On Wed, Mar 29, 2023 at 04:39:35PM +0100, Cristian Marussi wrote: > The ARM MHUv2 Receiver block can indeed support more interrupts, up to the > maximum number of available channels, but anyway no more than the maximum > number of supported interrupt for an AMBA device. > > Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx> > --- > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx> > Cc: devicetree@xxxxxxxxxxxxxxx > > .../devicetree/bindings/mailbox/arm,mhuv2.yaml | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml > index a4f1fe63659a..5a57f4e2a623 100644 > --- a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml > +++ b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml > @@ -69,10 +69,15 @@ properties: > > interrupts: > description: | > - The MHUv2 controller always implements an interrupt in the "receiver" > - mode, while the interrupt in the "sender" mode was not available in the > - version MHUv2.0, but the later versions do have it. > - maxItems: 1 > + The MHUv2 controller always implements at least an interrupt in the > + "receiver" mode, while the interrupt in the "sender" mode was not > + available in the version MHUv2.0, but the later versions do have it. > + In "receiver" mode, beside a single combined interrupt, there could be > + multiple interrupts, up to the number of implemented channels but anyway > + no more than the maximum number of interrupts potentially supported by > + AMBA. > + minItems: 1 > + maxItems: 9 I am not sure 9 is the correct value here. IIUC it is just what Linux defines as AMBA_NR_IRQS. Looking at the history it was bumped from 2 to 9 for use by PL330 DMA driver. I couldn't find anything to relate this 9 in any AMBA or other related specification. Ideally I would say we don't know what the max here. We just have a platform implementing 2 interrupts now. Do we for with 2 for now and change it if some new users require more in the future ? I will leave that to the DT maintainers but 9 is simply random based on Linux code so I would rather choose some other random number with a better reasoning than 9 as AMBA code in the kernel is limiting it to 9. -- Regards, Sudeep
