Patchwork [v3,3/3] ARM: at91/rtc: disable interrupts at shutdown

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Submitter Johan Hovold
Date Oct. 16, 2013, 9:56 a.m.
Message ID <1381917376-21107-4-git-send-email-jhovold@gmail.com>
Download mbox | patch
Permalink /patch/283908/
State New
Headers show

Comments

Johan Hovold - Oct. 16, 2013, 9:56 a.m.
Make sure RTC-interrupts are disabled at shutdown.

As the RTC is generally powered by backup power (VDDBU), its interrupts
are not disabled on wake-up, user, watchdog or software reset. This
could cause troubles on other systems (e.g. older kernels) if an
interrupt occurs before a handler has been installed at next boot.

Let us be well-behaved and disable them on clean shutdowns at least (as
do the RTT-based rtc-at91sam9 driver).

Signed-off-by: Johan Hovold <jhovold@gmail.com>
---
 drivers/rtc/rtc-at91rm9200.c | 9 +++++++++
 1 file changed, 9 insertions(+)
Nicolas Ferre - Nov. 15, 2013, 10:43 a.m.
On 16/10/2013 11:56, Johan Hovold :
> Make sure RTC-interrupts are disabled at shutdown.
>
> As the RTC is generally powered by backup power (VDDBU), its interrupts
> are not disabled on wake-up, user, watchdog or software reset. This
> could cause troubles on other systems (e.g. older kernels) if an
> interrupt occurs before a handler has been installed at next boot.
>
> Let us be well-behaved and disable them on clean shutdowns at least (as
> do the RTT-based rtc-at91sam9 driver).
>
> Signed-off-by: Johan Hovold <jhovold@gmail.com>

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

Thank you Johan.

Andrew, could you add this patch to your rtc queue or should I re-send it ?

Best regards,

> ---
>   drivers/rtc/rtc-at91rm9200.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
>
> diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
> index 7418926..ea088e9 100644
> --- a/drivers/rtc/rtc-at91rm9200.c
> +++ b/drivers/rtc/rtc-at91rm9200.c
> @@ -442,6 +442,14 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
>   	return 0;
>   }
>
> +static void at91_rtc_shutdown(struct platform_device *pdev)
> +{
> +	/* Disable all interrupts */
> +	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
> +					AT91_RTC_SECEV | AT91_RTC_TIMEV |
> +					AT91_RTC_CALEV);
> +}
> +
>   #ifdef CONFIG_PM_SLEEP
>
>   /* AT91RM9200 RTC Power management control */
> @@ -480,6 +488,7 @@ static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
>
>   static struct platform_driver at91_rtc_driver = {
>   	.remove		= __exit_p(at91_rtc_remove),
> +	.shutdown	= at91_rtc_shutdown,
>   	.driver		= {
>   		.name	= "at91_rtc",
>   		.owner	= THIS_MODULE,
>

Patch

diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index 7418926..ea088e9 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -442,6 +442,14 @@  static int __exit at91_rtc_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void at91_rtc_shutdown(struct platform_device *pdev)
+{
+	/* Disable all interrupts */
+	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
+					AT91_RTC_SECEV | AT91_RTC_TIMEV |
+					AT91_RTC_CALEV);
+}
+
 #ifdef CONFIG_PM_SLEEP
 
 /* AT91RM9200 RTC Power management control */
@@ -480,6 +488,7 @@  static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 
 static struct platform_driver at91_rtc_driver = {
 	.remove		= __exit_p(at91_rtc_remove),
+	.shutdown	= at91_rtc_shutdown,
 	.driver		= {
 		.name	= "at91_rtc",
 		.owner	= THIS_MODULE,