Hi there, I try to install a DS3231 RTC-Modul.
Specs
Installed the Module to pin 1 to 5 of the 40 GPIO Header.
Then installed the “i2c-tools”:
dnf install i2c-tools python3-i2c-tools
What I read is, that the p4 would use device trees.
So in the config file I added two parameters to enable the ic2 bus system and rebooted. The device tree should load all needed kernel modules, at least is that what I understood.
vi /boot/efi/config.txt
dtparam=i2c_arm=on
dtoverlay=i2c-rtc,ds3231
However a rtc kernel module seems not to be loaded.
I get some output using the i2c-tool that should actually be the DS3231 rtc hardware clock:
[root@p4:~]# i2cdetect -y 3
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
Somewhere I read that the “68” should be an “UU” in case it is working correctly.
But reading or setting the clock is not possible, regardles if I do load a rtc kernel module manually or not, by:
modprobe rtc-ds1307
It always says:
[root@p4:~]# hwclock -r --verbose
hwclock von util-linux 2.36.2
Systemzeit: 1633193843.655069
Versuch zu öffnen: /dev/rtc0
Versuch zu öffnen: /dev/rtc
Versuch zu öffnen: /dev/misc/rtc
Keine brauchbare Uhrschnittstelle gefunden.
hwclock: Es wurde keine Zugriffsart gefunden, mit der auf die Hardwareuhr zugegriffen werden konnte.
German output basically means that it could not open said path, they are not present. No way to access the hardware clock.
So obviously something is missing.
Do I need to install driver or something else?