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

Delphine_CC_Chiu/WYHQ/Wiwynn
2023-10-31T06:07:19Z

> -----Original Message-----
> From: Conor Dooley <conor@kernel.org>
> Sent: Thursday, October 26, 2023 11:26 PM
> To: Guenter Roeck <linux@roeck-us.net>
> Cc: Delphine_CC_Chiu/WYHQ/Wiwynn <Delphine_CC_Chiu@wiwynn.com>;
> patrick@stwcx.xyz; Jean Delvare <jdelvare@suse.com>; Rob Herring
> <robh+dt@kernel.org>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@linaro.org>; Conor Dooley <conor+dt@kernel.org>;
> Jonathan Corbet <corbet@lwn.net>; linux-i2c@vger.kernel.org;
> linux-hwmon@vger.kernel.org; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-doc@vger.kernel.org
> Subject: Re: [PATCH v2 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver
> bindings
>
> 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@roe
> > > ck-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.
We will use adi,vrange-low-enable instead of adi,vrange-select-25p6

>
> Cheers,
> Conor.