Re: [PATCH 3/4] dt-bindings: Add power-efuse binding

[Zev Weiss]

On Thu, Feb 17, 2022 at 02:35:12PM PST, Rob Herring wrote:
> On Thu, Feb 17, 2022 at 02:44:43AM -0800, Zev Weiss wrote:
> > This can be used to describe a power output supplied by a regulator
> > device that the system controls.
> >
> > Signed-off-by: Zev Weiss <zev@xxxxxxxxxxxxxxxxx>
> > ---
> >  .../devicetree/bindings/misc/power-efuse.yaml | 37 +++++++++++++++++++
> >  1 file changed, 37 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/misc/power-efuse.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/misc/power-efuse.yaml b/Documentation/devicetree/bindings/misc/power-efuse.yaml
> > new file mode 100644
> > index 000000000000..cadce15d2ce7
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/misc/power-efuse.yaml
> > @@ -0,0 +1,37 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/misc/power-efuse.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Generic power efuse device
>
> No idea what this is, but I doubt any such generic device exists. This
> needs sufficient description to be convincing that it is indeed generic.

I was struggling a bit to come up with a reasonably concise title; this 
admittedly isn't great.

Would a description like the following clarify it adequately?

  description: |
    This binding describes a physical power output supplied by a 
    regulator providing efuse functionality (manual on/off control, and 
    auto-shutoff if current, voltage, or thermal limits are exceeded).
    
    These may be found on systems such as "smart" network PDUs, and 
    typically supply power to devices entirely separate from the system 
    described by the device-tree by way of an external connector such as 
    an Open19 power cable:

    https://www.open19.org/marketplace/coolpower-cable-assembly-8ru/


> > +
> > +maintainers:
> > + - Zev Weiss <zev@xxxxxxxxxxxxxxxxx>
> > +
> > +properties:
> > +  compatible:
> > +    const: power-efuse
> > +
> > +  vout-supply:
> > +    description:
> > +      phandle to the regulator providing power for the efuse
> > +
> > +  error-flags-cache-ttl-ms:
> > +    description:
> > +      The number of milliseconds the vout-supply regulator's error
> > +      flags should be cached before re-fetching them.
>
> What are 'error flags'? Not something I've heard with respect to
> regulators.

That refers to the REGULATOR_ERROR_* flags in 
include/linux/regulator/consumer.h, in whatever "physical" form those 
ultimately take -- for example, in the PMBus-based case I'm currently 
aiming to support, they'd map to the flags returned by PMBus STATUS_* 
commands.  


Thanks for the review,
Zev