diff options
Diffstat (limited to 'drivers/rtc/rtc-sysfs.c')
| -rw-r--r-- | drivers/rtc/rtc-sysfs.c | 129 |
1 files changed, 100 insertions, 29 deletions
diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c index 69df94b4484..babd43bf3dd 100644 --- a/drivers/rtc/rtc-sysfs.c +++ b/drivers/rtc/rtc-sysfs.c @@ -17,16 +17,22 @@ /* device attributes */ +/* + * NOTE: RTC times displayed in sysfs use the RTC's timezone. That's + * ideally UTC. However, PCs that also boot to MS-Windows normally use + * the local time and change to match daylight savings time. That affects + * attributes including date, time, since_epoch, and wakealarm. + */ + static ssize_t -rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr, - char *buf) +name_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", to_rtc_device(dev)->name); } +static DEVICE_ATTR_RO(name); static ssize_t -rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr, - char *buf) +date_show(struct device *dev, struct device_attribute *attr, char *buf) { ssize_t retval; struct rtc_time tm; @@ -39,10 +45,10 @@ rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr, return retval; } +static DEVICE_ATTR_RO(date); static ssize_t -rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr, - char *buf) +time_show(struct device *dev, struct device_attribute *attr, char *buf) { ssize_t retval; struct rtc_time tm; @@ -55,10 +61,10 @@ rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr, return retval; } +static DEVICE_ATTR_RO(time); static ssize_t -rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr, - char *buf) +since_epoch_show(struct device *dev, struct device_attribute *attr, char *buf) { ssize_t retval; struct rtc_time tm; @@ -72,14 +78,60 @@ rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr, return retval; } +static DEVICE_ATTR_RO(since_epoch); + +static ssize_t +max_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq); +} + +static ssize_t +max_user_freq_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t n) +{ + struct rtc_device *rtc = to_rtc_device(dev); + unsigned long val = simple_strtoul(buf, NULL, 0); + + if (val >= 4096 || val == 0) + return -EINVAL; + + rtc->max_user_freq = (int)val; + + return n; +} +static DEVICE_ATTR_RW(max_user_freq); -static struct device_attribute rtc_attrs[] = { - __ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL), - __ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL), - __ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL), - __ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL), - { }, +/** + * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time + * + * Returns 1 if the system clock was set by this RTC at the last + * boot or resume event. + */ +static ssize_t +hctosys_show(struct device *dev, struct device_attribute *attr, char *buf) +{ +#ifdef CONFIG_RTC_HCTOSYS_DEVICE + if (rtc_hctosys_ret == 0 && + strcmp(dev_name(&to_rtc_device(dev)->dev), + CONFIG_RTC_HCTOSYS_DEVICE) == 0) + return sprintf(buf, "1\n"); + else +#endif + return sprintf(buf, "0\n"); +} +static DEVICE_ATTR_RO(hctosys); + +static struct attribute *rtc_attrs[] = { + &dev_attr_name.attr, + &dev_attr_date.attr, + &dev_attr_time.attr, + &dev_attr_since_epoch.attr, + &dev_attr_max_user_freq.attr, + &dev_attr_hctosys.attr, + NULL, }; +ATTRIBUTE_GROUPS(rtc); static ssize_t rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr, @@ -89,13 +141,13 @@ rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr, unsigned long alarm; struct rtc_wkalrm alm; - /* Don't show disabled alarms; but the RTC could leave the - * alarm enabled after it's already triggered. Alarms are - * conceptually one-shot, even though some common hardware - * (PCs) doesn't actually work that way. + /* Don't show disabled alarms. For uniformity, RTC alarms are + * conceptually one-shot, even though some common RTCs (on PCs) + * don't actually work that way. * - * REVISIT maybe we should require RTC implementations to - * disable the RTC alarm after it triggers, for uniformity. + * NOTE: RTC implementations where the alarm doesn't match an + * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC + * alarms after they trigger, to ensure one-shot semantics. */ retval = rtc_read_alarm(to_rtc_device(dev), &alm); if (retval == 0 && alm.enabled) { @@ -112,8 +164,11 @@ 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; + int adjust = 0; /* Only request alarms that trigger in the future. Disable them * by writing another time, e.g. 0 meaning Jan 1 1970 UTC. @@ -123,8 +178,20 @@ rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr, return retval; rtc_tm_to_time(&alm.time, &now); - alarm = simple_strtoul(buf, NULL, 0); - if (alarm > now) { + buf_ptr = (char *)buf; + if (*buf_ptr == '+') { + buf_ptr++; + if (*buf_ptr == '=') { + buf_ptr++; + push = 1; + } else + adjust = 1; + } + alarm = simple_strtoul(buf_ptr, NULL, 0); + if (adjust) { + 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. @@ -132,9 +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; @@ -176,9 +248,8 @@ void rtc_sysfs_add_device(struct rtc_device *rtc) err = device_create_file(&rtc->dev, &dev_attr_wakealarm); if (err) - dev_err(rtc->dev.parent, "failed to create " - "alarm attribute, %d", - err); + dev_err(rtc->dev.parent, + "failed to create alarm attribute, %d\n", err); } void rtc_sysfs_del_device(struct rtc_device *rtc) @@ -190,5 +261,5 @@ void rtc_sysfs_del_device(struct rtc_device *rtc) void __init rtc_sysfs_init(struct class *rtc_class) { - rtc_class->dev_attrs = rtc_attrs; + rtc_class->dev_groups = rtc_groups; } |