A really small nitpick below
On 03/02/2016 at 09:16:43 -0800, Joshua Clayton wrote :
> 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 <stillcompil...@gmail.com>
> ---
> Documentation/rtc.txt | 6 ++++++
> drivers/rtc/rtc-sysfs.c | 35 ++++++++++++++++++++++++++++++++++-
> 2 files changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt
> index 8446f1e..ddc3660 100644
> --- a/Documentation/rtc.txt
> +++ b/Documentation/rtc.txt
> @@ -157,6 +157,12 @@ wakealarm: The time at which the clock will
> generate a system wakeup
> 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.
> +offset: The amount which the rtc clock has been adjusted in
> firmware.
> + Visible only if the driver supports clock offset adjustment.
> + The unit is parts per billion, i.e. The number of clock ticks
> + which are added to or removed from the rtc's base clock per
> + billion ticks. A positive value makes a day pass more slowly,
> + longer, and a negative value makes a day pass more quickly.
>
> IOCTL INTERFACE
> ---------------
> diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
> index 463e286..f8d7f8d 100644
> --- a/drivers/rtc/rtc-sysfs.c
> +++ b/drivers/rtc/rtc-sysfs.c
> @@ -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)
This is not properly aligned.
> +{
> + 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;
> }
> --
> 2.5.0
>
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
