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Use the new clock_schedule() to arrange for clock_settime() to be called

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at the right time to keep the RTC hardware time in sync, instead of using
pause_sbt() to sleep until the right time.
This commit is contained in:
ian 2017-07-31 01:36:51 +00:00
parent 4b1f61b073
commit a0fd5a136c
2 changed files with 14 additions and 25 deletions
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20
sys/dev/iicbus/ds1307.c
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@ -295,8 +295,13 @@ ds1307_start(void *xdev)
CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
ds1307_sqw_out_sysctl, "IU", "DS1307 square-wave output state");
/* Register as a clock with 1 second resolution. */
/*
* Register as a clock with 1 second resolution. Schedule the
* clock_settime() method to be called just after top-of-second;
* resetting the time resets top-of-second in the hardware.
*/
clock_register_flags(dev, 1000000, CLOCKF_SETTIME_NO_TS);
clock_schedule(dev, 1);
}
static int
@ -352,19 +357,6 @@ ds1307_settime(device_t dev, struct timespec *ts)
sc = device_get_softc(dev);
/* Sleep until 1ms into the second, to align RTC's second to ours. */
getnanotime(ts);
waitns = 1000000 - ts->tv_nsec;
if (waitns < 0)
waitns += 1000000000;
pause_sbt("set1307", nstosbt(waitns), 0, C_PREL(31));
/* Grab a fresh post-sleep idea of the time. */
getnanotime(ts);
ts->tv_sec -= utc_offset();
ts->tv_nsec = 0;
clock_ts_to_ct(ts, &ct);
/* If the chip is in AM/PM mode, adjust hour and set flags as needed. */
if (sc->sc_use_ampm) {
pmflags = DS1307_HOUR_USE_AMPM;

19
sys/dev/iicbus/nxprtc.c
View File

@ -513,10 +513,15 @@ nxprtc_start(void *dev)
* we're using the timer to count fractional seconds, our resolution is
* 1e6/64, about 15.6ms. Without the timer we still align the RTC clock
* when setting it so our error is an average .5s when reading it.
* Schedule our clock_settime() method to be called at a .495ms offset
* into the second, because the clock hardware resets the divider chain
* to the mid-second point when you set the time and it takes about 5ms
* of i2c bus activity to set the clock.
*/
resolution = sc->use_timer ? 1000000 / TMR_TICKS_SEC : 1000000 / 2;
clockflags = CLOCKF_GETTIME_NO_ADJ | CLOCKF_SETTIME_NO_TS;
clock_register_flags(sc->dev, resolution, clockflags);
clock_schedule(sc->dev, 495000000);
}
static int
@ -599,7 +604,6 @@ nxprtc_settime(device_t dev, struct timespec *ts)
struct clocktime ct;
struct time_regs tregs;
struct nxprtc_softc *sc;
long waitns;
int err;
uint8_t cflag, cs1, pmflag;
@ -608,16 +612,9 @@ nxprtc_settime(device_t dev, struct timespec *ts)
/*
* We stop the clock, set the time, then restart the clock. Half a
* second after restarting the clock it ticks over to the next second.
* So to align the RTC, sleep until system time is halfway through the
* current second (shoot for .495 to allow time for i2c operations).
*/
getnanotime(ts);
waitns = 495000000 - ts->tv_nsec;
if (waitns < 0)
waitns += 1000000000;
pause_sbt("nxpset", nstosbt(waitns), 0, C_PREL(31));
/*
* So to align the RTC, we schedule this function to be called when
* system time is roughly halfway (.495) through the current second.
*
* Reserve use of the i2c bus and stop the RTC clock. Note that if
* anything goes wrong from this point on, we leave the clock stopped,
* because we don't really know what state it's in.