diff options
| -rw-r--r-- | drivers/rtc/class.c | 70 | ||||
| -rw-r--r-- | drivers/rtc/interface.c | 59 | ||||
| -rw-r--r-- | include/linux/rtc.h | 3 |
3 files changed, 131 insertions, 1 deletions
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 5a5ab4fa14f9..d37588f08055 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -211,6 +211,73 @@ static int rtc_device_get_id(struct device *dev) return id; } +static void rtc_device_get_offset(struct rtc_device *rtc) +{ + time64_t range_secs; + u32 start_year; + int ret; + + /* + * If RTC driver did not implement the range of RTC hardware device, + * then we can not expand the RTC range by adding or subtracting one + * offset. + */ + if (rtc->range_min == rtc->range_max) + return; + + ret = device_property_read_u32(rtc->dev.parent, "start-year", + &start_year); + if (!ret) { + rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0); + rtc->set_start_time = true; + } + + /* + * If user did not implement the start time for RTC driver, then no + * need to expand the RTC range. + */ + if (!rtc->set_start_time) + return; + + range_secs = rtc->range_max - rtc->range_min + 1; + + /* + * If the start_secs is larger than the maximum seconds (rtc->range_max) + * supported by RTC hardware or the maximum seconds of new expanded + * range (start_secs + rtc->range_max - rtc->range_min) is less than + * rtc->range_min, which means the minimum seconds (rtc->range_min) of + * RTC hardware will be mapped to start_secs by adding one offset, so + * the offset seconds calculation formula should be: + * rtc->offset_secs = rtc->start_secs - rtc->range_min; + * + * If the start_secs is larger than the minimum seconds (rtc->range_min) + * supported by RTC hardware, then there is one region is overlapped + * between the original RTC hardware range and the new expanded range, + * and this overlapped region do not need to be mapped into the new + * expanded range due to it is valid for RTC device. So the minimum + * seconds of RTC hardware (rtc->range_min) should be mapped to + * rtc->range_max + 1, then the offset seconds formula should be: + * rtc->offset_secs = rtc->range_max - rtc->range_min + 1; + * + * If the start_secs is less than the minimum seconds (rtc->range_min), + * which is similar to case 2. So the start_secs should be mapped to + * start_secs + rtc->range_max - rtc->range_min + 1, then the + * offset seconds formula should be: + * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1); + * + * Otherwise the offset seconds should be 0. + */ + if (rtc->start_secs > rtc->range_max || + rtc->start_secs + range_secs - 1 < rtc->range_min) + rtc->offset_secs = rtc->start_secs - rtc->range_min; + else if (rtc->start_secs > rtc->range_min) + rtc->offset_secs = range_secs; + else if (rtc->start_secs < rtc->range_min) + rtc->offset_secs = -range_secs; + else + rtc->offset_secs = 0; +} + /** * rtc_device_register - register w/ RTC class * @dev: the device to register @@ -247,6 +314,8 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, dev_set_name(&rtc->dev, "rtc%d", id); + rtc_device_get_offset(rtc); + /* Check to see if there is an ALARM already set in hw */ err = __rtc_read_alarm(rtc, &alrm); @@ -436,6 +505,7 @@ int __rtc_register_device(struct module *owner, struct rtc_device *rtc) return -EINVAL; rtc->owner = owner; + rtc_device_get_offset(rtc); /* Check to see if there is an ALARM already set in hw */ err = __rtc_read_alarm(rtc, &alrm); diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 25aebc5b448d..7cbdc9228dd5 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -23,12 +23,61 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer); static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer); +static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm) +{ + time64_t secs; + + if (!rtc->offset_secs) + return; + + secs = rtc_tm_to_time64(tm); + + /* + * Since the reading time values from RTC device are always in the RTC + * original valid range, but we need to skip the overlapped region + * between expanded range and original range, which is no need to add + * the offset. + */ + if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) || + (rtc->start_secs < rtc->range_min && + secs <= (rtc->start_secs + rtc->range_max - rtc->range_min))) + return; + + rtc_time64_to_tm(secs + rtc->offset_secs, tm); +} + +static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm) +{ + time64_t secs; + + if (!rtc->offset_secs) + return; + + secs = rtc_tm_to_time64(tm); + + /* + * If the setting time values are in the valid range of RTC hardware + * device, then no need to subtract the offset when setting time to RTC + * device. Otherwise we need to subtract the offset to make the time + * values are valid for RTC hardware device. + */ + if (secs >= rtc->range_min && secs <= rtc->range_max) + return; + + rtc_time64_to_tm(secs - rtc->offset_secs, tm); +} + static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm) { if (rtc->range_min != rtc->range_max) { time64_t time = rtc_tm_to_time64(tm); + time64_t range_min = rtc->set_start_time ? rtc->start_secs : + rtc->range_min; + time64_t range_max = rtc->set_start_time ? + (rtc->start_secs + rtc->range_max - rtc->range_min) : + rtc->range_max; - if (time < rtc->range_min || time > rtc->range_max) + if (time < range_min || time > range_max) return -ERANGE; } @@ -51,6 +100,8 @@ static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) return err; } + rtc_add_offset(rtc, tm); + err = rtc_valid_tm(tm); if (err < 0) dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n"); @@ -86,6 +137,8 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) if (err) return err; + rtc_subtract_offset(rtc, tm); + err = mutex_lock_interruptible(&rtc->ops_lock); if (err) return err; @@ -355,6 +408,8 @@ static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) err = rtc_valid_tm(&alarm->time); if (err) return err; + + rtc_subtract_offset(rtc, &alarm->time); scheduled = rtc_tm_to_time64(&alarm->time); /* Make sure we're not setting alarms in the past */ @@ -406,6 +461,8 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) err = rtc_timer_enqueue(rtc, &rtc->aie_timer); mutex_unlock(&rtc->ops_lock); + + rtc_add_offset(rtc, &alarm->time); return err; } EXPORT_SYMBOL_GPL(rtc_set_alarm); diff --git a/include/linux/rtc.h b/include/linux/rtc.h index c78528c394e5..82a3038f16ab 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -152,6 +152,9 @@ struct rtc_device { time64_t range_min; timeu64_t range_max; + time64_t start_secs; + time64_t offset_secs; + bool set_start_time; #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL struct work_struct uie_task; |