On Mon, 28 Oct 2024 at 09:06, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > > On Mon, Oct 28, 2024 at 08:11:14AM +0100, ahaslam@xxxxxxxxxxxx wrote: > > From: Axel Haslam <ahaslam@xxxxxxxxxxxx> > > > > Vcc, iovcc, vrefp, and vrefn are needed for the DAC to work. > > Add them as required bindings for ad5791. > > > > Signed-off-by: Axel Haslam <ahaslam@xxxxxxxxxxxx> > > --- > > .../bindings/iio/dac/adi,ad5791.yaml | 24 +++++++++++++++++++ > > 1 file changed, 24 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ad5791.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ad5791.yaml > > index fe664378c966..79cb4b78a88a 100644 > > --- a/Documentation/devicetree/bindings/iio/dac/adi,ad5791.yaml > > +++ b/Documentation/devicetree/bindings/iio/dac/adi,ad5791.yaml > > @@ -26,6 +26,22 @@ properties: > > vdd-supply: true > > vss-supply: true > > > > + vcc-supply: > > + description: > > + Supply that powers the chip. > > + > > + iovcc-supply: > > + description: > > + Supply for the digital interface. > > + > > + vrefp-supply: > > + description: > > + Positive referance input voltage range. From 5v to (vdd - 2.5) > > + > > + vrefn-supply: > > + description: > > + Negative referance input voltage range. From (vss + 2.5) to 0. > > + > > adi,rbuf-gain2-en: > > description: Specify to allow an external amplifier to be connected in a > > gain of two configuration. > > @@ -47,6 +63,10 @@ required: > > - reg > > - vdd-supply > > - vss-supply > > + - vcc-supply > > + - iovcc-supply > > + - vrefp-supply > > + - vrefn-supply > > So you have six required supplies? > > Datasheet says "A voltage range of 2.7 V to 5.5 V *can* be connected", > so doesn't it mean this is optional? Although similar wording is for > other supplies, so maybe it's just imprecise language? looks like unfortunate wording. Like you said, Vdd, Vss are already required and have the same *can* word in their description like all other supplies which i think its meant for the voltage level options of the power supply. Vcc: is mentioned as need to "power on" in the startup sequence section of the datasheet, iovcc: we can't interface the chip without this supply. vrefp: minimum input of 5v. vrefn: from vss up to 0 volts max. so vcc, iovcc, and vrefp to me, look required for the hw to work. but i have a small doubt about vrefn since it could potentially be 0V. Does this mean it should be an optional binding where we assume its 0 if not present? or is it ok to leave it as required? Regards Axel. > > Best regards, > Krzysztof >
