Looking at the VF61 pinnout documentation (colibri_vf50_vf61_pinout.xlsx spreadsheet), it appears that signal PTB19 (SODIMM pin number 45) is a GPIO pin. However, I am unable to access this pin (gpio number 41) as a GPIO pin. When I try to export gpio number 41 by writing “41” to /sys/class/gpio/export, the write fails with status code -1, and I cannot use the pin for gpio.
Looking at the device tree it appears that this pin is being used as some sort of gpio-keys wakeup function. I have no need of any wakeup function. I would like to modify the device tree using a device tree overlay to eliminate the gpio-keys wakeup function on PTB19 so I can use it as a regular gpio pin. I am not an expert on device tree files. What do I need to add to my device tree overlay file to make PTB19 a regular GPIO pin?