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From:   =?UTF-8?Q?Rados=C5=82aw_Pietrzyk?= <radoslaw.pietrzyk@gmail.com>
Date:   Fri, 23 Feb 2018 10:05:35 +0100
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Subject: Re: [PATCH v2 1/2] irqchip: stm32: Optimizes and cleans up stm32-exti irq_domain
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        open list <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>, linux-gpio@vger.kernel.org,
        Ludovic BARRE <ludovic.barre@st.com>
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I think the HW is fairly simple and straightforward comparing to other
irq chips so it's rather a logic that concerned me the most i.e. why
gpio irqs were handled in a "simple" manner whereas the rest of
interrupts in "edge" manner. According to specification all interrupts
are edge driven and that's how are they treated in set_type callback.
First I thought that all can be handled as simple but then I realized
it makes more sense in handling all of them as edge as they should
according to specification. I will prepare a v3 series with more
detailed explanation in it.

2018-02-23 9:42 GMT+01:00 Thomas Gleixner <tglx@linutronix.de>:
> Radoslaw,
>
> On Fri, 23 Feb 2018, Radoslaw Pietrzyk wrote:
>
>> - discards setting handle_simple_irq handler for hierarchy interrupts
>> - removes acking in chained irq handler as this is done by
>> irq_chip itself inside handle_edge_irq
>> - removes unneeded irq_domain_ops.xlate callback
>
> if that's all functionally correct, then this is a nice cleanup. Though
> from the above changelog its hard to tell because it merily tells WHAT the
> patch does, but not WHY. The WHY is the important information for a
> reviewer who is not familiar with the particular piece of code/hardware.
>
> Can you please amend the changelog with proper explanations why a
> particular piece of code is not needed or has to be changed to something
> else?
>
> Thanks,
>
>         tglx