linux-arm-msm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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);
> +}
> +

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=159057264232.88029.4708934729701385486@swboyd.mtv.corp.google.com \
    --to=swboyd@chromium.org \
    --cc=agross@kernel.org \
    --cc=bjorn.andersson@linaro.org \
    --cc=dianders@chromium.org \
    --cc=evgreen@chromium.org \
    --cc=ilina@codeaurora.org \
    --cc=jason@lakedaemon.net \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lsrao@codeaurora.org \
    --cc=maz@kernel.org \
    --cc=mka@chromium.org \
    --cc=mkshah@codeaurora.org \
    --cc=rnayak@codeaurora.org \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).