[alsa-devel] [linux-sunxi] Re: [PATCH v9 2/2] Add mixer controls: Line-In, FM-In, Mic 2, Capture Source, Differential Line-In.

[Chen-Yu Tsai]

On Wed, Aug 31, 2016 at 3:49 PM, Danny Milosavljevic
<dannym at scratchpost.org> wrote:
> Hi Chen-Yu,
>
>> My apologies. I didn't notice that VMIC was already in the driver.
>> In that your original patch did everything right.
>
> Don't worry about it :)
>
> But I have a question:
>
> If I replace DAPM_INPUT by DAPM_MIC it wants a callback that is supposed to
> fiddle with the bias.
> Do I provide one?
> If so, will it conflict with the supply?
>
> Or do I leave it as DAPM_INPUT ?

I think leaving it as DAPM_INPUT will do. Also, if you use DAPM_MIC or any
other widget type that takes a callback, the callback can be NULL.

I took a quick look at other drivers. The codecs only use non-endpoint
types, like INPUT/OUTPUT. It's up to the card to provide endpoints
(HP/SPEAKER/LINE/MIC) and route them to the codec INPUT/OUTPUTs.


Regards
ChenYu