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From:   Oskar Senft <osk@google.com>
Date:   Thu, 16 Sep 2021 15:53:33 -0400
Message-ID: <CABoTLcST=74wRbtMA2SdmeHd0WmU7id05ouSfw4PFw2nJt_gLw@mail.gmail.com>
Subject: Re: [PATCH] dt-bindings: hwmon: Add nct7802 bindings
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jean Delvare <jdelvare@suse.com>,
        Rob Herring <robh+dt@kernel.org>
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> Ah, using the node name as indication for both sensor type and
> index ? SGTM, though we'd really need input from Rob.
> I guess one could also consider something more generic like
> "temperature-sensor@0", "voltage-sensor@0", and so on (instead
> of [mis-]using reg and a sensor-type field).

Hmm, in that case, maybe we should just remove the "sensors" section.

i2c {
    #address-cells = <1>;
    #size-cells = <0>;

    nct7802@28 {
        compatible = "nuvoton,nct7802";
        reg = <0x28>;
        #address-cells = <1>;
        #size-cells = <0>;

        temperature-sensor@0 { /* LTD */
            status = "okay";
            label = "my local temperature";
        };

        temperature-sensor@1 { /* RTD1 */
            status = "okay";
            mode = <0x2>; /* 3904 transistor */
            label = "other temperature";
        };

        temperature-sensor@3 { */ RTD3 */
            status = "okay";
            mode = <0x3>; /* thermal diode */
            label = "3rd temperature";
       };
   };
};

Now, with "sensors" removed and everything at "top-level", we'll need
to decide what to do if individual sensors are missing. I guess in
that case I would just leave the affected sensors alone, i.e. neither
configure nor disable them and instead read their status from HW. That
way prior uses of the nct7802 in device trees will continue to behave
as before as does the EEPROM-style configuration.

I would like to focus on the implementation of the temperature-sensor
entries for now (i.e. LTD, RTD1, RTD2, RTD3). Support for other sensor
types could be added in a separate change. Would that be acceptable?

Thanks
Oskar.