[alsa-devel] [PATCH 3/5] SOUND: SOC: CODECS: Add support for the TWL4030 audio codec

[Steve Sakoman]

On Fri, Sep 5, 2008 at 3:30 AM, Mark Brown <broonie at sirena.org.uk> wrote:
> On Thu, Sep 04, 2008 at 07:32:28AM -0700, Steve Sakoman wrote:
>> On Thu, Sep 4, 2008 at 3:26 AM, Jarkko Nikula <jarkko.nikula at nokia.com> wrote:
>
>> I could probably get rid of this function.  It was quite useful during
>> debugging and I was not aware of codec_reg_show.  IIRC, most of the
>> other codec drivers also have the equivalent of this function, so we
>> might want to clean them up too if there is a standard function to
>> replace them.
>
> Any references?  None of the in-tree drivers have them...

Heh, you are correct.

I could swear I did a cut'n'paste on the reg cache stuff including the
dump.  Perhaps just old timers disease . . .

>> It *seems* to work without them, but every historic TI driver seemed
>> to have them.  I figured that they might know something not reflected
>> in the documentation.  I will add a REVIST comment.
>
> This sort of stuff is very common in codec drivers - normally the delays
> are there to allow the analogue side of the system time to settle down
> (waiting for capacitors to charge/discharge or reference voltages to
> stabalise, for example).  Ideally they have comments saying what's going
> on, of course.  Missing these delays often won't actually stop things
> working completely but will instead do things like reduce performance or
> generate audio artefacts - and sometimes it's application dependant if
> these are important.

That was my assumption too, so I left them under the "better safe than
sorry" theory.

As suggested, I moved all sets and clears of CODEXPDZ to function
calls which include the delay.

Thanks again for the comments.

Steve