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

Delphine_CC_Chiu/WYHQ/Wiwynn
2023-10-31T05:58:00Z

> -----Original Message-----
> From: Guenter Roeck <groeck7@gmail.com> On Behalf Of Guenter Roeck
> Sent: Thursday, October 26, 2023 11:10 PM
> To: Conor Dooley <conor@kernel.org>; Delphine_CC_Chiu/WYHQ/Wiwynn
> <Delphine_CC_Chiu@wiwynn.com>
> Cc: 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
>
> Security Reminder: Please be aware that this email is sent by an external
> sender.
>
> 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
> >> +---
> >> +$id:
> >> +http://dev/
> >>
> +icetree.org%2Fschemas%2Fhwmon%2Flltc%2Cltc4286.yaml%23&data=05%7C
> 01%
> >>
> +7CWayne_SC_Liu%40wiwynn.com%7Cb250e206c9ef48fbc1c108dbd6359e51
> %7Cda6
> >>
> +e0628fc834caf9dd273061cbab167%7C0%7C0%7C638339298041650948%7CU
> nknown
> >>
> +%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haW
> wiL
> >>
> +CJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=gGQEDl33zRIJbfbinu2%2Bi2cC
> Ay6y0o
> >> +DSLzBpLL7hA%2F8%3D&reserved=0
> >> +$schema:
> >> +http://dev/
> >>
> +icetree.org%2Fmeta-schemas%2Fcore.yaml%23&data=05%7C01%7CWayne_S
> C_Li
> >>
> +u%40wiwynn.com%7Cb250e206c9ef48fbc1c108dbd6359e51%7Cda6e0628fc8
> 34caf
> >>
> +9dd273061cbab167%7C0%7C0%7C638339298041650948%7CUnknown%7CT
> WFpbGZsb3
> >>
> +d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
> %3D
> >>
> +%7C3000%7C%7C%7C&sdata=nl1IM1HpYptsJOHfiuXtKFmD%2FVlGMCW1IkoK
> HYco0sk
> >> +%3D&reserved=0
> >> +
> >> +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%2Fall%2F22f6364c-611c-ffb6-451c-9ddc20418d0a%40roeck-us.n
> e
> >
> t%2F&data=05%7C01%7CWayne_SC_Liu%40wiwynn.com%7Cb250e206c9ef48f
> bc1c108
> >
> dbd6359e51%7Cda6e0628fc834caf9dd273061cbab167%7C0%7C0%7C6383392
> 9804165
> >
> 0948%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
> IiLCJBT
> >
> iI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=OpwfD3rBS0vQBF
> jUhszrMg
> > 4mq581jU7gx54Ln8V3gUA%3D&reserved=0
> >
>
> At least the chip does officially exist now, and a datasheet is available.
>
> https://www.ana/
> log.com%2Fen%2Fproducts%2Fltc4287.html&data=05%7C01%7CWayne_SC_Li
> u%40wiwynn.com%7Cb250e206c9ef48fbc1c108dbd6359e51%7Cda6e0628fc83
> 4caf9dd273061cbab167%7C0%7C0%7C638339298041650948%7CUnknown%7
> CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiL
> CJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=CwT16Uipl8RymnFZ1WuBJzUJv
> fLCKdK3VlTcTBN0xxk%3D&reserved=0
>
> 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).
We will check the difference of coefficients for the telemetry commands with vendor.

>
> >> +
> >> + 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.
>
> Guenter