Re: RPI4 + ntpdate + unbound

> Am 03.07.2022 um 12:51 schrieb John Kennedy <[email protected]>:
> 
> On Fri, Jul 01, 2022 at 10:49:33PM -1000, David Cornejo wrote:
>> I always hated this about the RPIs - I put a DS3231 on mine and the
>> problem disappears. ...
> 
> Yeah.  Not sure where Eben would cram it (much less the battery), but
> one of these days his form factor needs to expand a bit.  But with what
> I do with the RPI4 it runs hot, so I've got a good passive case, but
> this one hides the GPIO pins entirely and the active-cooling one I'm
> looking at is a big chunk of aluminum + fans, which means some pretty
> significant risers/headers to get it to clear the heatsink and some
> contention with the PWR/GRD pins to power the fan.
> 
> Haven't dug into what RTC driver FreeBSD may support to see where I
> can stick the RTC.  I do want one, just not seeing options that jump out
> at me.

Before this just ended weekend, I would have recommended the DS3231 as well, because it is working very well on my BeagleBone's Black for years now. It is very well documented and FreeBSD comes with a kernel module for it. Beginning on last Friday I started with FreeBSD 13.1-RELEASE on a brand new RPi 4 B 2 GB, and with that one, attaching the DS3231 became a major hassle.

Here is the whole story:
  https://lists.freebsd.org/archives/freebsd-arm/2022-February/001024.html

On 19.02.2022 6:01, Brian Scott wrote:
> The MAX77620 driver introduced for an NVIDIA TEGRA210 system seems to 
> unilaterally claim anything at address 68. It doesn't understand the 
> DS3231 and fails to operate properly, but in claiming the device, the 
> ds3231 driver doesn't get a chance. This is compounded by the MAX77620 
> driver being compiled into the kernel by default so the loadable module 
> doesn't get to try until after the wrong driver has claimed it.

As suggested by Brian Scott, I compiled a custom kernel without the NVIDIA Tegra option. Only, with that custom kernel my RPi 4 (0xb03115) stuck at boot right before mounting the system partition. Then I switched to FreeBSD 14.0-CURRENT in which the problem has been resolved, and with that my RPi and the DS3231 is properly working.

I got this one: https://produto.mercadolivre.com.br/MLB-971284468-ds3231-shield-relogio-tempo-real-arduino-rtc-eeprom-at24c32-_JM

If you have a close look at the picture, you can see that I would have been able to change its address, by soldering the address pads A0, A1 and A2 respectively. Perhaps, I should have done this, since I would have liked to stay with RELEASE instead of CURRENT.

The DTS code for the DS3231 is given in said thread on the mailing list. Using the dtc utility, I compiled a .dtbo and placed it into /boot/msdos/overlays as ds3231-rpi4.dtbo. Then I added two lines to /boot/msdos/config.txt:

  gpio=2,3=a0
  dtoverlay=ds3231-rpi4

It is working now, but the operation felt like pulling teeth at the dentists. I am still surprised why we get the NVIDIA Tegra compiled in the kernel of a 13.1-RELEASE SD card image which according to its file name is destined to the Raspberry Pi's.