Re: [PATCH] genirq: fix trigger flags check for shared irqs

From: Thomas Gleixner
Date: Thu Jan 28 2016 - 15:07:32 EST

On Thu, 28 Jan 2016, Rob Herring wrote:
> On Thu, Jan 28, 2016 at 5:49 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > I've cc'ed the author and the device tree folks. Perhaps are they able to
> > explain what this commit tries to 'fix'.
> It's certainly not clear what driver was being fixed. I think the
> intention was to provide the trigger flags from the DT to drivers in a
> standard, non-DT specific way. The implementation of it certainly
> seems convoluted. The usecase I can think of is drivers may need the
> trigger information for cases where the device can support different
> trigger modes/polarity. The DT says which trigger mode to use and the
> device and irqchip need to be programmed to match. IIRC, SMSC ethernet
> chips frequently used on ARM boards do this.

I can see that the driver wants this information, but why would one feed that
back into request_irq() when the interrupt was already configured by DT.

Still confused.