Why can't i2c clock frequency be changed in devicetree?

[edemeno2525]

I have a quark carrier board for jetson nano . I have flashed my system to external storage.
I want to change i2c-1 clock frequency 100000 to 400000. I want to change this permanently because I cant change my i2c clock frequency with changing /sys/bus/i2c/devices/i2c-1/bus_clk_rate file everytime after boot.

I changed clock-frequency value under i2c@7000c400 dtb file contained in the /boot/dtb/ directory. I compile dts file to dtb file with new name (new_device_tree.dtb) and I add this file location in extlinux.conf file with FDT /boot/dtb/new_device_tree.dtb
After reboot nothing changed.
I checked clock-frequency with
xxd /sys/firmware/devicetree/base/i2c@7000c400/clock-frequency
output: 00000000: 0001 86a0 .... (186a0 = 100000)

I also looked my devicetree file located in /sys/firmware/devicetree. It didn’t changed too.

I decompile my dtb file (/boot/dtb/new_device_tree.dtb). In dts file I saw clock frequency value under i2c@7000c400 as 0x61a80.

[kayccc]

orry for the late response, have you managed to get issue resolved or still need the support? Thanks

[JerryChang]

hello edemeno2525,

is there kernel logs for reference,
may I also know which Jetpack release you’re using?

[edemeno2525]

I solved this problem thanks. I use external storage and my dtb files are in /mnt directory not in /boot. But after change dtb file my jetson doesn’t open and here is the boot output:

Welcome to minicom 2.8

OPTIONS: I18n
Port /dev/ttyUSB0, 09:22:56

Press CTRL-A Z for help on special keys

BOOTP broadcast 8
BOOTP broadcast 9
BOOTP broadcast 10
BOOTP broadcast 11
BOOTP broadcast 12
BOOTP broadcast 13
BOOTP broadcast 14
BOOTP broadcast 15
BOOTP broadcast 16
BOOTP broadcast 17

Retry time exceeded; starting again
missing environment variable: pxeuuid
Retrieving file: /boot/extlinux/pxelinux.cfg/01-48-b0-2d-81-d7-66
*** ERROR: serverip' not set Retrieving file: /boot/extlinux/pxelinux.cfg/00000000 *** ERROR: serverip’ not set
Retrieving file: /boot/extlinux/pxelinux.cfg/0000000
*** ERROR: serverip' not set Retrieving file: /boot/extlinux/pxelinux.cfg/000000 *** ERROR: serverip’ not set
Retrieving file: /boot/extlinux/pxelinux.cfg/00000
*** ERROR: serverip' not set Retrieving file: /boot/extlinux/pxelinux.cfg/0000 *** ERROR: serverip’ not set
Retrieving file: /boot/extlinux/pxelinux.cfg/000
*** ERROR: serverip' not set Retrieving file: /boot/extlinux/pxelinux.cfg/00 *** ERROR: serverip’ not set
Retrieving file: /boot/extlinux/pxelinux.cfg/0
*** ERROR: serverip' not set Retrieving file: /boot/extlinux/pxelinux.cfg/default-arm-tegra210-p3450-0000 *** ERROR: serverip’ not set
Retrieving file: /boot/extlinux/pxelinux.cfg/default-arm-tegra210
*** ERROR: serverip' not set Retrieving file: /boot/extlinux/pxelinux.cfg/default-arm *** ERROR: serverip’ not set
Retrieving file: /boot/extlinux/pxelinux.cfg/default
*** ERROR: `serverip’ not set
Config file not found
BOOTP broadcast 1
BOOTP broadcast 2
BOOTP broadcast 3
BOOTP broadcast 4
BOOTP broadcast 5
BOOTP broadcast 6
BOOTP broadcast 7
BOOTP broadcast 8
BOOTP broadcast 9
BOOTP broadcast 10
BOOTP broadcast 11
BOOTP broadcast 12
BOOTP broadcast 13
BOOTP broadcast 14
BOOTP broadcast 15
BOOTP broadcast 16
BOOTP broadcast 17

Retry time exceeded; starting again
BOOTP broadcast 1
BOOTP broadcast 2
BOOTP broadcast 3
BOOTP broadcast 4
BOOTP broadcast 5
BOOTP broadcast 6
BOOTP broadcast 7
BOOTP broadcast 8
BOOTP broadcast 9
BOOTP broadcast 10
BOOTP broadcast 11
BOOTP broadcast 12
BOOTP broadcast 13
BOOTP broadcast 14
BOOTP broadcast 15
BOOTP broadcast 16
BOOTP broadcast 17

Retry time exceeded; starting again

I am using JetPack 4.6.1 – L4T r32.7.1 which downloaded from here for jetson nano