linux-kernel - Re: [PATCH v4 6/6] gpio: uniphier: add UniPhier GPIO controller driver

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Message-ID: <20170911201515.d4vki3yhrywpmdvc@rob-hp-laptop>
Date:   Mon, 11 Sep 2017 15:15:15 -0500
From:   Rob Herring <robh@...nel.org>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Marc Zyngier <marc.zyngier@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Jason Cooper <jason@...edaemon.net>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        David Daney <david.daney@...ium.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Mark Rutland <mark.rutland@....com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v4 6/6] gpio: uniphier: add UniPhier GPIO controller
 driver

On Sat, Sep 09, 2017 at 12:14:45AM +0900, Masahiro Yamada wrote:
> Hi Rob,
> 
> 
> 2017-09-08 4:41 GMT+09:00 Rob Herring <robh+dt@...nel.org>:
> > On Thu, Sep 7, 2017 at 6:42 AM, Masahiro Yamada
> > <yamada.masahiro@...ionext.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@...ionext.com>
> >> ---
> >>
> >> 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.

Probably so, but I still don't know what you changed.

Rob