SPI issue on Jetson nano

[Sarim-Jalil]

Hi, I have read the https://github.com/OE4T/meta-tegra/issues/573 discussion and worked as described in it.

I am working with jetson nano and I am using branch Kirkston-lt4-r32.7.x
I have done all the settings mentioned in the discussion and flashed the jetson nano. My pins are coming up as spi1 and I have spidev enabled but when I try to do the spi loopback test it doesnot pass.

root@jetson-nano-devkit:/usr/bin# spiTest -v -D /dev/spidev0.0
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D | ......@....�..................�.
RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................

Below is my patch file and pinctrl outputs
pinctrl.txt
patch.txt

The only difference I could see is the Status = default as compare to Status = 2 in your pinctrl file.

Below is the procedure I have followed.

1- Made the patch file using devtool.
2- Enabled spidev from menuconfig.
3- Applied patch file and Built the image.
4- Flashed the dev-kit and sd-card using -b00.
5- Shorted pin 19 and 21 on my dekit.
6- Run the loopback test.

Kindly let me know if you need any other info or command run on the dev-kit.

[Sarim-Jalil]

@madisongh sorry for disturbing you but I need this a bit urgent.

[madisongh]

You missed removing the TEGRA_GPIO(C, pins from the gpio controller in your patch. Looks like that's still necessary with 32.7.5, I couldn't even get SPI working with the stock Jetson Linux without it. The attached patch includes the missing bits, and covers both -b00 and -a02 carriers. It also removes the SPI2 pins from the gpio controller, although it doesn't configure the function in the pinmux config.

0001-nvidia-platform-t210-configure-spi1-pins-on-40-pin-h.patch.txt

Here's the spidev_test output with this patch:

root@jetson-nano-devkit:~# modprobe spidev
root@jetson-nano-devkit:~# spidev_test -v -D /dev/spidev0.0 
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D  | ......@....�..................�.
RX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D  | ......@....�..................�.

[Sarim-Jalil]

Thank you so much. GPIO usage was indeed the issue and you are right you also have to flash the dev board in order to make it work otherwise only flashing the SD card wont work. One other thing is using the FAB parameter as by default the dtb selected in the scripts is for 2gb dev board.