Messages in this thread | | | Subject | Re: [PATCH 1/5] regulator: core: Resolve supply earlier | From | Jon Hunter <> | Date | Mon, 11 Apr 2016 11:59:02 +0100 |
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Hi Thierry,
On 07/04/16 15:22, Thierry Reding wrote: > From: Thierry Reding <treding@nvidia.com> > > Subsequent patches will need access to the parent supply from within the > set_machine_constraints() function to properly implement bypass mode. If > the parent supply hasn't been resolved by that time the voltage can't be > queried. > > Also, by making sure the supply is resolved early most of the changes in > set_machine_constraints() don't have to be undone if resolution fails. > > Suggested-by: Mark Brown <broonie@kernel.org> > Signed-off-by: Thierry Reding <treding@nvidia.com> > --- > drivers/regulator/core.c | 27 +++++++++++++++++++++------ > 1 file changed, 21 insertions(+), 6 deletions(-) > > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c > index 2786d251b1cc..cc0333a79924 100644 > --- a/drivers/regulator/core.c > +++ b/drivers/regulator/core.c > @@ -3972,18 +3972,27 @@ regulator_register(const struct regulator_desc *regulator_desc, > > dev_set_drvdata(&rdev->dev, rdev); > > + if (init_data && init_data->supply_regulator) > + rdev->supply_name = init_data->supply_regulator; > + else if (regulator_desc->supply_name) > + rdev->supply_name = regulator_desc->supply_name; > + > + /* > + * set_machine_constraints() needs the supply to be resolved in order > + * to support querying the current voltage in bypass mode. Resolve it > + * here to more easily handle deferred probing. > + */ > + ret = regulator_resolve_supply(rdev); > + if (ret < 0) > + goto scrub; > +
Thanks for sending this. However, I think that calling regulator_resolve_supply() can cause a deadlock, because the regulator_list_mutex is held at this point and regulator_resolve_supply() calls regulator_dev_lookup() which may try to request the mutex again.
So may be we need to move this call after the call to regulator_of_get_init_data() before we acquire the mutex.
Also, if we add this call, then I am wondering if we still need ...
class_for_each_device(®ulator_class, NULL, NULL, regulator_register_resolve_supply);
Cheers Jon
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