[Linux-stm32] STM32MP1 level triggered interrupts

[Marc Zyngier]

On 2020-01-21 17:12, Alexandre Torgue wrote:
> Hi Marek,
> 
> On 1/20/20 7:32 PM, Marek Vasut wrote:
>> Hi,
>> 
>> I have a device connected to STM32MP157C which requires active-low
>> level-triggered interrupt sink. The device interrupt line is connected
>> to the SoC gpio-C bank, which has it's interrupt line routed into 
>> EXTI,
>> which can only handle edge triggered interrupts to my understanding.
> 
> correct.
> 
>> 
>> However, ARM GIC should be able to do both and EXTI has this irqmux /
>> EXTImux functionality, which -- if my understanding is correct -- is
>> capable of routing a select GPIO line directly into the GIC as an 
>> EXTIn
>> interrupt signal. Thus, this might permit handling active low
>> level-triggered interrupts. Is there some DT binding to configure this 
>> yet ?
>> 
>> Or is there some other, better, way ?
>> 
> 
> For SPIs, GIC controller handles rising edge triggered interrupt and
> active high level-sensitive. GIC integration in STM32MP157c makes that
> only active high level-sensitive configuration for SPI interrupts is
> supported.

This statement is a slight exaggeration. *any* GIC will happily service
rising-edge triggered SPIs, as it is mandated by the spec. What I 
suspect
is that there is no SPI that is routed out of the SoC for anyone to 
directly
plug anything into it.

          M.
-- 
Jazz is not dead. It just smells funny...