Re: [PATCH v2 1/2] dt-bindings: hwmon: Add nct7802 bindings

From: Oskar Senft <osk@google.com>
To: Rob Herring <robh@kernel.org>
Cc: Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: hwmon: Add nct7802 bindings
Date: Fri, 24 Sep 2021 11:17:51 -0400	[thread overview]
Message-ID: <CABoTLcRpSuUUu-x-S8yTLUJCiN4RERi2kd8XATP_n3ZTRpAWDg@mail.gmail.com> (raw)
In-Reply-To: <YUzzjYMwNKwMFGSr@robh.at.kernel.org>

Hi Rob

> > +maintainers:
> > +  - Guenter Roeck <linux@roeck-us.net>
>
> Should be someone that cares about this h/w, not who applies patches.

Hmm, ok. After talking with Guenter, I thought that would be him. But
I can add myself, too, since we're obviously using that HW. Is that
what you mean?

> > +    properties:
> > +      ltd:
> > +        type: object
> > +        description: Internal Temperature Sensor ("LTD")
>
> No child properties?

Yes. We really just want the ability to enable / disable that sensor.
What's the correct way in the YAML to describe that? Same for RTD3.

> > +          "type":
> > +            description: Sensor type (3=thermal diode, 4=thermistor).
>
> 2nd time I've seen this property this week[1]. Needs to be more specific
> than just 'type'.

Ha yes, the example in [1] came from this patch. I went with this name
to stay in-line with the sysfs name, being "tempX_type". In the
hardware this would be called "mode".

My original proposal [2] was to have this property a string list named
"nuvoton,rtd-modes" with a set of accepted values, i.e. basically an
enum. Splitting this string list into individual sensors makes sense.

The other question that remains open (at least in my view), is whether
naming the sensors "ltd, rtd1, rtd2, rtd3" is the right approach or if
we should really go to naming them "sensor@X" with a reg property set
to X. Note that ltd and rtd3 do not accept any additional
configuration beyond "is enabled" (i.e. "status").

> > +            temperature-sensors {
> > +                ltd {
> > +                  status = "disabled";
>
> Don't show status in examples.
Hmm, ok. I found it useful to make clear that a sensor can be
disabled, but maybe that's just always the case?

I appreciate your other comments and will fix them in the next version
of the patch. But I'd like to get clarity wrt. recommended sensor and
property naming in the device tree before sending that.

Thoughts?

Thanks
Oskar.

> [1] https://lore.kernel.org/all/CAL_Jsq+NXuF+F7OE3vyEbTUj6sxyMHVWHXbCuPPoFaKjpyZREQ@mail.gmail.com/
[2] https://lore.kernel.org/all/20210910130337.2025426-1-osk@google.com/