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

From: Linus Walleij <linus.walleij@linaro.org>
To: Maulik Shah <mkshah@codeaurora.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: "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 14:31:53 +0100	[thread overview]
Message-ID: <CACRpkdZJ6yrisNKFG8MJEOhzAV7HRtUTniXpnFVd9fpVy75ruw@mail.gmail.com> (raw)
In-Reply-To: <1604561884-10166-1-git-send-email-mkshah@codeaurora.org>

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 :)

Yours,
Linus Walleij