On Thu, 2024-02-22 at 16:43 -0700, Rob Herring wrote: > On Fri, Feb 16, 2024 at 10:47:47AM +0100, Antonio Borneo wrote: > > The mapping of EXTI interrupts to its parent interrupt controller > > is both SoC and instance dependent. > > The current implementation requires adding a new table to the > > driver's code and a new compatible for each new EXTI instance. > > > > Add to the binding an interrupt nexus child node that will be > > used on the new EXTI instances and can be optionally used on the > > existing instances. > > The property 'interrupt-map' in the nexus node maps each EXTI > > interrupt to the parent interrupt. > > Align #address-cells and #interrupt-cells between the EXTI node > > and its nexus node. > > Looks like an abuse of interrupt-map. You avoid adding yourself to the > abuser list by putting it in a child node. Clever. (See list in > drivers/of/irq.c if you don't know what I'm talking about) Hi Rob, thanks for the review. Yes, I know already about the abuser list but, from the commit message and the associated comment, I interpret it as an incorrect use of the property interrupt-map with custom syntax thus relying on custom parsing code. The child nexus node in this series allows using the default parser in kernel. >From your reply, looks like my interpretation is incorrect and I missed the real concern about the abuser list. Could you please explain why this use of interrupt-map is incorrect and/or which are the correct use cases? > I assume the EXTI has 0..N interrupts. Just define 'interrupts' with N > entries with each entry mapping EXTI interrupt N to 'interrupts' entry > N. Yes, EXTI has 0..N interrupts that can be mapped to multiple parent interrupt controllers and the mapping table has holes. While the DT in this series only use one interrupt parent, a second parent will follow. So 'interrupts-extended' property would be a better matching than 'interrupts' to handle the multiple parents. But how to code the missing entries in an 'interrupts-extended' list? As in the example in Documentation/devicetree/bindings/dma/apple,admac.yaml ? The 'interrupt-map' contains the matching EXTI index, thus allowing a 'sparse' map where holes are simply ignored. Best Regards, Antonio
