Re: [alsa-devel] [PATCH 2/4] SOUND: SOC: CODECS: Add support for the TWL4030 audio codec

[David Brownell <david-b@pacbell.net>]

On Tuesday 02 September 2008, Mark Brown wrote:
> On Tue, Sep 02, 2008 at 09:36:29AM -0700, Steve Sakoman wrote:
> 
> > The chip allows 19.2 Mhz, 26 Mhz, or 38.4 Mhz input clocks to the
> > codec.  All existing boards (Overo, Beagle, and OMAP3 EVM) use 26 Mhz
> > (generated by a fixed external oscillator chip).  I'll check with the
> > Pandora folks, but I believe that they are also 26 Mhz.
> 
> OK, a comment to that effect somewhere (perhaps in set_sysclk() which
> only accepts 26MHz) probably wouldn't go amiss.  Someone working on a
> board where the hardware guys went for a different crystal will probably
> thank you for it some day :)

For that matter, as I've said on a separate thread, this board-specific
data can and should be set up as part of the TWL4030 initialization.

The paths by which boards can provide that data to the TWL4030 init
and thence to subsidiary device init (CODEC in this case) need to be
reworked before the TWL4030 code goes upstream.  Being able to pass
the relevant clock rate shouldn't be too hard.  :)

- Dave

p.s. As has come up in the context of Beagle, which is the most available
     of those boards:  the generally available version of TWL4030 will
     have a different part number.  Docs will be available for the catalog
     parts, but they're not yet released:

	http://focus.ti.com/docs/prod/folders/print/tps65950.html