On Thu, 22 Feb 2024 17:54:28 +0000 Conor Dooley <conor@xxxxxxxxxx> wrote: > On Thu, Feb 22, 2024 at 05:41:03PM +0100, Nuno Sá wrote: > > On Thu, 2024-02-22 at 15:40 +0000, Conor Dooley wrote: > > > On Thu, Feb 22, 2024 at 01:55:56PM +0100, Nuno Sa wrote: > > > > Add a property for the VDD power supply regulator. > > > > > > > > Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx> > > > > --- > > > > Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml | 2 ++ > > > > 1 file changed, 2 insertions(+) > > > > > > > > diff --git > > > > a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml > > > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml > > > > index dbb85135fd66..8aae867a770a 100644 > > > > --- a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml > > > > +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml > > > > @@ -57,6 +57,8 @@ properties: > > > > interrupts: > > > > maxItems: 1 > > > > > > > > + vdd-supply: true > > > > > > Although technically an ABI break, should we make this supply required? > > > It is, at the end of the day, required by the hardware for operation. > > > > > > > I thought about it but then realized it could break some existing users which is > > never a nice thing. > > Could you explain what scenario it actually breaks a system (not > produces warnings with dtbs_check)? > > If anything actually broke something, it would be the driver change that > actually assumed that the regulator was present and refused to probe > otherwise, right? In Linux at least, the regulator core will provide a > dummy regulator if one doesn't exist - otherwise patch 6/6 would > actually contain a DT ABI breakage, since it does: > > ret = devm_regulator_get_enable(&spi->dev, "vdd"); > if (ret) > return ret; > > IMO making a new property required is only a meaningful break of the ABI > when drivers reject probe when it is missing, but I must admit I don't > know if other operating systems handle missing regulators as nicely as > Linux does. Agreed - adding a requirement on a supply to the dt-binding shouldn't be a problem because of the dummy regulators. Jonathan > > > I recently (in another series - the IIO backend) went through some trouble to > > actually not break ABI. Meaning, I had to do some not so neat hacking in the > > driver because Rob was more comfortable with not breaking ABI in DT. So, I > > assumed he would not like for me to break it in here. >
