@secretlab.ca>, alsa-devel@alsa-project.org
Subject: Re: ASoC MPC5xxx PSC AC97 audio driver
Date: Thu, 8 Sep 2011 16:32:31 +0200	[thread overview]
Message-ID: <20110908163231.4b721973@archvile> (raw)
In-Reply-To: <CAKON4OwvYy6Dy-MfHT90syPyAUcTVRXqXca-qAVjk-KWkak53A@mail.gmail.com>


Dear Jon,

On Thu, 8 Sep 2011 06:55:56 -0400
"jonsmirl@gmail.com" <jonsmirl@gmail.com> wrote:

> On Thu, Sep 8, 2011 at 6:45 AM, David Jander <david.jander@protonic.nl>
> wrote:
> >
> > Dear Jon,
> >
> > Thanks for replying so quickly.
> >
> > On Thu, 8 Sep 2011 06:28:02 -0400
> > "jonsmirl@gmail.com" <jonsmirl@gmail.com> wrote:
> >> On Thu, Sep 8, 2011 at 6:16 AM, David Jander <david.jander@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 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.

  reply	other threads:[~2011-09-08 14:32 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20110908121600.267dee07@archvile>
2011-09-08 10:28 ` ASoC MPC5xxx PSC AC97 audio driver jonsmirl
     [not found]   ` <20110908124529.520c1388@archvile>
2011-09-08 10:55     ` jonsmirl
2011-09-08 14:32       ` David Jander [this message]
2011-09-08 17:52         ` jonsmirl
2011-09-09  6:48           ` David Jander
2011-09-08 18:44         ` torbenh
2011-09-09  6:28           ` David Jander
2011-09-09 10:02             ` ASoC audio fabric OF bindings RFC. was: " David Jander
2011-09-09 16:37               ` Mark Brown
2011-09-12  6:31                 ` David Jander
2011-09-12 11:09                   ` Mark Brown
2011-09-12 12:55                     ` David Jander
2011-09-12 13:19                       ` Mark Brown
2011-09-12 13:59                         ` David Jander
2011-09-12 14:52                           ` Mark Brown
2011-09-12 19:48                             ` Grant Likely
2011-09-13  6:31                               ` David Jander

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