how to enable RTC on HC4 OLED?

[Nox997]

Hello, (and a happy new year!)
I'm using the official 20.04 minimal image on my hc4 oled.

I would like to use the integrated RTC.
The manual on the wiki for the C4 does not work.

Is there a guide available somewhere? Or should this work out of the box?

Thank you very much in advance!

[tobetter]

Please refer to the link,
https://wiki.odroid.com/odroid-hc4/appl ... =homecloud

Or simply install odroid-homecloud-display.

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sudo apt update
sudo apt install odroid-homecloud-display

[Nox997]

Hi @tobetter,

thank you for your reply!
However, it seems this still does not enable the RTC for me - after a reboot, I get:

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root@smaug ~ # timedatectl
               Local time: Fri 2021-01-01 11:06:30 CET
           Universal time: Fri 2021-01-01 10:06:30 UTC
                 RTC time: n/a
                Time zone: Europe/Berlin (CET, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no
root@smaug ~ #

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root@smaug ~ # ls -l /dev |grep -i rtc
1 root@smaug ~ #

and

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130 root@smaug ~ # lsmod | grep rtc
1 root@smaug ~ # lsmod | grep i2c
i2c_meson_master       20480  1
root@smaug ~ #

Do i need to load the pcf8563.dtbo overlay from /media/boot/amlogic/overlays/odroidc4 manually?


edit:
I have modified /media/boot/config.ini and included the pcf8563.dtbo in the overlays array:

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; Device Tree Overlay
overlay_resize=16384
overlay_profile=
overlays="spi0 i2c0 i2c1 uart0 pcf8563"

Then, the rtc is available in /dev as well as it is shown in timedatectl:

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root@smaug ~ # timedatectl
               Local time: Fri 2021-01-01 11:17:27 CET
           Universal time: Fri 2021-01-01 10:17:27 UTC
                 RTC time: Fri 2021-01-01 10:17:28
                Time zone: Europe/Berlin (CET, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Is this the way it's supposed to be configured / enabled?

[tobetter]

edit:
I have modified /media/boot/config.ini and included the pcf8563.dtbo in the overlays array:

Code: Select all

; Device Tree Overlay
overlay_resize=16384
overlay_profile=
overlays="spi0 i2c0 i2c1 uart0 pcf8563"

Then, the rtc is available in /dev as well as it is shown in timedatectl:

Code: Select all

root@smaug ~ # timedatectl
               Local time: Fri 2021-01-01 11:17:27 CET
           Universal time: Fri 2021-01-01 10:17:27 UTC
                 RTC time: Fri 2021-01-01 10:17:28
                Time zone: Europe/Berlin (CET, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Is this the way it's supposed to be configured / enabled?

Apparently, it is ... if you can see and use hwclock then adding pcf8563 to boot.ini is correct.

[Nox997]

hello,

unfortunately, even with pcf8563 loaded, during a reboot, the system is not getting the first time information from the RTC but defaults to the unix epoch.
The last command shows what I mean:

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xxxx@odroidhc4 ~ % last
xxxx     pts/0        192.168.17.26    Wed Jan 13 21:39    gone - no logout
reboot   system boot  4.9.241-66       Thu Jan  1 01:00   still running
xxxx     pts/0        192.168.17.26    Wed Jan 13 21:37 - 21:39  (00:01)
reboot   system boot  4.9.241-66       Thu Jan  1 01:00 - 21:39 (18640+20:38)

dmesg output might give a hint as to why this is:

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xxxx@odroidhc4 ~ % sudo dmesg |grep -i rtc
[    9.574066] hctosys: unable to open rtc device (rtc0)
[   16.032098] rtc-pcf8563 0-0051: rtc core: registered rtc-pcf8563 as rtc0

So it seems the rtc is registered way later that the point in time when the kernel tries to get the time from the RTC.

What can I do about this? Is this a configuration error on my side?

Thank you very much in advance for your help!

[rooted]

So it seems the rtc is registered way later that the point in time when the kernel tries to get the time from the RTC.

What can I do about this? Is this a configuration error on my side?

Thank you very much in advance for your help!

See this:

viewtopic.php?t=41488

[neal]

So it seems the rtc is registered way later that the point in time when the kernel tries to get the time from the RTC.

What can I do about this? Is this a configuration error on my side?

Thank you very much in advance for your help!

See this:

viewtopic.php?t=41488

See this wiki as well:
https://wiki.odroid.com/accessory/add-o ... rtc_shield