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 <biju.das.jz@xxxxxxxxxxxxxx> --- drivers/rtc/rtc-isl1208.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c index e50c23ee1646..c58063d917d6 100644 --- a/drivers/rtc/rtc-isl1208.c +++ b/drivers/rtc/rtc-isl1208.c @@ -7,6 +7,7 @@ #include <linux/bcd.h> #include <linux/clk.h> +#include <linux/delay.h> #include <linux/i2c.h> #include <linux/module.h> #include <linux/of.h> @@ -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 -- 2.43.0
