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authorJohn Stultz <john.stultz@linaro.org>2012-03-06 17:16:09 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-02 09:53:10 -0700
commit61d38cd909ad35ff497bf1a84cd57b2baf6d9c49 (patch)
parentacff5ccd7dfccb0c28f367a2a684a7e8e3ee0112 (diff)
rtc: Provide flag for rtc devices that don't support UIE
commit 4a649903f91232d02284d53724b0a45728111767 upstream. Richard Weinberger noticed that on some RTC hardware that doesn't support UIE mode, due to coarse granular alarms (like 1minute resolution), the current virtualized RTC support doesn't properly error out when UIE is enabled. Instead the current code queues an alarm for the next second, but it won't fire until up to a miniute later. This patch provides a generic way to flag this sort of hardware and fixes the issue on the mpc5121 where Richard noticed the problem. Reported-by: Richard Weinberger <richard@nod.at> Tested-by: Richard Weinberger <richard@nod.at> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
3 files changed, 9 insertions, 1 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index c1edbf819652..565742b9f0d0 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -445,6 +445,11 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
if (rtc->uie_rtctimer.enabled == enabled)
goto out;
+ if (rtc->uie_unsupported) {
+ err = -EINVAL;
+ goto out;
+ }
if (enabled) {
struct rtc_time tm;
ktime_t now, onesec;
diff --git a/drivers/rtc/rtc-mpc5121.c b/drivers/rtc/rtc-mpc5121.c
index da60915818b6..0fc2d221bc8b 100644
--- a/drivers/rtc/rtc-mpc5121.c
+++ b/drivers/rtc/rtc-mpc5121.c
@@ -360,6 +360,8 @@ static int __devinit mpc5121_rtc_probe(struct platform_device *op)
&mpc5200_rtc_ops, THIS_MODULE);
+ rtc->rtc->uie_unsupported = 1;
if (IS_ERR(rtc->rtc)) {
err = PTR_ERR(rtc->rtc);
goto out_free_irq;
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 93f4d035076b..fcabfb4873c8 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -202,7 +202,8 @@ struct rtc_device
struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
int pie_enabled;
struct work_struct irqwork;
+ /* Some hardware can't support UIE mode */
+ int uie_unsupported;
struct work_struct uie_task;