Re: [PATCH v3 1/2] dt-bindings: can: m_can: add out-band-wakeup property

[Krzysztof Kozlowski <krzk@kernel.org>]

On Mon, Aug 24, 2026 at 05:50:20PM +0100, Conor Dooley wrote:
> On Fri, Aug 21, 2026 at 02:05:11PM -0500, Kendall Willis wrote:
> > On 17:45-20260821, Conor Dooley wrote:
> > > On Fri, Aug 21, 2026 at 11:07:00AM -0500, Kendall Willis wrote:
> > > > Add the out-band-wakeup property as a possible property. The property
> > > > indicates that the device can wakeup the system even when its power
> > > > domain is off.
> > > > 
> > > > Signed-off-by: Kendall Willis <k-willis@ti.com>
> > > > ---
> > > >  Documentation/devicetree/bindings/net/can/bosch,m_can.yaml | 2 ++
> > > >  1 file changed, 2 insertions(+)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/net/can/bosch,m_can.yaml b/Documentation/devicetree/bindings/net/can/bosch,m_can.yaml
> > > > index 2c9d37975bedd652b3060ab11ba75c37565edaad..0663beaa532bcc4a71cd6ad01520a4dfea294d0c 100644
> > > > --- a/Documentation/devicetree/bindings/net/can/bosch,m_can.yaml
> > > > +++ b/Documentation/devicetree/bindings/net/can/bosch,m_can.yaml
> > > > @@ -150,6 +150,8 @@ properties:
> > > >      description:
> > > >        List of phandles to system idle states in which mcan can wakeup the system.
> > > >  
> > > > +  out-band-wakeup: true
> > > 
> > > Where is "-wakeup" defined genericly, or out-band-wakeup defined that
> > > you're getting the property definition from?
> > 
> > I sent a PR to define out-band-wakeup in the wakeup-source.yaml binding
> > in dt-schema repo. I figured it made more sense to be defined in the
> > wakeup-source.yaml binding to allow other drivers the option to use it.
> > 
> > dt-schema PR:
> > https://github.com/devicetree-org/dt-schema/pull/205
> 
> This sounds like something you should be able to determine from
> device specific compatibles for these platforms. Not sure why they are
> not used for this particular device, but this is an indication to me
> that that is a mistake.

Yeah, it looks a bit too much replicating Linux PM detail. I can imagine
that some devices on some board are capable of waking up the system even
when power domain is off, but this does not look like a capability of
the actual device, but power domain. Device does not have different
wakeups. (by device I mean this individual schema - Bosch CAN)

Happy to see some bigger picture through DTS or board layouts. Actually
DTS, showing same Bosch CAN devices which are different on a board -
some are wakeups and some out of band wakeups - would illustrate it
better.

Best regards,
Krzysztof