Add option to allow reset pin numbers on different chip sets

[riplatt]

Summary

Request to add a configuration option to allow reset pin numbers outside gpio chipset 0 ("/dev/gpiochip0")

What is the use-case?

Some custom boards have set the LoRa reset pin to different chipset, a current example is the SeeedStudio LoRaWAN Gateway this has the reset pin set to gpiochip1 pin 17 (pin 49)

Implementation description

add a optional parameter to the setup_pins function in rest.rs and default it to 0

Can you implement this by yourself and make a pull request?

I'm not a rust programmer but I can google just as well as the next programmer, maybe a option would be to check for the existence of chipset_number in the configuration file and set to that value else set to None.

i.e. in main change

// configure concentrator reset pin
if config.gateway.model_config.reset_pin.is_some() {
    reset::setup_pins(config.gateway.model_config.reset_pin.unwrap(), None)
        .expect("setup reset pin error");
}

to some thing like

// configure concentrator pins
let reset_pin = if config.gateway.model_config.reset_pin.is_some() {config.gateway.model_config.reset_pin.unwrap()} else {None};
let chipset_number = if config.gateway.model_config.chipset_number.is_some() {config.gateway.model_config.chipset_number.unwrap()} else {0};
let power_pin = if config.gateway.model_config.power_pin.is_some() {config.gateway.model_config.power_pin.unwrap()} else {None};

reset::setup_pins(reset_pin, chipset_number, power_pin)
    .expect("setup reset pin error");

[brocaar]

Hi @riplatt, the above commit implement this. For now, I'm not planning to expose this through the TOML config, as the use-case is more for Raspberry Pi gateways (e.g. where the end-user will wire the shield to the Pi or when different bridge shields exist for the same shield, but with different pin mappings).

If you would be able to create a pull-request to add the vendor config for https://www.seeedstudio.com/LoRaWAN-Gateway-US915-p-4306.html board, that would be great :)