Re: [PATCH v2 1/4] dt-bindings: bluetooth: add new wcn3991 compatible to fix bd_addr

[Johan Hovold <johan@kernel.org>]

On Mon, Mar 18, 2024 at 04:17:24PM +0200, Dmitry Baryshkov wrote:
> On Mon, 18 Mar 2024 at 15:17, Johan Hovold <johan@kernel.org> wrote:
> > On Mon, Mar 18, 2024 at 03:00:40PM +0200, Dmitry Baryshkov wrote:
> > > On Mon, 18 Mar 2024 at 13:09, Johan Hovold <johan+linaro@kernel.org> wrote:
> > > > The only device out there that should be affected by this is the WCN3991
> > > > used in some Chromebooks. To maintain backwards compatibility, mark the
> > > > current compatible string as deprecated and add a new
> > > > 'qcom,wcn3991-bt-bdaddr-le' for firmware which conforms with the
> > > > binding.
> >
> > > This compatible doesn't describe new hardware kind. As such, I think,
> > > the better way would be to continue using qcom,wcn3991-bt compatible
> > > string + add some kind of qcom,bt-addr-le property.
> >
> > No, you can't handle backwards compatibility by *adding* a property.
> >
> > I wanted to avoid doing this, but if we have to support Google's broken
> > boot firmware for these devices, then this is how it needs to be done.
> 
> One hardware compat string per hardware type.

Again, no. Not when there is an incompatible change in the binding. Then
we add a new compatible string and deprecate the old binding.

Johan