[alsa-devel] [PATCH 1/3] ASoC: bt-sco: enable OF support

[Barry Song]

2013/7/17 Mark Brown <broonie at kernel.org>:
> On Wed, Jul 17, 2013 at 09:40:39AM +0100, Mark Rutland wrote:
>> On Wed, Jul 17, 2013 at 07:12:14AM +0100, Barry Song wrote:
>
>> > this makes users be able to add a bt-sco node in dts instead of
>> > hardcoding a platform device in mach.
>
>> I'm slightly confused by this. The driver doesn't seem to pick up any
>> information out of the dts, and the binding doesn't even describe any
>> linkage to a piece of hardware. I'm not familiar with bluetooth or ASoC,
>> could you give an explanation as to why this is needed?
>
>> I don't think this should be in the dt as is. Could this not be
>> registered based on the presence of a bluetooth controller that supports
>> this?
>
> Audio devices are linked together by a separate board binding which
> specifies how all the different components in the audio subsystem on the
> board are wired together.  Even where things have no meanignful software
> control (as is the case here and for a lot of simple DACs or ADCs) the
> rest of the system needs information on their capabilites and ideally
> the ability to interchange them with more substantial devices.  If there
> were meaningful control there'd be a control bus here.
>
> There is likely to be a control interface for the BT device hanging off
> a UART but it's not clear there's much more meaningful data for those
> than there is here.

so the idea is that we don't add codec platform device in uart, and we
add a dt node for it as we are doing here?

-barry