RP2040: Writing to digital pin after analogRead on the same pin fails

[Daft-Freak]

(I've only tested this on a Pi Pico, no idea if any other boards are affected)

This breaks libraries like https://github.com/adafruit/Adafruit_TouchScreen.

Relevant part of the code (stripped down):

  // X - this works fine the first time, does not work after reading Y
  pinMode(_yp, INPUT);
  pinMode(_ym, INPUT);
  pinMode(_xp, OUTPUT);
  pinMode(_xm, OUTPUT);

  digitalWrite(_xp, HIGH);
  digitalWrite(_xm, LOW); // does not work after analogRead in Y code

  analogRead(_yp); // breaks the write below

  // ...

  // Y -  this does not work after the read above
  pinMode(_xp, INPUT);
  pinMode(_xm, INPUT);
  pinMode(_yp, OUTPUT);
  pinMode(_ym, OUTPUT);

  digitalWrite(_ym, LOW);
  digitalWrite(_yp, HIGH); // does not work after analogRead above

  analogRead(_xm); // breaks next X read

Removing either of the reads causes the other axis to read reasonable values. Also manually calling gpio_init after the analogRead works:

  // X
  _gpio_init(_xm); // <--

  pinMode(_yp, INPUT);
  pinMode(_ym, INPUT);
  pinMode(_xp, OUTPUT);
  pinMode(_xm, OUTPUT);

  digitalWrite(_xp, HIGH);
  digitalWrite(_xm, LOW); 

  analogRead(_yp);

  // Y
  _gpio_init(_yp); // <--

  pinMode(_xp, INPUT);
  pinMode(_xm, INPUT);
  pinMode(_yp, OUTPUT);
  pinMode(_ym, OUTPUT);

  digitalWrite(_ym, LOW);
  digitalWrite(_yp, HIGH);

  analogRead(_xm);