From 0dbd610c426ed695eef5d26584259d96b6250c76 Mon Sep 17 00:00:00 2001 From: Biju Das Date: Tue, 18 Jun 2024 16:26:30 +0100 Subject: rtc: isl1208: Add a delay for clearing alarm 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. [1]https://www.renesas.com/us/en/document/dst/raa215300-datasheet?r=1506351 Signed-off-by: Biju Das Link: https://lore.kernel.org/r/20240618152635.48956-2-biju.das.jz@bp.renesas.com Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-isl1208.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/rtc') diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c index 206f96b90f58..6877e2f3bde6 100644 --- a/drivers/rtc/rtc-isl1208.c +++ b/drivers/rtc/rtc-isl1208.c @@ -7,6 +7,7 @@ #include #include +#include #include #include #include @@ -628,6 +629,18 @@ isl1208_rtc_interrupt(int irq, void *data) struct isl1208_state *isl1208 = i2c_get_clientdata(client); int handled = 0, sr, err; + if (!isl1208->config->has_tamper) { + /* + * The INT# output is pulled low 250ms 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. + */ + msleep(250); + } + /* * I2C reads get NAK'ed if we read straight away after an interrupt? * Using a mdelay/msleep didn't seem to help either, so we work around -- cgit v1.2.3-70-g09d2