lkml.org 
[lkml]   [2018]   [Sep]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ASoC: tlv320aic31xx: Add MICBIAS off setting
On Tue, Sep 04, 2018 at 10:10:24AM -0500, Andrew F. Davis wrote:
> On 09/04/2018 09:55 AM, Mark Brown wrote:

> > you get to keep the pieces" territory. If we really want to have a way
> > of explicitly specifying that some widgets should never be turned on
> > then it feels like rather than have something device and widget specific
> > like this we should instead have a higher level way of doing that which
> > can be applied to any widget, that is something that could be useful
> > especially with things like speaker drivers where there's real potential
> > for physical damage to the system.

> Not sure how that could even look, it would need to be in DT as only
> that layer knows the connections, but then the it would also have to
> have internal knowledge of the widgets used in the driver..

We already have a bunch of DT code that knows about and uses the
external widgets the device has (which are I'd guess the only ones where
this is an issue)? I was thinking just have a property that lists the
widgets that should never be turned on.

> > Like I said in my original reply I'm also worried that this will break
> > existing boards by causing them to change to a voltage of 0 when they
> > had managed to end up with the default of 2V which happened to work for
> > them.

> Then only time this could happen is if they specified MICBIAS_OFF in DT
> but got the default 2v instead. In which case, yes, the behavior would
> change, but it would also be changing to the correct behavior. We can't
> avoid fixing code on the off chance someone depended on the broken
> behavior, no progress could ever be made.

I'm really having a lot of trouble seeing MICBIAS_OFF as a useful
voltage to specify in DT in the first place.
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-09-04 17:58    [W:0.057 / U:0.924 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site