I don’t see there is such implementation on the coming release on WP76.
However, I check the code (yocto/kernel/driver/gpio/gpiolib.c) of yocto of WP8548.
I guess it is not difficult to implement.
In WP76 yocto source code (yocto/kernel/driver/gpio/gpiolib-sysfs.c) , you can add some new GPIO in ext_gpio_map ext_gpio_wp:
{“101”,xx,FUNCTION_EMBEDDED_HOST},
{“102”,xx,FUNCTION_EMBEDDED_HOST},
{“103”,xx,FUNCTION_EMBEDDED_HOST},
And map those xx number to the MDM CHIP UART DCD/DTR/DSR.
After that you should be able to control in console like:
echo 101 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio101/direction
echo 1 > /sys/class/gpio/gpio101/value
echo 102 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio102/direction
echo 1 > /sys/class/gpio/gpio102/value
echo 103 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio103/direction
echo 1 > /sys/class/gpio/gpio103/value
Currently I don’t have the information of xx of MDM CHIP UART number.
And there might be potential issue that the 8-wire UART may also control those pins.
I think you need to contact distributor of your region for the xx information or ask them for this new feature development in coming release.