Re: [PATCH 4/7] phy: meson: add USB2 PHY support for Meson8b and GXBB

[Philipp Zabel <p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

Hi Martin,

Am Mittwoch, den 14.09.2016, 23:23 +0200 schrieb Martin Blumenstingl:
[...]
> > We could add a triggered flag or a counter to struct reset_control, and
> > have reset_control_reset_once do nothing if it is already set /
> > incremented. Since the reset_control goes away with the last consumer,
> > the shared reset line would get triggered again after unbinding both PHY
> > devices.
> I guess that'd do the trick for us:
> - we could use devm_reset_control_get_optional_shared() during probe
> - power_on would then call reset_control_reset()
> - the code in reset_control_reset would be changed: the if
> (WARN_ON(rstc->shared)) would be removed. then we return 0 if
> (rstc->shared && atomic_read(&rstc->shared_triggered)). otherwise we
> proceed with the old logic, except that we use
> atomic_set(&rstc->shared_triggerred, 1) in case of success (if an
> error was returned we leave it as "not triggered").
> 
> Let me know if you want me to (at least try to) implement that and send an RFC.

Yes, please give it a try. reset_control_reset should still WARN if the
deassert count is set, and reset_(de)assert should do so if triggered is
set. Mixing the two won't work. And it should be documented that shared
reset_control_reset may do nothing if the reset was already triggered by
another consumer.

regards
Philipp

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