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authorTony Lindgren <tony@atomide.com>2016-03-30 20:36:06 +0300
committerTony Lindgren <tony@atomide.com>2016-03-30 20:36:06 +0300
commit1809de7e7d37c585e01a1bcc583ea92b78fc759d (patch)
tree76c5b35c2b04eafce86a1a729c02ab705eba44bc /drivers/rtc/interface.c
parentebf24414809200915b9ddf7f109bba7c278c8210 (diff)
parent3ca4a238106dedc285193ee47f494a6584b6fd2f (diff)
downloadlinux-1809de7e7d37c585e01a1bcc583ea92b78fc759d.tar.xz
Merge tag 'for-v4.6-rc/omap-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v4.6/fixes
ARM: OMAP2+: first hwmod fix for v4.6-rc Fix a longstanding bug in the hwmod code that could cause hardware SYSCONFIG register values to not match the kernel's idea of what they should be, and that could result in lower performance during IP block idle entry. Basic build, boot, and PM test logs are available here: http://www.pwsan.com/omap/testlogs/omap-hwmod-fixes-a-for-v4.6-rc/20160326231727/
Diffstat (limited to 'drivers/rtc/interface.c')
-rw-r--r--drivers/rtc/interface.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 5836751b8203..9ef5f6f89f98 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -939,4 +939,58 @@ void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
mutex_unlock(&rtc->ops_lock);
}
+/**
+ * rtc_read_offset - Read the amount of rtc offset in parts per billion
+ * @ rtc: rtc device to be used
+ * @ offset: the offset in parts per billion
+ *
+ * see below for details.
+ *
+ * Kernel interface to read rtc clock offset
+ * Returns 0 on success, or a negative number on error.
+ * If read_offset() is not implemented for the rtc, return -EINVAL
+ */
+int rtc_read_offset(struct rtc_device *rtc, long *offset)
+{
+ int ret;
+
+ if (!rtc->ops)
+ return -ENODEV;
+
+ if (!rtc->ops->read_offset)
+ return -EINVAL;
+
+ mutex_lock(&rtc->ops_lock);
+ ret = rtc->ops->read_offset(rtc->dev.parent, offset);
+ mutex_unlock(&rtc->ops_lock);
+ return ret;
+}
+/**
+ * rtc_set_offset - Adjusts the duration of the average second
+ * @ rtc: rtc device to be used
+ * @ offset: the offset in parts per billion
+ *
+ * Some rtc's allow an adjustment to the average duration of a second
+ * to compensate for differences in the actual clock rate due to temperature,
+ * the crystal, capacitor, etc.
+ *
+ * Kernel interface to adjust an rtc clock offset.
+ * Return 0 on success, or a negative number on error.
+ * If the rtc offset is not setable (or not implemented), return -EINVAL
+ */
+int rtc_set_offset(struct rtc_device *rtc, long offset)
+{
+ int ret;
+
+ if (!rtc->ops)
+ return -ENODEV;
+
+ if (!rtc->ops->set_offset)
+ return -EINVAL;
+
+ mutex_lock(&rtc->ops_lock);
+ ret = rtc->ops->set_offset(rtc->dev.parent, offset);
+ mutex_unlock(&rtc->ops_lock);
+ return ret;
+}