cm3588 nas - rtc device

[Marco Schirrmeister]

Just an information about the `edge` kernel (6.18) when used on the cm3588-nas system.

 

The rtc driver is not initialized on a `poweron`.

 

After a poweron, you will see the following in the log.

Nov 11 01:17:10 uhutest kernel: rtc-hym8563 6-0051: could not init device, -6
Nov 11 01:17:10 uhutest systemd[1]: System time advanced to built-in epoch: Tue 2025-11-11 01:17:09 CET

 

If you have `fake-hwclock` running, you will see the following a moment later. fake-hwclock restores the time, but the service will not properly start, because of the rtc device error.

Nov 11 01:17:12 uhutest fake-hwclock.sh[461]: Restoring saved system time
Nov 20 13:22:43 uhutest fake-hwclock.sh[466]: Thu Nov 20 01:22:43 PM CET 2025
Nov 20 13:22:43 uhutest fake-hwclock.sh[468]: hwclock: Cannot access the Hardware Clock via any known method.
Nov 20 13:22:43 uhutest fake-hwclock.sh[468]: hwclock: Use the --verbose option to see the details of our search for an access method.
Nov 20 13:22:43 uhutest systemd[1]: fake-hwclock.service: Main process exited, code=exited, status=1/FAILURE
Nov 20 13:22:43 uhutest systemd[1]: fake-hwclock.service: Failed with result 'exit-code'.
Nov 20 13:22:43 uhutest systemd[1]: Failed to start Restore system time on boot and save it on shutdown.

 

You would need to restart the fake-hwclock service, if you want that it saves time before the next restart.

 

If you do a `restart` of the system, the rtc device will get properly initialized and time is good. Following is seen in the logs.

Nov 20 13:26:14 uhutest kernel: rtc-hym8563 6-0051: registered as rtc0
Nov 20 13:26:14 uhutest kernel: rtc-hym8563 6-0051: setting system clock to 2025-11-20T12:26:11 UTC (1763641571)

Nov 20 13:26:16 uhutest fake-hwclock.sh[455]: Not restoring old system time

 

I have seen the issue right now only with the 6-18-RC kernel. The following patch mentioned here works as a pure workaround. https://patchwork.kernel.org/project/linux-rockchip/patch/20220608161150.58919-2-linux@fw-web.de/

Lets see how the development of kernel 6.18 goes and if the final version will not have this issue.