Real Time Clock (RTC)¶

Setting the RTC¶

Please note that starting from kernel 5.x the RTC node in the device tree must not include the IRQ pin declaration if it is not actually connected. If a wrong declaration is present the hwclock command will fail.

First set the system date & time:

date --set="20171231 23:59"

Then set the HW RTC using the system date & time:

hwclock --systohc --utc

Power down your board, wait 5 minutes and power up again, then check you system date & time and verify it is correct:

date

Wakeup using the RTC¶

The RTC node uses compatible = "dallas,ds1337". The kernel configuration enables the RTC_DRV_DS1307 driver, which supports this device. The kernel configuration option is CONFIG_RTC_DRV_DS1307.

For VAR-SOM-MX8M-MINI on the carrier board, the RTC node has no interrupt or wakeup-source configuration. RTC wakeup is not enabled in this configuration.