xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

rtc: implement a sysfs interface for clock offset

Browse Source 
clock offset may be set and read in decimal parts per billion
attribute is /sys/class/rtc/rtcN/offset
The attribute is only visible for rtcs that have set_offset implemented.

Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Joshua Clayton
2016-02-05 12:41:12 -08:00
committed by Alexandre Belloni
parent b3967067c2
commit 5495a4159f
2 changed files with 40 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/rtc/rtc-sysfs.c
View File

@@ -218,6 +218,34 @@ wakealarm_store(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RW(wakealarm);
static ssize_t
offset_show(struct device *dev, struct device_attribute *attr, char *buf)
{
ssize_t retval;
long offset;
retval = rtc_read_offset(to_rtc_device(dev), &offset);
if (retval == 0)
retval = sprintf(buf, "%ld\n", offset);
return retval;
}
static ssize_t
offset_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t n)
{
ssize_t retval;
long offset;
retval = kstrtol(buf, 10, &offset);
if (retval == 0)
retval = rtc_set_offset(to_rtc_device(dev), offset);
return (retval < 0) ? retval : n;
}
static DEVICE_ATTR_RW(offset);
static struct attribute *rtc_attrs[] = {
&dev_attr_name.attr,
&dev_attr_date.attr,
@@ -226,6 +254,7 @@ static struct attribute *rtc_attrs[] = {
&dev_attr_max_user_freq.attr,
&dev_attr_hctosys.attr,
&dev_attr_wakealarm.attr,
&dev_attr_offset.attr,
NULL,
};
@@ -249,9 +278,13 @@ static umode_t rtc_attr_is_visible(struct kobject *kobj,
struct rtc_device *rtc = to_rtc_device(dev);
umode_t mode = attr->mode;
if (attr == &dev_attr_wakealarm.attr)
if (attr == &dev_attr_wakealarm.attr) {
if (!rtc_does_wakealarm(rtc))
mode = 0;
} else if (attr == &dev_attr_offset.attr) {
if (!rtc->ops->set_offset)
mode = 0;
}
return mode;
}