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

From: Tomasz Figa
Date: Thu Jun 13 2013 - 12:44:19 EST


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@xxxxxxxxxxxx>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> ---
> 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@xxxxxxxxxxx>

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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