linux-kernel - Re: [PATCH v2 1/4] gpio: gpiolib: Allow GPIO IRQs to lazy disable

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Date:   Mon, 25 May 2020 14:22:26 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Maulik Shah <mkshah@...eaurora.org>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Marc Zyngier <maz@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Evan Green <evgreen@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        MSM <linux-arm-msm@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Andy Gross <agross@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Doug Anderson <dianders@...omium.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Lina Iyer <ilina@...eaurora.org>, lsrao@...eaurora.org
Subject: Re: [PATCH v2 1/4] gpio: gpiolib: Allow GPIO IRQs to lazy disable

On 25/05/2020 13:55, Linus Walleij wrote:
> On Sat, May 23, 2020 at 7:11 PM Maulik Shah <mkshah@...eaurora.org> wrote:
> 
>> With 'commit 461c1a7d4733 ("gpiolib: override irq_enable/disable")' gpiolib
>> overrides irqchip's irq_enable and irq_disable callbacks. If irq_disable
>> callback is implemented then genirq takes unlazy path to disable irq.
>>
>> Underlying irqchip may not want to implement irq_disable callback to lazy
>> disable irq when client drivers invokes disable_irq(). By overriding
>> irq_disable callback, gpiolib ends up always unlazy disabling IRQ.
>>
>> Allow gpiolib to lazy disable IRQs by overriding irq_disable callback only
>> if irqchip implemented irq_disable. In cases where irq_disable is not
>> implemented irq_mask is overridden. Similarly override irq_enable callback
>> only if irqchip implemented irq_enable otherwise irq_unmask is overridden.
>>
>> Fixes: 461c1a7d47 (gpiolib: override irq_enable/disable)
>> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
> 
> I definitely want Hans Verkuils test and review on this, since it
> is a usecase that he is really dependent on.

Maulik, since I am no longer subscribed to linux-gpio, can you mail the
series to me?

I have two use-cases, but I can only test one (I don't have access to the
SBC I need to test the other use-case for the next few months).

Once I have the whole series I'll try to test the first use-case and at
least look into the code if this series could affect the second use-case.

Regards,

	Hans

> 
> Also the irqchip people preferredly.
> 
> But it does seem to mop up my mistakes and fix this up properly!
> 
> So with some testing I'll be happy to merge it, even this one
> patch separately if Hans can verify that it works.
> 
> Yours,
> Linus Walleij
>