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@xxxxxxxxxxx> > > 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.
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