Re: [PATCH] dt-bindings: microchip: atmel,at91rm9200-tcb: remove mandatory interrupts property

From: Rob Herring
Date: Fri Feb 11 2022 - 09:21:55 EST


On Fri, Feb 04, 2022 at 11:36:02AM +0100, Alexandre Belloni wrote:
> On 04/02/2022 10:28:43+0000, Eugen.Hristev@xxxxxxxxxxxxx wrote:
> > On 2/4/22 11:46 AM, Alexandre Belloni wrote:
> > > On 04/02/2022 10:14:46+0200, Eugen Hristev wrote:
> > >> The timer block can be used only to be read and to measure time in a polling
> > >> fashion. This can be used by Linux like this for example, or it can be used
> > >> by different projects which do not have interrupt controllers, or do not
> > >> wish to enable them (e.g. U-boot).
> > >> As DT is ABI, the binding should relate to all possible use cases and describe
> > >> the hardware and the requirements.
> > >> The interrupt is not a hard requirement for the timer to function in a
> > >> specific way.
> > >> Thus, choose to remove the interrupts property from the mandatory list of
> > >> properties.
> > >>
> > >
> > > The correct hardware description is that the interrupt is present on the
> > > IP. Having software behave differently depending on the presence of that
> > > property is configuration, not hardware description.
> >
> > I agree. The interrupt is present on the IP, thus the property exists
> > and it's described.
> > However, the interrupt is not mandatory for IP operations. Thus it
> > should not be in the list of mandatory properties.
> >
>
> If the interrupt is always present, it is mandatory, it doesn't matter
> whether is is used or necessary to get the IP to work.

Agreed.