[alsa-devel] [PATCH 3/3] asoc tlv320aic3x: add more routing controls

[Takashi Iwai]

At Fri, 25 Apr 2008 11:30:40 +0200,
Daniel Mack wrote:
> 
> On Fri, Apr 25, 2008 at 11:22:10AM +0200, Takashi Iwai wrote:
> > > Add more routing controls to AIC3x chips to allow things like routing
> > > the left PGA input to right line out.
> > > 
> > > Signed-off-by: Daniel Mack <daniel at caiaq.de>
> > 
> > It should be implemented rather with stereo mixer switches in
> > general...
> 
> Not necessarily as left and right inputs of let's say the line input can
> be used for entierly different things. Same is counts for the outputs. 
> This is the case in my setup and I guess for mobile phone (what the chip
> is made for) there will be more cases.
> 
> Controlling them with stereo mixers would just cause more confusion in
> the already over-engineered chip, I fear.

Well, for such a complex system, switches don't suite well as the end
point representation.  A switch is the easiest way to implement in a
driver, but you'll have a mess in the end if there are too many
switches.

We can hide these in an higher abstraction layer (e.g. alsa-lib mixer
interface) if it were implemented.  Otherwise, think about a more
reasonable (can be less-flexible though) setup, e.g. using enum
controls to represent the hardware configuration intead of combination
of lots of switches.

Honestly, in the case of existing asoc drivers, I don't care much, and
likely I'll let it be.  But, this is an issue we need to reconsider
for the future development.


thanks,

Takashi