So I've received few APDS-9900 sensors and found out, there's no library for it (9960 type is supported only). I took that library and device documentation, and created similar library.
Ambient light detection (without interrupts) works well, but there's trouble with proximity detection:
The "Auto-Increment protocol transaction" which should be initiated by writing (0xA0 | reg) to command register, does not work and returns two zeros instead of two bytes. See page 18 of the PDF docs (in repo).
0xE0 (Repeated Byte protocol transaction) returns at least second byte (seems so) of the ADC proximity integration result registers.
https://github.com/suculent/APDS9900_Ambient_Light_and_Proximity_Sensor
