This adds in the ability for the rtc sysfs code to handle += characters at the beginning of a wakealarm setting string. This will allow the user to attempt to push out an existing wakealarm by a provided amount.
In the case that the += characters are provided but the alarm is not active -EVINVAL is returned. Signed-off-by: Bernie Thompson <[email protected]> --- Documentation/rtc.txt | 7 ++++--- drivers/rtc/rtc-sysfs.c | 20 +++++++++++++++----- 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt index 32aa400..596b60c 100644 --- a/Documentation/rtc.txt +++ b/Documentation/rtc.txt @@ -153,9 +153,10 @@ since_epoch: The number of seconds since the epoch according to the RTC time: RTC-provided time wakealarm: The time at which the clock will generate a system wakeup event. This is a one shot wakeup event, so must be reset - after wake if a daily wakeup is required. Format is either - seconds since the epoch or, if there's a leading +, seconds - in the future. + after wake if a daily wakeup is required. Format is seconds since + the epoch by default, or if there's a leading +, seconds in the + future, or if there is a leading +=, seconds ahead of the current + alarm. IOCTL INTERFACE --------------- diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c index b70e2bb..4b26f86 100644 --- a/drivers/rtc/rtc-sysfs.c +++ b/drivers/rtc/rtc-sysfs.c @@ -164,6 +164,7 @@ rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr, { ssize_t retval; unsigned long now, alarm; + unsigned long push = 0; struct rtc_wkalrm alm; struct rtc_device *rtc = to_rtc_device(dev); char *buf_ptr; @@ -180,13 +181,17 @@ rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr, buf_ptr = (char *)buf; if (*buf_ptr == '+') { buf_ptr++; - adjust = 1; + if (*buf_ptr == '=') { + buf_ptr++; + push = 1; + } else + adjust = 1; } alarm = simple_strtoul(buf_ptr, NULL, 0); if (adjust) { alarm += now; } - if (alarm > now) { + if (alarm > now || push) { /* Avoid accidentally clobbering active alarms; we can't * entirely prevent that here, without even the minimal * locking from the /dev/rtcN api. @@ -194,9 +199,14 @@ rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr, retval = rtc_read_alarm(rtc, &alm); if (retval < 0) return retval; - if (alm.enabled) - return -EBUSY; - + if (alm.enabled) { + if (push) { + rtc_tm_to_time(&alm.time, &push); + alarm += push; + } else + return -EBUSY; + } else if (push) + return -EINVAL; alm.enabled = 1; } else { alm.enabled = 0; -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
