[0/2] Update correct procedure for clearing alarm

Message

Biju Das June 18, 2024, 3:26 p.m. UTC

As per the latest HW manual[1], the INT# output is pulled low after the
alarm is triggered. After the INT# output is pulled low, it is low for at
least 250ms, even if the correct action is taken to clear it. It is
impossible to clear ALM if it is still active. The host must wait for the
RTC to progress past the alarm time plus the 250ms delay before clearing
ALM. Apart from this, there is an internal delay(~250 microsec) from
setting ALME = 0 to disabling the alarm function, so the user must add a
short delay of greater than 250µs between setting ALME = 0 and clearing
ALM.

Currently setting of ALME = 0 is done after clearing the ALM, so just
reverse the operation and add a delay of 275 microsec. Also add a
250msec delay before clearing the ALM.

[1]https://www.renesas.com/us/en/document/dst/raa215300-datasheet?r=1506351

Biju Das (2):
  rtc: isl1208: Add a delay for clearing alarm
  rtc: isl1208: Add correct procedure for clearing alarm

 drivers/rtc/rtc-isl1208.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

Comments

Alexandre Belloni June 27, 2024, 10:34 p.m. UTC | #1

On Tue, 18 Jun 2024 16:26:29 +0100, Biju Das wrote:
> As per the latest HW manual[1], the INT# output is pulled low after the
> alarm is triggered. After the INT# output is pulled low, it is low for at
> least 250ms, even if the correct action is taken to clear it. It is
> impossible to clear ALM if it is still active. The host must wait for the
> RTC to progress past the alarm time plus the 250ms delay before clearing
> ALM. Apart from this, there is an internal delay(~250 microsec) from
> setting ALME = 0 to disabling the alarm function, so the user must add a
> short delay of greater than 250µs between setting ALME = 0 and clearing
> ALM.
> 
> [...]

Applied, thanks!

[1/2] rtc: isl1208: Add a delay for clearing alarm
      https://git.kernel.org/abelloni/c/0dbd610c426e
[2/2] rtc: isl1208: Update correct procedure for clearing alarm
      https://git.kernel.org/abelloni/c/43696b3a9e46

Best regards,