On Tue, Nov 19, 2013 at 5:22 PM, Grygorii Strashko
[off-list ref] wrote:

On 11/19/2013 01:06 AM, Linus Walleij wrote:

quoted

The problem that appear is if someone is using platform data-provided
IRQs off the irq_chip without calling gpio_to_irq() on the GPIO line
first. This has been determined to be legal to do, so preferably
create the map when registering the lines.

Ok, I understand. It may fail in case if someone will define/calculate
 IRQ number for device manually in board code, like:
 dev_irq = (DA850_N_CP_INTC_IRQ + gpioN)

Usually people just hardcode the IRQ value or use some
#define, like they have often also done with GPIO numbers ...

Also, looks like It is possible to fail if Main/arch IRQ controller
code doesn't make call of irq_alloc_descs() during init, so
allocated_irqs will be empty.

If you use irq_domain_add_simple() the irqdomain core
will actually attempt to do this.

But if you use a linear domain, you have to create these
irqdescs as you go. The simplest way to do this is to call
irq_create_mapping() on all IRQs, because that call will
also allocate some descriptor.

Before recommending that, I've checked Davinci platform code and didn't
find any risk places - BUT, Seems my findings need to be confirmed by
Sekhar.

It's no big deal, but I just want you to be aware that this
may cause a problem at some point.

quoted

I think you should try to keep the 5 irqdomains, but whatever
gives the simplest code is usually the right answer, and
divide-and-conquer (split down the problem) is usually a good
idea.

How the GPIO block(s) are represented in the device tree is
another totally separate issue about hardware description,
do not let the device tree model your driver structure.

Thanks for you comments, but looks like I have to be more specific :)

How irq_find_host() will look for proper IRQ domain in our case?
And will it work at all, taking into account that all (5) IRQ domains
will have the same value of "of_node" property?
of_irq_to_resource()
|-irq_of_parse_and_map()
  |-irq_create_of_mapping()
    |-irq_find_host(irq_data->np)
 where np will point on GPIO node.

As result my question is about what do DT core frameworks allow or not
allow to do? And according to that implementation of driver can be
changed.

Hm, I'm not like a super-expert on the interrupt core, but maybe
you need to create subnodes inside the top node to represent this,
then use of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
to populate them from the main node.

Yours,
Linus Walleij