[PATCH 1/1] of/irq: store IRQ trigger/level in struct resource flags

Grant Likely grant.likely at secretlab.ca
Wed Jun 5 19:26:47 EDT 2013

On Tue, 09 Apr 2013 00:44:05 +0200, Javier Martinez Canillas <javier.martinez at collabora.co.uk> wrote:
> On 04/09/2013 12:05 AM, Rob Herring wrote:
> > On 04/05/2013 02:48 AM, Javier Martinez Canillas wrote:
> >> This means that drivers that need the IRQ type/level flags defined in
> >> the DT won't be able to get it.
> > 
> > But the interrupt controllers that need the information should be able
> > to get to it via irqd_get_trigger_type. What problem exactly are you
> > trying to fix? What driver would use this?
> >
> Yes but this is not about the interrupt controller wanting this information but
> a device driver that is using the IORESOURCE_IRQ struct resource that has the
> information about the virtual IRQ associated with a GPIO-IRQ.
> The driver doesn't know neither care if its IRQ line is connected to a line of
> an real IRQ controller or to a GPIO controller that allows a GPIO line to be
> used as an IRQ.
> > My understanding of the IORESOURCE_IRQ_xxx (and DMA) bits are they are
> > ISA specific and therefore should not be used on non-ISA buses.
> > 
> Many TI OMAP2+ SoC based boards have an SMSC LAN911x/912x controller
> (drivers/net/ethernet/smsc/smsc911x.c) that is connected to the OMAP processor
> through its General-Purpose Memory Controller (GPMC) and this LAN driver obtain
> its IRQ and I/O address space from a struct resource IORESOURCE_IRQ and
> IORESOURCE_MEM respectively, that is filled by the DeviceTree core.
> It does this:
> irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> irq_flags = irq_res->flags & IRQF_TRIGGER_MASK;
> Since of_irq_to_resource() doesn't fill the trigger/level flags on the
> IORESOURCE_IRQ struct resource, irq_flags will always be 0 regarding the value
> specified on the second cell of the "interrupts" DT property.
> A previous discussion about this can be found here [1].

I can't remember if there was ever a reason for not returning the IRQ
flags, but I don't have any major objection to doing so if drivers find
them useful. The one concern I do have however is if it will cause any
problems with drivers that expect flags == IORESOURCE_IRQ without any
additional flags. Any users doing that are buggy anyway, but I do want
to be careful about breakage.

I'll go over your patch and reply with comments.


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