2009-04-06 16:50:43

by Atsushi Nemoto

Subject: [PATCH] rtc-ds1553: Drop IRQF_DISABLED

IRQF_DISABLED should be be used with IRQF_SHARED. Drop IRQF_DISABLED
and add spin_lock_irqsave/spin_unlock_irqrestore to the interrupt
handler.

Signed-off-by: Atsushi Nemoto <[email protected]>
---
drivers/rtc/rtc-ds1553.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-ds1553.c b/drivers/rtc/rtc-ds1553.c
index 38d472b..395f01b 100644
--- a/drivers/rtc/rtc-ds1553.c
+++ b/drivers/rtc/rtc-ds1553.c
@@ -195,14 +195,19 @@ static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned long events = RTC_IRQF;
+ unsigned long flags;

+ spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
/* read and clear interrupt */
- if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
+ if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF)) {
+ spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
return IRQ_NONE;
+ }
if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
events |= RTC_UF;
else
events |= RTC_AF;
+ spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
rtc_update_irq(pdata->rtc, 1, events);
return IRQ_HANDLED;
}
@@ -329,7 +334,7 @@ static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
if (pdata->irq > 0) {
writeb(0, ioaddr + RTC_INTERRUPTS);
if (request_irq(pdata->irq, ds1553_rtc_interrupt,
- IRQF_DISABLED | IRQF_SHARED,
+ IRQF_SHARED,
pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = 0;
--
1.5.6.3

2009-04-06 19:32:23

by Peter Zijlstra

Subject: Re: [PATCH] rtc-ds1553: Drop IRQF_DISABLED

On Tue, 2009-04-07 at 01:50 +0900, Atsushi Nemoto wrote:
> IRQF_DISABLED should be be used with IRQF_SHARED. Drop IRQF_DISABLED
> and add spin_lock_irqsave/spin_unlock_irqrestore to the interrupt
> handler.

I think you should use IRQF_DISABLED if at all possible. Only broken
hardware has an excuse not to.

NAK

> Signed-off-by: Atsushi Nemoto <[email protected]>
> ---
> drivers/rtc/rtc-ds1553.c | 9 +++++++--
> 1 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/rtc/rtc-ds1553.c b/drivers/rtc/rtc-ds1553.c
> index 38d472b..395f01b 100644
> --- a/drivers/rtc/rtc-ds1553.c
> +++ b/drivers/rtc/rtc-ds1553.c
> @@ -195,14 +195,19 @@ static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
> struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
> void __iomem *ioaddr = pdata->ioaddr;
> unsigned long events = RTC_IRQF;
> + unsigned long flags;
>
> + spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
> /* read and clear interrupt */
> - if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
> + if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF)) {
> + spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
> return IRQ_NONE;
> + }
> if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
> events |= RTC_UF;
> else
> events |= RTC_AF;
> + spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
> rtc_update_irq(pdata->rtc, 1, events);
> return IRQ_HANDLED;
> }
> @@ -329,7 +334,7 @@ static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
> if (pdata->irq > 0) {
> writeb(0, ioaddr + RTC_INTERRUPTS);
> if (request_irq(pdata->irq, ds1553_rtc_interrupt,
> - IRQF_DISABLED | IRQF_SHARED,
> + IRQF_SHARED,
> pdev->name, pdev) < 0) {
> dev_warn(&pdev->dev, "interrupt not available.\n");
> pdata->irq = 0;

2009-04-07 12:49:28

by Atsushi Nemoto

Subject: Re: [PATCH] rtc-ds1553: Drop IRQF_DISABLED

On Mon, 06 Apr 2009 21:33:42 +0200, Peter Zijlstra <[email protected]> wrote:
> > IRQF_DISABLED should be be used with IRQF_SHARED. Drop IRQF_DISABLED
> > and add spin_lock_irqsave/spin_unlock_irqrestore to the interrupt
> > handler.
>
> I think you should use IRQF_DISABLED if at all possible. Only broken
> hardware has an excuse not to.
>
> NAK

OK, then I will drop IRQF_SHARED instead. There is no in-tree user of
this driver and only out-of-tree user I know uses dedicated irq line
for this RTC.

---
Atsushi Nemoto