linux-kernel - Re: [PATCH v2 3/3] pinctrl: exynos: ack level-triggered interrupts before unmasking

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Date:	Thu, 13 Jun 2013 18:44:11 +0200
From:	Tomasz Figa <tomasz.figa@...il.com>
To:	Doug Anderson <dianders@...omium.org>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Olof Johansson <olof@...om.net>,
	Simon Glass <sjg@...omium.org>,
	Luigi Semenzato <semenzato@...omium.org>,
	ilho215.lee@...sung.com, eunki_kim@...sung.com,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] pinctrl: exynos: ack level-triggered interrupts before unmasking

On Thursday 13 of June 2013 09:38:42 Doug Anderson wrote:
> A level-triggered interrupt should be acked after the interrupt line
> becomes inactive and before it is unmasked, or else another interrupt
> will be immediately triggered.  Acking before or after calling the
> handler is not enough.
> 
> Signed-off-by: Luigi Semenzato <semenzato@...omium.org>
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> ---
> Changes in v2:
> - Greatly simplified using Tomasz's suggestion of irqd_get_trigger_type
> - Moved acking out of the bank spinlock since since it's not needed.
> - Linus W. has already applied parts 1 and 2, so not resending.
> 
>  drivers/pinctrl/pinctrl-exynos.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)

Looks good. Thanks.

Acked-by: Tomasz Figa <t.figa@...sung.com>

Best regards,
Tomasz

> diff --git a/drivers/pinctrl/pinctrl-exynos.c
> b/drivers/pinctrl/pinctrl-exynos.c index c0729a3..ef75321 100644
> --- a/drivers/pinctrl/pinctrl-exynos.c
> +++ b/drivers/pinctrl/pinctrl-exynos.c
> @@ -84,6 +84,17 @@ static void exynos_gpio_irq_unmask(struct irq_data
> *irqd) unsigned long mask;
>  	unsigned long flags;
> 
> +	/*
> +	 * Ack level interrupts right before unmask
> +	 *
> +	 * If we don't do this we'll get a double-interrupt.  Level 
triggered
> +	 * interrupts must not fire an interrupt if the level is not
> +	 * _currently_ active, even if it was active while the interrupt 
was
> +	 * masked.
> +	 */
> +	if (irqd_get_trigger_type(irqd) & IRQ_TYPE_LEVEL_MASK)
> +		exynos_gpio_irq_ack(irqd);
> +
>  	spin_lock_irqsave(&bank->slock, flags);
> 
>  	mask = readl(d->virt_base + reg_mask);
> @@ -302,6 +313,17 @@ static void exynos_wkup_irq_unmask(struct irq_data
> *irqd) unsigned long mask;
>  	unsigned long flags;
> 
> +	/*
> +	 * Ack level interrupts right before unmask
> +	 *
> +	 * If we don't do this we'll get a double-interrupt.  Level 
triggered
> +	 * interrupts must not fire an interrupt if the level is not
> +	 * _currently_ active, even if it was active while the interrupt 
was
> +	 * masked.
> +	 */
> +	if (irqd_get_trigger_type(irqd) & IRQ_TYPE_LEVEL_MASK)
> +		exynos_wkup_irq_ack(irqd);
> +
>  	spin_lock_irqsave(&b->slock, flags);
> 
>  	mask = readl(d->virt_base + reg_mask);
--
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