Hi Jon,
Thanks for your reply! The reason that failed to read i2c at addr 4C is that I didn’t reset CS4270 when it poweron.
I got another problem that I need to configure the 40-pin and then I found the changes were saved to the file /boot/tegra194-p3668-all-p3509-0000-user-custom.dtb.
And I found in /boot/extlinux/extlinux.conf shows:
user@Jetson-xavier-NX:~$ cat /boot/extlinux/extlinux.conf
TIMEOUT 30
DEFAULT JetsonIO
MENU TITLE L4T boot options
LABEL primary
MENU LABEL primary kernel
LINUX /boot/Image
INITRD /boot/initrd
APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyTCU0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0
# When testing a custom kernel, it is recommended that you create a backup of
# the original kernel and add a new entry to this file so that the device can
# fallback to the original kernel. To do this:
#
# 1, Make a backup of the original kernel
# sudo cp /boot/Image /boot/Image.backup
#
# 2, Copy your custom kernel into /boot/Image
#
# 3, Uncomment below menu setting lines for the original kernel
#
# 4, Reboot
# LABEL backup
# MENU LABEL backup kernel
# LINUX /boot/Image.backup
# INITRD /boot/initrd
# APPEND ${cbootargs}
LABEL User Custom [2021-03-30-101212]
MENU LABEL User Custom [2021-03-30-101212]
LINUX /boot/Image
FDT /boot/tegra194-p3668-all-p3509-0000-user-custom-[2021-03-30-101212].dtb
INITRD /boot/initrd
APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyTCU0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0
FDT /boot/tegra194-p3668-all-p3509-0000.dtb
LABEL JetsonIO
MENU LABEL Custom 40-pin Header Config
LINUX /boot/Image
FDT /boot/tegra194-p3668-all-p3509-0000-user-custom.dtb
INITRD /boot/initrd
APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyTCU0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0
user@Jetson-xavier-NX:~$
As I had added the subnode CS4270 under i2c@31e0000, so I need to use
FDT /boot/tegra194-p3668-all-p3509-0000.dtb
which enables my configuration on CS4270, however I also need to configure the 40-pin to enable the i2s pin( as mentioned above changes saved to an dtb file), and these changes need the below command：
FDT /boot/tegra194-p3668-all-p3509-0000-user-custom.dtb
Then I found the two covers each other whatever I change the command sequence.
How can enable the two configurations at the same time?
Or how can I add the 40-pin changes into the /boot/tegra194-p3668-all-p3509-0000.dtb ?
Thanks
Yun