On Tuesday 14 August 2018 02:53 PM, Johan Hovold wrote:
> On Wed, Jul 25, 2018 at 11:21:22AM +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 v5:
>>
>> * Added an additional check to see if ALARM2 status is not set
>> before retrying.
>> * Cleaned up comments
>> * Also reduced mdelay to 1S lesser as per this commit
>>
>> drivers/rtc/rtc-omap.c | 28 ++++++++++++++++++----------
>> 1 file changed, 18 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
>> index 44ff4cc..caa6da6 100644
>> --- a/drivers/rtc/rtc-omap.c
>> +++ b/drivers/rtc/rtc-omap.c
>> @@ -421,12 +421,6 @@ static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
>> * The RTC can be used to control an external PMIC via the pmic_power_en pin,
>> * which can be configured to transition to OFF on ALARM2 events.
>> *
>> - * Notes:
>> - * The two-second alarm offset is the shortest offset possible as the alarm
>> - * registers must be set before the next timer update and the offset
>> - * calculation is too heavy for everything to be done within a single access
>> - * period (~15 us).
>> - *
>> * Called with local interrupts disabled.
>> */
>> static void omap_rtc_power_off(void)
>> @@ -435,17 +429,20 @@ static void omap_rtc_power_off(void)
>> struct rtc_time tm;
>> unsigned long now;
>> u32 val;
>> + int seconds;
>
> Nit: I'd place this above val to maintain the reverse xmas-tree style.
okay
>
>>
>> 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:
>> + /* 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");
>> @@ -470,14 +467,25 @@ 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);
>> +
>> + /*
>> + * first check if ALARM2 has fired, if not then check if
>> + * our calculations started right before the rollover, try again
>> + * in case of rollover
>> + */
>
> This is unnecessarily verbose; I'd rephrase it as something like:
>
> /* Retry in case roll over happened before alarm was armed. */
Okay
>
>> + if (!(OMAP_RTC_STATUS_ALARM2 && rtc_read(omap_rtc_power_off_rtc,
>> + OMAP_RTC_STATUS_REG)) &&
>> + seconds != rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_SECONDS_REG))
>> + goto again;
>
> And this is clearly broken. First, you use boolean && instead of the &
> bit operation.
Ah my bad. I will fix it.
>
> Second, you need to check the status register *after* checking for
> roll-over, as I already mentioned.
>
> Also, use the rtc pointer rather than omap_rtc_power_off_rtc, which will
> allow for more readable code.
Okay
>
> I also strongly suggest you split the conditional, and use val to store
> the status register value, that is:
>
> if (rtc_read(rtc, OMAP_RTC_SECONDS_REG) != seconds) {
> val = rtc_read(rtc, OMAP_RTC_STATUS_REG);
> if (!(val & OMAP_RTC_STATUS_ALARM2))
> goto again;
> }
>
>> +
>> rtc->type->lock(rtc);
>>
>> /*
>> - * Wait for alarm to trigger (within two seconds) and external PMIC to
>> + * Wait for alarm to trigger (within one second) and external PMIC to
>> * power off the system. Add a 500 ms margin for external latencies
>> * (e.g. debounce circuits).
>> */
>> - mdelay(2500);
>> + mdelay(1500);
>> }
>>
>> static const struct rtc_class_ops omap_rtc_ops = {
>
> Johan
>
