Le Potato GPIO Line 95 (GPIOX_16)

[rtomenchok]

I am in the process of porting my embedded application from Raspberry Pi over to Le Potato and I cannot seem to get GPIOX_16 to accept gpiod_line_request_bulk_falling_edge_events() it returns -1 ENODEV. I contacted the author of the library and we confirmed that the underlying ioctl code seems to be correct.

Is this line unsuitable for an IRQ? What are my options? Do I need to pick another GPIO line? I am using the overlays spicc-cs1 and spicc-cs1-spidev. GPIOX-16 does show up under gpioinfo and gpiofind.

[librecomputer]

Can you install the lc-lts kernel and try?

Le Potato with DHT22

MCU code will never work with Linux. DHT11 is already part of the Linux kernel. Check what the driver is doing here: linux/dht11.c at master · torvalds/linux · GitHub Use device tree overlays (since they use fast kernel drivers and not random userspace libraries). We don’t have any device to test. DHT11 uses the gpiod_to_irq function so it needs an IRQ enabled kernel. sudo apt update sudo apt install linux-image-lc-lts-arm64

[rtomenchok]

After installing the kernel and rebooting I issued the command gpiomon gpiochip1 95 which resulted in gpiomon: error waiting for events: Invalid argument. Note that gpioinfo reports line 95: “7j1 Header Pin32” unused input active-high
It appears that we are a step closer. What should I do now?

[librecomputer]

It is trying to monitor both edges. Use gpiomon -f 1 95 or gpiomon -r 1 95.