Hi Rob,


2017-09-08 4:41 GMT+09:00 Rob Herring [off-list ref]:

On Thu, Sep 7, 2017 at 6:42 AM, Masahiro Yamada
[off-list ref] wrote:

quoted

This GPIO controller device is used on UniPhier SoCs.

It also serves as an interrupt controller, but interrupt signals are
just delivered to the parent irqchip without any latching or OR'ing.
This is implemented by using hierarchy IRQ domain.

Implementation note:
Unfortunately, the IRQ mapping from this controller to the parent is
random. (48, 49, ..., 63, 154, 155, ...)
If "interrupts" property is used, IRQ resources may be statically
allocated when platform devices are populated from DT.  This can be
a problem for the hierarchy IRQ domain because IRQ allocation must
happen from the outer-most domain up to the root domain in order to
build up the stacked IRQ.  (https://lkml.org/lkml/2017/7/6/758)
Solutions to work around it could be to hard-code parent hwirqs or
to invent a driver-specific DT property.

Here, the new API irq_domain_push_irq() was merged by v4.14-rc1.
It allows to add irq_data to the existing hierarchy.  It will help
to make this driver work whether the parent has already initialized
the hierarchy or not.

Signed-off-by: Masahiro Yamada <redacted>
---

Changes in v4:
  - Add COMPILE_TEST and select IRQ_DOMAIN_HIERARCHY
  - Reimplement irqchip part by using irq_domain_push_irq()

Changes in v3:
  - Add .irq_set_affinity() hook
  - Use irq_domain_create_hierarchy() instead of legacy
    irq_domain_add_hierarchy()

Changes in v2:
  - Remove +32 offset for parent interrupts to follow the GIC
    binding convention
  - Let uniphier_gpio_irq_alloc() fail if nr_irqs != 1
  - Allocate gpio_chip statically because just one instance is
    supported
  - Fix suspend and resume hooks

 .../devicetree/bindings/gpio/gpio-uniphier.txt     |  43 ++

What happened to my ack? One line here more that before, but I'm not
going to diff your patches for you.

I changed the binding for this version.
It includes a new one you have not acked yet.

Maybe I was too worried about it.

BTW, it is preferred to split bindings to a separate patch.

I will do so next time.



-- 
Best Regards
Masahiro Yamada