diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt index 2745e8197fd..9104c106208 100644 --- a/Documentation/rtc.txt +++ b/Documentation/rtc.txt @@ -143,6 +143,8 @@ rtc attributes without requiring the use of ioctls. All dates and times are in the RTC's timezone, rather than in system time. date: RTC-provided date +hctosys: 1 if the RTC provided the system time at boot via the + CONFIG_RTC_HCTOSYS kernel option, 0 otherwise max_user_freq: The maximum interrupt rate an unprivileged user may request from this RTC. name: The name of the RTC corresponding to this sysfs directory diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c index 2531ce4c9db..7dd23a6fc82 100644 --- a/drivers/rtc/rtc-sysfs.c +++ b/drivers/rtc/rtc-sysfs.c @@ -102,6 +102,19 @@ rtc_sysfs_set_max_user_freq(struct device *dev, struct device_attribute *attr, return n; } +static ssize_t +rtc_sysfs_show_hctosys(struct device *dev, struct device_attribute *attr, + char *buf) +{ +#ifdef CONFIG_RTC_HCTOSYS_DEVICE + if (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 struct device_attribute rtc_attrs[] = { __ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL), __ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL), @@ -109,6 +122,7 @@ static struct device_attribute rtc_attrs[] = { __ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL), __ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq, rtc_sysfs_set_max_user_freq), + __ATTR(hctosys, S_IRUGO, rtc_sysfs_show_hctosys, NULL), { }, };