Unfortunately, FITs does not have any settings for SMBus enable/disable and so on. In general, this program for Edisonville_Rangeley is very poor settings.

Thanks for youre advice Kyösti! I add files with logs. I tried to play with the enable_smbus() function but without result. Rather, the result is the same - no devices on i2c-1.
You can see the comparison of devices on (SMBus0) i2c-1 bus with the OEM Bios and with Coreboot bios in i2cdetect.log.
Could nuvoton superio somehow affect the SMBus?

I also noticed errors in dmesg output such:
[   93.737732] i801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
[   93.744750] i801_smbus 0000:00:1f.3: Transaction timeout

Best Regards,
Dmitry Ponamorev  

пт, 31 мая 2019 г. в 07:50, Kyösti Mälkki <kyosti.malkki@gmail.com>:
On Wed, May 29, 2019 at 5:48 PM <dponamorev@gmail.com> wrote:
>
> There is motherboard based on the Intel Rangeley Atom C2000 (C2758) series processor. How to enable the SMBus0 in coreboot? If I use OEM BIOS or BIOS from Intel (EDVLCRB1.86B.0048.R00.1508181657_MPK) for mohon peak crb, then I see on the SMBus0 (i2c-1 in Fedora 28) memory DIMM spd (0x50 & 0x52), clock generator (0x69) and other devices. If I use a coreboot based bios for the Mohon peak platform - I do not see any devices on i2c-1. I see an data exchange on the SMBus0 with oscilloscope at boot time only. When I send "i2cdetect -y 1" command in Linux no activity on SMBus0 and no device found.

Your chances of getting support are much better when you provide more
context and logfiles. We would probably need relevant lines from
system logs (dmesg) and outputs from 'i2cdetect' and 'lspci -xx' here,
both OEM BIOS and coreboot. For coreboot, also 'cbmem -1'. Would not
hurt if you pushed your mainboard port as a draft to gerrit or make
your work otherwise accesible.

What we have in rangeley_smbus_read_resources() does not look that
good, it may leave SMBUS IO BAR unset in the hardware. Might be simply
case of calling enable_smbus() in romstage for the board to get that
fixed.

Regards,
Kyösti Mälkki