[PATCH v2 4/7] rtc: cmos: Report supported alarm limit to rtc infrastructure

From: Guenter Roeck
Date: Thu Aug 17 2023 - 18:57:07 EST


The alarm window supported by the cmos RTC depends on the chip
and its configuration. Report the limit to the RTC core.

Cc: Brian Norris <briannorris@xxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v2: Rename range_max_offset -> alarm_offset_max

drivers/rtc/rtc-cmos.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index c9416fe8542d..228fb2d11c70 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -913,6 +913,10 @@ static inline void cmos_check_acpi_rtc_status(struct device *dev,
#define INITSECTION __init
#endif

+#define SECS_PER_DAY (24 * 60 * 60)
+#define SECS_PER_MONTH (28 * SECS_PER_DAY)
+#define SECS_PER_YEAR (365 * SECS_PER_DAY)
+
static int INITSECTION
cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
{
@@ -1019,6 +1023,13 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
goto cleanup0;
}

+ if (cmos_rtc.mon_alrm)
+ cmos_rtc.rtc->alarm_offset_max = SECS_PER_YEAR - 1;
+ else if (cmos_rtc.day_alrm)
+ cmos_rtc.rtc->alarm_offset_max = SECS_PER_MONTH - 1;
+ else
+ cmos_rtc.rtc->alarm_offset_max = SECS_PER_DAY - 1;
+
rename_region(ports, dev_name(&cmos_rtc.rtc->dev));

if (!mc146818_does_rtc_work()) {
--
2.39.2