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    SubjectRe: [PATCH V2] regulator: core: Don't use regulators as supplies until the parent is bound

    On 11/01/17 17:14, Jon Hunter wrote:
    > When regulators are successfully registered, we check to see if the
    > regulator is a supply for any other registered regulator and if so
    > add the new regulator as the supply for the existing regulator(s).
    > Some devices, such as Power Management ICs, may register a series of
    > regulators when probed and there are cases where one of the regulators
    > may fail to register and defer the probing of the parent device. In this
    > case any successfully registered regulators would be unregistered so
    > that they can be re-registered at some time later when the probe is
    > attempted again. However, if one of the regulators that was registered
    > was added as a supply to another registered regulator (that did not
    > belong to the same parent device), then this supply regulator was
    > unregister again because the parent device is probe deferred, then a
    > regulator could be holding an invalid reference to a supply regulator
    > that has been unregistered. This will lead to a system crash if that
    > regulator is then used.
    > Although it would be possible to check when unregistering a regulator
    > if any other regulator in the system is using it as a supply, it still
    > may not be possible to remove it as a supply if this other regulator is
    > in use. Therefore, fix this by preventing any regulator from adding
    > another regulator as a supply if the parent device for the supply
    > regulator has not been bound and if the parent device for the supply
    > and the regulator are different. This will allow a parent device that is
    > registering regulators to be probe deferred and ensure that none of the
    > regulators it has registered are used as supplies for any other
    > regulator from another device.
    > Signed-off-by: Jon Hunter <>
    > ---
    > Changes since V1:
    > - Updated patch per Mark's input to only prevent resolving the supply
    > if the supply's parent is different from the regulator's and the
    > supply's parent device is not bound.
    > - Added comment.
    > drivers/regulator/core.c | 13 +++++++++++++
    > 1 file changed, 13 insertions(+)
    > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
    > index 04baac9a165b..00466a82c3ad 100644
    > --- a/drivers/regulator/core.c
    > +++ b/drivers/regulator/core.c
    > @@ -1553,6 +1553,19 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
    > }
    > }
    > + /*
    > + * If the supply's parent device is not the same as the
    > + * regulator's parent device, then ensure the parent device
    > + * is bound before we resolve the supply, in case the parent
    > + * device get probe deferred and unregisters the supply.
    > + */

    Ugh ... looks like I screwed up the formatting here. Also ...


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