[PATCH 06/12] rtc: ab8500: let the core handle the alarm resolution

From: Alexandre Belloni
Date: Sun Nov 07 2021 - 17:55:16 EST


Tell the RTC core UIE are not supported because the resolution of the alarm
is a minute.

Note that this is in fact also fixing how the resolution is reported as the
previous test was simply ensuring the alarm was more than a minute in the
future while the register has a minute resolution.
This would be ok if the alarm was a countdown but ab8500_rtc_read_alarm
suggests otherwise and the AB8500 datasheet states that the RTC
documentation is not public.

Finally, the comment is wrong and what makes the UIE emulation work is
uie_unsupported being set.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
---
drivers/rtc/rtc-ab8500.c | 23 ++++-------------------
1 file changed, 4 insertions(+), 19 deletions(-)

diff --git a/drivers/rtc/rtc-ab8500.c b/drivers/rtc/rtc-ab8500.c
index b40048871295..ea33e149d545 100644
--- a/drivers/rtc/rtc-ab8500.c
+++ b/drivers/rtc/rtc-ab8500.c
@@ -184,25 +184,9 @@ static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
int retval, i;
unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
- unsigned long mins, secs = 0, cursec = 0;
- struct rtc_time curtm;
+ unsigned long mins;

- /* Get the number of seconds since 1970 */
- secs = rtc_tm_to_time64(&alarm->time);
-
- /*
- * Check whether alarm is set less than 1min.
- * Since our RTC doesn't support alarm resolution less than 1min,
- * return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
- */
- ab8500_rtc_read_time(dev, &curtm); /* Read current time */
- cursec = rtc_tm_to_time64(&curtm);
- if ((secs - cursec) < 59) {
- dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
- return -EINVAL;
- }
-
- mins = secs / 60;
+ mins = (unsigned long)rtc_tm_to_time64(&alarm->time) / 60;

buf[2] = mins & 0xFF;
buf[1] = (mins >> 8) & 0xFF;
@@ -394,7 +378,8 @@ static int ab8500_rtc_probe(struct platform_device *pdev)
dev_pm_set_wake_irq(&pdev->dev, irq);
platform_set_drvdata(pdev, rtc);

- rtc->uie_unsupported = 1;
+ set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
+ clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);

rtc->range_max = (1ULL << 24) * 60 - 1; // 24-bit minutes + 59 secs
rtc->start_secs = RTC_TIMESTAMP_BEGIN_2000;
--
2.31.1