On Tue, Sep 04, 2018 at 11:02:14AM -0500, Andrew F. Davis wrote: > On 09/04/2018 10:56 AM, Mark Brown wrote: > > I'm really having a lot of trouble seeing MICBIAS_OFF as a useful > > voltage to specify in DT in the first place. > I don't see the usefulness in specifying any bias voltage in DT at all, > it is a configuration and can be made at runtime, it has no place in DT. > But it is already here, so lets allow all available voltages a board may > need and the CODEC can supply, even 0. It is very rare for it to be useful to select the bias voltage at runtime - it's usually something that's decided by the electrical engineering at system design time and linked to selection of passive components rather than something that a user could usefully vary. I suspect in the situations where it is useful to vary it you'd want a layer of indirection mapping it onto some user observable behaviour (or the system should just do this autonomously as with the various low power mic detect solutions out there). What situations are you aware of where runtime configuration is useful?
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