Mark Brown wrote at Tuesday, February 08, 2011 1:59 PM:
On Tue, Feb 08, 2011 at 12:34:09PM -0800, Stephen Warren wrote:
Maybe I should just not implement mic detection for Harmony due to these issues? In which case, I'd just let mic bias be enabled whenever capture was active, just like the speaker enable GPIO.
It certainly seems way more trouble than it's worth: as soon as the on board mic is used the jack detection will get confused as it'll see it. Of course, the internal mic is actually plugged in to a header on the main board so it may be absent too (I believe a lot of units were shipped without a case...) which means detecting the internal mic might actually be useful :)
Well, one other option is to completely ignore (and disable) the internal mic, and just support the external mic (jack). Then, mic detection could be implemented. The advantage here is similarity to other boards without the mic bias sharing issue. Plus, the jack is probably far more useful than the internal mic on this board:
I honestly don't know how many boards (if any) actually have anything plugged into the internal mic header on the board. Mine certainly didn't originally; I used a PC speaker I stole from somewhere else as the internal mic;-)