On Thursday 19 July 2018 03:32 PM, Johan Hovold wrote:
> On Thu, Jul 12, 2018 at 10:37:37AM +0530, Keerthy wrote:
>> Cut down the shutdown time from 2 seconds to 1 sec. In case of roll
>> over try again.
>>
>> Signed-off-by: Keerthy <j-keerthy@xxxxxx>
>> ---
>>
>> Changes in v4:
>>
>> * Fixed a compilation issue.
>> * Extended the roll over check post interrupt programming.
>>
>> drivers/rtc/rtc-omap.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
>> index 323ff55..88da927 100644
>> --- a/drivers/rtc/rtc-omap.c
>> +++ b/drivers/rtc/rtc-omap.c
>
> First, the comment above this function would need to be updated as part
> of this patch as it refers to the two-second alarm offset.
Yes, will change that.
>
>> @@ -435,17 +435,23 @@ static void omap_rtc_power_off(void)
>> struct rtc_time tm;
>> unsigned long now;
>> u32 val;
>> + int seconds;
>>
>> rtc->type->unlock(rtc);
>> /* enable pmic_power_en control */
>> val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
>> rtc_writel(rtc, OMAP_RTC_PMIC_REG, val | OMAP_RTC_PMIC_POWER_EN_EN);
>>
>> - /* set alarm two seconds from now */
>> +again:
>> + /* Clear any existing ALARM2 event */
>> + rtc_writel(rtc, OMAP_RTC_STATUS_REG, OMAP_RTC_STATUS_ALARM2);
>
> Why is this needed? Any pending interrupt is cleared at probe, and a
> previous attempt to set the alarm really led to the alarm going off, why
> would we retry?
Yes this is not needed.
>
>> +
>> + /* set alarm one second from now */
>> omap_rtc_read_time_raw(rtc, &tm);
>> + seconds = tm.tm_sec;
>> bcd2tm(&tm);
>> rtc_tm_to_time(&tm, &now);
>> - rtc_time_to_tm(now + 2, &tm);
>> + rtc_time_to_tm(now + 1, &tm);
>>
>> if (tm2bcd(&tm) < 0) {
>> dev_err(&rtc->rtc->dev, "power off failed\n");
>> @@ -470,6 +476,9 @@ static void omap_rtc_power_off(void)
>> val = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
>> rtc_writel(rtc, OMAP_RTC_INTERRUPTS_REG,
>> val | OMAP_RTC_INTERRUPTS_IT_ALARM2);
>
> Add a newline here.
Okay
>
>> + /* Our calculations started right before the rollover, try again */
>
> Nit: use all lower case unless writing full sentences, which also
> matches most of the other comments in this file.
okay
>
>> + if (seconds != rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_SECONDS_REG))
>> + goto again;
>
> Here the alarm may have gone off as part of the roll over, in which case
> you shouldn't retry.
Ex: We programmed at Sec = 2 and we expect ALARM2 to fire at sec = 3.
In the event of Roll over before setting the
OMAP_RTC_INTERRUPTS_IT_ALARM2 bit in the OMAP_RTC_INTERRUPTS_REG will we
not miss the ALARM2 event? Then poweroff would fail right?
Hence the attempt to retry the next second. This sequence would begin
right at the beginning of a new second and we expect the full sequence
to get over without having to retry again.
Hope i am clear.
>
> Add a newline here too.
Okay
>
>> rtc->type->lock(rtc);
>>
>> /*
>
> Thanks,
> Johan
>
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