Per https://github.com/bndw/wifi-card/blob/5d7fbbda1e8eac5802c8d..., the QR code text is of this form:

  WIFI:T:WPA;S:{ssid};P:{password};;

https://github.com/zxing/zxing/wiki/Barcode-Contents#wi-fi-n... seems to be where this format came from. (That page describes various other forms of QR codes too.)

bndw: looks like some characters need escaping: backslash, semicolon, comma and colon. Maybe more too, given the treatment of double quotes in that last link (I’ve filed https://github.com/zxing/zxing/issues/1292 about that inconsistency).