Problem with connecting the SPI to the Jetson Nano

illyaverb · May 10, 2023, 9:44pm

Hi, I’m having a problem using SPI on a Jetson Nano, can anyone who has experienced this help me?

I enabled the use of SPI1 via jetson-io.

Replaced in nvidia, function rsvd1 with spi1, for all spi1__**

Loaded spidev via sudo modprobe spidev bufsiz=65563

Tested with sudo ./spidev_test -D /dev/spidev0.0 -g16 -zz (pins 19 and 21 connected in a loop)*
using device: /dev/spidev0.0
setting spi mode for read, write
setting spi bpw
setting max speed for rd/wr
spi mode: 0
bits per word: 8 bytes per word: 1
max speed: 10000000 Hz (10000 KHz)
no. runs: 1
Using seed: 0x645a676b
loop count = 0
using sequential pattern ....
transfer bytes [16]
0000: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
transfer: Return actual transfer length: 16
receive bytes [16]
0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
mismatch index 1
^^^ 00 00 00 00 00 00 00 00 00 00 00 /dev/spidev0.0: TEST FAILED !!!!! (status:-1)

Checked dmesg | grep -i kernel

Checked sudo cat /boot/extlinux/extlinux.conf
TIMEOUT 30
DEFAULT JetsonIO

MENU TITLE L4T boot options

LABEL primary
MENU LABEL primary kernel
LINUX /boot/arducam/Image
INITRD /boot/initrd
APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyS0,115200n8 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 JetsonIO
MENU LABEL Custom Header Config: <HDR40 User Custom [2023-05-08-002158]>
LINUX /boot/arducam/Image
FDT /boot/kernel_tegra210-p3448-0000-p3449-0000-b00-user-custom.dtb
INITRD /boot/initrd
APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyS0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0

Here is the result of running cat /etc/nv_tegra_release
# R32 (release), REVISION: 7.3, GCID: 31982016, BOARD: t210ref, EABI: aarch64, DATE: Tue Nov 22 17:30:08 UTC 2022

Also checked sudo cat /sys/kernel/debug/tegra_gpio and it seems to be a problem with this, because the result does not match the examples in similar threads on the forum, but I can’t figure out how to fix it

KevinFFF · May 11, 2023, 4:56am

Hi illyaverb,

Are you using the devkit or custom board for Jetson Nano?

It seems you’ve done some setups for SPI1.

Could you help to refer to the following thread to do loopback test step-by-step?
Jetson Nano SPI Bus Not Working - #10 by KevinFFF

illyaverb · May 24, 2023, 2:51pm

Hi, I apologize for the delayed response. I attempted to perform a new kernel build; however, the error persists. Perhaps you could assist me in identifying where I made the mistake?

illyaverb · May 24, 2023, 7:42pm

I assembled the kernel according to the instructions (Kernel Customization — Jetson Linux Developer Guide documentation sources) and solutions in this topic (How to install custom kernel with Jetpack 4.4 - #12 by manthey).

Also, here I added an option to backup the kernel image, so as not to break the system due to a custom kernel.

illyaverb · May 29, 2023, 12:42pm

Hi again, could you please help me with what you suggested as it did not fix the SPI loopback test failure?

illyaverb · May 31, 2023, 11:43pm

Hi, here is what I’ve done additionally.

I set the correct kernel image folder in extlinux.conf.
Since the Jetson-IO application crashed after opening, I added pinmux manually:

exp-header-pinmux {
    phandle = <0x131>;
    linux,phandle = <0x131>;

    hdr40-pin26 {
            nvidia,enable-input = <0x1>;
            nvidia,tristate = <0x0>;
            nvidia,pull = <0x2>;
            nvidia,function = "spi1";
            nvidia,pins = "spi1_cs1_pc4";
    };
    hdr40-pin24 {
            nvidia,enable-input = <0x1>;
            nvidia,tristate = <0x0>;
            nvidia,pull = <0x2>;
            nvidia,function = "spi1";
            nvidia,pins = "spi1_cs0_pc3";
    };
    hdr40-pin23 {
            nvidia,enable-input = <0x1>;
            nvidia,tristate = <0x0>;
            nvidia,pull = <0x1>;
            nvidia,function = "spi1";
            nvidia,pins = "spi1_sck_pc2";
    };
    hdr40-pin21 {
            nvidia,enable-input = <0x1>;
            nvidia,tristate = <0x0>;
            nvidia,pull = <0x1>;
            nvidia,function = "spi1";
            nvidia,pins = "spi1_miso_pc1";
    };
    hdr40-pin19 {
            nvidia,enable-input = <0x1>;
            nvidia,tristate = <0x0>;
            nvidia,pull = <0x1>;
            nvidia,function = "spi1";
            nvidia,pins = "spi1_mosi_pc0";
    };
};

The SPI test failed, and the GPIO check (sudo cat /sys/kernel/debug/tegra_gpio) also failed. Here’s the output of the GPIO check:

