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

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Message-ID: <alpine.DEB.2.11.1601282105150.3886@nanos>
Date:	Thu, 28 Jan 2016 21:06:20 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Rob Herring <robh+dt@...nel.org>
cc:	Brian Starkey <brian.starkey@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Marc Zyngier <marc.zyngier@....com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Frank Rowand <frowand.list@...il.com>,
	Grant Likely <grant.likely@...aro.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH] genirq: fix trigger flags check for shared irqs

On Thu, 28 Jan 2016, Rob Herring wrote:
> On Thu, Jan 28, 2016 at 5:49 AM, Thomas Gleixner <tglx@...utronix.de> 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.

Thanks,

	tglx