Messages in this thread |  | | Subject | Re: [PATCH] drm/panfrost: Fix regulator_get_optional() misuse | From | Steven Price <> | Date | Thu, 5 Sep 2019 10:37:53 +0100 |
| |
On 05/09/2019 09:21, Rob Herring wrote: > +Steven > > On Wed, Sep 4, 2019 at 1:30 PM Mark Brown <broonie@kernel.org> wrote: >> >> The panfrost driver requests a supply using regulator_get_optional() >> but both the name of the supply and the usage pattern suggest that it is >> being used for the main power for the device and is not at all optional >> for the device for function, there is no meaningful handling for absent >> supplies. Such regulators should use the vanilla regulator_get() >> interface, it will ensure that even if a supply is not described in the >> system integration one will be provided in software. > > I guess commits e21dd290881b ("drm/panfrost: Enable devfreq to work > without regulator") and c90f30812a79 ("drm/panfrost: Add missing check > for pfdev->regulator") > in -next should be reverted or partially reverted?
Ah, I didn't realise that regulator_get() will return a dummy regulator if none is provided in the DT. In theory that seems like a nicer solution to my two commits. However there's still a problem - the dummy regulator returned from regulator_get() reports errors when regulator_set_voltage() is called. So I get errors like this:
[ 299.861165] panfrost e82c0000.mali: Cannot set voltage 1100000 uV [ 299.867294] devfreq devfreq0: dvfs failed with (-22) error
(And therefore the frequency isn't being changed)
Ideally we want a dummy regulator that will silently ignore any regulator_set_voltage() calls.
Steve
|  |