Voltage divider with pull up resistors
No, you don't need R3.

Be aware of the current draw of your input. Input circuitry impedance isn't infinite, and some logic circuits might struggle to "understand" the signal if the resistance is too high.

I don't know what is U2, but your device should not suffer if you were to use a single pullup resistor. It's common for ICs to have over-voltage protection circuitry inside, and some 3v3 powered ICs even have 5V tolerant inputs







simulate this circuit &ndash; Schematic created using CircuitLab

For input current draw and input voltage tolerance, you should read the datasheet.