On Fri, Sep 23, 2016 at 04:27:37PM -0500, Rob Herring wrote:
On Thu, Sep 22, 2016 at 09:50:06PM +0800, Xing Zheng wrote:
From: Wonjoon Lee woojoo.lee@samsung.com
Pop happens when mclk applied but dmic's own boot-time
This statement doesn't make sense.
It is very clear if you're familiar with the problem domain - because a DMIC is digital it's got an on/off state which means that when it transitions from off and not outputting anything to outputting something you get a sudden DC transition which manifests as a pop in the audio output.
Specify dmic delay times in dt to make sure clocks are ready earlier than dmic working
I don't think this really belongs in DT. Seems like better control of the init order is needed. Or why not just a fixed delay in the driver?
The changelog says this is due to the DMICs having a startup time of their own so needing a delay after they've started. That's going to be a system dependent thing since it'll depend on the specific component selected and DMICs are easily interchangable.