On Mon, May 13, 2024 at 1:52 PM Rob Herring <robh@xxxxxxxxxx> wrote:
>
> On Fri, May 10, 2024 at 10:43:18AM -0500, David Lechner wrote:
> > On Fri, May 10, 2024 at 9:19 AM Angelo Dureghello
> > <adureghello@xxxxxxxxxxxx> wrote:
> > >
> > > From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> > >
> > > The adi,gain-scaling-p/n values are an inverted log2,
> > > so initial naiming was set correct, but the driver uses just
> > > adi,gain-scaling-p/n, so uniforming documentation, that seems
> > > a less-risk fix for future rebases, and still conformant to datasheet.
> > >
> > > Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> > > ---
> > > .../devicetree/bindings/iio/dac/adi,ad3552r.yaml | 16 ++++++++--------
> > > 1 file changed, 8 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml
> > > index 17442cdfbe27..9e3dbf890bfa 100644
> > > --- a/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml
> > > +++ b/Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml
> > > @@ -94,13 +94,13 @@ patternProperties:
> > > maximum: 511
> > > minimum: -511
> > >
> > > - adi,gain-scaling-p-inv-log2:
> > > - description: GainP = 1 / ( 2 ^ adi,gain-scaling-p-inv-log2)
> > > + adi,gain-scaling-p:
> > > + description: GainP = 1 / ( 2 ^ adi,gain-scaling-p)
> > > $ref: /schemas/types.yaml#/definitions/uint32
> > > enum: [0, 1, 2, 3]
> > >
> > > - adi,gain-scaling-n-inv-log2:
> > > - description: GainN = 1 / ( 2 ^ adi,gain-scaling-n-inv-log2)
> > > + adi,gain-scaling-n:
> > > + description: GainN = 1 / ( 2 ^ adi,gain-scaling-n)
> > > $ref: /schemas/types.yaml#/definitions/uint32
> > > enum: [0, 1, 2, 3]
> > >
> > > @@ -109,8 +109,8 @@ patternProperties:
> > >
> > > required:
> > > - adi,gain-offset
> > > - - adi,gain-scaling-p-inv-log2
> > > - - adi,gain-scaling-n-inv-log2
> > > + - adi,gain-scaling-p
> > > + - adi,gain-scaling-n
> > > - adi,rfb-ohms
> > >
> > > required:
> > > @@ -214,8 +214,8 @@ examples:
> > > reg = <1>;
> > > custom-output-range-config {
> > > adi,gain-offset = <5>;
> > > - adi,gain-scaling-p-inv-log2 = <1>;
> > > - adi,gain-scaling-n-inv-log2 = <2>;
> > > + adi,gain-scaling-p = <1>;
> > > + adi,gain-scaling-n = <2>;
> > > adi,rfb-ohms = <1>;
> > > };
> > > };
> > > --
> > > 2.45.0.rc1
> > >
> > >
> >
> > The DT bindings are generally considered immutable. So unless we can
> > prove that no one has ever put adi,gain-scaling-n-inv-log2 in a .dtb
> > file,
>
> You can't ever prove that.
>
> > we probably need to fix this in the driver rather than in the
> > bindings. (The driver can still handle adi,gain-scaling-p in the
> > driver for backwards compatibility but the official binding should be
> > what was already accepted in the .yaml file)
>
> If we can reasonable assume that the Linux driver is the only consumer,
> there are no upstream dts users (in kernel or other opensource
> projects), and/or the property is somewhat recent, then that's good
> enough IMO.
>
> Rob
Ack. I stand corrected then.
