[PATCH 8/9] RFC: rtc: hctosys: support rtc_read_timeval() for high precision clocks
From: Alexander Holler
Date: Fri Jun 14 2013 - 12:55:51 EST
Some RTCs do provide a higher precision than seconds. Add support for them
by trying rtc_read_timeval() before using rtc_read_time() to get the time
in the hctosys mechanism.
Signed-off-by: Alexander Holler <holler@xxxxxxxxxxxxx>
---
drivers/rtc/class.c | 35 ++++++++++++++++++++++++-----------
1 file changed, 24 insertions(+), 11 deletions(-)
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 625076b..1cdd506 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -150,16 +150,25 @@ static int rtc_resume(struct device *dev)
static void hctosys(struct rtc_device *rtc)
{
struct rtc_time now;
- struct timespec ts = {
- .tv_nsec = NSEC_PER_SEC >> 1,
- };
+ struct timespec ts;
+ struct timeval tv = { 0, 0 };
int rc;
- rc = rtc_read_time(rtc, &now);
- if (unlikely(rc)) {
- dev_err(rtc->dev.parent,
- "rtc core: error reading time from RTC: %d\n", rc);
- return;
+ rc = rtc_read_timeval(rtc, &tv);
+ if (rc || (!tv.tv_sec && !tv.tv_usec)) {
+ rc = rtc_read_time(rtc, &now);
+ if (unlikely(rc)) {
+ dev_err(rtc->dev.parent,
+ "rtc core: error reading time from RTC: %d\n",
+ rc);
+ return;
+ }
+ rtc_tm_to_time(&now, &ts.tv_sec);
+ ts.tv_nsec = NSEC_PER_SEC >> 1;
+ } else {
+ rtc_time_to_tm(tv.tv_sec, &now);
+ ts.tv_sec = tv.tv_sec;
+ ts.tv_nsec = tv.tv_usec*NSEC_PER_USEC;
}
rc = rtc_valid_tm(&now);
if (unlikely(rc)) {
@@ -167,7 +176,6 @@ static void hctosys(struct rtc_device *rtc)
"rtc core: timestamp from RTC is invalid\n");
return;
}
- rtc_tm_to_time(&now, &ts.tv_sec);
if (systime_was_set)
return;
rc = do_settimeofday(&ts);
@@ -176,12 +184,17 @@ static void hctosys(struct rtc_device *rtc)
"rtc core: error setting system clock: %d\n", rc);
return;
} else if (systime_was_set) {
+ char usbuf[8];
rtc_hctosys_dev_id = rtc->id;
+ if (tv.tv_sec)
+ snprintf(usbuf, sizeof(usbuf), ":%06ld", tv.tv_usec);
+ else
+ *usbuf = 0;
dev_info(rtc->dev.parent,
"rtc core: setting system clock to "
- "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
+ "%d-%02d-%02d %02d:%02d:%02d%s UTC (%u)\n",
now.tm_year + 1900, now.tm_mon + 1, now.tm_mday,
- now.tm_hour, now.tm_min, now.tm_sec,
+ now.tm_hour, now.tm_min, now.tm_sec, usbuf,
(unsigned int) ts.tv_sec);
}
}
--
1.8.1.4
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