RPI4/8GB i2c not working?

[Klaus Küchemann]

> Am 10.03.2021 um 00:51 schrieb Mark Millard <marklmi at yahoo.com>:
> 
> 
> Nor do I see *ds3231* at:
> 
> https://github.com/raspberrypi/firmware/tree/1.20210303/boot/overlays/
…
I was only GUESSING ;-) that "the other Mark M.“ :-)  is trying to connect an RTC because 
one of the most annoying things on cheap arm boards is that if you forgot to set ‚date' then kernel builds have the wrong date, I even rebuilt kern when I forgot, I also always forgot to order a bunch of RTCs :-)
do you have one to test ?

There’s a README by scrolling page down on the above link.


e.g for the ds3231 it’s here :
--
Name:   i2c-rtc-gpio
Info:   Adds support for a number of I2C Real Time Clock devices
        using the software i2c controller
Load:   dtoverlay=i2c-rtc-gpio,<param>=<val>
Params: abx80x                  Select one of the ABx80x family:
                                  AB0801, AB0803, AB0804, AB0805,
                                  AB1801, AB1803, AB1804, AB1805

..
—   ds1339                  Select the DS1339 device
—

So, something like :
dtoverlay=i2c-rtc-gpio,<param>=<val>
in config.txt
and additional put i2c-rtc-gpio.dtbo in 
dtb/overlays on the msdos-partition of 14-snap
should make it working.

So this just as an example for rtc, although I can’t test at the moment and don’t know if there’s additional rtc-driver in src.

.. time to order a bunch of RTCs :-)

Regards

K.