Re: [PATCH 1/4] ASoC: wm9713: add binding for WM9713 codec

From: Robert Jarzmik
Date: Thu Feb 25 2016 - 20:34:02 EST

Mark Brown <broonie@xxxxxxxxxx> writes:

>> > It will eumerate the AC'97 bus by itself and does not need the CODEC to
>> > be described.
>> I think I still don't get it.
>> So let's rephrase it another way : how will the function wm9713_probe() be
>> called, ie. what is the possible function backtrace leading to that call ?
> It will not be called, the generic AC'97 code will be used.

Ok, if it's not called no code in sound/soc/codecs/wm9713.c will be used, right
In that case wm9713_set_dai_clkdiv() will never be used, nor will the
wm9713_audio_map or wm9713_dapm_widgets be created, which will break all
userspace programs relying on these mixers and DAPM routes.

Or am I missing something ?

>> Do you have a devicetree example somewhere, with (ac97 host, audio codec) pair I
>> can have a look at to understand ?
> Some Atmel boards do this IIRC, as does the AACI driver (via AMBA but
> same effect).
I suppose you mean sound/arm/aaci.c, which is more a platform_data like driver
(if I understood the integrator code correctly).

I suppose we can achieve comparable result with sound/arm/pxa2xx-ac97.c, but as
to know if the functionality will be comparable to sound/soc/pxa/pxa2xx-ac97.c,
it's hard to say. If I count the DMA requestors, I see 5 in the sound/soc
version, and 2 in sound/arm.

That makes me believe the sound/arm version is inferior.