Can I use MOSI, MISO, SCK pings for reading input in AT89S52?
In general many pins you find on a microcontroller have a primary purpose (IO) and a secondary purpose (like the SPI pins or INT pins). You can use SPI pins (MISO, MOSI, SCK) as IO pins as you would use any other pin although you might not be able to program the MC because of possible interference from the IO line, but if you use a PDIP version of the chip (through hole), the easiest solution (not the best though!) is to simply remove the chip and program it on a breadboard, then reinsert it into the circuit (use an IC socket). The interrupt pins also work as general IO pins unless you configure them to do otherwise.

I'd also suggest exploring the possiblity of using a newer model of your microcontroller because the AT89S52 is quite outdated.