From: Stephen Boyd <swboyd@chromium.org>
To: Maulik Shah <mkshah@codeaurora.org>,
bjorn.andersson@linaro.org, evgreen@chromium.org,
linus.walleij@linaro.org, maz@kernel.org, mka@chromium.org
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-gpio@vger.kernel.org, agross@kernel.org,
tglx@linutronix.de, jason@lakedaemon.net, dianders@chromium.org,
rnayak@codeaurora.org, ilina@codeaurora.org,
lsrao@codeaurora.org, Maulik Shah <mkshah@codeaurora.org>
Subject: Re: [PATCH v2 1/4] gpio: gpiolib: Allow GPIO IRQs to lazy disable
Date: Wed, 27 May 2020 02:44:02 -0700 [thread overview]
Message-ID: <159057264232.88029.4708934729701385486@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <1590253873-11556-2-git-send-email-mkshah@codeaurora.org>
Quoting Maulik Shah (2020-05-23 10:11:10)
> 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)
This isn't a proper Fixes line. Should have quotes
Fixes: 461c1a7d4733 ("gpiolib: override irq_enable/disable")
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> ---
> drivers/gpio/gpiolib.c | 55 +++++++++++++++++++++++++++++----------------
> include/linux/gpio/driver.h | 13 +++++++++++
> 2 files changed, 49 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index eaa0e20..3810cd0 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -2465,32 +2465,37 @@ static void gpiochip_irq_relres(struct irq_data *d)
> gpiochip_relres_irq(gc, d->hwirq);
> }
>
> +static void gpiochip_irq_mask(struct irq_data *d)
> +{
> + struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +
> + if (gc->irq.irq_mask)
> + gc->irq.irq_mask(d);
> + gpiochip_disable_irq(gc, d->hwirq);
How does this work in the lazy case when I want to drive the GPIO? Say I
have a GPIO that is also an interrupt. The code would look like
struct gpio_desc *gpio = gpiod_get(...)
unsigned int girq = gpiod_to_irq(gpio)
request_irq(girq, ...);
disable_irq(girq);
gpiod_direction_output(gpio, 1);
In the lazy case genirq wouldn't call the mask function until the first
interrupt arrived on the GPIO line. If that never happened then wouldn't
we be blocked in gpiod_direction_output() when the test_bit() sees
FLAG_USED_AS_IRQ? Or do we need irqs to be released before driving
gpios?
> +}
> +
> +static void gpiochip_irq_unmask(struct irq_data *d)
> +{
> + struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +
> + gpiochip_enable_irq(gc, d->hwirq);
> + if (gc->irq.irq_unmask)
> + gc->irq.irq_unmask(d);
> +}
> +
next prev parent reply other threads:[~2020-05-27 9:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 17:11 [PATCH v2 0/4] irqchip: qcom: pdc: Introduce irq_set_wake call Maulik Shah
2020-05-23 17:11 ` [PATCH v2 1/4] gpio: gpiolib: Allow GPIO IRQs to lazy disable Maulik Shah
2020-05-25 11:55 ` Linus Walleij
2020-05-25 12:22 ` Hans Verkuil
2020-05-26 4:45 ` Maulik Shah
2020-05-27 10:38 ` Hans Verkuil
2020-05-27 13:56 ` Linus Walleij
2020-05-27 14:15 ` Russell King - ARM Linux admin
2020-05-27 9:44 ` Stephen Boyd [this message]
2020-05-27 11:26 ` Maulik Shah
2020-05-28 1:08 ` Stephen Boyd
2020-05-28 13:11 ` Maulik Shah
2020-05-28 22:22 ` Stephen Boyd
2020-05-29 9:57 ` Maulik Shah
2020-05-28 21:33 ` Linus Walleij
[not found] ` <159070486671.69627.662167272601689396@swboyd.mtv.corp.google.com>
2020-06-03 12:28 ` Linus Walleij
2020-05-23 17:11 ` [PATCH v2 2/4] pinctrl: qcom: Remove irq_disable callback from msmgpio irqchip Maulik Shah
2020-05-23 17:11 ` [PATCH v2 3/4] pinctrl: qcom: Add msmgpio irqchip flags Maulik Shah
2020-05-27 9:47 ` Stephen Boyd
2020-05-27 12:30 ` Maulik Shah
2020-05-23 17:11 ` [PATCH v2 4/4] irqchip: qcom-pdc: Introduce irq_set_wake call Maulik Shah
2020-05-27 10:15 ` Stephen Boyd
2020-05-29 9:20 ` Maulik Shah
2020-05-30 19:26 ` Stephen Boyd
2020-06-01 11:38 ` Maulik Shah
2020-06-16 11:57 ` Stephen Boyd
2020-06-18 10:03 ` Maulik Shah
2020-06-19 9:26 ` Stephen Boyd
2020-06-22 9:19 ` Maulik Shah
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