Re: [PATCH v2 1/2] dt-binding: clock: cs2600: Add support for the CS2600

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Thu, Dec 19, 2024 at 12:39:38PM +0100, Krzysztof Kozlowski wrote:
> On 19/12/2024 12:02, Charles Keepax wrote:
> > On Thu, Dec 19, 2024 at 09:51:00AM +0100, Krzysztof Kozlowski wrote:
> >> On Wed, Dec 18, 2024 at 08:46:30PM -0600, Paul Handrigan wrote:
> >>> +/* CS2600 Auxiliary Output */
> >>> +#define CS2600_AUX_OUTPUT_FREQ_UNLOCK	0
> >>> +#define CS2600_AUX_OUTPUT_PHASE_UNLOCK	1
> >>> +#define CS2600_AUX_OUTPUT_NO_CLKIN	2
> >>
> >> I still don't see why these three are supposed to be bindings. Drop
> >> them.
> > 
> > In a binding one would presumably do:
> > 
> > cirrus,aux-output-source = <CS2600_AUX_OUTPUT_FREQ_UNLOCK>;
> > 
> > Apologies but I don't quite understand what you mean by the values
> > are not used in the binding? The driver reads the property and sets
> 
> There is no user of these defines, so not a binding.
> 
> > the pin to have the appropriate function. Admittedly one could drop
> 
> It's not a proof that this is a binding.
> 
> > the defines and then DTS would just have to do:
> > 
> > cirrus,aux-output-source = <0>;
> > 
> > But that feels a bit less helpful when reading the binding.
> 
> Binding and being helpful are two different things. This to be the
> binding, it has to be used as a binding, so some translation layer
> between driver and DTS. It must have an user in DTS. I keep repeating
> this over and over...
> 

Apologies, but I not sure I totally follow this, and apologies if
you have already explained this are there some docs I can look
at?

I think you are saying because these defines merely represent the
valid values for a device tree property and are not translated
into different values you can't put defines for them in the binding
header?

So this would not be allowed:

  #define CS2600_AUX_OUTPUT_FREQ_UNLOCK 0

  cirrus,aux-output-source = <CS2600_AUX_OUTPUT_FREQ_UNLOCK>;

  device_property_read_u32(dev, "cirrus,aux-output-source", &val);
  regmap_write(regmap, CS2600_OUTPUT_CFG2, val);

But this would be fine:

  #define CS2600_AUX_OUTPUT_FREQ_UNLOCK 1

  cirrus,aux-output-source = <CS2600_AUX_OUTPUT_FREQ_UNLOCK>;

  device_property_read_u32(dev, "cirrus,aux-output-source", &val);
  switch (val) {
  case CS2600_AUX_OUTPUT_FREQ_UNLOCK:
    regmap_write(regmap, CS2600_OUTPUT_CFG2, 0);
  }

And this would also be fine?

  cirrus,aux-output-source = <0>;

  device_property_read_u32(dev, "cirrus,aux-output-source", &val);
  regmap_write(regmap, CS2600_OUTPUT_CFG2, val);

Thanks,
Charles