Re: wm8960 sleep time is too long when system suspend

[Zidan Wang <zidan.wang@freescale.com>]

On Mon, Nov 02, 2015 at 09:18:55AM +0000, Charles Keepax wrote:
> On Mon, Nov 02, 2015 at 04:44:04PM +0800, Zidan Wang wrote:
> > Hi Mark,
> > 
> > In wm8960 codec driver, suspend_bias_off has been enabled. So when system suspend, the wm8960 codec will go to bias off,
> > it will disable VMID and VREF, then sleep 600ms. It seems that 600ms is too long for system suspend.
> > 
> > Because the wm8960 datasheet don't mentioned the sleep time, so i want to check with you if we can shorten the sleep time.
> 
> I can't say that I am explicit familiar with the required delay
> there, but the comment in the code says that we are letting VMID
> and VREF discharge, which I certainly could believe would take a
> while. My guess would be that we likely weren't super excited
> about putting a 600mS delay in, which probably means it was
> necessary for some reason.
> 
> How much where you hoping to reduce it by? I can see if I can
> find a hardware engineer who still remembers enough about the
> part to discuss it with.
> 

Some customer can't accept such long system suspend time. It's better to spend less than 100ms for system suspend.
Codec suspend is a part of system suspend, so it should be less than 100ms, and as short as possible.


Best Regards,
Zidan Wang

> Thanks,
> Charles