From: Valentine Barshak <valentine.barshak@cogentembedded.com> To: linux-sh@vger.kernel.org, linux-gpio@vger.kernel.org Cc: Simon Horman <horms@verge.net.au>, Magnus Damm <magnus.damm@gmail.com>, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Linus Walleij <linus.walleij@linaro.org> Subject: [PATCH V2] gpio: rcar: Fix level interrupt handling Date: Fri, 29 Nov 2013 18:04:09 +0000 [thread overview] Message-ID: <1385748249-27170-1-git-send-email-valentine.barshak@cogentembedded.com> (raw) According to the manual, if a port is set for level detection using the corresponding bit in the edge/level select register and an external level interrupt signal is asserted, the corresponding bit in INTDT does not use the FF to hold the input. Thus, writing 1 to the corresponding bits in INTCLR cannot clear the corresponding bits in the INTDT register. Instead, when an external input signal is stopped, the corresponding bit in INTDT is cleared automatically. Since the INTDT bit cannot be cleared for the level interrupts until the interrupt signal is stopped, we end up with the infinite loop when using deferred (threaded) IRQ handling. Since a deferred interrupt is disabled by the low-level handler and re-enabled only when the deferred handler is completed, Fix the issue by dropping disabled interrupts from the pending mask as suggested by Laurent Pinchart <laurent.pinchart@ideasonboard.com> Changes in V2: * Drop disabled interrupts from pending mask altogether instead of dropping level interrupts one by one once they get handled. Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com> --- drivers/gpio/gpio-rcar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c index d3f15ae..fd2d827 100644 --- a/drivers/gpio/gpio-rcar.c +++ b/drivers/gpio/gpio-rcar.c @@ -169,7 +169,8 @@ static irqreturn_t gpio_rcar_irq_handler(int irq, void *dev_id) u32 pending; unsigned int offset, irqs_handled = 0; - while ((pending = gpio_rcar_read(p, INTDT))) { + while ((pending = gpio_rcar_read(p, INTDT) & + gpio_rcar_read(p, INTMSK))) { offset = __ffs(pending); gpio_rcar_write(p, INTCLR, BIT(offset)); generic_handle_irq(irq_find_mapping(p->irq_domain, offset)); -- 1.8.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Valentine Barshak <valentine.barshak@cogentembedded.com> To: linux-sh@vger.kernel.org, linux-gpio@vger.kernel.org Cc: Simon Horman <horms@verge.net.au>, Magnus Damm <magnus.damm@gmail.com>, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Linus Walleij <linus.walleij@linaro.org> Subject: [PATCH V2] gpio: rcar: Fix level interrupt handling Date: Fri, 29 Nov 2013 22:04:09 +0400 [thread overview] Message-ID: <1385748249-27170-1-git-send-email-valentine.barshak@cogentembedded.com> (raw) According to the manual, if a port is set for level detection using the corresponding bit in the edge/level select register and an external level interrupt signal is asserted, the corresponding bit in INTDT does not use the FF to hold the input. Thus, writing 1 to the corresponding bits in INTCLR cannot clear the corresponding bits in the INTDT register. Instead, when an external input signal is stopped, the corresponding bit in INTDT is cleared automatically. Since the INTDT bit cannot be cleared for the level interrupts until the interrupt signal is stopped, we end up with the infinite loop when using deferred (threaded) IRQ handling. Since a deferred interrupt is disabled by the low-level handler and re-enabled only when the deferred handler is completed, Fix the issue by dropping disabled interrupts from the pending mask as suggested by Laurent Pinchart <laurent.pinchart@ideasonboard.com> Changes in V2: * Drop disabled interrupts from pending mask altogether instead of dropping level interrupts one by one once they get handled. Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com> --- drivers/gpio/gpio-rcar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c index d3f15ae..fd2d827 100644 --- a/drivers/gpio/gpio-rcar.c +++ b/drivers/gpio/gpio-rcar.c @@ -169,7 +169,8 @@ static irqreturn_t gpio_rcar_irq_handler(int irq, void *dev_id) u32 pending; unsigned int offset, irqs_handled = 0; - while ((pending = gpio_rcar_read(p, INTDT))) { + while ((pending = gpio_rcar_read(p, INTDT) & + gpio_rcar_read(p, INTMSK))) { offset = __ffs(pending); gpio_rcar_write(p, INTCLR, BIT(offset)); generic_handle_irq(irq_find_mapping(p->irq_domain, offset)); -- 1.8.3.1
next reply other threads:[~2013-11-29 18:04 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-11-29 18:04 Valentine Barshak [this message] 2013-11-29 18:04 ` [PATCH V2] gpio: rcar: Fix level interrupt handling Valentine Barshak 2013-12-09 19:25 ` Valentine 2013-12-09 19:25 ` Valentine 2013-12-10 1:39 ` Laurent Pinchart 2013-12-10 1:39 ` Laurent Pinchart 2013-12-11 9:44 ` Magnus Damm 2013-12-11 9:44 ` Magnus Damm 2013-12-12 19:54 ` Linus Walleij 2013-12-12 19:54 ` Linus Walleij 2013-12-13 12:31 ` Magnus Damm 2013-12-13 12:31 ` Magnus Damm
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