Re: [PATCH v2 2/4] dt-bindings: iio: ti,tmp117: add binding for the TMP116

Marco Felsch
2022-12-23T15:04:05Z

On 22-12-23, Jonathan Cameron wrote:
> On Wed, 21 Dec 2022 10:27:59 +0100
> Marco Felsch <m.felsch@pengutronix.de> wrote:
>
> > The TMP116 is the predecessor of the TMP117.
> >
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> I'm not sure this is introducing a valid fallback. The driver changes
> imply some things the tmp117 driver supports, that this device
> does not. A fallback compatible would mean that a new DT
> with an old kernel would load the tmp117 against a tmp116 and
> expect it to fully work.

Since driver does all the detection an update of the bindings isn't
really necessary. It is just to have a compatible already in place in
case there a things we can't detected during runtime. This flow is
common for a lot of SoC drivers. The fallback will be used as long as
possible and once a specific feature can't be detected only via the
binding, the driver adds the new binding to it of_compatible.

Regards,
Marco

> An example is calibbias which you've dropped from the channels
> array entry.
>
> Jonathan
>
>
> > ---
> > v2:
> > - drop items from single enum
> >
> > .../bindings/iio/temperature/ti,tmp117.yaml | 14 ++++++++++----
> > 1 file changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml b/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
> > index 8d1ec4d39b28..9b78357d6a79 100644
> > --- a/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
> > +++ b/Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
> > @@ -7,8 +7,9 @@ $schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > title: "TI TMP117 - Digital temperature sensor with integrated NV memory"
> >
> > description: |
> > - TI TMP117 - Digital temperature sensor with integrated NV memory that supports
> > - I2C interface.
> > + TI TMP116/117 - Digital temperature sensor with integrated NV memory that
> > + supports I2C interface.
> > + https://www.ti.com/lit/gpn/tmp116
> > https://www.ti.com/lit/gpn/tmp117
> >
> > maintainers:
> > @@ -16,8 +17,13 @@ maintainers:
> >
> > properties:
> > compatible:
> > - enum:
> > - - ti,tmp117
> > + oneOf:
> > + - enum:
> > + - ti,tmp117
> > + - items:
> > + - enum:
> > + - ti,tmp116
> > + - const: ti,tmp117
> >
> > reg:
> > maxItems: 1
>
>