On Thu, Aug 22, 2019 at 03:44:03PM +0800, Rahul Tanwar wrote:
> Use a newly introduced optional "status" property of "motorola,mc146818"
> compatible DT node to determine if RTC is supported. Skip read/write from
> RTC device only when this node is present and status is "disabled". In all
> other cases, proceed as before.
Can't we rather update ->get_wallclock() and ->set_wallclock() based on this?
> Suggested-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
> Signed-off-by: Rahul Tanwar <rahul.tanwar@xxxxxxxxxxxxxxx>
> ---
> arch/x86/kernel/rtc.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
> index 586f718b8e95..f9f760a8e76a 100644
> --- a/arch/x86/kernel/rtc.c
> +++ b/arch/x86/kernel/rtc.c
> @@ -32,6 +32,11 @@ EXPORT_SYMBOL(cmos_lock);
> DEFINE_SPINLOCK(rtc_lock);
> EXPORT_SYMBOL(rtc_lock);
>
> +static const struct of_device_id of_cmos_match[] = {
> + { .compatible = "motorola,mc146818" },
> + {}
> +};
> +
> /*
> * In order to set the CMOS clock precisely, set_rtc_mmss has to be
> * called 500 ms after the second nowtime has started, because when
> @@ -42,9 +47,14 @@ EXPORT_SYMBOL(rtc_lock);
> int mach_set_rtc_mmss(const struct timespec64 *now)
> {
> unsigned long long nowtime = now->tv_sec;
> + struct device_node *node;
> struct rtc_time tm;
> int retval = 0;
>
> + node = of_find_matching_node(NULL, of_cmos_match);
> + if (node && !of_device_is_available(node))
> + return -EINVAL;
> +
> rtc_time64_to_tm(nowtime, &tm);
> if (!rtc_valid_tm(&tm)) {
> retval = mc146818_set_time(&tm);
> @@ -63,8 +73,15 @@ int mach_set_rtc_mmss(const struct timespec64 *now)
> void mach_get_cmos_time(struct timespec64 *now)
> {
> unsigned int status, year, mon, day, hour, min, sec, century = 0;
> + struct device_node *node;
> unsigned long flags;
>
> + node = of_find_matching_node(NULL, of_cmos_match);
> + if (node && !of_device_is_available(node)) {
> + now->tv_sec = now->tv_nsec = 0;
> + return;
> + }
> +
> /*
> * If pm_trace abused the RTC as storage, set the timespec to 0,
> * which tells the caller that this RTC value is unusable.
> --
> 2.11.0
>
--
With Best Regards,
Andy Shevchenko
