drivers/rtc: Provide y2038 safe rtc_class_ops.set_mmss() replacement

Currently the rtc_class_op's set_mmss() function takes a 32-bit
second value (on 32-bit systems), which is problematic for dates
past y2038.

This patch provides a safe version named set_mmss64() using
y2038 safe time64_t.

After this patch, set_mmss() is deprecated and all its users
will be fixed to use set_mmss64(), it can be removed when having
no users.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
[jstultz: Add whitespace fix for checkpatch]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1427945681-29972-8-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 11 insertions, 2 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 37215cf983e9..d43ee409a5f2 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -72,7 +72,11 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
                 err = -ENODEV;
         else if (rtc->ops->set_time)
                 err = rtc->ops->set_time(rtc->dev.parent, tm);
-        else if (rtc->ops->set_mmss) {
+        else if (rtc->ops->set_mmss64) {
+                time64_t secs64 = rtc_tm_to_time64(tm);
+
+                err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
+        } else if (rtc->ops->set_mmss) {
                 time64_t secs64 = rtc_tm_to_time64(tm);
                 err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
         } else
@@ -96,6 +100,8 @@ int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
 
         if (!rtc->ops)
                 err = -ENODEV;
+        else if (rtc->ops->set_mmss64)
+                err = rtc->ops->set_mmss64(rtc->dev.parent, secs);
         else if (rtc->ops->set_mmss)
                 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
         else if (rtc->ops->read_time && rtc->ops->set_time) {
diff --git a/drivers/rtc/systohc.c b/drivers/rtc/systohc.c
index ef3c07a52c3a..7728d5e32bf4 100644
--- a/drivers/rtc/systohc.c
+++ b/drivers/rtc/systohc.c
@@ -35,7 +35,10 @@ int rtc_set_ntp_time(struct timespec64 now)
         if (rtc) {
                 /* rtc_hctosys exclusively uses UTC, so we call set_time here,
                  * not set_mmss. */
-                if (rtc->ops && (rtc->ops->set_time || rtc->ops->set_mmss))
+                if (rtc->ops &&
+                    (rtc->ops->set_time ||
+                     rtc->ops->set_mmss64 ||
+                     rtc->ops->set_mmss))
                         err = rtc_set_time(rtc, &tm);
                 rtc_class_close(rtc);
         }