Re: Activate a Real Time Clock chip on I2C in Raspberry Pi 4B with Debian (not Raspbian)

["Rick Thomas" <rick.thomas@pobox.com>]

Sadly,   when I do:
    i2cdetect -l
I get nothing back.  Leading me to conclude that there are no busses available.

FWIW, when I do:
    /sbin/hwclock -vr
I get:
    hwclock from util-linux 2.36.1
    System Time: 1681724077.614748
    Trying to open: /dev/rtc0
    Trying to open: /dev/rtc
    Trying to open: /dev/misc/rtc
    No usable clock interface found.
    hwclock: Cannot access the Hardware Clock via any known method.

Also FWIW, when I do:
    ls -l /dev/i2c*
I get:
    ls: cannot access '/dev/i2c*': No such file or directory

Further confirming that there are no available busses.

Is it possible that I need to modprobe a different (or additional) module than "i2c_bcm2835"?

Thanks!
Rick

PS:  I'm still wondering if there is some kind of documentation of these modules and what they do that would give me a bit of background for this project.


On Mon, Apr 17, 2023, at 1:10 AM, Reco wrote:
> Hi.
>
> On Sun, Apr 16, 2023 at 06:41:53PM -0700, Rick Thomas wrote:
>> I found this in journalctl :
>>     Apr 16 18:23:33 pi kernel: rtc-ds1307: probe of 1-0068 failed with error -121
>>     Apr 16 18:23:33 pi kernel: i2c i2c-1: new_device: Instantiated device ds1307 at 0x68
>> 
>> Is rtc_ds1307 the wrong module for my DS3231 rtc hardware?
>
> No, because ds1307 kernel module should work with DS3231.
> But the address of the device (0x68) on I2C bus could be different,
> or the device is actually connected to another I2C bus (i.e. - not 1st).
>
> Consider running i2cdetect to clarify things.
>
> Reco