Messages in this thread | | | Subject | Re: [PATCH v4 6/6] gpio: uniphier: add UniPhier GPIO controller driver | From | David Daney <> | Date | Tue, 12 Sep 2017 08:44:09 -0700 |
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On 09/12/2017 07:03 AM, Linus Walleij wrote: > On Thu, Sep 7, 2017 at 1:42 PM, Masahiro Yamada > <yamada.masahiro@socionext.com> wrote: > >> 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 <yamada.masahiro@socionext.com> >> --- >> >> Changes in v4: >> - Add COMPILE_TEST and select IRQ_DOMAIN_HIERARCHY >> - Reimplement irqchip part by using irq_domain_push_irq() > > Awesome improvement. There was a build error and I also > would like David Daney to have a look at this so we know we > use things the right way,
It looks correct to me.
I haven't verified it, but I think the OF device-tree probing code for the platform devices will automatically xlat-and-map all those irqs, so that the irq_domain_push_irq() is required to get the domain hierarchy properly configured. It would be similar to the PCI case where we configure all the MSI-X and then do the irq_domain_push_irq() in the Cavium ThunderX driver.
If interrupt handling has been verified to work with this driver, I would say that we are probably using things "the right way".
David.
> but overall I am happy after this > so I hope I will be able to apply next version. > > Yours, > Linus Walleij >
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