Problem with pulled-low RST pin on SparkFun Si4703 boards

[dpwe]

This code is referenced in a nice tutorial on using the Si4703 with the RPi that I found: https://tutorials-raspberrypi.com/use-raspberry-pi-as-a-radio-receiver-fm-car-radio-car-pc

However, that tutorial is built around the currently-available Si470x boards from Amazon, which appear to be based on the design from SparkFun. Unlike the PL102RT-S board targeted by this code, the SparkFun boards pull RST low (instead of high). This means that the strategy of setting GPIO23 as INPUT, used in the current code to take the device out of Reset mode, doesn't work - the pin stays low.

The tutorial author writes a small separate program which allows RdSpi to run once, but the more useful solution is to change RdSpi to affirmatively set GPIO23 as Output-High to pull the device out of RST.

I've implemented this change in my own fork: https://github.com/dpwe/RdSpi/tree/sparkfun-board

Although, on RPI4/Buster, I still have a problem that the reset only "works" every second invocation, so you have to run "./rdspi reset" twice to wake the device up. I think this is general decay of the SYSFS GPIO interface, but I'm not sure.