On Mon, Sep 23, 2019 at 11:36:11AM -0700, Doug Anderson wrote: > On Mon, Sep 23, 2019 at 11:14 AM Mark Brown <broo...@kernel.org> wrote:
> > Boot on means that it's powered on when the kernel starts, it's
> > for regulators that we can't read back the status of.
> 1. Would it be valid to say that it's always incorrect to set this
> property if there is a way to read the status back from the regulator?
As originally intended, yes. I'm now not 100% sure that it won't
break any existing systems though :/
> 2. Would this be a valid description of how the property is expected to behave
> a) At early boot this regulator will be turned on if it wasn't already on.
> b) If no clients are found for this regulator after everything has
> loaded, this regulator will be automatically disabled.
> If so then I don't _think_ #2b is happening, but I haven't confirmed.
> > boot-on just refers to the status at boot, we can still turn
> > those regulators off later on if we want to.
> How, exactly? As of my commit 5451781dadf8 ("regulator: core: Only
> count load for enabled consumers") if you do:
> r = regulator_get(...)
> regulator_disable(r)
> ...then you'll get "Underflow of regulator enable count". In other
> words, if a given regulator client disables more times than it enables
> then you will get an error. Since there is no client that did the
> initial "boot" enable then there's no way to do the disable unless it
> happens automatically (as per 2b above).
It should be possible to do a regulator_disable() though I'm not
sure anyone actually uses that. The pattern for a regular
consumer should be the normal enable/disable pair to handle
shared usage, only an exclusive consumer should be able to use
just a straight disable.
> ...or do you mean that people could call regulator_force_disable()?
> Couldn't they also do that with an always-on regulator?
No, nothing should use that in a non-emergency situation.
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