Re: [PATCH v5 1/2] dt-bindings: hwmon: Add ina3221 documentation

[Rob Herring <robh@kernel.org>]

On Tue, Sep 25, 2018 at 06:52:29PM -0700, Guenter Roeck wrote:
> Hi Nicolin,
> 
> On 09/25/2018 03:59 PM, Nicolin Chen wrote:
> > Texas Instruments INA3221 is a triple-channel shunt and bus
> > voltage monitor. This patch adds a DT binding doc for it.
> > 
> > Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> > ---
> > Changelog
> > v4->v5:
> >   * Replaced "input-id" with "reg" and added address-cells and size-cells
> >   * Replaced "input-label" with "label"
> >   * Replaced "shunt-resistor" with "shunt-resistor-micro-ohms"
> > v3->v4:
> >   * Removed the attempt of putting labels in the node names
> >   * Added a new optional label property in the child node
> >   * Updated examples accordingly
> > v2->v3:
> >   * Added a simple subject in the line 1
> >   * Fixed the shunt resistor value in the example
> > v1->v2:
> >   * Dropped channel name properties
> >   * Added child node definitions.
> >   * * Added shunt resistor property in the child node
> >   * * Added status property to indicate connection status
> >   * * Changed to use child node name as the label of input source
> > 
> >   .../devicetree/bindings/hwmon/ina3221.txt     | 49 +++++++++++++++++++
> >   1 file changed, 49 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/hwmon/ina3221.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/hwmon/ina3221.txt b/Documentation/devicetree/bindings/hwmon/ina3221.txt
> > new file mode 100644
> > index 000000000000..e17a897f4803
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/hwmon/ina3221.txt
> > @@ -0,0 +1,49 @@
> > +Texas Instruments INA3221 Device Tree Bindings
> > +
> > +1) ina3221 node
> > +  Required properties:
> > +  - compatible: Must be "ti,ina3221"
> > +  - reg: I2C address
> > +
> > +  Optional properties:
> > +  = The node contains optional child nodes for three channels =
> > +  = Each child node describes the information of input source =
> > +
> > +  - #address-cells: Required only if a child node is present. Must be 1.
> > +  - #size-cells: Required only if a child node is present. Must be 0.
> > +
> > +  Example:
> > +
> > +  ina3221@40 {
> > +          compatible = "ti,ina3221";
> > +          reg = <0x40>;
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +
> > +          [ child node definitions... ]
> > +  };
> > +
> > +2) child nodes
> > +  Required properties:
> > +  - reg: Must be 0, 1 or 2, corresponding to IN1, IN2 or IN3 port of INA3221
> > +
> > +  Optional properties:
> > +  - label: Name of the input source
> > +  - shunt-resistor-micro-ohms: Shunt resistor value in micro-Ohm
> > +  - status: Should be "disabled" if no input source
> > +
> > +  Example:
> > +
> > +  input@0 {
> > +          reg = <0x0>;
> > +          status = "disabled";
> 
> I kind of feel embarrassed that I asked for the reg change ... especially while
> saying at the same time that I would like to see this work for other chips
> as well.
> 
> Other chips have different kinds of sensors. Voltage, current, power, temperature,
> and others. Whatever we come up with should support that.
> 
> I see two possibilities right now. We can stick with reg and add a "type" property,
> or we can make the index something like
> 	{voltage,current,power,temperature,humidity}-{id,index}
> 
> I personally prefer "type", but I don't really have a strong opinion.
> What do you think ? Or maybe we should really wait for feedback from Rob.

reg and 'type' is my preference though just 'type' may be too vague. For 
this case I don't think we need it if there's only one possible type as 
the driver should know that.

Rob