Re: [PATCH] pinctrl: qcom: Move clearing pending IRQ to .irq_request_resources callback

From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Maulik Shah <mkshah@codeaurora.org>,
	Andy Gross <agross@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	MSM <linux-arm-msm@vger.kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	"open list:GPIO SUBSYSTEM <linux-gpio@vger.kernel.org>,
	Andy Gross <agross@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Doug Anderson <dianders@chromium.org>,
	Rajendra Nayak <rnayak@codeaurora.org>,
	Lina Iyer <ilina@codeaurora.org>,"  <dianders@chromium.org>,
	Stephen Boyd <swboyd@chromium.org>,
	Evan Green <evgreen@chromium.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Rajendra Nayak <rnayak@codeaurora.org>,
	Lina Iyer <ilina@codeaurora.org>,
	"open list:GPIO SUBSYSTEM <linux-gpio@vger.kernel.org>,
	Andy Gross <agross@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Doug Anderson <dianders@chromium.org>,
	Rajendra Nayak <rnayak@codeaurora.org>,
	Lina Iyer <ilina@codeaurora.org>,"  <lsrao@codeaurora.org>
Subject: Re: [PATCH] pinctrl: qcom: Move clearing pending IRQ to .irq_request_resources callback
Date: Tue, 10 Nov 2020 15:28:13 -0600	[thread overview]
Message-ID: <20201110212813.GF807@yoga> (raw)
In-Reply-To: <CACRpkdZJ6yrisNKFG8MJEOhzAV7HRtUTniXpnFVd9fpVy75ruw@mail.gmail.com>

On Tue 10 Nov 07:31 CST 2020, Linus Walleij wrote:

> On Thu, Nov 5, 2020 at 8:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
> 
> > When GPIOs that are routed to PDC are used as output they can still latch
> > the IRQ pending at GIC. As a result the spurious IRQ was handled when the
> > client driver change the direction to input to starts using it as IRQ.
> >
> > Currently such erroneous latched IRQ are cleared with .irq_enable callback
> > however if the driver continue to use GPIO as interrupt and invokes
> > disable_irq() followed by enable_irq() then everytime during enable_irq()
> > previously latched interrupt gets cleared.
> >
> > This can make edge IRQs not seen after enable_irq() if they had arrived
> > after the driver has invoked disable_irq() and were pending at GIC.
> >
> > Move clearing erroneous IRQ to .irq_request_resources callback as this is
> > the place where GPIO direction is changed as input and its locked as IRQ.
> >
> > While at this add a missing check to invoke msm_gpio_irq_clear_unmask()
> > from .irq_enable callback only when GPIO is not routed to PDC.
> >
> > Fixes: e35a6ae0eb3a ("pinctrl/msm: Setup GPIO chip in hierarchy")
> > Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> 
> This looks critical so I applied it for fixes so we get some
> rotation in linux-next.
> 
> If Bjorn has other opinions he will tell us :)
> 

No objections, the patch looks reasonable to me.

Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn