Re: [PATCH v2 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver bindings

Conor Dooley
2023-10-26T15:26:21Z

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On Thu, Oct 26, 2023 at 08:09:52AM -0700, Guenter Roeck wrote:
> On 10/26/23 07:25, Conor Dooley wrote:
> > Hey,
> >
> > On Thu, Oct 26, 2023 at 04:15:11PM +0800, Delphine CC Chiu wrote:
> > > Add a device tree bindings for ltc4286 driver.
> >
> > Bindings are for devices, not for drivers.
> >
> > >
> > > Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> > >
> > > Changelog:
> > > v2 - Revise vrange_select_25p6 to adi,vrange-select-25p6
> > > - Add type for adi,vrange-select-25p6
> > > - Revise rsense-micro-ohms to shunt-resistor-micro-ohms
> > > ---
> > > .../bindings/hwmon/lltc,ltc4286.yaml | 50 +++++++++++++++++++
> > > MAINTAINERS | 10 ++++
> > > 2 files changed, 60 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml b/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
> > > new file mode 100644
> > > index 000000000000..17022de657bb
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
> > > @@ -0,0 +1,50 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/hwmon/lltc,ltc4286.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: LTC4286 power monitors
> > > +
> > > +maintainers:
> > > + - Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> > > +
> > > +properties:
> > > + compatible:
> > > + enum:
> > > + - lltc,ltc4286
> > > + - lltc,ltc4287
> >
> > I don't recall seeing an answer to Guenter about this ltc4287 device:
> > https://lore.kernel.org/all/22f6364c-611c-ffb6-451c-9ddc20418d0a@roeck-us.net/
> >
>
> At least the chip does officially exist now, and a datasheet is available.
>
> https://www.analog.com/en/products/ltc4287.html
>
> It shows that coefficients for the telemetry commands are different,
> meaning that indeed both chips need to be explicitly referenced
> in the properties description (and handled in the driver, which proves
> my point of needing a datasheet before accepting such a driver).

Oh neat, would've been good if that'd been mentioned!

> > > +
> > > + reg:
> > > + maxItems: 1
> > > +
> > > + adi,vrange-select-25p6:
> > > + description:
> > > + This property is a bool parameter to represent the
> > > + voltage range is 25.6 or not for this chip.
> >
> > 25.6 what? Volts? microvolts?
> > What about Guenter's suggestion to name this so that it better matches
> > the other, similar properties?
> >
>
> I still would prefer one of the more common properties.
> I still prefer adi,vrange-high-enable.

I think, from reading the previous version, that this is actually the
lower voltage range, as there is a 102.x $unit range too that is the
default in the hardware. Obviously, the use of the property could be
inverted to match that naming however.

Cheers,
Conor.

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