Name:Bank:Port CNF OE OUT IN INT_STA INT_ENB INT_LVL
 A: 0:0 64 40 40 24 00 00 000000
 B: 0:1 f0 00 00 00 00 00 000000
 C: 0:2 1f 00 00 1b 00 00 000000
 D: 0:3 00 00 00 00 00 00 000000
 E: 1:0 40 00 00 00 00 00 000000
 F: 1:1 00 00 00 00 00 00 000000
 G: 1:2 0c 00 00 00 00 00 000000
 H: 1:3 fd 99 00 60 00 00 000000
 I: 2:0 07 07 03 02 00 00 000000
 J: 2:1 f0 00 00 00 00 00 000000
 K: 2:2 00 00 00 00 00 00 000000
 L: 2:3 00 00 00 00 00 00 000000
 M: 3:0 00 00 00 00 00 00 000000
 N: 3:1 00 00 00 00 00 00 000000
 O: 3:2 00 00 00 00 00 00 000000
 P: 3:3 00 00 00 00 00 00 000000
 Q: 4:0 00 00 00 00 00 00 000000
 R: 4:1 00 00 00 00 00 00 000000
 S: 4:2 a0 80 00 00 00 00 000000
 T: 4:3 01 01 00 00 00 00 000000
 U: 5:0 00 00 00 00 00 00 000000
 V: 5:1 01 00 00 00 00 00 000000
 W: 5:2 00 00 00 00 00 00 000000
 X: 5:3 78 08 08 70 00 60 606000
 Y: 6:0 06 00 00 02 00 00 000000
 Z: 6:1 0f 08 08 04 00 06 020600
AA: 6:2 00 00 00 00 00 00 000000
BB: 6:3 01 00 00 00 00 00 000000
CC: 7:0 92 80 80 00 00 12 121200
DD: 7:1 01 00 00 00 00 00 000000
EE: 7:2 00 00 00 00 00 00 000000
FF: 7:3 00 00 00 00 00 00 000000

The kernel image check (uname -a) shows that the new image is in use:

Linux jetson-desktop 4.9.299-tegra #1 SMP PREEMPT Wed May 24 13:13:41 EEST 2023 aarch64 aarch64 aarch64 GNU/Linux

I checked the DTB result with dtc -I fs /proc/device-tree -O dts -o extracted_proc.dts, and it shows the same as what I set.
Here is the updated content of extlinux.conf:

TIMEOUT 30
DEFAULT JetsonIO

MENU TITLE L4T boot options

LABEL primary
      MENU LABEL primary kernel
      LINUX /boot/arducam/Image
      INITRD /boot/initrd
      APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyS0,115200n8 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/arducam/Image.backup
    FDT /boot/kernel_tegra210-p3448-0000-p3449-0000-b00-user-custom.dtb
    INITRD /boot/initrd
    APPEND ${cbootargs} root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyS0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0

LABEL JetsonIO
        MENU LABEL Custom Header Config: <HDR40 User Custom [2023-05-24-170431]>
        LINUX /boot/arducam/Image
        FDT /boot/dtb/tegra210-p3448-0000-p3449-0000-b00-custom-kernel.dtb
        INITRD /boot/initrd
        APPEND ${cbootargs} quiet root=/dev/mmcblk0p1 rw rootwait rootfstype=ext4 console=ttyS0,115200n8 console=tty0 fbcon=map:0 net.ifnames=0

I don’t know what else I can do to fix this. Help please.

illyaverb · June 1, 2023, 9:10am

@KevinFFF Sorry for bothering you, but I followed the steps you mentioned (except that I had to manually install the pinmux due to Jetson-IO utility crashing). However, the loopback test still doesn’t work. Could you please help? I also realized that I didn’t answer your question regarding the board type. I’m using a dev kit.

KevinFFF · June 2, 2023, 7:59am

What is “custom” kernel meaning?
Are you using custom board or you just modify something but you are using the devkit?

If you are using the devkit, you should be able to use Jetson-IO to configure pinmux. I think that would be a easier way for you to configure pinmux instead of generating from spreadsheet or modify in dtsi file.

Is there any error messages while crashing?
Please run the following command on your board.

$sudo /opt/nvidia/jetson-io/jetson-io.py

illyaverb · June 2, 2023, 10:01am

Thank you for your reply.

I’m definitely using devkit and I’ve only modified dtb and Image.
Maybe I worded it wrong, by custom kernel I meant the kernel I put together after removing GPIO usage in that device tree as per your advice Jetson Nano SPI Bus Not Working - #10 by KevinFFF and according to the instructions here Kernel Customization — Jetson Linux Developer Guide documentation. Then copied the created Image to /boot/arducam and /boot.

I agree with you that it is easier, before that I did it that way, but after changing the path to dtb in extlinux.conf:

LABEL JetsonIO
        MENU LABEL Custom Header Config: <HDR40 User Custom [2023-05-24-170431]>
        LINUX /boot/arducam/Image
        FDT /boot/dtb/tegra210-p3448-0000-p3449-0000-b00-custom-kernel.dtb

it crashes quietly without any error message. I tried running this command again and I don’t even know how to show you that the console window flashes (for less than a second) while trying to open the utility (gray screen with a console frame), but immediately returns to the normal view.