Activating SPI on Orin NX

[johannesschrimpf]

Hi,

I'm trying to get SPI to run on my Orin NX, but it does not seem to work.

My setup:

• Orin Nano devkit with Orin NX 8GB
• meta-tegra master (36.4.0 binaries)
• Using NVMe disk with initrd-flash

I tried to adjust the confirguration here https://github.com/orgs/OE4T/discussions/1604#discussioncomment-9959312 to my own image, but KERNEL_DEVICETREE_APPLY_OVERLAYS does not seem to exist anymore. Therefore, I included the overlay directly in tegra234-p3768-0000+p3767-0001-nv.dts. The spidev devices themselves are already included from tegra234-p3768-0000-p3767-xxxx-nv-common.dtsi and the kernel module is loaded.

I shorted MOSI and MISO pins on the 40-pin header (19-21 and 22-37) and am trying to run spidev_test with the following result for both ports:

root@p3768-0000-p3767-0001:/proc/device-tree# 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 | 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  |................................|

My suspicion is that the pinmux is not set correctly:

root@p3768-0000-p3767-0001:/proc/device-tree# grep 'spi1' /sys/kernel/debug/pinctrl/2430000.pinmux/pinmux-pins
root@p3768-0000-p3767-0001:/proc/device-tree# 

Setting the pinmux in the kernel does not seem to do anything, but changing tegra234-mb1-bct-pinmux-p3767-dp-a03.dtsi right before flashing seems to at least set the function in pinconf-groups that were before stuck at rsvd1 independently on what I did in the kernel device tree.

root@p3768-0000-p3767-0001:/proc/device-tree# cat /sys/kernel/debug/pinctrl/2430000.pinmux/pinconf-groups
...
79 (spi1_cs0_pz6): 
        pull=2
        tristate=0
        enable-input=1
        open-drain=0
        io-reset=0
        rcv-sel=0
        io-hv=0
        schmitt=0
        pull-down-strength=0
        pull-up-strength=0
        drive-type=0
        gpio-mode=0
        function=spi1
...
81 (spi1_miso_pz4): 
        pull=1
        tristate=0
        enable-input=1
        open-drain=0
        io-reset=0
        rcv-sel=0
        io-hv=0
        schmitt=0
        pull-down-strength=0
        pull-up-strength=0
        drive-type=0
        gpio-mode=0
        function=spi1
...
83 (spi1_sck_pz3): 
        pull=1
        tristate=0
        enable-input=1
        open-drain=0
        io-reset=0
        rcv-sel=0
        io-hv=0
        schmitt=1
        pull-down-strength=0
        pull-up-strength=0
        drive-type=0
        gpio-mode=0
        function=spi1
84 (spi3_sck_py0): 
        pull=1
        tristate=1
        enable-input=1
        open-drain=1
        io-reset=1
        rcv-sel=1
        io-hv=1
        schmitt=1
        pull-down-strength=0
        pull-up-strength=0
        drive-type=0
        gpio-mode=0
        function=rsvd1
...
86 (spi1_mosi_pz5): 
        pull=1
        tristate=0
        enable-input=1
        open-drain=0
        io-reset=0
        rcv-sel=0
        io-hv=0
        schmitt=0
        pull-down-strength=0
        pull-up-strength=0
        drive-type=0
        gpio-mode=0
        function=spi1
...

• Do you have any suggestions what I can try next?
• Should the spi1 be found in both pinconf-groups and pinmux-pins?
• Is it correct that the pinmux can only be set from mb1 directly and that the pinmux in the kernel dts is ignored?

[johannesschrimpf]

In addition to activating SPI, I also needed to deactivate the GPIO as described here: https://forums.developer.nvidia.com/t/orin-nx-16gb-spi-pinmux-not-work/249078/13

Now, it works:

root@p3768-0000-p3767-0001:~# spidev_test -v -D /dev/spidev0.1 
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  |......@.........................|