On 24-02-21, Conor Dooley wrote: > On Wed, Feb 21, 2024 at 08:45:18PM +0100, Marco Felsch wrote: > > Hi Conor, > > > > On 24-02-21, Conor Dooley wrote: > > > On Wed, Feb 21, 2024 at 08:16:44PM +0100, Marco Felsch wrote: > > > > On 24-02-21, Conor Dooley wrote: > > > > > On Wed, Feb 21, 2024 at 06:58:10PM +0100, Marco Felsch wrote: > > > > > > Add the iis2mdc magnetometer support which is equivalent to the lis2mdl. > > > > > > > > > > > > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> > > > > > > --- > > > > > > Documentation/devicetree/bindings/iio/st,st-sensors.yaml | 1 + > > > > > > 1 file changed, 1 insertion(+) > > > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/iio/st,st-sensors.yaml b/Documentation/devicetree/bindings/iio/st,st-sensors.yaml > > > > > > index fff7e3d83a02..ee593c8bbb65 100644 > > > > > > --- a/Documentation/devicetree/bindings/iio/st,st-sensors.yaml > > > > > > +++ b/Documentation/devicetree/bindings/iio/st,st-sensors.yaml > > > > > > @@ -64,6 +64,7 @@ properties: > > > > > > - st,lsm9ds0-gyro > > > > > > - description: STMicroelectronics Magnetometers > > > > > > enum: > > > > > > + - st,iis2mdc > > > > > > > > > > Without a fallback compatible to the equivilent device, how does a > > > > > driver bind to this device? > > > > > > > > I skimed the datasheets and the driver already handles this binding > > > > exactly the same as the st,lis2mdl, so my assumption is they do match. > > > > > > > > Why do I you think we need a fallback compatible here? > > > > > > I didn't look at the driver, there was no mention of the driver already > > > having (undocumented) support for it. Since there was no driver change > > > alongside this patch, I thought you'd need a fallback compatible to > > > allow the driver to match against a compatible it recognises. > > > > I explicitly did not mention the driver in the commit message else I > > would have got a response like "dt-bindings have no dependency to > > drivers" ;) > > Putting it under the --- line is always an option. Where there are > existing users but the compatible is just undocumented, this it's > helpful to do. > > > > Besides, having fallback compatibles is the norm when one device has the > > > same programming model as another. > > > > Not for this binding according the driver. > > If they don't have the same programming model, then describing them as > "equivalent" wouldn't be correct. That said, they seem to use the same > sensor settings when alls said and done (see st_magn_sensors_settings), > so I think they are actually compatible even if the driver has separate > match data for each. I told you that I have checked the driver and skimed the datasheets and came to the exact same conclusion. Regards, Marco > > Cheers, > Conor.
