Re: [PATCH] regulator: core: Allow for regulators that can't be read at bootup
From: David Collins
Date: Wed May 16 2018 - 18:14:53 EST
On 05/15/2018 03:07 PM, Douglas Anderson wrote:
> As discussed in the patches to try to support the RPMh regulators [1],
> the fact that regulators are write-only means that its driver's
> get_voltage_sel() should return an error code if it's called before
> any calls to set_voltage_sel(). This causes problems in
> machine_constraints_voltage() when trying to apply the constraints.
This problem specifically arises in the latest RPMh regulator patch [1] if
regulator-min-microvolt and regulator-max-microvolt are specified for a
VRM managed RPMh regulator device but the qcom,regulator-initial-microvolt
property is not provided. Therefore, listing
qcom,regulator-initial-microvolt is a way to avoid regulator registration
issues.
> In this patch I propose the error code -ENOTRECOVERABLE. In errno.h
> this error is described as "State not recoverable".
I'm fine with this constant. Hopefully Mark is as well.
> If this patch is accepted then we'll need to update the latest RPMh
> regulator patch to return it. The current patch returns -EINVAL which
> means that the regulator always fails.
I'll make this modification if needed.
Take care,
David
[1] https://lkml.org/lkml/2018/5/11/703
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