[PATCH v8 03/12] gpio: pl061: allocate irq dynamically

[Linus Walleij]

On Mon, Feb 11, 2013 at 6:10 PM, Haojian Zhuang
<haojian.zhuang at linaro.org> wrote:

We don't convert drivers to irqdomain without actually *using*
the irqdomain. I don't know where this pattern comes from,
but I'm suspicious about patch sets that just focus on enabling
DT functionality without considering irqdomain stuff as a concept
of its own.

The biggest problem with this patch is what is missing from it:

- irq_base shall be *deleted* from struct pl061_gpio
- instead a struct irqdomain  * shall be stored for offsetting IRQs
- everywhere chip->irq_base is referenced, use irq_find_mapping()
- In pl061_to_irq, irq_create_mapping() shall be used, so it will
  allocate a descriptor even if we're using the driver with
  SPARSE_IRQ and a linear domain.

Look at e.g. gpio-langwell.c for guidance.

> +       chip->irq_base = irq_alloc_descs(chip->irq_base, 0, PL061_GPIO_NR, 0);
> +       if (chip->irq_base < 0)
> +               return chip->irq_base;
> +       if (!irq_domain_add_legacy(adev->dev.of_node, PL061_GPIO_NR,
> +                                  chip->irq_base, 0, &pl061_domain_ops, chip))
>                 return -ENODEV;

Instead of the above, please use:

chip->irqdomain = irq_domain_add_simple(adev->dev.of_node,
                                         PL061_GPIO_NR,
                                         chip->irq_base,
                                         &pl061_domain_ops,
                                         chip);

Notice that I don't throw the domain away after creation either...

This call will allocate descriptors for you as long as the
irq_base > 0, which it should be, since 0 is NO_IRQ.

It make things easier the day you start using a purely
dynamic approach.

Yours,
Linus Walleij