Re: [PATCH 1/2] dt-bindings: pwm: sophgo: add pwm controller for SG2044

Inochi Amaoto
2025-04-08T02:34:09Z

On Mon, Apr 07, 2025 at 09:11:19AM -0500, Rob Herring wrote:
> On Mon, Apr 07, 2025 at 02:31:24PM +0200, Uwe Kleine-König wrote:
> > Hello,
> >
> > On Mon, Apr 07, 2025 at 03:20:38PM +0800, Longbin Li wrote:
> > > diff --git a/Documentation/devicetree/bindings/pwm/sophgo,sg2042-pwm.yaml b/Documentation/devicetree/bindings/pwm/sophgo,sg2042-pwm.yaml
> > > index bbb6326d47d7..e0e91aa237ec 100644
> > > --- a/Documentation/devicetree/bindings/pwm/sophgo,sg2042-pwm.yaml
> > > +++ b/Documentation/devicetree/bindings/pwm/sophgo,sg2042-pwm.yaml
> > > @@ -17,7 +17,9 @@ allOf:
> > >
> > > properties:
> > > compatible:
> > > - const: sophgo,sg2042-pwm
> > > + enum:
> > > + - sophgo,sg2042-pwm
> > > + - sophgo,sg2044-pwm
> >
> > Given that the sg2044 has more registers (to e.g. implement different
> > polarity), but the sg2042 registers are identical, I wonder if the 2044
> > device should use:
> >
> > compatible = "sophgo,sg2044-pwm", "sophgo,sg2042-pwm";
> >
> > Note, I'm unsure here, only providing input to people who are more
> > knowledgeable in DT that I am.
>
> Depends if s/w only understanding "sophgo,sg2042-pwm" will work on the
> 2044. IOW, will a kernel without the driver change here work?
>

No luck, the logic for SG2042 is broken on SG2044. In fact, it seems
to be more familiar to the pwm ip on CV1800 than it on SG2042.

Regards,
Inochi